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研究者情報

マスター

アカウント（マスター）

  • 氏名

    神谷　裕一(カミヤ　ユウイチ), カミヤ　ユウイチ

所属（マスター）

  • 地球環境科学研究院　物質機能科学部門　機能材料化学分野

所属（マスター）

  • 地球環境科学研究院　物質機能科学部門　機能材料化学分野

独自項目

syllabus

  • 2021, 大学院共通授業科目（一般科目）：自然科学・応用科学, Inter-Graduate School Classes(General Subject):Natural and Applied Sciences, 修士課程, 大学院共通科目, ケミカルハザード、食の安全、毒性学、環境汚染、シェルターメディスン、リスクアセスメント、GIS、生態学、薬理学、病理学、免疫毒性学、分子毒性学、地球規模課題、リスクアナリシス、コンピューターシミュレーション、R、ドッキングシミュレーション、分析化学、環境化学
  • 2021, 環境物質科学基礎論Ⅰ, Fundamental Course in Materials Science I, 修士課程, 環境科学院, 化学結合、電子構造、原子軌道、分子軌道、結晶構造 Chemical Bonding, Electronic Structure, Atomic Orbital, Molecular Orbital, Crystal Structure
  • 2021, ナノ環境材料化学特論Ⅰ, Advanced Course in Environmental Nano-Materials Chemistry I, 修士課程, 環境科学院, 触媒化学、環境修復、グリーンケミストリー、大気化学、オゾン層、オゾンホール、光化学オキシダント、反応速度論 Catalytic chemistry, Environmental remediation, Green sustainable chemistry, Atmospheric chemistry, Ozone layer, Ozone hole, Photochemical oxidant, Chemical kinetics
  • 2021, 大学院共通授業科目（教育プログラム）：PARE, Inter-Graduate School Classes(Educational Program):PARE, 修士課程, 大学院共通科目, populations, human activities, environments, resources, food, land, rivers, coasts, atmosphere, soil, water, groundwater, geo-environment, water cycle, element cycles, ecosystems, poverty, sustainability, climate change, erosion, chemical substances, pollution, risk management, green technology
  • 2021, 化学Ⅰ, Chemistry I, 学士課程, 全学教育, 原子の構造、原子軌道、化学結合、混成軌道、物質の三態、電解質溶液
  • 2021, 自然科学実験, Laboratory Exercise in Natural Sciences, 学士課程, 全学教育, 自然科学実験、物理学、化学、生物学

researchmap

プロフィール情報

学位

  • 博士（工学）（名古屋大学）

プロフィール情報

  • 姓

    神谷, カミヤ

  • 名

    裕一, ユウイチ

  • ID各種

    200901014648464974

対象リソース

業績リスト

研究キーワード

  • 触媒化学   Environmental Science   Material Chemistry   Catalysis   

研究分野

  • ものづくり技術（機械・電気電子・化学工学） / 触媒プロセス、資源化学プロセス

経歴

  • 2015年04月 - 現在 大学院地球環境科学研究院 物質機能科学部門 教授
  • 2007年04月 - 2015年03月 大学院地球環境科学研究院 准教授
  • 2005年03月 - 2007年03月 大学院地球環境科学研究院 助教授
  • 2005年 - 2007年 Associate Professor, Faculty of Environmental Earth Science

学歴

  • 1995年04月 - 1997年03月   名古屋大学   大学院   工学研究科応用化学専攻修士課程
  • 1991年04月 - 1995年03月   名古屋大学   工学部   応用化学科

受賞

  • 2008年05月 石油学会 平成19年度石油学会奨励賞
     "層状化合物を前駆体とする結晶性バナジウムーリン複合酸化物触媒の合成とその選択酸化触媒作用に関する研究"
  • 2004年 Young Scientist Prize of the International Association of Catalysis Societies (13th International Congress on Catalysis)

論文

  • Ryoichi Otomo, Taichi Nakamura, Yuichi Kamiya
    Microporous and Mesoporous Materials 378 113246 - 113246 2024年10月 [査読有り][通常論文]
  • Bobo Yan, Koki Kato, Shuhei Shimoda, Ryoichi Otomo, Yuichi Kamiya
    Chemical Engineering Journal 155721 - 155721 2024年09月
  • Tzu-Ming Lin, Philip Anggo Krisbiantoro, Miyu Sato, Yu-Chia Chang, Eduardo C. Atayde, Weisheng Liao, Yuichi Kamiya, Ryoichi Otomo, Kevin C.-W. Wu
    ChemSusChem 2024年08月30日 [査読有り][通常論文]
     
    Herein, potassium carbonate (K2CO3) was used as a low‐cost, readily available, and highly active solid base catalyst for low‐temperature PC methanolysis in the presence of THF as a solvent, producing highly pure and crystalline bisphenol A (BPA) and with a catalytic performance higher than group IIA metal oxides (MgO, CaO, and SrO) and some group IA metal carbonates (NaHCO3, KHCO3, and Na2CO3). THF was the best solvent in aiding the reaction owing to it having a similar polar parameter (δp) to that of PC according to Hansen solubility parameters. By the reaction over the catalyst, 100% PC conversion, 97% BPA yield, and 86% dimethyl carbonate yield were achieved within just 20 min at 60 °C. The catalyst possessed an apparent activation energy (Ea) of 52.3 kJ mol–1, which is the lowest value so far for heterogeneous catalysts, while the mechanistic study revealed that the reaction proceeded via the methoxide pathway. The reusability test demonstrated that the catalyst was reusable at least four times. Furthermore, this catalytic system was successfully applied to actual post‐consumable PC wastes and other polyesters, including polyethylene terephthalate (PET) and polylactic acid (PLA).
  • Shunsaku Yasumura, Ken Nagai, Shinta Miyazaki, Yucheng Qian, Duotian Chen, Takashi Toyao, Yuichi Kamiya, Ken-ichi Shimizu
    Journal of the American Chemical Society 146 30 20982 - 20988 2024年07月20日 [査読有り][通常論文]
  • Jieqiong Zhang, Yuan Huang, Miyu Sato, Xin Zheng, Shin-ichiro Noro, Ryoichi Otomo, Yuichi Kamiya
    Journal of Water Process Engineering 64 105658 - 105658 2024年07月 [査読有り][通常論文]
  • Dewi Agustiningsih, Eko Sri Kunarti, Nuryono Nuryono, Sri Juari Santosa, Muhammad Idham Darussalam Mardjan, Yuichi Kamiya, Ryoichi Otomo
    Heliyon 10 14 e34614 - e34614 2024年07月 [査読有り][通常論文]
  • Yuan Huang, Wontae Kim, Ryoichi Otomo, Shuhei Shimoda, Kevin C.‐W. Wu, Yuichi Kamiya
    ChemCatChem 2024年05月02日 [査読有り]
     
    Abstract Metal particle on a support material should be small and homogeneous in size, which is desirable when using it as a catalyst. In this study, we investigated to introduce Pd nanoparticles (NPs) with narrow size distribution into NH2‐MIL‐53, which was prepared by the reaction of aluminum(III) nitrate with 2‐aminoterephthalic acid. Only by immersing it in an aqueous PdCl2 solution, followed by the reduction with NaBH4, Pd NPs of about 2 nm with unform distribution were formed in NH2‐MIL‐53 up to 3.5 wt.% Pd loadings. Amino group on the linkers in NH2‐MIL‐53 played a critical role for the introduction of (PdCl3)− as a precursor for Pd NPs, while no Pd was introduced into MIL‐53 without amino group. The obtained catalysts (Pd@NH2‐MIL‐53) showed high catalytic performance for reduction of nitrite in water. The specific activity per Pd site exposed on the surface changed greatly depending on the Pd loadings despite the size of Pd NPs unchanged. Pd@NH2‐MIL‐53 with low Pd loadings showed higher specific activity (TOF=2.9×102 h−1), which might be due to the preferential exposure of Pd(111) facet on Pd NPs.
  • Philip Anggo Krisbiantoro, Tzu-Jung Kuo, Yu-Chia Chang, Weisheng Liao, Jih-Peng Sun, Chun-Yen Yang, Yuichi Kamiya, Fa-Kuen Shieh, Chia-Chin Chen, Kevin C.-W Wu
    Materials Today Nano 25 100459 - 100459 2024年03月 [査読有り][通常論文]
  • Philip Anggo Krisbiantoro, Miyu Sato, Tzu-Ming Lin, Yu-Chia Chang, Tzu-Yun Peng, Yun-Chih Wu, Weisheng Liao, Yuichi Kamiya, Ryoichi Otomo, Kevin C.-W. Wu
    Langmuir 40 10 5338 - 5347 2024年02月26日 [査読有り][通常論文]
  • Dewi Agustiningsih, Ryoichi Otomo, Yuichi Kamiya, Nuryono Nuryono, Sri Juari Santosa, Eko Sri Kunarti
    Applied Catalysis A: General 672 119606 - 119606 2024年02月 [査読有り][通常論文]
  • Feri Mukhayani, Yuichi Kamiya, Ryoichi Otomo, Eko Sri Kunarti, Nuryono Nuryono
    Materials Advances 5 9 3838 - 3849 2024年 [査読有り][通常論文]
     
    A magnetically separable solid Lewis base catalyst composed of natural magnetic material, chitosan, and glycidyltrimethylammonium chloride was developed. The catalyst is effective for esterification of levulinic acid to produce ethyl levulinate.
  • Feri Mukhayani, Eko Sri Kunarti, Yuichi Kamiya, Nuryono Nuryono
    Indonesian Journal of Chemistry 24 2 444 - 458 2024年 [査読有り][通常論文]
  • Ratih Lestari, Tutik Dwi Wahyuningsih, Yuichi Kamiya, Indriana Kartini
    Diamond and Related Materials 139 110271 - 110271 2023年11月 [査読有り][通常論文]
  • Mitsuru Kanno, Jun Hirata, Taiki Umezawa, Wataru Ninomiya, Yuichi Kamiya
    Journal of the Japan Petroleum Institute 66 4 128 - 131 2023年07月01日 [査読有り][通常論文]
  • Daiki Yoshida, Jiahao Liu, Kaili Huang, Ryoichi Otomo, Yuichi Kamiya
    Applied Catalysis A: General 649 118982 - 118982 2023年01月 [査読有り][通常論文]
  • Philip Anggo Krisbiantoro, Yu-Wen Chiao, Weisheng Liao, Jih-Peng Sun, Daiki Tsutsumi, Hideki Yamamoto, Yuichi Kamiya, Kevin C.-W. Wu
    Chemical Engineering Journal 450 137926 - 137926 2022年12月 [査読有り]
  • Bonusa Nabila Huda, Endang Tri Wahyuni, Yuichi Kamiya, Mudasir Mudasir
    Materials Chemistry and Physics 282 126005 - 126005 2022年04月 [査読有り]
  • Taichi Nakamura, Yuichi Kamiya, Ryoichi Otomo
    Microporous and Mesoporous Materials 333 111743 - 111743 2022年03月 [査読有り]
  • Kaito Matsuda, Yuto Kobayashi, Sayaka Inoue, Yusuke Morita, Tomoya Ishikawa, Takeshi Uyama, Akinori Shimono, Takeru Ito, Makoto Misono, Yuichi Kamiya, Kei Inumaru
    Chemistry Letters 50 10 1736 - 1739 2021年10月05日 [査読有り]
  • Haruka Aihara, Sou Watanabe, Atsuhiro Shibata, Lina Mahardiani, Ryoichi Otomo, Yuichi Kamiya
    Progress in Nuclear Energy 139 103872 - 103872 2021年09月 [査読有り][通常論文]
     
    To prevent unexpected accidents at nuclear facilities caused by accumulated ammonium nitrate in an aqueous liquid waste containing ammonium salts and nitric acid, NH4+ in the liquid waste must be decomposed under mild reaction conditions. In this study, we investigated the oxidative decomposition of NH4+ with O-3 at 333 K in the presence of a homogeneous Co2+ catalyst and Cl in the wide pH range of the test solution. The reaction behavior was greatly affected by pH of the test solution. In a basic solution at pH 12, high conversion of NH4+ was obtained even in the absence of Co2+ and Cl, and the main product was NO3. However, Co2+ and Cl in the solution greatly enhanced the decomposition rate of NH4+ in acidic to mild basic solutions (pH 1-8), while only low conversion of NH4+ was observed unless both Co2+ and Cl were present. For the reaction with Co2+ and Cl in the solutions, NH4+ was transformed mainly into chloramines (NHxCl3 x, x = 1-3) by the reaction with HClO, which was formed by the reaction of Cl with O-3 catalyzed by the homogeneous Co2+ catalyst, and led to the high decomposition rate of NH4+. Cl suppressed the formation of the precipitate CoO(OH) during the reaction and consequently the Co2+ catalyst stably existed in the reaction solution, which was another reason for the high decomposition rate of NH4+ in the presence of Cl. Owing to the swift decomposition of NH4+ under mild reaction conditions and small formation of secondary waste, the oxidative decomposition of NH4+ in the presence of the homogeneous Co2+ catalyst and Cl is suitable and applicable for the treatment of the aqueous liquid waste containing ammonium salts and nitric acid.
  • Ichiro Yamane, Kota Sato, Ryoichi Otomo, Takashi Yanase, Akira Miura, Taro Nagahama, Yuichi Kamiya, Toshihiro Shimada
    Nanomaterials 11 4 1040 - 1040 2021年04月19日 [査読有り][通常論文]
     
    A metal–organic framework (MOF) consisting of Cu-benzenetricarboxylic acid was processed under ultrahigh pressure (5 GPa) and at temperature of up to 500 °C. The products were characterized with TEM, FTIR, and XAFS. The decomposition of the MOF started at 200 °C at 5 GPa. This temperature was much lower than that in the vacuum. Single-nanometer Cu nanoparticles were obtained in carbon matrix, which was significantly smaller than the Cu particles prepared at ambient pressure. The catalytic activity for Huisgen cycloaddition was examined, and the sample processed at 5 GPa showed a much improved performance compared with that of the MOF-derived Cu nanoparticles prepared without high pressure.
  • Ahmad Bikharudin, Sutarno Sutarno, Yuichi Kamiya, Nuryono Nuryono
    Key Engineering Materials 884 290 - 297 2021年 
    This study reports the preparation of white mineral trioxide aggregate (WMTA) using precipitate calcium carbonate (PCC) by sol-gel method at various thermal treatments 900, 1100, and 1300 °C. The composition of WMTA included PCC (55% CaO), C6H16O3Si-TEOS (21% SiO2), Al(NO3)3⋅9H2O (2% Al2O3), and Bi2O3. WMTA 1100 with the highest purity was proven by the presence of C3S, C3A, and α-Bi2O3 phase in X-ray diffraction patterns. Results show that based on the SEM image WMTA 1100 formed a smaller crystal agglomeration (6-8 µm) and FTIR analysis found Bi-O (BiO3) vibration in Bi2O3 at 1100 and 950 cm-1, a characteristic of the β-C2S phase. The radiopacity value of WMTA 1100 resembles ProRoot MTA, namely 6.86±0.36 millimeters of aluminum (mm Al). WMTA 1100 gives the highest compressive strength, smallest solubility, highest pH, and calcium levels in comparison to WMTA 900 and WMTA 1300.
  • Andreas Schneemann, Yuan Jing, Jack D. Evans, Takashi Toyao, Yuh Hijikata, Yuichi Kamiya, Ken-ichi Shimizu, Nicholas C. Burtch, Shin-ichiro Noro
    Dalton Transactions 50 30 10423 - 10435 2021年 [査読有り][通常論文]
     

    The alkyl decorated MOF Zn2(TM-bdc)2(dabco) shows good adsorption selectivity towards ethane over ethylene, which was revealed by breakthrough, coadsorption and high pressure adsorption.

