相转移催化合成2,2-二甲基-1,3-环氧丙烷

Synthesis of 2,2-Dimethyl-1,3-epoxypropane by Phase Transfer Catalysis

研究了2,2-二甲基-3-氯丙醇在相转移催化作用下进行环氧化反应合成2,2-二甲基-1,3-环氧丙烷的影响因素和反应动力学,并提出在十二烷基三甲基氯化铵(DTAC)作用下的相转移催化环氧化反应机理。通过考察不同相转移催化剂、氢氧化钠用量及其浓度等因素对环氧化反应的影响,得出的较佳反应条件为:相转移催化剂十二烷基三甲基氯化铵用量为2,2-二甲基-3-氯丙醇质量的3%,氢氧化钠与2,2-二甲基-3-氯丙醇的物质的量的比为1.4:1,氢氧化钠质量分数为45%,在此条件下环氧化反应产物收率为91%以上。研究表明相转移催化下的环氧化反应动力学为拟一级反应,活化能为1 603.41J.mol-1,指前因子为14.39×10-2 min-1。

The reaction mechanism,kinetics and conditions for epoxidation of 2,2-dimethyl-3-chloropropanol to prepare 2,2-dimethyl-1,3-epoxypropane by phase transfer catalysis were investigated.The obtained optimum reaction conditions e.g.the different phase transfer catalysts and its usage,sodium hydroxide usage and its concentration are as following：were using dodecyl trimethyl ammonium chloride as the phase transfer catalyst,the phase transfer catalyst dosage 3%（based on 2,2-dimethyl-3-chloro-propanol dosage）,n（sodium hydroxide）：n（2,2-dimethyl-3-chloro-propanol）=1.4：1 and the concentration of sodium hydroxide 45%.Under above conditions,the yield of product was higher than 91%.It was shown that the kinetics of the epoxidation was a pseudo first-order reaction;the activation energy was 1 603.41 J·mol-1 and the pre-exponential factor was 14.39×10-2min-1.