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Yuichi Kamiya
Faculty of Environmental Earth Science　Materials Science　Functional Materials Chemistry
Professor
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Last Updated :2024/05/09

Researcher Profile and Settings

Affiliation

  • Faculty of Environmental Earth Science　Materials Science　Functional Materials Chemistry

Job Title

  • Professor

URL

Research funding number

  • 10374638

J-Global ID

Research Interests

  • 触媒化学   Environmental Science   Material Chemistry   Catalysis   

Research Areas

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Catalytic processes and resource chemistry

Educational Organization

Academic & Professional Experience

  • 2015/04 - Today Faculty of Environmental Earth Science Section of Materials Science Professor
  • 2007/04 - 2015/03 大学院地球環境科学研究院 准教授
  • 2005/03 - 2007/03 大学院地球環境科学研究院 助教授
  • 2005 - 2007 Associate Professor, Faculty of Environmental Earth Science

Education

  • 1995/04 - 1997/03  Nagoya University
  • 1991/04 - 1995/03  Nagoya University  School of Engineering

Association Memberships

  • ゼオライト学会   触媒学会   日本化学会   石油学会   

Research Activities

Published Papers

  • 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 2588-8420 2024/03 [Refereed]
  • Dewi Agustiningsih, Ryoichi Otomo, Yuichi Kamiya, Nuryono Nuryono, Sri Juari Santosa, Eko Sri Kunarti
    Applied Catalysis A: General 672 119606 - 119606 0926-860X 2024/02 [Refereed][Not invited]
  • Ratih Lestari, Tutik Dwi Wahyuningsih, Yuichi Kamiya, Indriana Kartini
    Diamond and Related Materials 139 110271 - 110271 0925-9635 2023/11 [Refereed][Not invited]
  • Mitsuru Kanno, Jun Hirata, Taiki Umezawa, Wataru Ninomiya, Yuichi Kamiya
    Journal of the Japan Petroleum Institute 66 (4) 128 - 131 1346-8804 2023/07/01 [Refereed][Not invited]
  • Daiki Yoshida, Jiahao Liu, Kaili Huang, Ryoichi Otomo, Yuichi Kamiya
    Applied Catalysis A: General 649 118982 - 118982 0926-860X 2023/01 [Refereed][Not invited]
  • 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 1385-8947 2022/12 [Refereed]
  • Bonusa Nabila Huda, Endang Tri Wahyuni, Yuichi Kamiya, Mudasir Mudasir
    Materials Chemistry and Physics 282 126005 - 126005 0254-0584 2022/04 [Refereed]
  • Taichi Nakamura, Yuichi Kamiya, Ryoichi Otomo
    Microporous and Mesoporous Materials 333 111743 - 111743 1387-1811 2022/03 [Refereed]
  • 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 0366-7022 2021/10/05 [Refereed]
  • Haruka Aihara, Sou Watanabe, Atsuhiro Shibata, Lina Mahardiani, Ryoichi Otomo, Yuichi Kamiya
    Progress in Nuclear Energy 139 103872 - 103872 0149-1970 2021/09 [Refereed][Not invited]
     
    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 2021/04/19 [Refereed][Not invited]
     
    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.
  • 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 1477-9226 2021 [Refereed][Not invited]
     

    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 1566-7367 2021/01 [Refereed][Not invited]
     
    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 0920-5861 2020/08 [Refereed][Not invited]
     
    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 2214-7144 2020/08 [Refereed][Not invited]
  • 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 0254-0584 2020/07 [Refereed][Not invited]
     
    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 2044-4753 2020/07 [Refereed][Not invited]
     

    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 0926-860X 2020/04 [Refereed][Not invited]
     
    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 1944-8244 2020/01/15 [Refereed][Not invited]
     
    © 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 0366-7022 2020/01/05 [Refereed][Not invited]
     
    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.
  • Ryoichi Otomo, Momo Fujimoto, Masanori Nagao, Yuichi Kamiya
    Molecular Catalysis 475 2468-8231 2019/10 [Refereed][Not invited]
     
