以乙二醇、w(氢溴酸)=47%和冰醋酸为原料,在带水剂的作用下合成了2-溴乙基乙酸酯。考察了带水剂类型、追加醋酸或醋酸酐量及杂多酸催化剂对产率的影响,并通过气质联用对粗产品进行了分析测定。结果表明:较适宜的合成条件为乙二醇1 mol,n(乙二醇)∶n(氢溴酸)∶n(冰醋酸)=1∶1∶1.3,在带水剂甲苯(100 mL)的作用下,回流反应5 h,约4 h后分两次追加0.12×2 mol醋酸酐,合成效果最好,产率可达到95%,反应副产2-溴乙醇及少量的1,2-二溴乙烷、乙二醇二乙酸酯和二乙二醇二乙酸酯。
2-Bromoethyl acetate was synthesized by reacting 4thylene glycol with an aqueous solution of hydrogen bromide(47%) and acetic acid(1 : 1 : 1.3) in the water-carrying agent,which formed an azeotrope with water but not with 2-bromoethyl acetate. The effects of the type of water-carrying agent, the additional quantity of acetic acid or acetic anhydride and heteropoly acid catalysts on the yield was investigated, meanwhile, the crude product was analyzed by GC-MS. The experimental result showed that three byproducts was formed and the optimal condition was as follows:the molar ratio of ethylene glycol,hydrogen bromide,and acetic acid was 1 " 1 ~ 1.3,when ethylene glycol was 1 mol,refluxed 5 h under the action of 100 mL toluene. After reacting about 4 h, added 0.12 N 2 tool acetic anhydride,the yield was high up to 95% with the main byproducts 2-bromoethanol and small amount of 1,2-dibromoethane, 1,2-diacetoxyethane, diethyleneglycol diacetate.