2,4,6-三甲基苯叉丙二酸二乙酯的合成工艺  

Synthesis and Process of Diethyl 2-(2,4,6-Trimethylbenzylidene)malonat

作　　者：徐冬青[1] 李凯波[1] 何领[1] 刘玉莹[1] 潘忠稳[1] 

机构地区：[1]安徽大学化学化工学院,合肥230039

出　　处：《农药》2011年第1期26-28,共3页Agrochemicals

摘　　要：[目的]2,4,6-三甲基苯叉丙二酸二乙酯是合成除草剂肟草酮的关键中间体,前人报道的合成方法收率低,而本文报道了新的合成工艺并研究了催化剂种类、用量、原料摩尔比、反应时间和共沸脱水时间对收率的影响。[结果]以哌啶为催化剂,物料比n(2,4,6-三甲基苯甲醛):n(丙二酸二乙酯)为1:1.5,哌啶用量与2,4,6-三甲基苯甲醛等摩尔,回流4 h后,苯共沸脱水4 h,收率可达到97.7%(以2,4,6-三甲基苯甲醛计);用IR、1H RMR、元素分析表征了其结构。[结论]在最优条件下,以哌啶为催化剂,2,4,6-三甲基苯甲醛与丙二酸二乙酯通过Knoevenagel缩合高收率获得2,4,6-三甲基苯叉丙二酸二乙酯。[Aims] Diethyl 2-（2,4,6-trimethylbenzylidene）malonat was the key intermediate of herbicide Tralkoxydim. The synthesis with low yield was reported in a previous study. Here, the new process and the influences of factors on the yield were studied, such as the kinds and the quantity of catalyst, reaction time, the ratio of raw material and the time of azeotropic dehydration. [Results] The results showed that the optimum reaction conditions were obtained as follow： piperidine as catalyst, n（mesitaldehyde）：n（piperidine）：n（diethylmalonate） =I：1：1.5, re fluxing time 4 h, azeotropic dehydration time 4 h. The yield reached up to 97.7% （based on mesitaldehyde） under the optimum reaction conditions. The structure was confirmed by IR, ＇H NMR and elemental analysis. [Conclusions] Under the optimum reaction conditions, diethyl 2-（2,4,6-trimethylbenzylidene）malonat was gained higher yield by Knoevenagel condensation using mesitaldehyde and diethylmalonate in presence of piperidine.

关 键 词：2 4 6-三甲基苯叉丙二酸二乙酯 KNOEVENAGEL缩合 工世 

分 类 号：TQ457.2[化学工程—农药化工]