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

研究超临界水中新型反应路径及其控制的量子化学方法

• 批准号: 15360422
• 负责人: NITTA Tomoshige
• 金额: $ 7.55万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15360422/
• 关键词: Density 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

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 phaseIn 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 alcoholQuantum 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.

通过以下两个受试者总结的结果。丁二醇在热水中的脱水量已列出，如下所示。相互作用的能量代替了常规的空间分布函数在质子转移反应的过渡状态（TS）中，激活能量在气态中极高（〜70 kcal/mol），它在热水中的电子状态降低了。与反应物相比，极性溶剂会导致TS。

项目成果

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)

Hideaki Takahashi：“环境水和超临界水状态下质子转移催化的新型反应的量子力学/分子力学研究”化学物理杂志。

A real-space-grid QM/MM study on the ionic/radical association reaction in aqueous phase : HCHO+OH→HCHO-OH

水相中离子/自由基缔合反应的实空间网格 QM/MM 研究：HCHO+OH→HCHO-OH

• 发表时间: 2003
• 期刊: Journal of Molecular Structure (THEOCHEM) 632
• 作者: 三上一行;Hideaki Takahashi
• 通讯作者: Hideaki Takahashi

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)

Hideaki Takahashi：“使用混合量子化学计算进行体内化学反应的研究”CICSJ 公告 21(6) (2003)。

An application of the novel quantum mechanical/molecular mechanical method combined with the theory of energy representation

新型量子力学/分子力学方法结合能量表示理论的应用

• 发表时间: 2005
• 期刊: Journal of Chemical Physics 119
• 作者: H.Takakashi

Quantum mechanical/molecular mechanical studies of a novel reaction catalyzed by proton transfers in ambient and supercritical states of water

• DOI: 10.1063/1.1610440
• 发表时间: 2003-10
• 期刊: Journal of Chemical Physics
• 影响因子: 4.4
• 作者: H. Takahashi;H. Hashimoto;T. Nitta