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化学学报
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化学学报 ›› 1990, Vol. 48 ›› Issue (5): 506-510. 上一篇    下一篇

研究论文

分子内反应与分子内催化I:分子内苯并咪唑基一般碱催化2-(2'-苯并咪唑基)乙酸乙酯及3-(2'-苯并咪唑基)丙酸乙酯水解机理的探讨

夏炽中;夏道宏   

  1. 山西大学分子科学研究所
  • 发布日期:1990-05-15

Intramolecular reaction and intramolecular catalysis I: An approach to the hydrolysis mechanism of intramolecular general base-catalysis by the benzimidazolyl group of ethyl 2-(2'-benzimidazolyl)acetate and ethyl 3-(2'-benzimidazolyl)propionate

XIA CHIZHONG;XIA DAOHONG   

  • Published:1990-05-15

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本工作测定了2-(2'-苯并咪唑基)乙酸乙酯及3-(2'-苯并咪唑基)丙酸乙酯在不同pH值下的表观水解速率常数在碱性较强的溶液中, 酯的水解反应主要是由氢氧根离子进行分子间特殊碱催化来完成;而在接近中性pH值范围的溶液中, 苯并咪唑基以一般碱催化方式参与了分子内催化酯的水解反应。实验结果与所提出的理论模型较好地吻合。

关键词: 催化, 丙酸 P, 反应机理, 乙酸乙酯, 乙酯, 苯并咪唑, 碱, 水解反应

The observed hydrolysis rate constants of the title compounds were determine at different pH values. The experimental results show that in more alkaline solution, the intermol. specific base-catalyzed hydrolysis of these two esters by hydroxide ion predominates, while at pH values close to neutral the intramol. general base-catalyzed hydrolysis of esters by the benzimidazolyl group occurs.

Key words: CATALYSIS, METHYLACETIC ACID P, REACTION MECHANISM, ETHYL ACETATE, ETHYL ESTER, BENZIMIDAZOLE, BASE, HYROLYSIS

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