酯水解行为与其烷基极化效应指数关系和酯与阿拉伯胶缔合行为的研究和应用

Study on Hydrolysis of Fatty Acid Esters and Their Combination Behavior with Gum Acacia and Application

本文运用电导法测定了不同浓度的乙醇溶液中脂肪酸酯的水解速率常数(k),并对脂肪酸乙酯类化合物的分子结构、水解条件与k的关系进行了相关分析,并推导得出酯类化合物k与烷基极化效应指数PEI(R)及体系介电常数(ε)间的关系表达式:lgk=a+blgPEI(R)+clgε,为研究酯水解机理主要影响因素、预测其k和判断酯的结构提供了一定的理论依据。同时研究了38%(V/V)乙醇溶液中阿拉伯胶(简称GA)与脂肪酸酯之间的缔合行为,并建立了定量确定缔合常数(A)的方法,推导并验证了定量表达酯水解速率常数k与GA浓度(M)关系的数学表达式:k’=k/(1+AM),得出了GA对脂肪酸酯水解起禁阻作用的结论。其研究结果用于38°清香型汾酒稳定性的提高取得了令人满意的效果。

By the method of electrical conductance, the hydrolysis rate constants（k） of a series of fatty acid esters have been measured in different contents of ethanol solution, and some correlative analyses have been done about the relationship among the molecular structure of a series of fatty acid esters, the conditions of hydrolysis and hydrolysis rate constants（k）. A good linear relationship among the hydrolysis rate constants（k）, the polarizability effect indices（PEI） of alkyl group R and dielectric constant （ e ） is deduced and this behavior can be expressed as lgk=a＋blgPEI（R）＋clg e. Simultaneously, how the gum acacia affects the hydrolysis rate constants（k） of fatty acid esters in 38.6%（V/V） ethanol solution, and the combination behavior between gum acacia and fatty acid esters have been found. And the way to determine the combination costants（A） between them quantitatively is also found. In addition, the validated quantitative mathematic expression between hydrolysis rate constants（k） of ester and the concentration of gum acacia （M）： k=k＇/（ 1 ＋AM） is verified. The result shows that the gum acacia can inhibit the hydrolysis reaction of fatty acid ester.