  • Philip Anggo Krisbiantoro, Tomokazu Togawa, Koki Kato, Jieqiong Zhang, Ryoichi Otomo, Yuichi Kamiya
    Catalysis Communications 149 106204 - 106204 2021年01月 [査読有り][通常論文]
     
    Al2O3-supported precious metal catalysts were tested for the oxidative decomposition of NH4+ in water with O-3 and the effects of support on the catalytic activity of Pd were investigated. Pd/CeO2 was found to be the best catalyst in terms of activity, selectivity and stability and was more active and selective than Co3O4, which is one of the best catalysts reported so far. The reaction proceeded only in the presence of Cl-. The moderate value of the d-band center relative to the Fermi level of Pd was found to be favorable for the activation of reactants, leading to a high catalytic performance.
  • Marina Kobune, Dai Takizawa, Jun Nojima, Ryoichi Otomo, Yuichi Kamiya
    Catalysis Today 352 204 - 211 2020年08月 [査読有り][通常論文]
     
    Pollution of groundwater with NO3- is a serious problem in the world. While catalytic reduction of NO3- over Pd-bimetallic catalysts including Cu-Pd and Sn-Pd is a promising method for purification of the groundwater, the use of precious metal is a major obstacle for practical applications. In the present study, we applied Ni/Al2O3 for the catalytic reduction of NO3- and compared the catalytic performance with that of unsupported Ni catalyst. The reaction rate over 5 wt.% Ni/Al2O3 was about 5 times higher than that of the unsupported Ni catalyst, based on unit weight of catalyst. While the unsupported Ni catalyst was completely deactivated in low partial pressure of H-2 (=0.75 atm) and high concentration of NO3- (= 800 ppm), Ni/Al2O3 was still active even under less reductive conditions ([NO3-](0)= 800 ppm and P(H-2) = 0.5 atm). The unsupported Ni catalyst had the Ni-0 particles formed by the reduction of NiO with H-2 at 310-420 degrees C. On the other hand, 5 wt.% Ni/Al2O3 possessed the Ni-0 particles formed from NiAl2O4 on Al2O3 by the reduction with H-2 above 450 degrees C. It is plausible that those Ni-0 particles had different properties, giving different catalytic properties. The Ni loadings for Ni/Al2O3 had a significant impact on the catalytic properties. The reaction orders with respect to both NO3- and H-2 were 0.8 for 5 wt.% Ni/Al2O3, while those were 0 and -0.2, respectively, for 10 wt.% Ni/Al2O3. On 10 wt.% Ni/Al2O3, there were two kinds of the Ni degrees particles, which were formed by low (310-420 degrees C) and high (above 450 degrees C) temperature H-2 reductions. Unlike the Pd-bimetallic catalysts, the reduction of NO3- over Ni/Al2O3 did not proceed through NO2-.
  • Toshiki Miyazato, Nuryono Nuryono, Mrina Kobune, Bambang Rusdiarso, Ryoichi Otomo, Yuichi Kamiya
    Journal of Water Process Engineering 36 101302 - 101302 2020年08月 [査読有り][通常論文]
  • Nuryono Nuryono, Dikki Miswanda, Satya Candra Wibawa Sakti, Bambang Rusdiarso, Philip Anggo Krisbiantoro, Nastiti Utami, Ryoichi Otomo, Yuichi Kamiya
    Materials Chemistry and Physics 255 123507 - 123507 2020年07月 [査読有り][通常論文]
     
    It is keenly desired to develop an environmentally benign and highly stable magnetic adsorbent for efficient recovery of Au(III) ion from an acidic solution. In the present study, we investigated the synthesis of magnetic adsorbents that the magnetic particles, which was prepared from natural iron sand, were modified with silica layer on which chitosan was fixed through 3-chloropropyltrymethoxysilane (CPTMS) by a sol-gel process. Since the magnetic particles were almost completely covered with the silica layer and chitosan was tightly fixed on it through CPTMS, the adsorbent was highly stable in an acidic solution with pH 3 or lower. Excess CPTMS significantly lowered the adsorption capacity for Au(III) ion, while lead to little improvement in the stability. Thus, 1 mmol of CPTMS against 4 mmol of chitosan gave the best magnetic adsorbent in terms of stability and adsorption capacity, of which the maximum was 112 mg g(-1) for Au(III) ion at pH 5. The adsorbent showed high selectivity of Au(III) adsorption in the solution containing Cu(II) and Zn(II), and was reusable for two times keeping high selectivity without fatal decline in the adsorption performance. The magnetic adsorbent was separable from the solution simply with an external magnet, while the modification caused a slight decrease of the saturated magnetization.
  • Kazutaka Hashimoto, Ryoichi Otomo, Yuichi Kamiya
    Catalysis Science & Technology 10 18 6342 - 6349 2020年07月 [査読有り][通常論文]
     

    A series of SrFe1−xSnxO3−δ showed high catalytic activity for benzene combustion. The partial substitution of Fe with Sn increased specific surface area and accelerated redox rates of Fe, resulting in the improvement of the catalytic activity.

  • Philip Anggo Krisbiantoro, Tomokazu Togawa, Lina Mahardiani, Haruka Aihara, Ryoichi Otomo, Yuichi Kamiya
    Applied Catalysis A: General 596 117515 - 117515 2020年04月 [査読有り][通常論文]
     
    In this study, the reaction mechanisms for ozonation of ammonia nitrogen in the presence of Co3O4 or MgO were investigated. For the reaction over Co3O4, Cl- in the reaction solution was indispensable and ClO- was formed by a non-catalytic oxidation of Cl-. Co3O4 promoted the reaction of NH4+ with ClO- to give the products including NO3-, chloramines and gaseous products. In contrast, Cl- was unnecessary for the reaction with MgO. pH of the reaction solution was maintained at around 9 throughout the reaction owing to partial dissolution of MgO. Ammonia nitrogen was decomposed to mainly NO3(-) by non-catalytic radical reaction involving OH center dot, which was formed by the reaction of OH- with O-3 in weakly basic solution. To keep the reaction solution weakly basic, H+ formed with the decomposition of NH4+ was neutralized. As a result, about the same amount of Mg2+ as that of decomposed ammonia nitrogen was dissolved.
  • Masanori Nagao, Sayaka Misu, Jun Hirayama, Ryoichi Otomo, Yuichi Kamiya
    ACS Applied Materials and Interfaces 12 2 2539 - 2547 2020年01月15日 [査読有り][通常論文]
     
    © 2019 American Chemical Society. Alongside TiO2, Magneli-phase titanium suboxide having the composition of TinO2n-1 is a kind of attractive functional materials composed of titanium. However, there still remain problems to be overcome in the synthesis of titanium suboxide; the existing synthesis methods require high temperature typically over 1000 °C and/or postsynthesis purification. This study presents a novel approach to synthesis of titanium suboxide nanoparticles through solid-phase reaction of TiO2 with TiH2. Crystal phases of titanium suboxide were easily controlled by changing TiO2/TiH2 molar ratios in a TiO2-TiH2 mixed precursor, and a series of titanium suboxide nanoparticles including Ti2O3, Ti3O5, Ti4O7, and Ti8O15 were successfully obtained. The reaction of TiO2 with TiH2 proceeded at a relatively low temperature due to the high reactivity of TiH2, giving titanium suboxide nanoparticles without any postsynthesis purification. Ti2O3 nanoparticles and TiO2 were applied as solid acid catalysts for reaction of furfural with 2-propanol. Ti2O3 showed a high catalytic activity and high selectivity for acetalization of furfural, while TiO2 showed only poor activity for transfer hydrogenation of furfural. The difference in catalytic properties is discussed in terms of the acid properties of Ti2O3 and TiO2,.
  • Wontae Kim, Loida O. Casalme, Taiki Umezawa, Fuyuhiko Matsuda, Ryoichi Otomo, Yuichi Kamiya
    Chemistry Letters 49 1 71 - 74 2020年01月05日 [査読有り][通常論文]
     
    A method to create adjacent acid-base pair sites, which are carboxyl and amino groups, respectively, on silica through hydrolysis of pre-anchored amide is proposed. This method can produce an adjacent acid-base pair site. The catalyst showed excellent catalytic performance for aldol condensation of 4-nitrobenzaldehyde with acetone, overwhelming the catalyst having only amino group and an acid-base catalyst prepared in a conventional manner.
  • Free na and less fe compositions of SiO2 extracted from rice husk ash as the silica source for synthesis of white mineral trioxide aggregate
    Muhamad Ghadafi, Sri Juari Santosa, Yuichi Kamiya, Nuryono Nuryono
    Key Engineering Materials 840 311 - 317 2020年 
    In this research, we report the use of free sodium and less Fe ion silica (SiO2) for preparation of White Mineral Trioxide Aggregate (WMTA). SiO2 was extracted from rice husk ash (RHA) using NaOH 2 M and HCl 37% (v/v) and removal of Na was performed by washing the extracted SiO2 using deionized water with various volumes and techniques. Before extraction, RHA was calcined at a temperature of 700 °C for 3 h. Preparation of WMTA began with mixing the extracted SiO2 20%, CaO 60%, Al2O3 2%, and Bi2O3 18% (w/w). The mixture was calcined at temperatures of 1100 °C for 4 h, grounded to produce WMTA 200 mesh in size and then was characterized using Fourier Transformed Infrared (FTIR) spectrophotometer, X-ray Diffraction (XRD) and Scanning Electron Microscopy-Energy Dispersion X-ray (SEM-EDX). The WMTA characteristics were compared to that of the commercial WMTA ProRoot. The result shows that the silica that was potential as the silica source for WMTA preparation was extracted from RHA involving sonication and washing with 360 mL of deionized water per 10 g of RHA. It contained SiO2 of 94.2%, Fe2O3 of 0.03%, no Na2O, and the particle size of 1.51±0.46 µm. The characterization of WMTA shows that produced WMTA contained tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A) and BiO2, which is comparable to the commercial WMTA ProRoot.
  • Synthesis and characterization of white mineral trioxide aggregate using precipitated calcium carbonate extracted from limestone
    Maulidia Fa’izzah, Widjijono Widjijono, Yuichi Kamiya, Nuryono Nuryono
    Key Engineering Materials 840 330 - 335 2020年 
    White Mineral Trioxide Aggregate (WMTA) using precipitated CaCO3 (PCC) from limestone has been synthesized. PCC in calcite structure was extracted from limestone by calcination at 900 °C for 3 h, dissolved in 0.8 M nitric acid solution and followed with carbonation for 60 minutes. PCC was used for the synthesis of WMTA by mixing with tetraethoxyorthosilicate, bismuth oxide, aluminum oxide, catalyst of with HNO3 and NH3 solution and thermally treated at 1100 °C for 3 h. The products were characterized with Thermal Gravimetric Analysis-Differential Thermal Analysis (TGA-DTG), X-ray Diffraction (XRD), Frontier-Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and X-ray Fluorescence (XRF). The results showed that the PCC dominated calcite structure was obtained with 75.25% in yield and 99.42% in purity. The WMTA has been successfully synthesized by low thermal treatment at 1100 °C using catalysts of HNO3 and NH3 solution, proven by the presence of tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), and Bi2O3 in WMTA.
  • Ryoichi Otomo, Momo Fujimoto, Masanori Nagao, Yuichi Kamiya
    Molecular Catalysis 475 2019年10月 [査読有り][通常論文]
     
    © 2019 Elsevier B.V. Various metal oxides (MgO, Al2O3, SiO2, TiO2, ZrO2, Nb2O5, and CeO2) were treated with NH3 for incorporating nitrogen into the structure of metal oxides. The pristine and NH3-treated metal oxides were used as solid base catalysts for isomerization of glucose to f7ructose in water. SiO2 and Nb2O5 showed a large increment of nitrogen content by the treatment with NH3. FT-IR study on NH3-treated SiO2 revealed that NH3 reacted with terminal silanol groups and siloxane bonds to form Si-NH2 and Si-NH-Si groups. Meanwhile, nitrogen was incorporated into bulk crystal of Nb2O5, causing amorphization of the crystal. Of all the samples, pristine and NH3-treated MgO showed highest catalytic activity for the isomerization of glucose. However, the selectivity to fructose was low due to subsequent reactions of formed fructose. Catalytic activity of Al2O3 and SiO2 was increased by the treatment with NH3, while that of the other metal oxides was not affected. Particularly, the catalytic activity of SiO2 emerged after the treatment with NH3 and was enhanced by increasing the temperature for the treatment up to 800 °C. While fructose was consumed by subsequent reactions over MgO, decreasing the selectivity, such reactions of fructose were not noticeable over NH3-treated SiO2. Consequently, NH3-treated SiO2 showed higher selectivity to fructose and gave higher carbon balance than MgO.
  • Ryoichi Otomo, Ryota Osuga, Junko N. Kondo, Yuichi Kamiya, Toshiyuki Yokoi
    APPLIED CATALYSIS A-GENERAL 575 575 20 - 24 2019年04月 [査読有り][通常論文]
     
    Ion-exchange of an Al-rich zeolite beta, synthesized by organic structure-directing agent-free method (Beta-OF), was studied for application as a base catalyst. While the as-synthesized Beta-OF in Na-form itself had base sites and showed moderate catalytic activity for Knoevenagel condensation, the ion-exchange with Cs+ improved the catalytic activity. For Knoevenagel condensation of benzaldehyde with ethyl acetoacetate, the catalytic activity of Beta-OF ion-exchanged with Cs+ largely surpassed that of the conventional zeolite beta with less Al content. CO2-TPD and IR observation with chloroform as a probe molecule revealed that the Cs-exchanged Beta-OF had strong base sites comparable to Cs-exchanged Y zeolite. Base strength of Beta-OF was stronger than that expected by Sanderson's theory. A local high density of Al atoms in the framework of Beta-OF resulted in the unexpected base property and high catalytic activity.
  • Jun Hirayama, Kei-ichiro Yasuda, Sayaka Misu, Ryoichi Otomo, Yuichi Kamiya
    Catalysis Science & Technology 9 15 4017 - 4022 2019年 [査読有り]
     

    Product drastically changed from NH3 to N2 when O2 was added to the H2 stream for the hydrogenation of NO2− with H2 in water over Pt/Al2O3.

  • Ryoichi Otomo, Chiaki Yamaguchi, Daiki Iwaisako, Shun Oyamada, Yuichi Kamiya
    ACS Sustainable Chemistry & Engineering 7 3 3027 - 3033 2019年 [査読有り][通常論文]
     
    Catalytic properties of metal phosphates were investigated for gas-phase dehydration of 1,2-propanediol to propanal in the presence and absence of steam in the temperature range of 150-340 degrees C. Boron, aluminum, and nickel phosphates showed promising catalytic activity for the dehydration reaction. Especially, boron phosphate showed outstanding catalytic activity at a low reaction temperature and high selectivity to propanal without formation of competitive dehydration products such as acetone and allyl alcohol. The catalytic activity of boron phosphate was remarkably enhanced in the presence of steam cofed with 1,2-propanediol. The additional steam was also favorable for promoting hydrolysis of dioxolane, which is a byproduct formed through acetalization of propanal, resulting in the high yield of propanal over 95%. Boron phosphate showed more durable catalytic activity and much higher yield of propanal than conventional solid acid catalysts such as ZSM-5, silica-alumina and niobium oxide that have been reported to be active for the dehydration of 1,2-propanediol.
  • Shuhei Yasuda, Atsuki Iwakura, Jun Hirata, Mitsuru Kanno, Wataru Ninomiya, Ryoichi Otomo, Yuichi Kamiya
    Catalysis Communications 125 43 - 47 2019年 [査読有り][通常論文]
     
    Gas-phase oxidation of methacrolein to methacrylic acid was carried out over an acid-modified Cr2O3/SiO2 catalyst. While only total oxidation occurred over bare Cr2O3/SiO2, the acid-modified Cr2O3/SiO(2 )showed catalytic activity for the formation of methacrylic acid. In particular, H3PW12O40 strong Bronsted acid was the most effective modifier for improving both activity and selectivity. The interface between Cr2O3 and H3PW12O40 particles on SiO2 appears to be responsible for the formation of active sites for the selective formation of methacrylic acid. The strong Bronsted acid would help the activation of methacrolein through rendering it more electrophilic, which is a key step for the formation of methacrylic acid over the present catalyst.
  • Sou Watanabe, Hiromichi Ogi, Yoichi Arai, Haruka Aihara, Yoko Takahatake, Atsuhiro Shibata, Kazunori Nomura, Yuichi Kamiya, Noriko Asanuma, Haruaki Matuura, Toshio Kubota, Noriaki Seko, Tsuyoshi Arai, Tetsuji Moriguchi
    Progress in Nuclear 117 103090 - 103090 2019年 [査読有り][通常論文]
  • Nuryono Nuryono, Ani Qomariyah, Wontae Kim, Ryoichi Otomo, Bambang Rusdiarso, Yuichi Kamiya
    Molecular Catalysis 475 2019年 [査読有り][通常論文]
     
    Modifications of propylsulfonic acid-fixed Fe3O4@SiO2 with three organosilanes (C-2, C-8, and phenyl) were investigated to develop a magnetically separable solid acid catalyst active for hydrolysis of ethyl acetate in excess water. Among the organosilanes, triethoxy(octyl)silane was the best modifier for improvement in catalytic activity, with activity of approximately twice that of the unmodified catalyst. The catalytic activity was comparable to those of Cs2.5H0.5PW12O40 and H3PW12O40 anchored on hydrophobic SBA-15 if compared per acid sites, though the acid strength of sulfonic acid was much weaker than that of H3PW12O40. High hydrophobicity over the surface and around the acid sites created by the octyl group was responsible for the high catalytic activity and the high stability in water. In addition to the improvement in catalytic activity, modification with the octyl group provided high stability for repeated uses of the catalyst in the reaction and there was little decrease in activity over at least four reuses. The catalyst was easily separated from the reaction solution by application of an external magnetic field.
  • Shuhei Yasuda, Jun Hirata, Mitsuru Kanno, Wataru Ninomiya, Ryoichi Otomo, Yuichi Kamiya
    Applied Catalysis A 570 164 - 172 2019年 [査読有り][通常論文]
     
    Role of steam in selective oxidation of methacrolein with molecular oxygen over H3PMo12O40 catalyst was investigated. Addition of steam to feed gas significantly enhanced both catalytic activity and selectivity to methacrylic acid, which were fivefold and twice increases, respectively, under the optimal steam pressure (P-H2O = 0.13 atm). Kinetic analysis demonstrated that the addition of steam caused 200-fold increase in the pre-exponential factor for the formation of methacrylic acid, leading to the significant increase in the activity. The steam in the feed gas varied hydrous state of H3PMo12O40 under the reaction conditions, while did not alter redox property, molecular and crystalline structures, and surface area of the catalyst. In the presence of steam at 573 K, three H2O per one H3PMo12O40 were absorbed and hydrated protons like [H3O](+) were formed in the bulk of H3PMo12O40. Methacrolein was adsorbed on the surface of the hydrous catalyst, but not on anhydrous one at all. Based on the results, it was concluded that activation of methacrolein readily occurred on the catalyst in the presence of steam, leading to the significant increase in the pre-exponential factor. Quantum chemical calculation supported the smooth activation of methacrolein by the reaction with [H3O](+) without any transition state.
  • Ryoichi Otomo, Toshiki Nishitoba, Ryota Osuga, Yusuke Kunitake, Yuichi Kamiya, Takashi Tatsumi, Toshiyuki Yokoi
    Journal of Physical Chemistry C 122 2 1180 - 1191 2018年01月18日 [査読有り][通常論文]
     