    © 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 0926-860X 2019/04 [Refereed][Not invited]
     
    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 2044-4753 2019 [Refereed]
     

    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 2168-0485 2019 [Refereed][Not invited]
     
    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 1566-7367 2019 [Refereed][Not invited]
     
    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 0149-1970 2019 [Refereed][Not invited]
  • Nuryono Nuryono, Ani Qomariyah, Wontae Kim, Ryoichi Otomo, Bambang Rusdiarso, Yuichi Kamiya
    Molecular Catalysis 475 2468-8231 2019 [Refereed][Not invited]
     
    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-GENERAL 570 164 - 172 0926-860X 2019 [Refereed][Not invited]
     
    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 1932-7455 2018/01/18 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • Jun Hirayama, Yuichi Kamiya
    JOURNAL OF CATALYSIS 348 306 - 313 0021-9517 2017/04 [Refereed][Not invited]
     
    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 0947-6539 2016/07 [Refereed][Not invited]
     
    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 1346-8804 2016/01 [Refereed][Not invited]
     
    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 2044-4753 2016 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • Yukari Iwase, Shogo Sano, Lina Mahardiani, Ryu Abe, Yuichi Kamiya
    JOURNAL OF CATALYSIS 318 34 - 42 0021-9517 2014/10 [Refereed][Not invited]
     
    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 0920-5861 2014/09 [Refereed][Not invited]
     
    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 2155-5435 2014/07 [Refereed][Not invited]
     
    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 0926-3373 2014/01 [Refereed][Not invited]
     
    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 1387-1811 2013/07 [Refereed][Not invited]
     
    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.
  • Yasuda Shuhei, Hasegawa Toshio, Yasukawa Toshiya, Ninomiya Wataru, Ooyachi Ken, Kamiya Yuichi
    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute 公益社団法人 石油学会 2013 41 - 41 2013 
    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 1566-7367 2012/04 [Refereed][Not invited]
     
    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 0366-7022 2012/03 [Refereed][Not invited]
     
    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 2044-4753 2012 [Refereed][Not invited]
     
    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 0926-3373 2012/01 [Refereed][Not invited]
     
    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 1566-7367 2011/10 [Refereed][Not invited]
     
    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 1932-7447 2011/08 [Refereed][Not invited]
     
    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 0732-8303 2011 [Refereed][Not invited]
     
    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.
  • Doi Hayato, Kamiya Yuichi
    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute 公益社団法人 石油学会 2011 147 - 147 2011 
    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 0366-7022 2010/08 [Refereed][Not invited]
     
    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 1381-1169 2010/07 [Refereed][Not invited]
     
    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 0021-9517 2010/07 [Refereed][Not invited]
     
    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.
  • Doi Hayato, Yamamoto Takuma, Kamiya Yuichi
    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute 公益社団法人 石油学会 2010 40 - 40 2010 
    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 1346-8804 2009/11 [Refereed][Not invited]
     
    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 0366-7022 2009/07 [Refereed][Not invited]
     
    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 0926-860X 2009/06 [Refereed][Not invited]
     
    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 0926-860X 2009/05 [Refereed][Not invited]
     
    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 0366-7022 2009/03 [Refereed][Not invited]
     
    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 0926-860X 2009/01 [Refereed][Not invited]
     
    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 1433-7851 2009 [Refereed][Not invited]
  • Yuichi Kamiya, Hiroyuki Imai, Toshio Okuhara
    Journal of the Japan Petroleum Institute 52 (3) 81 - 89 1346-8804 2009 [Refereed][Not invited]
  • Takashi Kawakami, Yasunobu Ooka, Hideshi Hattori, Wenling Chu, Yuichi Kamiya, Toshio Okuhara
    APPLIED CATALYSIS A-GENERAL 350 (1) 103 - 110 0926-860X 2008/11 [Refereed][Not invited]
     
    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.
  • Yoshinori Sakamoto, Mitsuru Kanno, Toshio Okuhara, Yuichi Kamiya
    CATALYSIS LETTERS 125 (3-4) 392 - 395 1011-372X 2008/10 [Refereed][Not invited]
     
