高沸点溶剂法合成原乙酸三甲酯

对低沸点溶剂法制备原乙酸三甲酯工艺进行了改进，比较了煤油、2-乙基己醇、氯苯、异佛尔酮、邻苯二甲酸二丁酯、乙二醇二丁醚等高沸点溶剂对反应的影响，筛选出最优高沸点溶剂煤油：研究了新反应体系的醇解pH值、溶剂的循环使用次数对反应的影响及溶剂循环损耗率，结果表明，醇解的最佳pH值为5．6；随着溶剂循环次数增加，原乙酸三甲酯收率从83．6％(1次)逐渐下降到76．7％(16次)；溶剂次平均损耗率4．6％。实现了直接蒸馏产品，溶剂循环使用的新工艺。避免了旧工艺先蒸溶剂，后蒸产品，产品大量分解，收率低等缺点。

Synthesis of Trimethyl Orthoacetate with High Boiling Point Solvents

A method using low boiling point solvents to prepare trimethyl orthoacetate (TMO) was improved.Kerosine was selected as the best high boiling point solvent from screening tests comparing the effect of kerosine, 2-ethyl-hexanol, chlorobenzene, isophorone, dibutyl phthalate, and ethylene glycol dibutyl ether on the synthesisreaction. Tests were conducted on the effect of hydrolysis pH and number of solvent recirculation events on thesynthesis reaction and on solvent usage during recirculation. Tests results indicated that optimum hydrolysis pH was5.6, and TMO recovery steadily decreased from 83.6% with one solvent circulation to 76.7% with 16 recirculations,and solvent consumption averaged 4.6% per circulation event. With this new synthesis method, TMO was distilleddirectly and the solvents were recycled, thereby avoiding the disadvantages of first evaporating the solvent followedby product evaporation, as well as of product decomposition and low yield.