    A series of MCM-68 zeolites with different Si/Al ratios were prepared by treatment with nitric acid and compared with beta zeolites. Speciation of aluminum and location of acid sites changed depending on the Si/Al ratio. The location of Brønsted acid sites in MCM-68 samples was able to be classified by FT-IR measurements with pyridine and 2,6-di-tert-butylpyridine as probe molecules, and the number of Brønsted acid sites was quantified according to the locations. For high-aluminum MCM-68, Brønsted acid sites were broadly distributed in both the 12-ring channel and 10-ring windows as well as inside the supercage. The Brønsted acid sites in the 12-ring channel were easily removed by the acid treatment, and consequently, high-silica MCM-68 had Brønsted acid sites predominantly in the 10-ring windows and inside the supercage. 27Al MQMAS NMR spectra of high-silica MCM-68 showed two specific peaks assignable to T6 and T7 sites, which did not face the 12-ring channel, forming the Brønsted acid sites highly tolerant to the acid treatment. MCM-68 catalysts showed better catalytic performance in dehydration of sorbitol than beta, mordenite, and ZSM-5. Large void spaces at the intersection of 12- and 10-ring channels and inside the supercage for MCM-68 made it easy to take bulky transition states in the dehydration of sorbitol, resulting in its high catalytic performance.
  • Jun Hirayama, Yuichi Kamiya
    Catalysis Science & Technology 8 4985 - 4993 2018年 [査読有り][通常論文]
  • Jun Hirayama, Yuichi Kamiya
    JOURNAL OF CATALYSIS 348 306 - 313 2017年04月 [査読有り][通常論文]
     
    A tandem reaction system consisting of a photocatalyst (Pt/TiO2) and a nonphotocatalyst (SnPd/Al2O3) promoted the reduction of NO3- into gaseous products (mainly N-2) under light irradiation (lambda > 300 nm) in the presence of glucose as a hole scavenger. Photocatalytic H-2 evolution (2H(+) + 2(e-) -> H-2) proceeded over Pt/TiO2, and conventional catalytic reduction of NO3- with H-2 (NO3-- + 5/2H(2) -> 1/2N(2) + 2H(2)O + OH-) occurred over SnPd/Al2O3. We optimized the loading amount of Pt on TiO2, the Sn/Pd ratio, the loading amount of SnPd on Al2O3, and the two catalyst dosages. The optimized tandem system gave a high reduction rate of NO3- and a high selectivity for gas (94%) from the photocatalytic reduction of NO3- in water. On the other hand, a typical semiconductor photocatalyst SnPd/TiO2 with an optimized Sn/Pd ratio and an optimized loading amount of SnPd bimetal on TiO2 reduced NO3- about two-thirds as fast as the tandem system and was less selective for gas (70%). The tandem system suppressed the wasted H2 formation, resulting in high light use efficiency for the NO3- reduction (95%), which is defined as the ratio of the number of electrons consumed for NO3- reduction to the total number of electrons consumed for both NO3- reduction and photocatalytic H-2 evolution, though the tandem and SnPd/TiO2 systems consumed about the same total number of electrons. The tandem system has two advantages: (i) the Pt/TiO2 and SnPd/Al2O3 subsystems can be separately designed to give highly efficient photocatalytic and catalytic reactions, respectively; and (ii) the reaction rates of photocatalytic and catalytic reactions can be easily controlled by changing the catalyst dosage in the reactor. Those advantages brought about a high reduction rate for NO3-, high selectivity for gas, and high light use efficiency for NO3- reduction in the photocatalytic reduction of NO3- in water. (C) 2017 Elsevier Inc. All rights reserved.
  • Rika Ochi, Shin-ichiro Noro, Yuichi Kamiya, Kazuya Kubo, Takayoshi Nakamura
    CHEMISTRY-A EUROPEAN JOURNAL 22 31 11042 - 11047 2016年07月 [査読有り][通常論文]
     
    A two-dimensional (2D) layered Mg-II coordination polymer (CP) with a high tolerance for H2O was designed, synthesised, and crystallographically characterised. The synthesis was achieved by the introduction of a flexible 2D layered structure composed of MgII ions and isonicotinate N-oxide ligands. Owing to its high H2O tolerance, the obtained 2D layered structure has the flexibility to repeatedly adsorb a large amount of H2O associated with interlayer expansion and enable the removal of H2O from a H2O/2-propanol mixed vapour. These results indicate that the CP could be an excellent dehydrating agent.
  • Lina Mahardiani, Yuichi Kamiya
    JOURNAL OF THE JAPAN PETROLEUM INSTITUTE 59 1 31 - 34 2016年01月 [査読有り][通常論文]
     
    Catalytic activity of Co3O4 for oxidative decomposition of NH4+ with O-3 in water was greatly enhanced with each reuse of the catalyst under the reaction conditions while maintaining its high selectivity towards gaseous compounds. On the other hand, other metal oxide catalysts showed no or only a little enhancement of the activity. Formation of -NHx, groups on the surface of Co3O4 during the reaction caused the enhancement of the catalytic activity.
  • Ryoichi Otomo, Ryota Kosugi, Yuichi Kamiya, Takashi Tatsumi, Toshiyuki Yokoi
    CATALYSIS SCIENCE & TECHNOLOGY 6 8 2787 - 2795 2016年 [査読有り][通常論文]
     
    Sn-Beta was post-synthetically modified with various cations such as Li+, Na+, K+, Cs+, and NH4+. During the modification process, the ion-exchange of the cations with silanol groups occurred along with a reversible change between "closed" and "open" Sn sites through hydrolysis of the Si-O-Sn bonds. The IR study showed that Sn-Beta had weak Bronsted acid sites, which were passivated by the ion-exchange, in addition to the Lewis acid sites and that surprisingly, basic sites were formed on the modified zeolites. The ion-exchange with a small amount of Li+, Na+ and NH4+ was effective for suppressing side-reactions, leading to an improvement in selectivity to caprolactone in the Baeyer-Villiger oxidation of cyclohexanone with H2O2. The modification of Sn-Beta with such cations also effectively enhanced the catalytic activity in the Baeyer-Villiger oxidation of 2-adamantanone.
  • Hiyoshi, N., Kamiya, Y.
    Chemical Communications 51 49 9975 - 9978 2015年 [査読有り][通常論文]
  • Yukari Iwase, Shogo Sano, Lina Mahardiani, Ryu Abe, Yuichi Kamiya
    JOURNAL OF CATALYSIS 318 34 - 42 2014年10月 [査読有り][通常論文]
     
    Bimodal CsxH4-x[SiW12O40] (Csx-bimodal) with mesopores interconnected with micropores were synthesized from microporous CsxH4-x[SiW12O40 (Csx-micro) with x = 1.0-2.5, which were prepared in advance by titrating an aqueous solution of H-4[SiW12O40] with an aqueous solution of Cs2CO3, followed by treatment in refluxing ethanol to mainly dissolve the H-4[SiW12O40] in the particles. Mesopore size distributions and their pore volumes changed depending on x in Csx-micro. Microporous Cs2.5-micro transformed into bimodal Cs2.5-bimodal with mesopores having average diameters of 3.7 nm and large mesopore volumes. Although Cs2.5-bimodal exhibited only low catalytic activity for the decomposition of isopropyl acetate, post-treatment in H2SO4 enhanced the catalytic activity due to substitution of the Cs' ions on the surface with H+center dot H2SO4-treated Csx-bimodal showed high activity toward transesterification of glyceryl tributyrate with methanol due to its strong acid strength and mesoporosity. (C) 2014 Elsevier Inc. All rights reserved.
  • Sho-ichi Ichikawa, Lina Mahardiani, Yuichi Kamiya
    CATALYSIS TODAY 232 192 - 197 2014年09月 [査読有り][通常論文]
     
    Oxidative decomposition of NH4* (10 mmol L-1) with 03 in water was studied at 333 K over a variety of metal oxide catalysts without pH control of the solution. Although MgO and NiO had the highest catalytic activities, large amounts of undesired NO3- formed due to low selectivity to gaseous products as well as high activity. Co304, which was slightly less active than MgO and NiO, was the best catalyst in terms of activity, selectivity to gaseous products, and dissolution degree among the metal oxide catalysts studied. Over Co304, NH4* was selectively oxidized to N2 with 88% selectivity in water, and the dissolution degree of Co304 was less than 1%. Fe203, Sn02, Mn304, CuO, MgO, and Al203 were less selective to gaseous products or much less active for the reaction. The selectivities to gaseous products were strongly related to the standard enthalpy changes of formation per mol of oxygen atom ( AH'f) of the metal oxides. The metal oxide catalysts with low AH'f, like Co304, showed high selectivity to gaseous products probably due to the low surface density of the active oxygen formed from 03 on the catalysts. Chloride ions (Cl present in the reaction solution significantly accelerated the reaction rate for NH4' decomposition with 03 in the presence of Co304. This was due to the involvement of Cl- in the catalytic cycle. For instance, C10-, which may form by the reaction of Cl- with 03 over Co304, could further oxidize NH4*. 2013 Elsevier B.V. All rights reserved.
  • Jun Hirayama, Yuichi Kamiya
    ACS CATALYSIS 4 7 2207 - 2215 2014年07月 [査読有り][通常論文]
     
    We investigated photocatalytic reduction of NO3- in real groundwater in the presence of the photocatalyst Pt/TiO2 and the nonphotocatalyst SnPd/Al2O3, which were dispersed in the groundwater, under irradiation at lambda > 300 nm, with glucose as a hole scavenger. In this system, photocatalytic H-2 evolution (2H(+) + 2e(-) -> H-2) proceeded over Pt/TiO2, and nonphotocatalytic, that is, conventional catalytic, reduction of NO3- with H-2 (NO3- + 5/2H(2) -> 1/2N(2) 2H(2)O + OH-) occurred over SnPd/Al2O3. NO3- (1.0 mmol dm(-3)) in the groundwater completely and selectively decomposed to N-2 (yield 83%) after 120 h with a 300 W Xe lamp (lambda > 300 nm) over the Pt/TiO2-SnPd/Al2O3 system in combination with photooxidative pretreatment of the groundwater over Pt/TiO2 to decompose organic compounds. The decomposition rate of NO3- in the groundwater was still slower than that in an aqueous NO3- solution even after the pretreatment of the groundwater. The lower photocatalytic performance was due to poisoning of Pt/TiO2 with sulfate and silicate ions and poisoning of SnPd/Al2O3 with polymerized silicate ions. On the other hand, cations, including Na+, K+, Mg2+, and Ca2+, in the groundwater did not affect the photocatalytic and catalytic performances of the system. Sulfate ions adsorbed on the Pt sites on Pt/TiO2, where H-2 evolution occurs, and silicate ions deactivated the oxidation sites on TiO2 by reacting with the surface hydroxyl groups, leading to a decline in the photocatalytic performance of Pt/TiO2.
  • Jun Hirayama, Ryu Abe, Yuichi Kamiya
    APPLIED CATALYSIS B-ENVIRONMENTAL 144 721 - 729 2014年01月 [査読有り][通常論文]
     
    Photocatalytic reduction of nitrate in water in the co-presence of Pt/SrTiO3:Rh and SnPd/Al2O3 under visible light irradiation (lambda > 420 nm) was investigated. This reaction system efficiently and selectively promoted the photocatalytic reduction of nitrate to nitrogen, whereas Pt/SrTiO3:Rh or SnPd/Al2O3 alone showed little activity under the reaction conditions. The selectivity to N-2 was 94% under the optimum reaction conditions, where the amounts of Pt/SrTiO3:Rh and SnPd/Al2O3 loaded in the reaction system were 500 mg and 150 mg, respectively. This reaction system showed a superior nitrate decomposition rate and superior selectivity to nitrogen compared with SrTiO3:Rh directly modified with SnPd bimetal. From analysis of the reaction mechanism, hydrogen formed by photoreduction of water over Pt/SrTiO3:Rh acted as the reductant for a non-photocatalytic nitrate conversion reaction over SnPd/Al2O3. Moreover, the products, including formaldehyde and formic acid, formed by photo-oxidation of methanol over Pt/SrTiO3:Rh acted as reductants for nitrate over SnPd/Al2O3. (C) 2013 Elsevier B.V. All rights reserved.
  • Yu-ki Miura, Hiroyuki Imai, Toshiyuki Yokoi, Takashi Tatsumi, Yuichi Kamiya
    MICROPOROUS AND MESOPOROUS MATERIALS 174 34 - 43 2013年07月 [査読有り][通常論文]
     
    Microporous cesium salts of modified and unmodified tetravalent Keggin-type polyoxometalates, including Cs-4[SiW12O40], Cs-4[PW11O39(Sn-n-C4H9)], and Cs-4[PW11O39(Sn-OH)], were synthesized. The crystalline structures, which had body-centered cubic (bcc) arrangements, the lattice constants, and the pore-size distributions of the three Cs salts were similar, regardless of the presence or absence and types of functional groups introduced. The Cs salts had only micropores and no mesopores. The micropore size distributions were determined from adsorption isotherms of Ar, which showed a sharp peak at 0.59 nm and a shoulder at 0.62 nm. The fractions of the external surface areas to the total surface areas of the Cs salts were less than 6%. It is plausible that the micropores originate from the heteropoly anion defects in the crystallite, which form to avoid mismatches in the Cs+/(heteropoly anion) ratio required for charge balance (=4) and for a bcc structure (=3). The surface of the Cs salt introduced with n-butyl groups was hydrophobic, although the surface density of the n-butyl groups was low. On the other hand, the hydroxyl groups present on the surface of Cs-4[PW11O39(Sn-OH)] had little effect on the adsorption of water, methanol, ethanol, and hexane but a great impact on that for benzene due to the interactions between the -OH groups and the aromatic rings (-OH center dot center dot center dot pi). (C) 2013 Elsevier Inc. All rights reserved.
  • 保田 修平, 長谷川 俊雄, 安川 隼也, 二宮 航, 大谷内 健, 神谷 裕一
    石油学会 年会・秋季大会講演要旨集 2013 41 - 41 公益社団法人 石油学会 2013年 
    H4PMo11VO40上でのメタクロレン酸化反応において反応ガスへの水蒸気の添加は触媒性能を維持するために不可欠である。水蒸気の役割についての知見を得るためにH4PMo11VO40と水蒸気との酸素交換挙動を、H2(18O)を基質に用い、触媒のIRスペクトルを測定して調べた。反応温度573Kにおいて、Mo=OもしくはV=Oの10%が18Oに交換された。また、Mo-O-MoもしくはMo-O-Vの一部も18Oに交換された。しかし、P-Oの酸素原子は18Oには交換されなかった。
  • Jun Hirayama, Hirofumi Kondo, Yu-ki Miura, Ryu Abe, Yuichi Kamiya
    CATALYSIS COMMUNICATIONS 20 99 - 102 2012年04月 [査読有り][通常論文]
     
    Photocatalytic reduction of NO3- under UV irradiation in the presence of ethanol was carried out in the presence of semiconductor photocatalyst Pt/TiO2 and supported bimetallic non-photocatalyst Sn-Pd/Al2O3, which were dispersed in water. This system effectively and selectively promoted the photocatalytic reduction of NO3- to N-2, whereas Pt/TiO2 or Sn-Pd/Al2O3 alone showed no or little activity under the reaction conditions. The decomposition rate of NO3- and selectivity to gaseous nitrogen compounds (mainly N-2) for the present photocatalytic system were higher than those for TiO2 photocatalyst directly-modified with Sn-Pd particles. (C) 2012 Elsevier BM. All rights reserved.
  • Yu-ki Miura, Yuichi Kamiya
    CHEMISTRY LETTERS 41 3 331 - 333 2012年03月 [査読有り][通常論文]
     
    Cesium-potassium salt of the lacunary phosphotungstate Cs6.1K0.9[PW11O39), which is a nonporous ionic solid, absorbed only water and methanol, whereas larger alcohols (C >= 2) and hydrocarbons were completely excluded. Cs6.1K0.9[PW11O39] selectively removed water from water-ethanol mixed gas and was reusable by vacuum treatment at room temperature.
  • Ken-ichi Shimizu, Yuichi Kamiya, Kaoru Osaki, Hisao Yoshida, Atsushi Satsuma
    CATALYSIS SCIENCE & TECHNOLOGY 2 4 767 - 772 2012年 [査読有り][通常論文]
     
    The palladium oxidation state of an SiO2-supported palladium catalyst was quantitatively determined by Pd L-3-edge XANES (X-ray absorption near-edge structure) analysis. By changing the time of CO-reduction pre-treatment at 673 K, a series of 5 wt% Pd-loaded SiO2 catalysts (PdOx/2/SiO2) containing different amounts of the Pd metal and PdO phases were prepared, and the average oxidation number (x) was estimated from the number of CO2 molecules formed during the CO-reduction treatment. L-3-edge XANES spectra of these samples and a reference sample (Pd powder) were recorded, and the white line area of the spectra was evaluated. A good linear relationship was confirmed between the white line area intensity and the average oxidation number (x), indicating that the oxidation state of Pd in structurally unknown Pd samples could be quantitatively determined by a simple XANES analysis. To demonstrate the utility of this method in a catalytic study, the effect of the oxidation number (x) on the CO oxidation activity of PdOx/2/SiO2 was also examined, and metallic Pd-0 sites in PdOx/2/SiO2 were shown to be active species.
  • Ken-ichi Shimizu, Tomonori Oda, Yoshinori Sakamoto, Yuichi Kamiya, Hisao Yoshida, Atsushi Satsuma
    APPLIED CATALYSIS B-ENVIRONMENTAL 111 509 - 514 2012年01月 [査読有り][通常論文]
     