    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 0366-7022 2008/10 [Refereed][Not invited]
     
    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 0926-860X 2008/07 [Refereed][Not invited]
     
    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 1571-1013 2008/06 [Refereed][Not invited]
     
    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 0021-9517 2008/04 [Refereed][Not invited]
     
    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 1387-1811 2008/04 [Refereed][Not invited]
     
    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 0021-9517 2008/03 [Refereed][Not invited]
     
    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
    RESEARCH ON CHEMICAL INTERMEDIATES 34 (8-9) 669 - 677 0922-6168 2008 [Refereed][Not invited]
     
    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 0922-6168 2008 [Refereed][Not invited]
     
    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.
  • Nishii Hiromi, Kamiya Yuichi, Okuhara Toshio
    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute 公益社団法人 石油学会 2008 32 - 32 2008 
    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。
  • Kamiya Yuichi
    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute 公益社団法人 石油学会 2008 57 - 57 2008
  • Yun Hin Taufiq-Yap, Chee Keong Goh, Yuichi Kamiya
    REACTION KINETICS AND CATALYSIS LETTERS 92 (2) 275 - 284 0133-1736 2007/12 [Refereed][Not invited]
     
    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 1011-372X 2007/12 [Refereed][Not invited]
     
    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.
  • Hiroyuki Imai, Yuichi Kamiya, Toshio Okuhara
    JOURNAL OF CATALYSIS 251 (1) 195 - 203 0021-9517 2007/10 [Refereed][Not invited]
     
    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 0366-7022 2007/08 [Refereed][Not invited]
     
    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, Yulchi Kamiya, Toshio Okuhara
    MICROPOROUS AND MESOPOROUS MATERIALS 101 (1-2) 176 - 183 1387-1811 2007/04 [Refereed][Not invited]
     
    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.
  • Yuichi Kamiya, Yasunobu Ooka, Chisato Obara, Ryuichiro Ohnishi, Toshio Fujita, Youhei Kurata, Katsuyuki Tsuji, Tetsuo Nakajyo, Toshio Okuhara
    JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL 262 (1-2) 77 - 85 1381-1169 2007/02 [Refereed][Not invited]
     
    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 1433-7851 2007 [Refereed][Not invited]
  • 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 [Refereed][Not invited]
  • 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 [Refereed][Not invited]
  • Yi Wang, Yuichi Kmiya, Toshio Okuhara
    WATER RESEARCH 41 (2) 269 - 276 0043-1354 2007/01 [Refereed][Not invited]
     
    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.
  • Tsunayama Kazuyuki, Ohnishi Ryuichiro, Kamiya Yuichi, Okuhara Toshio
    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute 公益社団法人 石油学会 2007 182 - 182 2007 
    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。
  • Kamiya Yuichi
    Proceeding of Annual/Fall Meetings of the Japan Petroleum Institute 公益社団法人 石油学会 2007 55 - 55 2007 
    In this lecture, I would introduce our recent research on Friedel-Crafts reactions and skeletal isomerization over thin-layered heteropolyacids, and benzonitrile-TPD measuring the acidic properties of the outer-most surface of the thin-layered heteropolyacids. I further show you a composite water-tolerant solid acid composed of Cs2.5H0.5PW12O40 and aminosilane-functionalized silica and microporous CsxH4-xSiW12O40.
  • Naoto Horita, Yuichi Kamiya, Toshio Okuhara
    CHEMISTRY LETTERS 35 (12) 1346 - 1347 0366-7022 2006/12 [Refereed][Not invited]
     
    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 1011-372X 2006/11 [Refereed][Not invited]
     
    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.
  • Takeshi Sugii, Yuichi Kamiya, Toshio Okuhara
    APPLIED CATALYSIS A-GENERAL 312 45 - 51 0926-860X 2006/09 [Refereed][Not invited]
     
    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 0920-5861 2006/08 [Refereed][Not invited]
     
