CAJ | 학술논문

采用密度泛函理论(DFT)的B3LYP方法，在6-311++G(d, p)基组水平上，研究了在无催化剂、H2O参与、H3O+参与3种条件下苯并噻吩-2-甲酸脱羧的微观反应机理。结果表明,在无催化剂或H2O参与条件下,苯并噻吩-2-甲酸的脱羧反应的活化能分别为249.1和246.5 kJ·mol-1。在H3O+参与的反应中，反应主要经历了噻吩环α-C的质子化、羧基的水合以及C-C键断开的过程，羧基的水合反应为决速步骤，其活化能为177.6 kJ·mol-1，而C-C键断开所需克服的能垒仅为32.8 kJ·mol-1，从而表明H3O+能促进反应的进行。
채용밀도범함이론(DFT)적B3LYP방법，재6-311++G(d, p)기조수평상，연구료재무최화제、H2O삼여、H3O+삼여3충조건하분병새분-2-갑산탈최적미관반응궤리。결과표명,재무최화제혹H2O삼여조건하,분병새분-2-갑산적탈최반응적활화능분별위249.1화246.5 kJ·mol-1。재H3O+삼여적반응중，반응주요경력료새분배α-C적질자화、최기적수합이급C-C건단개적과정，최기적수합반응위결속보취，기활화능위177.6 kJ·mol-1，이C-C건단개소수극복적능루부위32.8 kJ·mol-1，종이표명H3O+능촉진반응적진행。
Density Function Theory (DFT) B3LYP method was employed to study the mechanism about three kinds of decarboxylation (without catalyst, with the assistance of H2O, or with the assistance of H3O+) of benzothiophene-2-carboxylic acid with the 6-311++G(d, p) basis sets. The potential energy of the decarboxylation of benzothiophene-2-carboxylic acid at the condition without any catalyst or aided with H2O was calculated to be 249.1 kJ·mol-1 and 246.5 kJ·mol-1, respectively. When aided with H3O+, the reaction mainly through theα-protonated of the thiophene ring, the hydration of the carboxyl group and the breaking of the C-C bond. The reaction was controlled by the hydration of the carboxyl group, the energy barrier was 177.6 kJ·mol-1, and the activation energy of the rupture of C-C bond was only 32.8 kJ·mol-1. Which suggest that the decarboxylation of benzothiophene-2-carboxylic acid may be catalyzed effectively by H3O+.