    Quantitative determination of average rhodium oxidation state for supported rhodium catalyst was examined by using Rh L-3-edge XANES (X-ray absorption near-edge structure) spectra. A series of Rh-loaded SiO2 catalysts (Rh2Ox/SiO2) containing different amount of Rh metal and Rh2O3 phases were prepared, and the average oxidation number (x) was determined by the amount of CO2 formed during CO reduction treatment as the final step of catalyst preparation. L-3-edge XANES spectra of these samples were recorded, and the white line area intensity of the spectra was evaluated. A good linear relationship was confirmed between the white line area intensity and the average oxidation number (x), indicating that the oxidation state of Rh species in structurally unknown Rh samples could be quantitatively determined by a simple L-3-edge XANES analysis. The effect of the oxidation number (x) on the Rh2O/SiO2-catalysed CO oxidation was discussed, in order to demonstrate a utility of this method in a catalytic study. (C) 2011 Elsevier B.V. All rights reserved.
  • Mitsuru Kanno, Yu-ki Miura, Toshiya Yasukawa, Toshio Hasegawa, Wataru Ninomiya, Ken Ooyachi, Hiroyuki Imai, Takashi Tatsumi, Yuichi Kamiya
    CATALYSIS COMMUNICATIONS 13 1 59 - 62 2011年10月 [査読有り][通常論文]
     
    Gas-phase oxidation of methacrolein to methacrylic acid has been carried out over various unsupported and supported H4PMo11VO40 catalysts. While SiO2-supported H(4)PMo(11)VO(40)showed low selectivity to methacrylic acid, H4PMo11VO40 supported on NH3-modified SiO2, which was prepared by using an impregnation method with acetone as the solvent, exhibited high selectivity (similar to 90%) and high activity for the formation of methacrylic acid. The activity of H4PMo11VO40/NH3-modified SiO(2)was more than five times higher than that of the corresponding unsupported catalysts. (C) 2011 Elsevier B.V. All rights reserved.
  • Jiao Zhang, Mitsuru Kanno, Yi Wang, Hiromi Nishii, Yu-ki Miura, Yuichi Kamiya
    JOURNAL OF PHYSICAL CHEMISTRY C 115 30 14762 - 14769 2011年08月 [査読有り][通常論文]
     
    Changes in surface acidity of H(4)SiW(12)O(40)/SiO(2) in relation to the loading amount were investigated by using temperature-programmed desorption (TPD) of benzonitrile (BN), BN infrared (BN-IR) spectroscopy, and test reactions, including skeletal isomerization of n-butane and double-bond shift of 1-butene. From BN-TPD profiles and BN-IR spectra, H(4)SiW(12)O(40)/SiO(2) had medium strength Bronsted (Mid-B site) and strong Bronsted acid sites (Strong-B site) on its outermost surface, whereas there was no evidence for Lewis acid sites regardless of the loading amount. The number of Strong-B sites correlated with the catalytic activity for the skeletal isomerization of n-butane and was a maximum when the loading amount was 50 wt %. On the other hand, the number of Mid-B sites was a maximum for 30 wt % H(4)SiW(12)O(40)/SiO(2), which had the highest activity for the double-bond shift reaction of 1-butene. Mid-B sites of H(4)SiW(12)O(40)/SiO(2) were present in the starting H(4)SiW(12)O(40), whereas the Strong-B sites formed when H(4)SiW(12)O(40) was supported on SiO(2). There were no Strong-B sites on H(4)SiW(12)O(40)/SiO(2) with low loadings, including 5 and 10 wt %. Thus, it was concluded that the direct interaction of H(4)SiW(12)O(40) with the surface of SiO(2) caused the Strong-B sites to form in the second-layer of H(4)SiW(12)O(40) exposed on the surface.
  • Hiroshi Hinou, Naohiro Saito, Takahiro Maeda, Masao Matsuda, Yuichi Kamiya, Shin-Ichiro Nishimura
    JOURNAL OF CARBOHYDRATE CHEMISTRY 30 7-9 575 - 586 2011年 [査読有り][通常論文]
     
    The simple doping of calcium chloride allowed highly improved yields in the glycosylation promoted by sulfated zirconia (SZ) without calcination. It was revealed by means of per-O-benzylated galactose trichloroacetimidate as a model glycosyl donor that this effect depends greatly on the cationic ion radius of used metal chlorides. Temperature-programmed desorption of ammonia (NH3 TPD) and the pyridine IR method showed clearly that coordination of calcium ion provides the SZ surface with newly formed Lewis acidic sites while the Bronsted acid site disappeared, indicating that the enhanced catalytic potency of SZ is due to the increased Lewis acid sites by doping the optimal calcium ions. The present findings might give insight into the relationship between a catalytic mechanism and superacidity of SZ, which is crucial for the design of novel superacid-based catalysts and environmentally benign glycosylation processes.
  • 土居 隼人, 神谷 裕一
    石油学会 年会・秋季大会講演要旨集 2011 147 - 147 公益社団法人 石油学会 2011年 
    担持イリジウム触媒のイリジウム表面酸化状態をCO昇温酸化法で調べた。担体の種類によらずイリジウム粒子の表面は酸化されていた。しかし、担体によってその程度は異なり、Ir/Al2O3 = Ir/SiO2-Al2O3 < Ir/SiO2 = Ir/TiO2 < Ir/CeO2の順に、より酸化されていた。1,3-ジメチルシクロペンタン水素化開環反応に対する担持イリジウム触媒の活性は用いた担体によって大きく変化し、イリジウム表面の酸化状態が低いほど、すなわち還元されている触媒ほど高い活性を示した。
  • Yuichi Kamiya, Shogo Sano, Yu-Ki Miura, Yohei Uchida, Yuki Ogawa, Yukari Iwase, Toshio Okuhara
    CHEMISTRY LETTERS 39 8 881 - 883 2010年08月 [査読有り][通常論文]
     
    An acidic Cs salt of H4SiW12O40 (Cs3HSiW12O40), which was prepared by titrating an aqueous solution of H4SiW12O40 with an aqueous solution of Cs2CO3, possessed only micropores and exhibited size-selective catalysis for acid-catalyzed reactions in liquid phase.
  • Jin Zhang, Mitsuru Kanno, Jiao Zhang, Ryuichiro Ohnishi, Kakeru Toriyabe, Hiromi Matsuhashi, Yuichi Kamiya
    JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL 326 1-2 107 - 112 2010年07月 [査読有り][通常論文]
     
    Modification of 15 wt% H(4)SiW(12)O(40)SiO(2) with Na(+) ions was investigated. Na-modified H(4)SiW(12)O(40)/SiO(2) showed higher selectivity for isobutene oligomerization in the preferential oligomerization of isobutene in an equimolar mixture of isobutene and 1-butene than the unmodified one and the selectivity increased with an increase in the Na(+) ion content. The highest selectivity (similar to 97%) was achieved by using Na(3)HSiW(12)O(40)/SiO(2). The activity decreased with an increase in the Na(+) ion content. Unmodified H(4)SiW(12)O(40)/SiO(2) had two kinds of acid sites with different acid strengths (medium and strong acid sites) on the outermost surface as revealed by temperature-programmed desorption of benzonitrile. However, the strong acid sites were eliminated by modification with alkaline metal cations: for example, Na(3)HSiW(12)O(40)/SiO(2) had a negligible amount of strong acid sites. Thus, we concluded that the absence of strong acid sites on the outermost surface is the reason for the high selectivity. Li(3)HSiW(12)O(40)/SiO(2) and K(3)HSiW(12)O(40)/SiO(2) also exhibited high selectivity for isobutene oligomerization with activities comparable to that of Na(3)HSiW(12)O(40)/SiO(2). (C) 2010 Elsevier B.V. All rights reserved.
  • Mitsuru Kanno, Toshiya Yasukawa, Wataru Ninomiya, Ken Ooyachi, Yuichi Kamiya
    JOURNAL OF CATALYSIS 273 1 1 - 8 2010年07月 [査読有り][通常論文]
     
    Catalytic oxidation of methacrolein (MAL) to methacrylic acid (MAA) over SiO(2)-supported H(4)PMo(11)VO(40) with different H(4)PMo(11)VO(40) loadings was investigated. H(4)PMo(11)VO(40)/SiO(2) showed high activity in comparison with unsupported H(4)PMo(11)VO(40), and 3.3 mol% H(4)PMo(11)VO(40)/SiO(2) (50 wt.% H(4)PMo(11)VO(40)) had the highest activity, which was five-times larger than that of unsupported H(4)PMo(11)VO(40) due to high dispersion of H(4)PMo(11)VO(40) on SiO(2), as determined by temperature-programmed desorption of benzonitrile. On the other hand, the supported catalysts were less selective toward the formation of MAA. From X-ray diffraction and Raman spectroscopy, it was determined that H(4)PMo(11)VO(40) decomposed to form MoO(3) on SiO(2) during the catalytic reaction. Since SiO(2)-supported MoO(3) and unsupported MoO(3) had only very low selectivity toward the formation of MAA in the oxidation of MAL, it was concluded that the formation of MoO(3) caused the decrease in the catalytic performance of the supported catalysts. (C) 2010 Elsevier Inc. All rights reserved.
  • 土居 隼人, 山本 拓真, 神谷 裕一
    石油学会 年会・秋季大会講演要旨集 2010 40 - 40 公益社団法人 石油学会 2010年 
    クリーンなガソリン基剤である多分岐アルカンを製造するルートの一つとして、ジメチルシクロペンタン類の水素化開環反応が注目されている。先に我々は、高担持量のIr/Al2O3触媒が1,3-ジメチルシクロペンタン水素化開環反応に高い活性と選択性を示すことを報告した。本研究では、担持量を系統的に変化させた種々の担持Ir触媒を調製し、1,3-ジメチルシクロペンタン水素化開環反応に対する担体の効果を調べた。また、Irの物性と触媒特性との関連を議論した。
  • Ryuichiro Ohnishi, Takeshi Sugu, Hayato Doi, Yoshinori Sakamoto, Yuichi Kamiya
    JOURNAL OF THE JAPAN PETROLEUM INSTITUTE 52 6 341 - 350 2009年11月 [査読有り][通常論文]
     
    Hydroconversion of methylcyclohexane was conducted over various noble metal-loaded catalysts at 493 K and atmospheric pressure. On the bases of the proposed reaction route and the rate of reaction over Ir/H-beta zeolite, which was the best catalyst examined, we concluded that the low yield of the desired dimethylpentanes (18%) and high yield of undesired methylhexanes (25%) were due to two reasons: (1) formation of ethylcyclopentane with high selectivity at low conversions and (2) higher ring-opening rate of ethylcyclopentane (a precursor of methylhexanes) than that of dimethylcyclopentanes (a precursor of dimethylpentanes). In order to improve the yield of dimethylpentanes, two catalysts for ring contraction from methylcyclohexane to ethyl- or dimethyl-cyclopentanes (Pt-H4SiW12O40/SiO2 or Pt/H-beta) and for ring opening of the produced cyclopentanes (Ir/Al2O3) were used either in one reactor as a physical mixture or in two separate reactors connected in series. When the physical mixture (Pt-H4SiW12O40/SiO2 and Ir/Al2O3) was used, there was only a slight increase in the dimethylpentanes yield (20%) with a large amount of undesired products, such as monobranched heptanes and cracked products. In contrast, when two consecutive reactors packed with Ir/H-beta and lr/Al2O3 were used, the yield of dimethylpentanes increased to 30%, which was nearly two times of that of methylhexanes, at a 65% conversion of methylcyclohexane, while the yield of undesired methylhexanes was about 15%.
  • Toshimitsu Goto, Yoshinori Sakamoto, Yuichi Kamiya
    CHEMISTRY LETTERS 38 7 736 - 737 2009年07月 [査読有り][通常論文]
     
    Cs2.5H0.5PW12O40 fixed on silica encapsulating iron oxide nanoparticles through (3-aminopropyl)triethoxysilane could magnetically be separated from an aqueous solution. The catalyst showed activity for the hydrolysis of ethyl acetate in the presence of excess water and was reusable without significant loss of its inherent activity.
  • Yi Wang, Yoshinori Sakamoto, Yuichi Kamiya
    APPLIED CATALYSIS A-GENERAL 361 1-2 123 - 129 2009年06月 [査読有り][通常論文]
     
    Catalytic reduction of nitrate (NO(3)(-)) in groundwater over a Cu-Pd catalyst supported on active carbon was investigated in a gas-liquid co-current flow system at 298 K. Although Cu-Pd/active carbon, in which the Cu/Pd molar ratio was more than 0.66, showed high activity, high selectivity for the formation of N(2) and N(2)O (98%), and high durability for the reduction of 100 ppm NO(3)(-) in distilled water, the catalytic performance decreased during the reduction of NO(3)(-) in groundwater. The catalyst also irreversibly deactivated during the reaction in groundwater. The organic species in the groundwater caused the decrease in the catalytic performance and the irreversible catalyst deactivation. Ozone-treatment of the groundwater to remove the organic species substantially helped to maintain the catalytic activity and to halt the irreversible deactivation of the catalyst. Chloride ion (Cl(-)) in the groundwater also caused the decrease in the activity and selectivity, but the effects of Cl were reversible. Sulfate ion (SO(4)(2-)) and cations, including Mg(2+), Ca(2+) and K(+), had little or no effect on the catalytic performance of Cu-Pd/active carbon, though they were present in the groundwater sample. More than an allowable level of NH(3) (NH(4)(+)) was formed during the catalytic reduction of NO(3)(-) in the groundwater, but was completely removed by the cation-exchange process using Na-mordenite. (C) 2009 Elsevier B.V. All rights reserved.
  • Hiromi Matsuhashi, Hideo Nakamura, Tatsumi Ishihara, Shinji Iwamoto, Yuichi Kamiya, Junya Kobayashi, Yoshihiro Kubota, Takashi Yamada, Takeshi Matsuda, Koichi Matsushita, Kazuyuki Nakai, Hiroyasu Nishiguchi, Masaru Ogura, Noriyasu Okazaki, Satoshi Sato, Ken-ichi Shimizu, Tetsuya Shishido, Seiji Yamazoe, Tatsuya Takeguchi, Keiichi Tomishige, Hiromi Yamashita, Miki Niwa, Naonobu Katada
    APPLIED CATALYSIS A-GENERAL 360 1 89 - 97 2009年05月 [査読有り][通常論文]
     
    The sulfated zirconia project was carried out in order to obtain a broad understanding of the preparation, characterization, and application of the solid superacids of sulfated zirconia. The sulfated zirconia catalysts were prepared by the equilibrium adsorption method and the ammonium sulfate kneading method using the reference catalysts JRC-ZRO-2, -3, -4, and -5, supplied by the Reference Catalyst Division of the Catalysis Society of Japan. The catalysts were characterized by elemental analysis, NH3TPD, XRD, TG-DTA, CO2-TPD, Raman spectroscopy, and measurements of the surface area, pore size distribution. coverage (by the BAT method), and heat of Ar adsorption. In order to compare the catalytic activities, we used the prepared catalysts in the isomerizations of butane and n-heptane, hydroisomerization of heptane, aldol condensation, acylation, esterification, and cracking of cumene. The sulfated zirconia prepared using JRC-ZRO-2 by the equilibrium adsorption method showed the highest activity and larger surface area. On the other hand, the kneading method provided catalysts with high reproducibility. (C) 2009 Elsevier B.V. All rights reserved.
  • Tomoaki Hamada, Yoshinori Sakamoto, Yasunobu Ooka, Toshio Okuhara, Yuichi Kamiya
    CHEMISTRY LETTERS 38 3 222 - 223 2009年03月 [査読有り][通常論文]
     
    Pd supported on sulfated zirconia with a S/Zr ratio of 0.077 exhibited high activity and high selectivity for the oxidation of ethylene to partially oxidized products, including acetaldehyde and acetic acid, in the vapor phase.
  • Jin Zhang, Ryuichiro Ohnishi, Toshio Okuhara, Yuichi Kamiya
    APPLIED CATALYSIS A-GENERAL 353 1 68 - 73 2009年01月 [査読有り][通常論文]
     
    Preferential oligomerization of isobutene in a mixture of isobutene and 1-butene (molar ratio of 1:1) over H(4)SiW(12)O(40)/SiO(2) was investigated with different loadings of H(4)SiW(12)O(40). The catalytic performance of H(4)SiW(12)O(40)/SiO(2) was compared with those of typical solid acids, such as H-beta, SiO(2)-Al(2)O(3), and SO(4)(2-)/ZrO(2). H(4)SiW(12)O(40)/SiO(2) was superior in activity and selectivity for isobutene oligomerization (defined as the fraction of isobutene converted against the total conversion) compared to other catalysts. The activity was sensitive to the H(4)SiW(12)O(40) loading on SiO(2), reaching a maximum at around 40 wt.%, due to the change in the acid amount of the outermost surface as determined by temperature-programmed desorption of benzonitrile. The selectivity for isobutene oligomerization also changed with the H(4)SiW(12)O(40) loading. The highest selectivity (similar to 95%) was achieved using 10 wt.% H(4)SiW(12)O(40)/SiO(2) at 293 K, due to the absence of strong acid sites on the outermost surface. In the conversion of linear butene (1- and 2-butene), an induction period occurred when 10 wt.% H(4)SiW(12)O(40)/SiO(2) Was used, because linear butene cannot adsorb on the acid sites when isobutene is present in the reaction mixture. (C) 2008 Elsevier B.V. All rights reserved
  • Shin-ichiro Noro, Ryo Tsunashima, Yuichi Kamiya, Kazuhiro Uemura, Hidetoshi Kita, Leroy Cronin, Tomoyuki Akutagawa, Takayoshi Nakamura
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 48 46 8703 - 8706 2009年 [査読有り][通常論文]
  • Yuichi Kamiya, Hiroyuki Imai, Toshio Okuhara
    Journal of the Japan Petroleum Institute 52 3 81 - 89 2009年 [査読有り][通常論文]
  • Takashi Kawakami, Yasunobu Ooka, Hideshi Hattori, Wenling Chu, Yuichi Kamiya, Toshio Okuhara
    APPLIED CATALYSIS A-GENERAL 350 1 103 - 110 2008年11月 [査読有り][通常論文]
     