    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 1381-1169 2006/05 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • N Ryumon, H Imai, Y Kamiya, T Okuhara
    APPLIED CATALYSIS A-GENERAL 297 (1) 73 - 80 0926-860X 2006/01 [Refereed][Not invited]
     
    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.
  • Y Sakamoto, K Nakamura, R Kushibiki, Y Kamiya, T Okuhara
    CHEMISTRY LETTERS 34 (11) 1510 - 1511 0366-7022 2005/11 [Refereed][Not invited]
     
    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 0366-7022 2005/10 [Refereed][Not invited]
     
    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 0366-7022 2005/09 [Refereed][Not invited]
     
    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 1387-1811 2005/06 [Refereed][Not invited]
     
    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 1011-372X 2005/06 [Refereed][Not invited]
     
    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 0366-7022 2005/05 [Refereed][Not invited]
     
    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 0133-1736 2005 [Refereed][Not invited]
     
    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 0366-7022 2004/07 [Refereed][Not invited]
     
    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 1011-372X 2004/04 [Refereed][Not invited]
     
    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 0926-860X 2004/03 [Refereed][Not invited]
     
    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 1381-1169 2004/02 [Refereed][Not invited]
     
    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 1381-1169 2004 [Refereed][Not invited]
  • Hiyoshi, N., Yamamoto, N., Ryumon, N., Kamiya, Y., Okuhara, T.
    Journal of Catalysis 221 (1) 225 - 233 0021-9517 2004 [Refereed][Not invited]
  • JX Mao, Y Kamiya, T Okuhara
    APPLIED CATALYSIS A-GENERAL 255 (2) 337 - 344 0926-860X 2003/12 [Refereed][Not invited]
     
    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 0926-860X 2003/10 [Refereed][Not invited]
     
    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 0926-860X 2003/10 [Refereed][Not invited]
     
    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 0009-2673 2003/04 [Refereed][Not invited]
     
    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%).
  • Kamiya, Y., Ueki, S., Hiyoshi, N., Yamamoto, N., Okuhara, T.
    Catalysis Today 78 (1-4 SPEC.) 281 - 290 2003 [Refereed][Not invited]
  • Y Kamiya, H Nishiyama, M Yashiro, A Satsuma, T Hattori
    JOURNAL OF THE JAPAN PETROLEUM INSTITUTE 46 (1) 62 - 68 1346-8804 2003/01 [Refereed][Not invited]
     
    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 1387-1811 2002/07 [Refereed][Not invited]
     
    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 0920-5861 2001/11 [Refereed][Not invited]
     
    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 0582-4664 2001/07 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • Y Kamiya, E Nishikawa, T Okuhara, T Hattori
    APPLIED CATALYSIS A-GENERAL 206 (1) 103 - 112 0926-860X 2001/01 [Refereed][Not invited]
     
    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 0926-860X 2000/03 [Refereed][Not invited]
     
    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 [Refereed][Not invited]
  • A Satsuma, Y Westi, Y Kamiya, T Hattori, Y Murakami
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 70 (6) 1311 - 1317 0009-2673 1997/06 [Refereed][Not invited]
     
    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 0366-7022 1997 [Refereed][Not invited]
     
    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.

Books etc

  • Design of Materials and technologies for Environmental Remediation
    Shunitz Tanaka, Masaaki Kurasaki, Masaaki Morikawa, Yuichi Kamiya (Joint work)
    Springer 2023 (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
  • 環境修復の科学と技術
    北海道大学出版会 2007
  • エコマテリアルハンドブック
    丸善株式会社 2006
  • Encyclopedia of Inorganic Chemistry-2nd Edition
    John Wiley & Sons, Ltd, 2005
  • 表面・界面工学大系（下巻）
    株式会社テクノシステム 2005

MISC

Industrial Property Rights

  • ヘテロポリ酸のアルカリ金属塩及びそれらからなるオレフィンオリゴマー化用触媒
    特開2010-260768
  • アルキル芳香族化合物の製造方法
    特開2007-77133
  • アルキル芳香族化合物の製造方法
    特開2007-77132
  • 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.  
    Kei Inumaru, Toru Ishihara, Toshio Okuhara, Yuichi Kamiya
  • 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  
    日比 卓男, 奥原 敏夫, 神谷 裕一

