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A quantum chemical approach to the study of a novel reaction path and its control in the supercritical water

Research Project

Project/Area Number 15360422
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Reaction engineering/Process system
Research InstitutionOsaka University

Principal Investigator

NITTA Tomoshige  Osaka University, Graduate School of Engineering Science, Professor, 大学院・基礎工学研究科, 教授 (00029480)

Co-Investigator(Kenkyū-buntansha) TAKAHASHI Hideaki  Osaka University, Graduate School of Engineering Science, Associate Professor, 大学院・基礎工学研究科, 助教授 (10291436)
FURUKAWA Shin-ichi  Osaka University, Graduate School of Engineering Science, Research Associate, 大学院・基礎工学研究科, 助手 (50333448)
Project Period (FY) 2003 – 2004
Project Status Completed (Fiscal Year 2004)
Budget Amount *help
¥11,800,000 (Direct Cost: ¥11,800,000)
Fiscal Year 2004: ¥4,700,000 (Direct Cost: ¥4,700,000)
Fiscal Year 2003: ¥7,100,000 (Direct Cost: ¥7,100,000)
KeywordsDensity functional theory / Real-space grid / QM / MM method / Free energy / Energy representation / MM-ER / ハイブリッド型第一原理分子動力学法 / 超臨界水 / 反応機構 / 溶媒効果 / 脱水反応 / ブタンジオール / 水触媒 / プロトン移動
Research Abstract

The results obtained by present work can be summarized by the following two subjects. One is that a novel methodology (QM/MM-ER) has been developed to compute the free energy change associated with a chemical reaction in a condensed phase. The other is that a novel reaction pathway has been explored by means of the QM/MM-ER simulations. It has been suggested that the proton transfers along the hydrogen bonds of water molecules promote the dehyderation of butanediol in hot water. The details of the results have been itemized as follows.
(1)Quantum chemical approach to the free energy calculation in condensed phase
In order to compute the free energy change associated with a chemical reaction in aqueous solution, we have combined the quantum mechanical/molecular mechanical approach with the theory of energy representation. Within the theory of the energy representation, the solvation free energy of a solute is described in terms of the distribution functions of the solute-solvent interaction energy instead of the spatial distribution function used in the conventional theory of solution. Since the method of the energy representation does not need the concept of the interaction site, the combination with the quantum chemical treatment is straightforward.
(2)Quantum chemical calculation for the dehydration reaction of alcohol
Quantum chemical calculations have revealed that butanediol forms a biradical electronic structure at the transition state (TS) of the proton transferring reaction. The activation energy is extremely high (〜70 kcal/mol) in the gaseous phase, however, it reduces to 〜50 kcal/mol in hot water. The electronic state of the TS forms a zwitterionic structure in the polar solvent, which leads to the stabilization of the TS as compared to the reactant. Thus it has been suggested that the proton-transfer mechanism catalyzes the dehydration reaction of alcohol in hot water.

Report

(3 results)
  • 2004 Annual Research Report   Final Research Report Summary
  • 2003 Annual Research Report
  • Research Products

    (15 results)

All 2005 2004 2003 Other

All Journal Article (9 results) Book (1 results) Publications (5 results)

  • [Journal Article] An application of the novel quantum mechanical/molecular mechanical method combined with the theory of energy representation2005

    • Author(s)
      H.Takakashi
    • Journal Title

      Journal of Chemical Physics 119

      Pages: 44504-44504

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] An application of the novel quantum mechanical/molecular mechanical method combined with the theory of energy representation2005

    • Author(s)
      H.Takahashi
    • Journal Title

      Journal of Chemical Physics 119

      Pages: 44504-44504

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] An application of the novel quantum mechanical/molecular mechanical method combined with the theory of energy representation2005

    • Author(s)
      H.Takahashi
    • Journal Title

      Journal of Chemical Physics 122

      Pages: 44504-44504

    • Related Report
      2004 Annual Research Report
  • [Journal Article] A quantum chemical approach to the free energy calculations in condensed systems2004

    • Author(s)
      H.Takahashi
    • Journal Title

      Journal of Chemical Physics 121

      Pages: 3989-3989

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] A quantum chemical approach to the free energy calculations in condensed systems2004

    • Author(s)
      H.Takakashi
    • Journal Title

      Journal of Chemical Physics 121

      Pages: 3989-3989

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Quantum mechanical/molecular mechanical studies of a novel reaction catalyzed by proton transfers in ambient and supercritical states of water2003

    • Author(s)
      Hideaki Takahashi
    • Journal Title

      Journal of Chemical Physic 119

      Pages: 7964-7964

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Hybrid quantum chemical studies for the methanol formation reaction assisted by the proton transfer mechanism in supercritical water : CH_3Cl+nH_2O→CH_3OH+HCl+(n-1)H_2O2003

    • Author(s)
      Takumi Hori
    • Journal Title

      Journal of Chemical Physics 119

      Pages: 8492-8492

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] A real-space-grid QM/MM study on the ionic/radical association reaction in aqueous phase : HCHO+OH→HCHO-OH2003

    • Author(s)
      Hideaki Takahashi
    • Journal Title

      Journal of Molecular Structure (THEOCHEM) 632

      Pages: 185-185

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Quantum mechanical/molecular mechanical studies of a novel reaction catalyzed by proton transfers in ambient and supercritical states of water2003

    • Author(s)
      Hideaki Takahashi
    • Journal Title

      Journal of Chemical Physics 119

      Pages: 7964-7964

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Book] 物性量子化学入門2004

    • Author(s)
      山口 兆 他編
    • Total Pages
      288
    • Publisher
      講談社
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Annual Research Report 2004 Final Research Report Summary
  • [Publications] 新田 友茂: "吸着現象の分子シミュレーションと分離技術への応用"分離技術. 33(3). 14-20 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] 高橋 英明: "ハイブリッド型の量子化学計算による生体内化学反応の研究"CICSJ Bulletin. 21(6). 119-122 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Hideaki Takahashi: "Quantum mechanical/molecular mechanical studies of a novel reaction catalyzed by proton transfers in ambient and supercritical states of water"Journal of Chemical Physics. 119. 7964-7971 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Takumi Hori: "Hybrid quantum chemical studies for the methanol formation reaction assisted by the proton transfer mechanism in supercritical water : CH_3Cl+nH_2O→CH_3OH+HCl+(n-1)H_2O"Journal of Chemical Physics. 119. 8492-8499 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] Hideaki Takahashi: "A real-space-grid QM/MM study on the ionic/radical association reaction in aqueous phase : HCHO+OH→HCHO-OH"Journal of Molecular Structure (THEOCHEM). 632. 185-195 (2003)

    • Related Report
      2003 Annual Research Report

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Published: 2003-04-01   Modified: 2016-04-21  

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