    The selective oxidation of ethene to acetic acid in the vapor phase over solid acid-supported Pd catalyst was investigated to elucidate the reaction mechanism and the roles of Pd and acidic sites in promoting the reaction. Two catalysts, Pd-H4SiW12O40/SiO2 and Pd/WO3-ZrO2, exhibited high catalytic activity. Variations in product distribution with contact time, the requirement for the presence of water vapor for the reaction to occur, and the reactivities of possible reaction intermediates indicated that acetic acid is formed via an acetaldehyde intermediate which is produced in a Wacker-type reaction, while the role of the acid sites is to re-oxidize Pd-0 into Pd2+ in the presence of O-2. It was concluded that catalytic efficiency is dependent on maximization of the interface between metallic Pd and acidic surface by establishing an appropriate ratio of Pd and acidic sites. (C) 2008 Elsevier B.V. All rights reserved.
  • SAKAMOTO Yoshinori, KANNO Mitsuru, OKUHARA Toshio, KAMIYA Yuichi
    Catalysis Letters 125 3-4 392 - 395 2008年10月 [査読有り][通常論文]
     
    Cu-Pd bimetallic clusters with a Cu/Pd atomic ratio of 2 supported on active carbon (AC) ([Cu(2)-Pd](cluster)/AC) selectively hydrogenated nitrate ions in water to harmless compounds, including N(2) and N(2)O (> 99% selectivity), and the formation of NH(3) was suppressed to tolerable levels (<.5 ppm). The activity and selectivity of [Cu(2)-Pd](cluster)/AC were superior to that of conventionally prepared Cu-Pd/AC. [Cu(2)-Pd](cluster)/AC showed stationary conversion and selectivity from the onset of the reaction and remained active for up to 110 h.
  • Yoshinori Sakamoto, Chenkai Wang, Toshio Okuhara, Yuichi Kamiya
    CHEMISTRY LETTERS 37 10 1024 - 1025 2008年10月 [査読有り][通常論文]
     
    Titanium dioxide-supported platinum catalyst, which was pretreated with H-2 at 353 K in a reactor just before the reaction. exhibited extremely high activity toward the oxidation of ammonium ions with nitrite ions into nitrogen in water at 353 K.
  • Yoshimi Yamamoto, Shigeru Hatanaka, Katsuyuki Tsuji, Kazuyuki Tsuneyama, Ryuichiro Ohnishi, Hiroyuki Imai, Yuichi Kamiya, Toshio Okuhara
    APPLIED CATALYSIS A-GENERAL 344 1-2 55 - 60 2008年07月 [査読有り][通常論文]
     
    The direct addition of acetic acid to ethylene to form ethyl acetate over H4SiW12O40/SiO2 using SiO2 with various surface areas and mesopore sizes was studied. H4SiW12O40/SiO2 was superior in activity to conventional solid acids including H3PO4/SiO2, Nafion-SiO2, WO3-ZrO2, and unsupported H4SiW12O40. While the selectivity for ethyl acetate was more than 98% regardless of the catalyst, the activities were significantly different. Maximum activity was obtained when SiO2 having a high surface area and moderate pore size (ave. 6 nm) was utilized. The temperature-programmed desorption of benzonitrile technique and XRD both confirmed that this catalyst had a large amount of acid sites located on the outermost surface due to the high dispersion of H4SiW12O40. In contrast, H4SiW12O40/SiO2, with SiO2 of very small mesopores (3 nm) showed a very low activity, despite having the largest amount of acid sites located on the outermost surfaces. On this catalyst, diffusion of the reactant and product were slow due to the very small-sized mesopores. This limited diffusion rate results in its low activity. (C) 2008 Elsevier B.V. All rights reserved.
  • Yuichi Kamiya, Toshio Okuhara, Makoto Misono, Atsuyuki Miyaji, Katsuyuki Tsuji, Tetsuo Nakajo
    CATALYSIS SURVEYS FROM ASIA 12 2 101 - 113 2008年06月 [査読有り][通常論文]
     
    This article reviews recent research and development of supported heteropolyacid (HPA) catalysts; focusing on the acidic and catalytic properties. First the basic knowledge of solid HPAs is provided briefly to facilitate understanding of heterogeneous catalysis of HPAs. Secondly, the structure as well as the physical and chemical properties of supported HPA catalysts is described. Especially the layer structure of HPA dispersed on the surface of SiO(2) and the changes in the surface acidity with the loading level of HPA are discussed. For this purpose, temperature programmed desorption of benzonitrile devised by Okuhara and Kamiya's group is useful. This method is capable to assess the surface acidity of the supported HPA, which controls the catalytic activity for the reactions proceeding by surface-type catalysis. Then, two new industrial processes developed by Showa Denko K. K. are described; (i) production of ethyl acetate from ethylene and acetic acid and (ii) oxidation of ethylene to acetic acid. Supported HPA catalysts are utilized for both processes, which were recently much improved by finely controlling the catalysts and reaction conditions.
  • Hiroyuki Imai, Yuichi Kamiya, Toshio Okuhara
    JOURNAL OF CATALYSIS 255 2 213 - 219 2008年04月 [査読有り][通常論文]
     
    The transformation of nano-sized VOHPO4 center dot 0.5H(2)O crystallites (340 nm x 40 nm) to (VO)(2)P2O7 was examined. The crystalline structure of VOHPO4 center dot 0.5H(2)O quickly collapsed to form an oxidized amorphous phase within I h (reaction conditions: 1.5% n-butane, 17% O-2, and 81.5% He at 663 K), followed by gradual crystallization to (VO)(2)P2O7, accompanied by the formation of sharply angular nano-sized crystallites (about 50 nm). No crystalline phases other than (VO)(2)P2O7 were formed during this transformation. This is quite different from the transformation of large and thick VOHPO4 center dot 0.5H(2)O crystallites, in which alpha(II)-VOPO4 and delta-VOPO4 have been detected in the resulting catalyst. The selectivity to maleic anhydride increases during the transformation as a result of the formation of (VO)(2)P2O7. The activity increases in the early stages of the transformation, then decreases with time. The decrease in activity is caused by gradual reduction of the catalyst surface during the transformation. (C) 2008 Elsevier Inc. All rights reserved.
  • Atsushi Satsuma, Hironaka Kanbe, Kannan Srinivasan, Shin-ich Komai, Yuichi Kamiya, Tadashi Hattori
    MICROPOROUS AND MESOPOROUS MATERIALS 110 2-3 528 - 533 2008年04月 [査読有り][通常論文]
     
    Nano-sized interlayer space of lamellar vanadyl benzylphosphate was controlled by water content in starting solution. Depending on the water content, three types of lamellar vanadyl benzylphosphate having basal spacings of 1.4 nm, 1.9 nm and 2.3 nm were obtained. It was suggested that the difference in the concentrations of benzyl and hydroxyl groups in the interlayer leads to the variation of the interlayer space. (C) 2007 Elsevier Inc. All rights reserved.
  • Jin Zhang, Ryuichiro Ohnishi, Yuichi Kamiya, Toshio Okuhara
    JOURNAL OF CATALYSIS 254 2 263 - 271 2008年03月 [査読有り][通常論文]
     
    Water minimized a decrease in conversion for the isomerization of linear butene to isobutene on silica-supported heteropolyacid (H4SiW12O40) catalysts while maintaining high selectivity toward isobutene. The role of water was related to surface acidic properties (number of surface acid sites and acid strength) and characteristics of hydrocarbon deposits (extent of deposits and hydrogen/carbon ratio), as determined by benzonitrile and ammonia temperature-programmed desorption as well as temperature-programmed oxidation of fresh and spent catalysts. It appears that highly unsaturated hydrocarbon deposits consisting of 8-12 carbon units covered surface acid sites, especially strong acid sites, limiting the isomerization reaction. Water in the feed was helpful in preserving the acid sites and decreasing the number of carbon units in the hydrocarbon deposits. Thus, conversion occurred more readily in the presence of water than in the absence of water. (C) 2008 Elsevier Inc. All rights reserved.
  • Hiroyuki Imai, Yuichi Kamiya, Toshio Okuhara
    Res. Chem. Intermed 34 8-9 669 - 677 2008年 [査読有り][通常論文]
     
    The exfoliation-reduction of VOPO(4) center dot 2H(2)O in 1-butanol or iso-butanol alone, and ill a 1-butanol/ethanol or iso-butanol/ethanol mixture, were conducted. Although all precursors were composed of a lamellar compound with intercalated alcohol molecules, VOHPO(4) center dot 0.5H(2)O was formed when the exfoliation-reduction process was carried out in the mixed alcohol. All precursors transformed to a single phase of (VO)(2)P(2)O(7) under the reaction conditions for n-butane oxidation, but the crystallinity Of (VO)(2)P(2)O(7) was different. The catalyst synthesized in iso-butanol/ethanol was well crystalline (VO)(2)P(2)O(7), and exhibited higher selectivity to maleic anhydride than that synthesized in iso-butanol alone for the n-butane oxidation.
  • Kannan Srinivasan, Hironaka Kanbe, Takuya Ohkura, Shin-Ichi Komav, Yuichi Kamiya, Tadashi Hattori, Atsushi Satsuma
    RESEARCH ON CHEMICAL INTERMEDIATES 34 5-7 455 - 465 2008年 [査読有り][通常論文]
     
    A novel approach for the preparation of promoted vanadyl pyrophosphate in well-defined structure was examined. Lamellar vanadyl benzylphosphate (LVBP) was used as a host material and iron acetylacetonate as a guest. It was found that iron acetylacetonate was successfully inserted into the interlayer of LVBP by heating of LVBP and iron acetylacetonate in toluene solution. Calcination of this intercalated material resulted in a well-crystallized vanadyl pyrophosphate phase with uniform dispersion of Fe in bulk and surface. The obtained Fe-promoted, vanadyl pyrophosphate showed an enhancement in the activity for selective oxidation-of n-butane, especially at high temperature and long contact time.
  • 西井 ひろみ, 神谷 裕一, 奥原 敏夫
    石油学会 年会・秋季大会講演要旨集 2008 32 - 32 公益社団法人 石油学会 2008年 
    H4SiW12O40/SiO2やCs2.5H0.5PW12O40は、p-キシレンとシクロヘキサンのFriedel-Craftsアルキル化反応に高い活性を示す。ベンゾニトリル-TPD測定から、これら高活性を示す触媒には非常に強い酸点が存在することが分かった。H4SiW12O40/SiO2の強酸点をLiで被毒した触媒や、強酸点を持たない低担持量のH4SiW12O40/SiO2は、本反応に低活性しか示さなかった。以上より、強酸点が活性サイトであると結論した。
  • 神谷 裕一
    石油学会 年会・秋季大会講演要旨集 2008 57 - 57 公益社団法人 石油学会 2008年
  • Yun Hin Taufiq-Yap, Chee Keong Goh, Yuichi Kamiya
    REACTION KINETICS AND CATALYSIS LETTERS 92 2 275 - 284 2007年12月 [査読有り][通常論文]
     
    The addition of 1% Mn promoter to vanadium phosphate catalyst led to doubling of the specific surface area from 20.3 (unpromoted) to 39.4 m(2) g(1). The XRD pattern of the Mn-promoted catalyst gave only the characteristics of the (VO)(2)P2O7 phase, indicating that the Mn was incorporated into the crystal lattice of the catalyst. The Mn-promoted catalyst was also twice as active in removing the total amount of oxygen. However, since the only oxygen species related to V4+ being removed and no oxygen species associated with V5+ was observed, the n-butane conversion was not much improved as compared to the unpromoted counterpart. A necessary amount and distribution of the V5+ phase in a well crystalline V4+ phase is essential in order to enhance the catalytic performance in the mild oxidation of n-butane to maleic anhydride.
  • Atsuyuki Miyaji, Tomoaki Hamada, Yuichi Kamiya, Tetsuo Nakajo, Toshio Okuhara
    CATALYSIS LETTERS 119 3-4 252 - 256 2007年12月 [査読有り][通常論文]
     
    The role of Te in Pd-Te-H4SiW12O40/SiO2, a highly active and selective catalyst for direct oxidation of ethylene to acetic acid, was investigated. Kinetic studies of ethylene oxidation over Pd-H4SiW12O40/SiO2 and Te-promoted Pd-H4SiW12O40/SiO2 demonstrated that doping with Te enhanced the rate of reaction of ethylene to acetaldehyde but reduced direct formation of CO2 from ethylene. In contrast, the successive reaction of acetaldehyde to acetic acid was not influenced to a significant extent by the addition of Te.
  • IMAI Hiroyuki, KAMIYA Yuichi, OKUHARA Toshio
    Journal of Catalysis 251 1 195 - 203 2007年10月 [査読有り][通常論文]
     
    Intercalation, exfoliation, and reduction of VOPO4 center dot 2H(2)O were conducted in 2-butanol alone and in a mixed-alcohol solvent (2-butanol and ethanol). Whereas both processes produced crystallites of pure VOHPO4 center dot 0.5H(2)O, much smaller and thinner crystallites (average size, 340 x 35 nm) were formed in the mixed alcohol compared with 2-butanol alone (average size 950 x 200 nm). The small, thin crystallites of precursor VOHPO4 center dot 0.5H(2)O could be transformed into sharply angular nanosized crystallites (60 nm long and 31 nm thick) of highly crystalline (VO)(2)P2O7, without mesopores. When used as a catalyst, this compound exhibited higher activity and selectivity to maleic anhydride (75% at 80% conversion) for selective oxidation of n-butane compared with that derived from the precursor prepared in 2-butanol alone. The high activity of the nanosized crystallites of (VO)(2)P2O7 is attributed to their large surface area (40 m(2) 9(-1)), which is due to their smaller dimensions, and their high selectivity may be attributed to the lack of mesopores as well as their highly crystalline state. (c) 2007 Elsevier Inc. All rights reserved.
  • Yi Wang, Tomohiro Kasuga, Ikkou Mikami, Yuichi Kamiya, Toshio Okuhara
    CHEMISTRY LETTERS 36 8 994 - 995 2007年08月 [査読有り][通常論文]
     
    Cu-Pd supported on active carbon (AC), in which Cu/Pd ratio is strictly controlled, is an excellent catalyst for selective hydrogenation of NO3- to harmless products in the presence of H-2 at low partial pressure. 3.6 wt % Cu; 2.0 wt % Pd/AC, coupled with another Pd/AC catalyst, showed high selectivity to N-2 (98% at 298 K), while suppressing NH3 production (2% selectivity, 0.5 from 100ppm of NO3-). Modification of the Cu-Pd/AC catalyst with PTFE results in further enhancement; the activity more than tripled, while suppression of NH3 production was retained.
  • Takako Mochida, ryuichiro Ohnishi, Naoto Horita, Yuichi Kamiya, Toshio Okuhara
    Micrporous and Mesoporoous Materials 101 1-2 176 - 183 2007年04月 [査読有り][通常論文]
     
    Acid catalyzed hydration of alpha-pinene in the presence of water was conducted over MFI, BEA, MOR and FAU type zeolites with various SiO2/AI(2)O(3) molar ratios and over many other catalysts. Except for MFI, the catalytic activity of all zeolites increased and, then, fell down with increasing SiO2/AI(2)O(3) ratio. Analysis of water adsorption isotherm and NH3-TPD revealed explicitly that, at high Al content, the crowded water molecules on an acid site inhibit the adsorption of alpha-pinene while, at low Al content, only a small number of water are competing with alpha-pinene to adsorb on an active site. The catalytic activity per acid site of all zeolites increased monotonously with increasing hydrophobicity. (c) 2006 Elsevier Inc. All rights reserved.
  • KAMIYA Yuichi, KAMIYA Yuichi, OOKA Yasunobu, OBARA Chisato, OHNISHI Ryuichiro, FUJITA Toshio, KURATA Youhei, TSUJI Katsuyuki, NAKAJYO Tetsuo, OKUHARA Toshio, OKUHARA Toshio
    Journal of Molecular catalysis A 262 1-2 77 - 85 2007年02月 [査読有り][通常論文]
     