Awards & Honors

  • 2008/05 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 Young Scientist Prize of the International Association of Catalysis Societies (13th International Congress on Catalysis)

Research Grants & Projects

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2021/04 -2024/03 
    Author : 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。
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Challenging Research (Exploratory)
    Date (from‐to) : 2019/06 -2021/03 
    Author : Kamiya Yuichi
     
    Adjacent acid-base pair sites, which were consisted of carboxyl and amine groups, were constructed on silica surface by hydrolysis of an amide compound, which were anchored on the silica in advance. It was found that this catalyst showed extremely high catalytic activity for cross-aldol condensation of 4-nitrobenzaldehyde with acetone. The acid-base pair sites that were three methylene groups away from each other, which were constructed using an diamide compound that contains three methylene groups in the structure, showed less activity for the reaction that the catalyst with adjacent acid-base pair sites, demonstrating that the distance between acid and base functional groups was important factor for the reaction.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
    Date (from‐to) : 2018/04 -2021/03 
    Author : Kamiya Yuichi
     
    Expose of supported nickel catalysts to air made their catalytic activity lost in reduction of nitrate with hydrogen in water. Thus, to bring out their inherent catalytic performances, it was necessary to remove air from the reaction systems as much as possible. The catalytic performances of supported nickel catalysts for reduction of nitrate with hydrogen in water were significantly changed depending on support for nickel and co-catalyst added to nickel. It was found that a supported nickel catalyst with alumina support and zinc as a co-catalyst with 0.04 of atomic ratio of zinc to nickel showed high catalytic activity and suppressed undesirable ammonia formation.
  • 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
    Date (from‐to) : 2016/11 -2017/11 
    Author : 神谷 裕一
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2014/04 -2017/03 
    Author : Kamiya Yuichi
     
    We have developed high performance cobalt oxide catalysts for oxidative decomposition of ammonia in waste water under mild reaction conditions. Catalytic performances of the cobalt oxide catalysts changed depending on their particle configuration and cubic and truncated octahedron shaped cobalt oxides gave high catalytic activity for the reaction. Thermal treatment of cobalt oxides in waste water containing ammonia brought about formation of amino group on the surface. leading to enhancement in the catalytic performance with repeated use for the reaction.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2012/04 -2014/03 
    Author : KAMIYA Yuichi
     
    Neutral cesium salts of Keggin-type heteropoly anions introduced with hydroxyl, n-butyl, and n-octyl groups were synthesized and their structures and catalytic performances were investigated. Regardless of the functional groups introduced into the Keggin-type heteropoly anions, the neutral cesium salts had the same crystal structure each other and were microporous materials with micropore of about 0.6 nm. Among the neutral cesium salts tested here, that with n-octyl group showed the highest activity for oxidation of alcohol with hydrogen peroxide. The hydrophobic reaction field formed inside the micropore with n-ocytl group may cause the high catalytic activity.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
    Date (from‐to) : 2011/04 -2014/03 
    Author : UEDA Wataru, TAKEGUCHI Tatsuya, SHIMIZU Kenichi, MURAYAMA Toru, SADAKANE Masahiro, KAMIYA Yuichi
     
    Structure engineering of functional solid catalysts has been conducted on the basis of unit-network methodology of molecular-type polyoxide units under hydrothermal condition for creating three-dimensional network structure of the units. The methods were applied to metal oxide components in 6, 5 and 4 element group and successfully gave various solids with nano-size structure with a heptagonal structural unit, confirming the applicability of the method for creating high-dimensional solid structures. This method was also found useful for creating a new three-dimensional zeolite-type porous solid based on molecular-type polyoxide units. The materials are totally new and showed unique adsorption property for CO2 and ethane. These obtained materials showed solid-acid property and incomparable catalytic property based on an asymmetric porous structure.
  • 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
    Date (from‐to) : 2009/11 -2010/10 
    Author : 神谷 裕一
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2008 -2010 
    Author : KAMIYA Yuichi
     
