相转移催化下取代芳香酯的合成研究

A Study on Synthesised Aromatic Carboxylates by Phase Transfer Catalysis

研究了利用相转移催化剂合成一些取代芳香酸酯的方法．实验中使用八种催化剂对九种取代苯甲酸丁酯进行了合成研究．并且研究了合成这些核酸酯的条件，测定了它们的物理常数，如：熔点、沸点、折光率等，本文通过实验，评价了所用的相转移催化剂的活性；得到了反应物的电子效应和空间效应对合成产物产率的影响．结果表明：十六烷基三下基溴化磷、四下基磷化铵具有较高的催化活性；产物的产率随反应物ＰＫａ的减少而呈线性增加，但羧基周围位阻的增加却对产物的产率影响不大．同时就反应物的这两种效应对产率的影响给予了合理的解释．根据实验亦得出了反应过程中合适的加水量，并提出了“饱和溶液”在这一领域中的应用．所合成的九种取代苯甲酸丁酯的结构均经元素分析、红外光谱分析、＇Ｈ─核磁共振谱分析加以确定和证实．

method of synthesising substituted aromatic carboxylates by phase transfer catalysis has been studied.Eight phase transfer catlysts were used to prepare nine n-butyl substituted benzoates in the experiments. The synthetic conditions of these esters were studied.Physical constants of the esters, such as melting points.boiling points and refractive index were also determined. Activity of the phase transfer catalysts used were evaluated and the influence of the electronic and space effects of the reactants on the yield of the products has been found by the experiments.it,s found that the activity of hexadecyltributyl phosphonium bromide and tetrabutyl ammonium iodide is rather high. The yield of the products increases linearly with the increase of the reactants PKa,but the increase of carboxyl hindering does not influence much on the yield.The influence of the electronic and space effect on the yield has also been explained. The appropriate amount of water added was determined in the experiments.The use of saturated solution in this field is presented. The structures of these esters have been determined by the analyses of elements,IR and 'H-NMR.