    Friedel-Crafts-type reaction of p-xylene with gamma-butyrolactone or vinylacetic acid over H4SiW12O40 supported on SiO2 have been investigated with different loadings of H4SiW12O40. The catalytic performance of H4SiW12O40/SiO2 have been compared with those of typical solid acid catalysts such as zeolites, ion-exchanged resins, and binary oxides. H4SiW12O40 supported on SiO2 was superior in activity and selectivity to 5,8-dimethyl-alpha-tetralone compared to other catalysts for the reaction between p-xylene and gamma-butyrolactone. SiO2-supported H4SiW12O40 also was efficient for the formation of 3,4,7-tetramethyl-alpha-indanone from p-xylene and vinylacetic acid. The formation of 5,8-dimethyl-a-tetralone is extremely sensitive to the load of H4SiW12O40 on SiO2, reaching a maximum at approximately 30 wt%, due to the change in the acid amount of the outermost surface as determined by benzonitrile-temperature programmed desorption. By analogy with reaction between 1,3,5-trimethylbenzene and gamma-butyrolactone, the reaction pathway involves initial alkylation of p-xylene with gamma-butyrolactone, followed by intramolecular acylation to 5,8-dimethyl-alpha-tetralone, which was supported by quantum calculations of gamma-butyrolactone and protonated gamma-butyrolactone. (c) 2006 Elsevier B.V. All rights reserved.
  • Kei Inumaru, Toru Ishihara, Yuichi Kamiya, Toshio Okuhara, Shoji Yamanaka
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 46 40 7625 - 7628 2007年 [査読有り][通常論文]
  • Promotional effect of Te for direct oxidation of ethylene over Pd-H4SiW12O40/SiO2
    Atsuyuki Miyaji, Yuichi Kamiya, Toshio Okuhara, Tetsuo Nakajo
    Studies in Surface Science and Catalysis 172 557 - 558 2007年 [査読有り][通常論文]
  • Cs2.5H0.5PW12O40-SiO2 composite as an excellent water-tolerant solid acid
    Yuichi Kamiya, Naoto Horita, Masaaki Kitakawa, Youhei Uchida, Toshio Okuhara
    Studies in Surface Science and Catalysis 172 421 - 424 2007年 [査読有り][通常論文]
  • Yi Wang, Yuichi Kmiya, Toshio Okuhara
    WATER RESEARCH 41 2 269 - 276 2007年01月 [査読有り][通常論文]
     
    Removal of low-concentration ammonia (2-10 ppm) in water by ion exchange with Na-form zeolites was investigated using a flow system at 278-333 K. Results indicated that Na-mordenite was the most efficient cation-exchanger (compared with Na-ferrierite, Na-ZSM-5, Na-beta, and Na-Y, as well as the K- and H-form mordenite) for the removal of low-concentration ammonia. The ammonia uptake and the ion-exchange level achieved using mordenite with NH4+ for removal of 10 ppm ammonia at 333 K were 1.21 mmol g(-1) and 79.1%, respectively The high efficiency of Na-mordenite for removal of low-concentration ammonia in water is due to the strong acidity of the corresponding H-form mordenite as demonstrated by ammonia temperature-programmed desorption. Ammonia uptake on the Na-mordenite was minimally influenced by operating temperature in the range of 278-333 K. The coexistent K+ and Na+ in water had little influence on ammonia uptake of the Na-mordenite. In contrast, coexistent Ca2+ and Mg2+ significantly lowered the efficiency of the Na-mordenite for ammonia removal. (c) 2006 Elsevier Ltd. All rights reserved.
  • 常山 和之, 大西 隆一郎, 神谷 裕一, 奥原 敏夫
    石油学会 年会・秋季大会講演要旨集 2007 182 - 182 公益社団法人 石油学会 2007年 
    n-ヘプタン骨格異性化反応においてクラッキング反応選択率を低下させる原因である。本研究では、Pd-H4SiW12O40/SiO2上でのn-ヘプタン骨格異性化反応における各生成物の生成挙動を追跡し、クラッキング反応の反応機構を調べた。その結果から2-メチルヘキサン、2,2-ジメチルペンタン、2,4-ジメチルペンタン、2,2,3-トリメチルブタンからクラッキング生成物が生成することが示唆された。
  • 神谷 裕一
    石油学会 年会・秋季大会講演要旨集 2007 55 - 55 公益社団法人 石油学会 2007年 
    薄層担持ヘテロポリ酸によるフリーデル・クラフツ反応やアルカン骨格異性化反応と、反応に直接関与する薄層担持ヘテロポリ酸の最外表面酸点の酸性質を評価するベンゾニトリル－TPD法を紹介する。また、アミノシラン修飾SiO2表面にCs2.5H0.5PW12O40ナノ微粒子を固定化したコンポジット水中固体酸やCsxH4-xSiW12O40マイクロ多孔体の構造と酸触媒機能についても紹介する。
  • HORITA Naoto, KAMIYA Yuichi, OKUHARA Toshio
    Chemistry Letters 35 12 1346 - 1347 2006年12月 [査読有り][通常論文]
     
    Cs2.5H0.5PW12O40-SiO2 composite combined with (3-aminopropyl)triethoxysilane exhibited greater activity and selectivity for hydration of alpha-pinene at 333 K in a triphasic system (alpha-pinene/water/solid acid) compared to previously reported water-tolerant catalysts such as zeolites, polymer-resins (Amberlyst 15 and Nation-H), oxides, and liquid acids such as H3PW12O40 and H2SO4. The selectivity toward alcohols, including mono- and dialcohols, was approximately 80% over Cs2.5H0.5PW12O40-SiO2 composite.
  • Yuichi Kamiya, Naonori Ryumon, Hiroyuki Imai, Toshio Okuhara
    CATALYSIS LETTERS 111 3-4 159 - 163 2006年11月 [査読有り][通常論文]
     
    Exfoliation-reduction of VOPO4 center dot 2H(2)O in a mixed alcohol consisting of 2-butanol and ethanol, followed by the thermal treatment in the presence of n-butane, O-2, and He at 663 K for 300 h, produces novel nano-sized crystallites (similar to 50 nm) of (VO)(2)P2O7. The nano-sized (VO)(2)P2O7 crystallites exhibit a high selectivity to maleic anhydride (similar to 84%) for the selective oxidation of n-butane.
  • SUGII Takeshi, KAMIYA Yuichi, KAMIYA Yuichi, OKUHARA Toshio, OKUHARA Toshio
    Applied Catalysis A 312 45 - 51 2006年09月 [査読有り][通常論文]
     
    We studied the conversion of methylcyclohexane into dimethylpentanes in the presence of hydrogen, catalyzed by It supported on H-beta zeolites with different Si/Al ratios. Ir/H-beta catalysts with a high Si/Al ratio (Si/Al = 75 or 150) showed activity in promoting both ring-contraction (from six-membered to five-membered rings) on the acidic sites of H-beta and ring-opening on Ir metal sites, resulting in high activity and selectivity toward dimethylpentanes. In contrast, Ir/H-beta catalysts with a low Si/Al ratio were less active in ring-opening on the Ir metal sites, which resulted in the high selectivity for dimethylcyclopentanes. In the conversions of methylcyclohexane, 2-methylhexane, and 2,4-dimethylpentane, the dependence of the conversion rate on W/F values demonstrated that, for the highly active and selective Ir/H-beta catalyst with Si/Al = 75, methylcyclohexane was first transformed into dimethylcyclopentanes on the acidic sites, followed by ring-opening on the Ir sites to form dimethylpentanes and methylhexanes. The skeletal isomerization of methylhexanes into dimethylpentanes over this catalyst was very slow under the reaction conditions studied. (C) 2006 Elsevier B.V. All rights reserved.
  • Takeshi Sugii, Ryuichiro Ohnishi, Jin Zhang, Atsuyuki Miyaji, Yuichi Kamiya, Toshio Okuhara
    CATALYSIS TODAY 116 2 179 - 183 2006年08月 [査読有り][通常論文]
     
    Difficulty in measuring acidic characters of heteropolyacid due to absorption of common bases such as ammonia and pyridine was circumvented using benzonitrile as an adsorbate. Acidity-attenuated and Pd-promoted heteropolyacid catalysts catalyzed n-heptane skeletal isomerization with high activity and high selectivity to branched heptanes, which are useful as clean high-octane fuels. Acidic characters measured by benzonitrile-TPD were well correlated with the catalytic performances. (C) 2006 Elsevier B.V. All rights reserved.
  • Y Sakamoto, Y Kamiya, T Okuhara
    JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL 250 1-2 80 - 86 2006年05月 [査読有り][通常論文]
     
    Hydrogenation of nitrate (200 ppm) in water with H-2 over Cu-Pd clusters supported on active carbon (AC) was investigated at 333 K using a gas-liquid co-current flow system. Two types of Cu-Pd bimetallic clusters, stabilized with either poly(vinylpyrrolidone) (PVP) or sodium citrate (SC), revealed that the catalysts possessed similar activity (per unit weight of Pd) and high selectivity toward nitrite when pH was 10.5 at the outlet of the reactor. The high selectivity toward nitrite on PVP-stabilized cluster/AC was minimally influenced by the atomic ratio of Cu/Pd (=0.5-4.0); activity was maximal at a ratio of 1:1. Increasing pH to 12.4 by addition of NaOH enhanced the selectivity toward nitrite to 93% over SC-stabilized Co-0.63-Pd cluster/AC, but caused a decrease in the reaction rate. Over Cu-0.63-Pd cluster/AC, hydrogenation of nitrite as an intermediate occurred much more slowly than that of nitrate at pH 10.5, suggesting that high selectivity toward nitrite is attained by OH- inhibiting adsorption of nitrite. XRD and STEM gave the size of the Cu-0.63-Pd cluster on AC as 4 nm; the structure of the cluster remained almost unchanged during the reaction. The activity and selectivity of the Cu-0.63-Pd cluster/AC was superior to those of the Cu-0.63-Pd cluster on oxides such as TiO2, Al2O3, and ZrO2. In addition, the Cu-0.63-Pd cluster/AC was more active and selective than conventionally prepared Cu-0.63-Pd/AC, indicating that the Cu-Pd cluster is an excellent precursor for selective catalysts in the hydrogenation of nitrate to nitrite. (c) 2006 Elsevier B.V. All rights reserved.
  • Promotional effect of bismuth in the Bi-Promoted (VO)2P2O7 catalysts on the selective Oxidation of n-butane to maleic anhydride.
    Yun Hin Taufiq-Yap, Yuichi Kamiya, K.P. Tan
    Journal of Natural Gas Chemistry 15 297 - 302 2006年 [査読有り][通常論文]
  • RYUMON Naonori, IMAI Hiroyuki, KAMIYA Yuichi, OKUHARA Toshio
    Applied Catalysis A: Chemical 297 1 73 - 80 2006年01月 [査読有り][通常論文]
     
    The transformation of VOHPO(4)(.)0.5H(2)O to (VO)(2)P2O7 has been studied in the absence and presence of water vapor (0-40 vol%) using small (340 urn x 40 nm) and large (10,000 nm x 410 nm) VOHPO(4)(.)0.5H(2)O crystallites. The small VOHPO(4)(.)0.5H(2)O crystallites were transformed into a single-phase of well-crystallized (VO)(2)P2O7 within 5 h under a reactant gas (0.9% n-butane, 10% O-2 and He(balance)) containing 40% water vapor, whereas the transformation took more than 100 h in reactant gas without water vapor. In the large-sized VOHPO(4)(.)0.5H(2)O crystallites, (VO)(2)P2O7 was the main phase formed in the presence of reactant gas containing 40% water vapor, whereas alpha(II)-VOPO4 was the main product in the absence of water vapor. It was found that, under the reaction conditions, water vapor accelerated two processes in the transformation of VOHPO(4)(.)0.5H(2)O to (VO)(2)P2O7; the crystallization of the amorphous VP phase containing V4+ and V5+ to (VO)(2)P2O7 and delta-VOPO4, and the transformation of delta-VOPO4 to (VO)(2)P(2)O7, On the other hand, water vapor inhibited the topotactic transformation of VOHPO(4)(.)0.5H(2)O to (VO)(2)P2O7. The two processes accelerated by water vapor resulted in the rapid transformation of VOHPO(4)(.)0.5H(2)O to (VO)(2)P2O7 under the reactant gas. The catalyst obtained in the presence of water vapor gave stationary conversion and selectivity for MA from immediately after the beginning of the reaction. This catalyst showed a high selectivity for MA in comparison to the catalyst transformed in the absence of water vapor. Furthermore, over the catalyst formed in the absence of water vapor, it took more than 100 h to reach stationary conversion and selectivity. (c) 2005 Elsevier B.V. All rights reserved.
  • SAKAMOTO Yoshinori, NAKAMURA Kyosuke, KUSHIBIKI Rie, KAMIYA Yuichi, OKUHARA Toshio
    Chemistry Letters 34 11 1510 - 1511 2005年11月 [査読有り][通常論文]
     
    To purify water contaminated with nitrate, a two-stage process was employed, involving nitrate hydrogenation to nitrite in the first stage (pH = 10.5) using 0.87 wt % Cu-Pd (2: 1) cluster/AC, and nitrite hydrogenation in the second stage (pH = 6.5) with 1.0 wt% Pd/beta-zeolite. The nitrate (100 ppm) was hydrogenated rapidly, suppressing ammonia levels to within concentrations acceptable for drinking water.
  • N Horita, M Yoshimune, Y Kamiya, T Okuhara
    CHEMISTRY LETTERS 34 10 1376 - 1377 2005年10月 [査読有り][通常論文]
     
    Unlike Cs2.5H0.5PW12O40, Cs2.5H0.5PW12O40-SiO2 composites combined using (3-aminopropyl)triethoxysilane are entirely insoluble and well sedimentable in reaction mixtures that contain a large excess of water. The catalytic activities for the hydration of olefin and hydrolysis of ester in the presence of excess water were comparable to those Of Cs2.5H0.5PW12O40 and were much higher than those of typical water-tolerant solid acids, such as H-ZSM-5 and Nb2O5.
  • B Fugetsu, WH Han, N Endo, Y Kamiya, T Okuhara
    CHEMISTRY LETTERS 34 9 1218 - 1219 2005年09月 [査読有り][通常論文]
     
    Dipole/dipole electrostatic attraction was used for the first time for disassembling the single-walled carbon nanotube (SWCNT) bundles. A self-assembled zwitterionic monolayer (SAZM) was created by modification of the SWCNT bundles with a sulfonate/quaternary-ammonium type of zwitterionic surfactants. The headgroups of the SAZM align at the terminal-end and form anti-parallel doublets. Dipole/dipole electrostatic attractions occurred readily as the SAZM approached to another. SWCNT bundles have been disassembled into individual tubes because of the strong dipole/dipole attractions. Large quantities of unbundled single-walled carbon nanotubes (SWCNTs) were obtained within a single step by this method. Concentric circular membranes containing the unbundled SWCNTs were prepared. The unbundled SWCNTs were found to have tendencies to curve around the circular direction.
  • Y Kamiya, N Yamamoto, H Imai, S Komai, T Okuhara
    MICROPOROUS AND MESOPOROUS MATERIALS 81 1-3 49 - 57 2005年06月 [査読有り][通常論文]
     
    Hexagonal- and lamellar-meso structured vanadium phosphorus oxides were synthesized by assembling exfoliated VOPO4 sheets using cationic surfactants (dodecyl-, tetradecyl-, hexadecyl-, and octadecyltrimethylammonium bromide, CTAB). The products were characterized using X-ray diffraction, SEM, TEM, IR spectroscopy, elemental analysis, and TG/DTA. When a suspension of VOPO4 center dot 2H(2)O crystallites in 2-propanol was thermally treated, 2-propanol intercalated between layers of VOPO4 center dot 2H(2)O, followed by exfoliation of the layers. C(n)TAB was added to the alcoholic solution at 343 K. Treatment of the solution at 343 K for 10 min, followed by evaporation of 2-propanol, which resulted in the formation of hexagonal- and lamellar-phases at C(n)TAB/VOPO4 molar ratios of 0.5, and 1.0, respectively, with chemical formulae of [C16H33N(CH3)(3)Br](0.5)(VOPO4)-0.4H(2)O and [C16H33N(CH3)(3)Br](1.0)(VOPO4), respectively. The unit cell constants of hexagonal- and lamellar-phases from C(16)TAB were a = 3.86 nm and c = 3.87 nm, respectively, and increased with carbon number of the primary chain of C,TAB. In the lamellar phases, the surfactant was incorporated as a double layer at an angle of approximately 27 degrees and its wall consisted of two VOPO4 sheets. (c) 2005 Elsevier Inc. All rights reserved.
  • WL Chu, Y Ooka, Y Kamiya, T Okuhara
    CATALYSIS LETTERS 101 3-4 225 - 228 2005年06月 [査読有り][通常論文]
     
    Pd-supported on WO3-ZrO2 (W/Zr atomic ratio=0.2) calcined at 1073 K was found to be highly active and selective for gas-phase oxidation of ethylene to acetic acid in the presence of water at 423 K and 0.6 MPa. Contact time dependence demonstrated that acetic acid is formed via acetaldehyde formed by a Wacker-type reaction, not through ethanol by hydration of ethylene.
  • WL Chu, Y Ooka, Y Kamiya, T Okuhara, H Hattori
    CHEMISTRY LETTERS 34 5 642 - 643 2005年05月 [査読有り][通常論文]
     
    Pd supported on WO3-ZrO2 calcined at temperatures of 973-1073 K exhibits a high activity and selectivity for the oxidation of ethylene to acetic acid in the vapor phase. The space time yield (STY) per unit volume of catalyst is higher for Pd/WO3ZrO2 than for Pd/H4SiW12O40-SiO2, the best catalyst reported to date.
  • YH Taufiq-Yap, CK Goh, KC Waugh, Y Kamiya
    REACTION KINETICS AND CATALYSIS LETTERS 84 2 271 - 278 2005年 [査読有り][通常論文]
     