    Pollution of groundwater with nitrate caused by overfertilization is increasing problem in the world. Active carbon-supported Cu-Pd catalyst decomposed almost all nitrate into nitrogen gas by the hydrogenation in water. However, the Active carbon-supported Cu-Pd catalyst was remarkably deactivated by chlorine contained in groundwater for remediation of actual groundwater. In contrast, active carbon-supported Sn-Pd catalyst showed high catalytic performance even in the reaction solution containing chlorine and remediated the actual groundwater polluted with nitrate. The reaction system consisted of platinum-modified titanium oxide and Sn-Pd/Al_2O_3 promoted effectively photocatalytic reduction of nitrate in the actual groundwater.
  • 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
    Date (from‐to) : 2007/04 -2008/03 
    Author : 神谷 裕一
  • 農業汚染地下水復元のためのナノクラスタ触媒システムの開拓
    科学研究費補助金 基盤研究C
    Date (from‐to) : 2005/04 -2007/03 
    Author : 奥原 敏夫, 神谷 裕一
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
    Date (from‐to) : 2005 -2006 
    Author : OKUHARA Toshio, KAMIYA Yuichi
     
    Pollution of groundwater with nitrate (NO_3^-) is a widespread problem, since excess intake of nitrate causes blue baby syndrome for infants and diabetes and cancers. The major sources are agricultural practices (fertilizers and excretions of livestock), and the remediation of groundwater is urgent issue. The biological treatment, ion exchange, and reverse osmosis have still much issues. Recently catalytic hydrogenation of NO_3^-to N_2 have attracted much attention. It is necessary to reduce the levels of harmful components to the maximum allowable levels, 50, 0.1-3, and 0.5 ppm for nitrate, nitrite (NO_2^-), and NH_3. We found that Cu-Pd clusters supported on active carbon are highly selective for the hydrogenation of NO_3^- to NO_2^- at high pH. On the other hand, Pd exchanged beta zeolite catalyzed selectively the hydrogenation of NO_2^- to N_2 and N_2O. From these findings, we were inspired in a two-stage process which allows catalysts optimized for each stage ; NO_3^-hydrogenation to NO_2^-in the first stage and NO_2^-hydrogenation in the second stage. Here we wish to report that the two-stage process consisting of Cu-Pd cluster/AC and Pd/beta-zeolite is promising for the purification of water contaminated nitrate. It should be emphasized that the concentration of NH_3 was only 0.7 and 0.6 ppm at 298 and 288 K, respectively which are very close to the allowable value (0.5 ppm) for drinking water. Then a one-stage process aimed at drinking water using a single catalyst, the catalyst with acceptable activity, selectivity, and stability for the practical use is searched 2wt%Pd-1.2wt%Cu/mordenite (Si/Al=37) was highly selective to N_2 and N_2O, depressing NH_3 (5 ppm from 200 ppm of nitrate) and exhibited robust stability at 278-333 K. Cu-Pd/mordenites that were prepared by ion-exchange method. Recently, Pd-Cu/hydrophobic AC catalysts prepared from Pd-Cu cluster exhibited was found to be high active and selective, that is, be greatly suppressed for the formation of ammonia. Furthermore, this catalyst has worked even in the presence of sulfated ion and chloride ion.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
    Date (from‐to) : 2005 -2006 
    Author : 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。

Educational Activities

Teaching Experience

  • Inter-Graduate School Classes(General Subject):Natural and Applied Sciences
    開講年度 : 2021
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : 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
  • Fundamental Course in Materials Science I
    開講年度 : 2021
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 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
  • Advanced Course in Environmental Nano-Materials Chemistry I
    開講年度 : 2021
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 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
  • Inter-Graduate School Classes(Educational Program):PARE
    開講年度 : 2021
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : 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
  • Chemistry I
    開講年度 : 2021
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 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
  • Laboratory Exercise in Natural Sciences
    開講年度 : 2021
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 自然科学実験、物理学、化学、生物学

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