    1% of Fe-doped and undoped vanadyl pyrophosphate catalysts were prepared via dihydrate method. The catalysts have been characterised by XRD, ICP, BET and SEM. The undoped catalyst was found to be more active and selective (77.6% selectivity at about 60% conversion at 703 K).
  • Y Sakamoto, K Nakata, Y Kamiya, T Okuhara
    CHEMISTRY LETTERS 33 7 908 - 909 2004年07月 [査読有り][通常論文]
     
    Cu-Pd/AC catalysts that are derived from Cu-Pd clusters were shown to possess high activity for the reduction of nitrate to nitrite, but were inactive for the reduction of nitrite. In contrast, the Pd/AC catalyst was inactive for the reduction of nitrate, whereas conventional Cu-Pd/AC afforded various products, including nitrite, nitrogen, and ammonia.
  • Y Kamiya, S Sakata, Y Yoshinaga, R Ohnishi, T Okuhara
    CATALYSIS LETTERS 94 1-2 45 - 47 2004年04月 [査読有り][通常論文]
     
    High surface area zirconium phosphate in an amorphous phase exhibits high activities for water-related reactions such as hydrolysis of ethyl acetate and esterification of acetic acid with ethanol. The zirconium phosphate is insoluble during the reaction, is recoverable by simple filtration, and can be reused at least five times without any treatment.
  • WL Chu, T Echizen, Y Kamiya, T Okuhara
    APPLIED CATALYSIS A-GENERAL 259 2 199 - 205 2004年03月 [査読有り][通常論文]
     
    Hydration of ethene over a variety of tungsten a-zirconia (WO3/ZrO2) catalysts of different W/Zr ratios using different calcination temperatures is studied at 473 K using a continuous fixed-bed reactor at atmospheric pressure. The maximum activity for ethene hydration is obtained by calcination at 1073 K with a W/Zr ratio of 0.4, while skeletal isomerization of n-butane is found to exhibit a maximum rate at W/Zr = 0.1. The most active WO3/ZrO2 catalysts is demonstrated to be superior in activity to other typical solid acids such as H4SiW12O40/SiO2, zeolites (H-ZSM-5 and H-beta), various mixed oxides, and polymer resins. Lifetime tests reveal that constant activity of Wo(3)/ZrO2 obtained at 72 h is about 70% of initial activity and that the activity is largely recovered by calcination at 773 K in air. The specific activity (per surface area) of WO3/ZrO2 is correlated with the hydrophobicity as estimated from the adsorption of water rather than with that estimated from the density of acid sites measured by NH3-TPD. Therefore, the pronounced activity Of WO3/ZrO2 is mainly brought about by the high hydrophobicity of the surface along with the inherent acidity. (C) 2003 Elsevier B.V. All rights reserved.
  • T Echizen, T Suzuki, Y Kamiya, T Okuhara
    JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL 209 1-2 145 - 153 2004年02月 [査読有り][通常論文]
     
    The reaction mechanism of skeletal isomerization of n-butane over typical solid acids such as CS2.5H0.5PW12O40, sulfated ZrO2, and WO3/ZrO2 and their Pt-promoted catalysts have been studied by the use of 1,4-C-13(2)-n-butane. Isotopic distributions in product isobutane and reactant n-butane were quantitatively analyzed by field-ionization mass spectrometry (FI-MS). On these solid acids, below 423 K, isobutane consisted of C-13(0)-C-13(4) isotopes, whose distributions were close to the corresponding binomial distributions, with the reactant n-butane being mainly C-13(2)-n-butane. This indicates that the isomerization proceeded with an intermolecular rearrangement through a bimolecular mechanism. In the temperature range of 493-523 K over these solid acids, the isotopic distributions in isobutane deviated from the binomial distributions; the fractions of C-13(2)-isobutane were greater than those expected from the binomial distributions, showing that an intramolecular (monomolecular) rearrangement became significant. Further, the product isobutane was found to consist of exclusively C-13(2)-isobutane over these Pt-promoted catalysts in the presence of 112, demonstrating the operation of a monomolecular mechanism on the bifunctional catalysts. (C) 2003 Elsevier B.V. All rights reserved.
  • Kamiya, Y., Hiyoshi, N., Ryumon, N., Okuhara, T.
    Journal of Molecular Catalysis A: Chemical 220 1 103 - 112 2004年 [査読有り][通常論文]
  • Hiyoshi, N., Yamamoto, N., Ryumon, N., Kamiya, Y., Okuhara, T.
    Journal of Catalysis 221 1 225 - 233 2004年 [査読有り][通常論文]
  • MAO J, KAMIYA Y, OKUHARA T
    Applied Catalsis A, General 255 2 337 - 344 2003年12月 [査読有り][通常論文]
     
    A Friedel-Crafts-type reaction of 1,3,5-trimethylbenzene with gamma-butyrolactone was conducted over various solid acid catalysts such as zeolites, polymer resins, and heteropolyacids. The alkylation to 4-(2,4,6-trimethylphenyl) butyric acid proceeded exclusively with these catalysts; no acylation to the ketone occurred. The heteropolyacids, such as H3PW12O40 and H4SiW12O40, were superior in activity to the other catalysts; they also accelerated the reaction of the product acid with gamma-butyrolactone to the corresponding carboxylic acid. When the heteropolyacids were supported on silica, alkylation proceeded efficiently with high mass balance, suppressing further reaction. The reusability of the supported heteropolyacids also was confirmed. (C) 2003 Elsevier B.V. All rights reserved.
  • LS Li, Y Kamiya, T Okuhara
    APPLIED CATALYSIS A-GENERAL 253 1 29 - 32 2003年10月 [査読有り][通常論文]
     
    Synthesis of dipentaerythritol (DPE) by dehydration of pentaerythritol (PE) has been studied using heteropoly compounds and various solid acids. Heteropoly compounds such as H3PW12O40, H4SiW12O40 and their supported catalysts were found to be effective. The addition of water in the reactant suppressed the consecutive reaction of dipentaerythritol with pentaerythritol over H3PW12O40. Under atmospheric pressure at 463 K, silica-supported H3PW12O40 gave 30% yield, while zeolites (H-beta, H-mordenite, and H-Y) and SiO2-Al2O3 were inactive. Turnover number reached 31 over 20 wt.% H3PW12O40/SiO2, indicating that this reaction took place catalytically on it. (C) 2003 Elsevier B.V. All rights reserved.
  • Y Kamiya, Y Kijima, T Ohkura, A Satsuma, T Hattori
    APPLIED CATALYSIS A-GENERAL 253 1 1 - 13 2003年10月 [査読有り][通常論文]
     
    Intercalation of Fe(acac)3 into lamellar vanadyl n-hexylphosphate, VO{(n-C6H13)(0.6)/H-0.4}PO4.(n-C6H13OH)(0.5) followed by calcination, has been investigated for preparation of Fe-doped (VO)(2)P2O7 catalyst; selective oxidation of n-butane to maleic anhydride was performed. Fe(acac)3 was successfully intercalated into the vanadyl n-hexylphosphate by heating in toluene. The obtained precursor was transformed to single phase (VO)(2)P2O7 by a calcination at 823 K in the presence of a mixture of 5% n-butane and 20% O-2, in N-2 (balance). The doped Fe ions uniformly spread in the bulk of the catalyst and were substituted for V4+ in the (VO)(2)P2O7 crystal. The catalytic activity for maleic anhydride formation per unit surface area on the Fe-doped catalyst was higher than that on the Fe-free catalyst prepared by calcination of the vanadyl n-hexylphosphate. Rates of reduction with n-butane and re-oxidation with air in the top few surface layers of the catalysts were estimated from weight decreases and increases detected on a TG/DTA apparatus. The Fe-doped catalysts gave high rates of both the reduction and re-oxidation. especially re-oxidation. XPS studies confirmed that the surface of the Fe-doped catalysts was in a higher oxidation state under the steady state of the reaction. In addition, the Fe-doped catalysts showed a smaller reaction order on partial pressure of O-2. Therefore, the doped Fe can enhance the redox ability, especially the re-oxidation, of the catalyst, resulting in the high catalytic performance. (C) 2003 Published by Elsevier B.V.
  • Y Kamiya, E Nishikawa, A Satsuma, T Okuhara
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 76 4 837 - 846 2003年04月 [査読有り][通常論文]
     
    Vanadyl alkylphosphates consisting of V4+ and p(5+) were synthesized by the reaction of a solid mixture of V,05 and V4O9 (2:3 in mol) with P2O5 in primary aliphatic (from C-1 to C-8), secondary aliphatic (C-3 and C-4), and alicyclic (C-5) alcohols, and were characterized by means of elemental analysis, thermogravimetric analysis, X-ray diffraction, IR spectroscopy, and magnetic susceptibility. The chemical formulae of the products were determined to be VO(RO)(3)(HO)(1-x)PO3.(ROH)(3) (x = 0.5-0.7, y = 0.3-0.5 for primary aliphatic alcohols x = 0.1-0.2. y = 0.4-0.9 for secondary aliphatic and alicyclic alcohols: and R = organic group), X-ray diffraction revealed that the compounds had a lamellar structure, where the organic groups existed as double layers with a tilt of about 56 against the basal plane. Magnetism and IR spectroscopy demonstrated that the construction of the basal planes in the vanadyl alkylphosphates was similar to that of VOHPO4.0.5H(2)O, which consists of V4+ dimers linked with PO4, except for vanadyl sec-butylphosphate. consisting of isolated V4+ monomers. Calcination of vanadyl methylphosphate and vanadyl cyclopentylphosphate brought about crystallites of (VO)(2)P2O7. These (VO)(2)P2O7 exhibited high selectivities to maleic anhydride (65-68%) for the selective oxidation of butane under a high concentration of butane (5.0%).
  • Yuichi Kamiya, Hiroyuki Nishiyama, Miki Yashiro, Atsushi Satsuma, Tadashi Hattori
    Sekiyu Gakkaishi (Journal of the Japan Petroleum Institute) 46 1 62 - 68 2003年
  • Yuichi Kamiya, Satoshi Ueki, Norihito Hiyoshi, Naoki Yamamoto, Toshio Okuhara
    Catalsis Today 78 1-4 SPEC. 281 - 290 2003年 [査読有り][通常論文]
  • Y Kamiya, H Nishiyama, M Yashiro, A Satsuma, T Hattori
    JOURNAL OF THE JAPAN PETROLEUM INSTITUTE 46 1 62 - 68 2003年01月 [査読有り][通常論文]
     
    Acidic properties of three types of (VO)(2)P2O7 Catalysts were investigated by temperature programmed desorption (TPD) using 3,5- and 2,6-dimethylpyridine as probes, and the selective oxidation of butane to maleic anhydride (MA) was performed. VPO-org was prepared in organic solvent, VPO-redu was obtained by reduction of VOPO4.2H(2)O, and VPO-aq was prepared in aqueous medium. 3,5-Dimethylpyridine (3,5-DMP) is adsorbed on both Bronsted and Lewis acid sites, whereas 2,6-dimethylpyridine (2,6-DMP) is selectively adsorbed on Bronsted acid sites due to the steric hindrance of the two methyl groups, so the amounts and strengths of the Bronsted and Lewis acid sites could be determined separately. The (VO)(2)P2O7 catalysts had four types of acid sites: weak and strong Bronsted acid sites, and weak and strong Lewis acid sites. The acidic properties were greatly dependent on the preparation methods as follows: VPO-org had a larger amount of the strong Bronsted acid sites and these acid sites were relatively weak. VPO-redu had a larger amount of the strong Lewis acid sites and VPO-aq had fewer acid sites. The selectivity to MA at low conversion increased with the amount of strong Lewis acid sites, indicating that the strong Lewis acid sites are important for MA formation. The strong Bronsted acid sites may promote the consecutive oxidation of MA.
  • Y Kamiya, E Nishikawa, A Satsuma, M Yoshimune, T Okuhara
    MICROPOROUS AND MESOPOROUS MATERIALS 54 3 277 - 283 2002年07月 [査読有り][通常論文]
     
    Highly porous vanadium phosphorus oxides (V-P oxides) of high specific surface area were synthesized by thermal treatment of layered vanadyl n-butylphosphate in M. The surface area of V-P oxides was greatly increased by thermal treatment within a temperature range of 500-550 K, and reached 225 m(2) g(-1) after treatment at 568 K. The N-2 adsorption-desorption isotherm of V-P oxide is a Type IV isotherm, indicating that this material is mesoporous. Micropore and mesopore size distributions were determined from Saito-Foley analysis using an Ar adsorption isotherm and Dollimore-Heal analysis using an N-2 desorption isotherm, respectively. The pores show a bimodal distribution in the micropore and mesopore region, and the micropores show a broad distribution with small volume (0.004 cm(3) g(-1)). The mesopores, which have a size of 4.4 nm and a volume of 0.272 cm(3)g(-1), were probably formed from fractures of microcrystallites along layers of vanadyl n-butylphosphate. (C) 2002 Elsevier Science Inc. All rights reserved.
  • A Satsuma, Y Kijima, S Komai, Y Kamiya, E Nishikawa, T Hatttori
    CATALYSIS TODAY 71 1-2 161 - 167 2001年11月 [査読有り][通常論文]
     
    A novel approach for preparation of promoted vanadium-phosphorous oxide (VPO) in well-defined structure was examined. Lamellar vanadyl benzylphosphate (LVPO) was used as a host material and Fe-complex as a guest. It was found that Fe-complex was successfully inserted into LVPO by heating of LVPO and Fe(acac)(3) in toluene solution. The obtained material was characterized by means of XRD, TEM, EDX, XPS, and FT/IR. It was confirmed that Fe(acac)(3) was uniformly dispersed in the interlayer of LVPO without significant distraction of lamellar structure of parent LVPO. (C) 2001 Elsevier Science B.V. All rights reserved.
  • Y Kamiya, E Nishikawa, A Satsuma, N Mizuno, T Okuhara
    SEKIYU GAKKAISHI-JOURNAL OF THE JAPAN PETROLEUM INSTITUTE 44 4 265 - 266 2001年07月 [査読有り][通常論文]
     
    Layered vanadyl alkylphosphates, where the alkyl groups are not only straight-chain but also branched and cyclic ones, were prepared by reaction of a mixture of V2O5 and V4O0 with P2O5 in alcohol. The distances between layers of the vanadyl alkylphosphates increased linearly as the length of the alcohol increased. The (VO)(2)P2O7 catalyst obtained by calcination of vanadyl methylphosphate exhibited a high performance in the oxidation of n-butane to maleic anhydride.
  • Hiyoshi, N., Yamamoto, N., Kamiya, Y., Nishikawa, E., Okuhara, T.
    Catalysis Today 71 1-2 129 - 135 2001年 [査読有り][通常論文]
  • Y Kamiya, E Nishikawa, T Okuhara, T Hattori
    APPLIED CATALYSIS A-GENERAL 206 1 103 - 112 2001年01月 [査読有り][通常論文]
     
    Selective oxidation of n-butane to maleic anhydride was studied at high concentrations of n-butane up to 5.0 vol.% using three kinds of (VO)(2)P2O7 catalysts having differently shaped microcrystallites; rose-petals (catalyst A), plates (catalyst B), and blocks (catalyst C). The catalytic activity for maleic anhydride formation per unit surface area greatly depended on the kinds of catalysts at the high concentration of n-butane (5.0 vol.%); catalyst A was much more active, while there was no difference at the low concentrations. That catalyst A gave higher rates of the re-oxidation and reduction, which was established from the measurements of reduction of the catalyst, aged in the reaction mixture, with n-butane and subsequently re-oxidation with O-2. In addition, catalyst A showed a larger reaction order of n-butane concentration. Therefore, the higher catalytic performance of catalyst A at the high concentration of n-butane is attributed to the higher redox ability of the catalyst, and this is probably brought about from the structural disorder of the surface. (C) 2001 Elsevier Science B.V. All rights reserved.
  • A Satsuma, Y Kamiya, Y Westi, T Hattori
    APPLIED CATALYSIS A-GENERAL 194 253 - 263 2000年03月 [査読有り][通常論文]
     
    Temperature-progammed desorption of dimethylpyridine (DMP-TPD) was performed for the measurement of strength of Bronsted acid-and Lewis acid sites on metal oxide catalysts. Alumina, alumina-boria, silica-magnesia and silica-alumina were employed as examples of solid acid catalysts. Infrared (IR) spectra of adsorbed pyridine (Py) and ammonia showed that Lewis acid sites were abundant on alumina, Bronsted acid sites were abundant on alumina-boria, and both were present on silica-magnesia and silica-alumina surfaces. 2,6-dimethylpyridine-TPD (2,6-DMP-TPD) spectra of alumina depended strongly on purging temperatures. The amount of desorbed 2,6-DMP decreased with the increase in the purging temperature, and only a negligible amount of 2,6-DMP was detected in the TPD run from 523 K. On the other hand, 3,5-dimethylpyridine (3,5-DMP) adsorbed on Lewis acid sites on alumina. Selective adsorption of 2,6-DMP on Lewis acid sites was also confirmed from in-situ IR spectra. In the case of alumina-boria on which Bronsted acid sites are abundant, both 2,6-DMP-TPD and 3,5-DMP-TPD spectra gave similar desorption profiles. Profiles of acid strength determined from DMP-TPD agreed well with those determined from the IR spectra of adsorbed 3,5-DMP. These results demonstrated the selective adsorption of 2,6-DMP on Bronsted acid sites because of steric hindrance of methyl groups, and the possibility of measurement of respective strength of Bronsted acid and Lewis acid sites. Through a comparison of 2,6-DMP-TPD and 3,5-DMP-TPD spectra of silica-magnesia and:silica-alumina, the scope of DMP-TPD for the measurement of strength of Bronsted and Lewis acid sites on metal oxide catalysts was discussed. (C) 2000 Elsevier Science B.V. All rights reserved.
  • Atsushi Satsuma, Naruaki Sugiyama, Yuichi Kamiya, Tadashi Hattori
    Studied in Surface Science and Catalysis 130 1799 - 1804 2000年 [査読有り][通常論文]
  • A Satsuma, Y Westi, Y Kamiya, T Hattori, Y Murakami
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 70 6 1311 - 1317 1997年06月 [査読有り][通常論文]
     
    The temperature-programmed desorption of pyridine (Py-TPD) was performed for measuring the acid strength and acid amount of binary oxide catalysts. First, the optimum measurement conditions were determined by comparing the TPD spectra with the infrared spectra of adsorbed pyridine measured under the same conditions in order to minimize the shift in the desorption temperature and contribution of physically absorbed and/or weakly held pyridine. The following conditions were found to be optimum: purging at 423 K for 2 h, W/F (W, sample weight; F, flow rate of the carrier) of 100 mg/150 cm(3) min(-1), and a heating rate of 5 K min(-1). This method was applied then to a series of binary mixed oxide catalysts. The amount of desorbed pyridine was 15-24% of the full coverage of pyridine on the catalyst surface with few exceptions. The highest acid strength, determined from the Py-TPD spectra, was well-correlated to that determined from a color change of Hammett indicators. The potential of the Py-TPD for determining the acid strength and the acid amount on binary oxide catalysts is discussed.
  • A Satsuma, N Sugiyama, Y Kamiya, T Hattori
    CHEMISTRY LETTERS 10 1051 - 1052 1997年 [査読有り][通常論文]
     
    Silica species prepared by in-situ method using silicon alkoxide as precursor were found to be active for radical type oxidation of butane at low temperatures, i.e., below 650 K.

MISC

書籍等出版物

  • Design of Materials and technologies for Environmental Remediation
    Shunitz Tanaka, Masaaki Kurasaki, Masaaki Morikawa, Yuichi Kamiya (担当:共著)
    Springer 2023年 (ISBN: 9789811952357)
  • 固定化触媒のルネッサンス
    株式会社シーエムシー出版 2007年
  • 環境修復の科学と技術
    北海道大学出版会 2007年
  • エコマテリアルハンドブック
    丸善株式会社 2006年
  • Encyclopedia of Inorganic Chemistry-2nd Edition
    John Wiley & Sons, Ltd, 2005年
  • 表面・界面工学大系（下巻）
    株式会社テクノシステム 2005年

所属学協会

  • ゼオライト学会   触媒学会   日本化学会   石油学会   

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2021年04月 -2024年03月 
    代表者 : 神谷 裕一, 大友 亮一
     
    アニオン交換体に市販の弱塩基性イオン交換樹脂（AER）を用い、AuCl4-水溶液にAERを加え38℃で8時間、撹拌することで、AERのアニオン交換サイトにAuCl4-を導入した。その後、水素気流下、80℃でAuCl4-を還元してAER内にAuナノ粒子を発生させた。AuCl4-水溶液の濃度が高くなるに従ってAERに導入されるAu量が上昇した。Au導入量の多いAu-AERでは、Au未導入のAERとほぼ同等のイオン交換特性を示したことから、AuCl4-はAu0へと還元され、このとき生じたCl-がAERのイオン交換サイトを再生したと考えた。 NO3-水溶液にAu-AERを加え38℃で撹拌して、Au-AERにNO3-を取り込んだ。このAu-AERを水素気流下で80℃に加熱すると、Au-AERに取り込まれたNO3-の一部（最大35%程度）が還元分解された。Au未導入のAERでは全くNO3-が分解されなかったことから、Auナノ粒子がNO3-還元分解の活性サイトを形成していることが確かめられた。このAu-AERは繰り返し使用でき、少なくとも3回の再使用において顕著な性能低下は見られなかった。 AERに導入したAu量が多いほど還元分解されたNO3-量は多くなったが、Au導入量 0.037 mmol/g以上では活性向上の程度が大幅に鈍化した。この導入量以上では、Au粒子の凝集が見られたことから、粗大なAu粒子がこの原因であると推測した。 Au粒子が凝集することなく、より多量のAuをAERに導入するために、複数回に分けてAuCl4-を導入することを試みたが、NO3-分解活性は向上しなかった。またAER粒子内部までAuCl4-を十分に拡散させることを意図して十分に粉砕したAER粉を用いてみたが、これも十分な効果は得られなかった。さらなる検討が必要である。
  • 日本学術振興会：科学研究費助成事業 挑戦的研究(萌芽)
    研究期間 : 2019年06月 -2021年03月 
    代表者 : 神谷 裕一, 大友 亮一, 梅澤 大樹
     
    シリカの表面に固定したアミド化合物を加水分解することで、酸点（カルボキシ基）と塩基点（アミノ基）が隣接した位置に必ず配置される酸ー塩基ペアサイトを持つ固体触媒を合成した。この触媒は4-ニトロベンズアルデヒドとアセトンとの交差アルドール縮合に高い触媒活性を示した。一方、その構造の内部に３つの炭素原子からなるメチレン基をリンカーとするジアミド化合物を用いて、酸点と塩基点がリンカー相当の距離だけ離れた酸ー塩基ペアサイトを持つ触媒を合成した。この触媒は隣接した酸ー塩基ペアサイトを持つ触媒よりも低い活性しか示さず、酸点と塩基点の間の距離が重要な支配因子であることが確かめられた。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2018年04月 -2021年03月 
    代表者 : 神谷 裕一, 大友 亮一
     
    担持Ni触媒への助触媒の添加に先立ち、担持Ni触媒の担体効果を調べた。CeO2担持Ni触媒は、反応開始直後は活性を示したが、反応時間の経過とともに活性は徐々に低下し5時間以降は完全に失活した。検討した触媒の中でSiO2担持Ni触媒が最も高い初期活性を示したが、CeO2担持Ni触媒と同様に活性が徐々に低下し、100%転化率に到達しなかった。これらに対してAl2O3担持Ni触媒とZrO2担持Ni触媒は反応の途中で失活することなく、ともに反応開始から10時間で100%転化率に到達した。Al2O3担持Ni触媒と比べてZrO2担持Ni触媒の方が、(1)望ましく無い生成物のNH3への選択率が低く、かつ(2) 触媒反応の再現性が高い（おそらく、空気がNi粒子表面を酸化することによる触媒失活が起こりにくいため）ことから、ZrO2担持Ni触媒を選択し、引き続き触媒性能のさらなる向上を検討した。 水酸化ジルコニウムの焼成温度を変えてアモルファル、単斜晶、正方晶を調製し、担体の結晶構造が担持Ni触媒の触媒性能に与える影響を調べたが、担体の結晶構造は触媒性能にほとんど影響しなかった。 続いてZrO2担持Ni触媒への助触媒の添加を検討した。助触媒の添加量はNiに対して1 wt%とした。CuおよびSnを添加すると触媒活性が大きく低下した。一方、FeおよびCoを添加すると、触媒活性が大きく向上した。Feの添加はNH3選択率を向上させたのに対して、Coの添加はNH3の生成も抑制した。Znの添加は活性には影響を与えなかったが、NH3の生成は未添加の触媒と比べて抑制された。
  • 小規模施設に適したアンモニア態窒素含有廃水高度処理のための高性能触媒の開発
    住友財団: 環境研究助成
    研究期間 : 2016年11月 -2017年11月 
    代表者 : 神谷 裕一
  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 神谷 裕一
     
    廃水中のアンモニアを温和な温度でオゾンを使って酸化分解する高性能な酸化コバルト触媒を開発した。酸化コバルトの触媒性能はその粒子形態によって異なり、立方体形状もしくは切頂八面体の酸化コバルト触媒が極めて高い触媒活性を発揮した。酸化コバルト触媒を廃水中で加熱するとアンモニアとの反応によって触媒表面にアミノ基が形成され、触媒性能がさらに向上した。
  • 日本学術振興会：科学研究費助成事業 若手研究(B)
    研究期間 : 2012年04月 -2014年03月 
    代表者 : 神谷 裕一
     
    ヒドロキシル基、n-ブチル基、n-オクチル基を導入したケギン型へテロポリアニオンのセシウム中性塩を合成し、その構造と触媒特性を調べた。導入した官能基の種類によらず得られたセシウム中性塩の結晶構造は同一であり、かつ約0.6 nmのミクロ孔を持つ多孔体であった。n-オクチル基を導入したセシウム中性塩は、過酸化水素を酸化剤とするアルコール酸化に高い触媒活性を示した。導入されたn-オクチル基によってミクロ孔内部に疎水反応場が構築され、これが高い触媒活性を与える理由と推定した。
  • 日本学術振興会：科学研究費助成事業 基盤研究(A)
    研究期間 : 2011年04月 -2014年03月 
    代表者 : 上田 渉, 竹口 竜弥, 清水 研一, 村山 徹, 定金 正洋, 神谷 裕一
     
    ユニットが平面性および球状のポリ酸を合成系中で発生させ、水熱条件下でそれぞれ2次元平面ネットワーク構造、３次元立体ネットワーク構造を構築した。前者は６族、５族、４族のほとんどの元素の組み合わせが可能となり、ナノレベルで5員環状ポリ酸ユニットのネットワーク化を達成し、合成を一般化した。後者の３次元構造形成では、ε型ケギンユニットと金属酸素八面体リンカーが三次元的にネットワーク化した新しいゼオライト様の結晶物質の合成に成功し、構造の確定、対象元素の拡張、ミクロ細孔特性の解析を進めた。二酸化炭素やエタンに対する特異的な親和性を示した。得られた物質の非対称性ミクロ細孔場は新しい触媒機能を示した。
  • 水資源の永続的確保のための水中硝酸イオン還元無害化に関する研究
    住友財団：環境研究助成
    研究期間 : 2009年11月 -2010年10月 
    代表者 : 神谷 裕一
  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    研究期間 : 2008年 -2010年 
    代表者 : 神谷 裕一
     
    農地への過剰な施肥を原因とする地下水の硝酸イオン汚染が顕在化している。蒸留水中の硝酸イオンをほぼ完全に窒素ガスへと還元分解できる銅-パラジウム合金触媒は、地下水に含まれる塩化物イオンによる反応阻害を受けるため実際の汚染地下水浄化には不適であった。一方、スズ-パラジウム合金触媒は塩化物イオンによる阻害を受けず、汚染地下水中の硝酸イオンを効率的に還元浄化した。また、白金修飾酸化チタンとスズ-パラジウム合金触媒を水中に共存させた反応系は、汚染地下水中の硝酸イオン光還元分解反応を迅速に進行させた。
  • 環状アルカンの高選択的水素化開環触媒の開発とクリーガソリン合成への適用
    石油学会：研究助成
    研究期間 : 2007年04月 -2008年03月 
    代表者 : 神谷 裕一
  • 日本学術振興会：科学研究費補助金 基盤研究C
    研究期間 : 2005年04月 -2007年03月 
    代表者 : 奥原 敏夫, 神谷 裕一
     
    世界的に地下水の硝酸汚染が深刻で、その対策が急務である。硝酸汚染の原因は、農業地区での過剰施肥や酪農での家畜し尿、さらに一般に生活廃水である。汚染井戸水からの人工乳による乳児のメトヘモグロビン症である。硝酸イオン濃度の許容値50ppmでも発症例がある。このほか糖尿病や癌を起こすと指摘されている。イオン交換法では根本的な除去にならず、逆浸透法ではコストが問題で、生物処理法も操作性や水汚濁など解決しなければならない。固体環境触媒法はこれらに代わる新規技術として期待がある。 本研究でCu-Pdクラスター/ACがアルカリ条件でNO_3^-(硝酸イオン)をNO_2^-(亜硝酸イオン)に選択還元(選択性は93%)することを見出した(OH^-の阻害効果による)。一方で、Pd-ゼオライトがNO_2^-を100%N_2Oに変換した。この二つ触媒で二段触媒プロセスとし、これらと、出口N_2OをPd/ACでN2に水素化することを組み合わせて、硝酸イオン高選択的かつ高活性還元(NH_30.6ppm)を実現した。 次のステップではよりシンプルな一段法にチャレンジした。中性条件では様々な触媒の中で活性炭担持Pd-Cu合金触媒が活性と選択性(NH_3の抑制)に優れていること、その中で疎水性の高い活性炭が有効であることを示した。さらに、Cu/Pdの比の制御や新規合成したPd-Cuクラスタを調製原料とした活性炭担持Pd-Cuが、NH_3生成を許容濃度(0.5ppm)に抑える事ができ、さらに、長時間(100時間以上)安定に機能できることを見出した。さらに、共存イオン(主に硫酸イオンや塩素イオン)の影響を検討した結果、硫酸イオンは触媒活性に大きな影響を与えず、また塩素イオンの共存による活性低下は少ないことを確認した。このことは、この触媒系が地下水浄化の実用に大きく近づいたことを示す。
  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    研究期間 : 2005年 -2006年 
    代表者 : 奥原 敏夫, 神谷 裕一
     
    世界的に地下水の硝酸汚染が深刻で、その対策が急務である。硝酸汚染の原因は、農業地区での過剰施肥や酪農での家畜し尿、さらに一般に生活廃水である。汚染井戸水からの人工乳による乳児のメトヘモグロビン症である。硝酸イオン濃度の許容値50ppmでも発症例がある。このほか糖尿病や癌を起こすと指摘されている。イオン交換法では根本的な除去にならず、逆浸透法ではコストが問題で、生物処理法も操作性や水汚濁など解決しなければならない。固体環境触媒法はこれらに代わる新規技術として期待がある。 本研究でCu-Pdクラスター/ACがアルカリ条件でNO_3^-(硝酸イオン)をNO_2^-(亜硝酸イオン)に選択還元(選択性は93%)することを見出した(OH^-の阻害効果による)。一方で、Pd-ゼオライトがNO_2^-を100%N_2Oに変換した。この二つ触媒で二段触媒プロセスとし、これらと、出口N_2OをPd/ACでN2に水素化することを組み合わせて、硝酸イオン高選択的かつ高活性還元(NH_30.6ppm)を実現した。 次のステップではよりシンプルな一段法にチャレンジした。中性条件では様々な触媒の中で活性炭担持Pd-Cu合金触媒が活性と選択性(NH_3の抑制)に優れていること、その中で疎水性の高い活性炭が有効であることを示した。さらに、Cu/Pdの比の制御や新規合成したPd-Cuクラスタを調製原料とした活性炭担持Pd-Cuが、NH_3生成を許容濃度(0.5ppm)に抑える事ができ、さらに、長時間(100時間以上)安定に機能できることを見出した。さらに、共存イオン(主に硫酸イオンや塩素イオン)の影響を検討した結果、硫酸イオンは触媒活性に大きな影響を与えず、また塩素イオンの共存による活性低下は少ないことを確認した。このことは、この触媒系が地下水浄化の実用に大きく近づいたことを示す。
  • 日本学術振興会：科学研究費助成事業 若手研究(B)
    研究期間 : 2005年 -2006年 
    代表者 : 神谷 裕一
     
    環境負荷の大きい硫酸を使った化学プロセスから固体酸触媒プロセスへの転換を実現する、水中で機能する固体酸触媒(水中固体酸)の開発を行った。水中固体酸には、水中で高活性、不溶、高沈降性が求められる。水中で高活性な固体酸のCs_<2.5>H_<0.5>PW_<12>O_<40>(Cs2.5)は、触媒の一部が水に溶出ことと、低沈降性かつ濾過回収できない問題があった。本研究では、3-アミノプロピルトリエトキシシランで表面修飾したアモルファルシリカ(SiO_2-APS)の表面にCs2.5ナノ微粒子を固定化することで、これら問題を可決することに成功した(ナノコンポジット水中固体酸)。 このナノコンポジット水中固体酸を、硫酸法で工業的に実施されているα-ピネン水和反応およびα-ピネン異性化反応への適用を試みた。α-ピネン水和反応に対して、検討した大部分の固体酸は本反応に活性を示さなかった。H-βがゼオライトの中で唯一活性を示したが、アルコール類選択率は50%であった。これらに対してナノコンポジット水中固体酸は、高活性かつ高選択的に水和反応を進行させることを見出した。この反応を水/α-ピネン/触媒の三相系で反応を行うと、α-ピネンの一水和物(α-テルピネオール)と二水和物(1,8-テルピン)の両方が生成するが、反応系に1,4-ジオキサンを加えて反応溶液/触媒の二相系で反応を行うと、アルコール類としてはα-テルピネオールのみが生成することを見出した。α-ピネン異性化反応に対しても、ヘテロポリ酸塩ナノコンポジット水中固体酸は、室温で高活性かつ高選択性を示した。

産業財産権

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    特開2010-260768
  • アルキル芳香族化合物の製造方法
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  • アルキル芳香族化合物の製造方法
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  • 撥水性を有する貴金属含有触媒
    特許第4759731号
  • ヘテロポリ酸塩と無機酸化物とから成る組成物及びその製造法
    特許第4524427号
  • 特願WO2008032459-A1:Organic group-bounded acidic catalyst for fragrance and pharmaceuticals, has organic group(s) coupled together on surface of solid catalyst.  
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  • 特願2006-248413:有機基結合酸触媒  
    犬丸 啓, 石原 亨, 奥原 敏夫, 神谷 裕一
  • 特願2005-237219:アルキルベンゼンの製造方法  
    日比 卓男, 奥原 敏夫, 神谷 裕一
  • 特願2005-237218:アルキルベンゼンの製造方法  
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