1,8-对孟烷二胺高效制备工艺

High Efficient Preparation Process of p-Menthane-1,8-diamine

在密封反应釜中,以1,8-对孟烷二乙酰胺为原料,正丁醇为溶剂,经氢氧化钠催化水解制备得到1,8-对孟烷二胺。当原料为0.1 mol,正丁醇用量为150 m L,原料与氢氧化钠物质的量之比为1∶5,反应温度175℃,体系自发升压至0.35～0.4 MPa,反应时间18 h时,原料转化率为100%,产物选择性大于96%,产物GC含量可达96.47%。与常压工艺相比,密封工艺的反应时间缩短了50%,产物选择性提高了20个百分点;并且当投料量扩大到10倍时,仍保持良好的反应效果,还可适当减少溶剂的添加比例。采用减压蒸馏对密封工艺产品进行分离提纯,减压精馏对常压工艺产品进行分离提纯,结果发现:蒸馏方法使产品提纯用时减少了7/8,溶剂回收率提高了5.3个百分点,且可多次重复利用,产品得率提高了55.7个百分点,产品得率可达85.6%,纯度为96.51%。

p-Menthane-1,8-diamine was prepared by hydrolysis of p-menthane-1,8-diacetamide in a sealed reaction kettle with n-butanol as solvent and sodium hydroxide as catalyst.While the amount of raw material was 0.1 mol,n-butanol was 150 mL,the molar ratio of the raw material to the catalyst was 1∶5,the reaction temperature was 175℃,the system pressure spontaneously increased to 0.35-0.4 MPa,and the reaction time was 18 h,a good result was obtained with 100% conversion of raw materials and more than 96% selectivity for the product,the GC content of which was 96.47%.Compared with the atmospheric process,the reaction time of the sealed process was shortened by 50%,the product selectivity was increased by 20 percentage points.Besides,good results were obtained when the inventory was increased by 10 times,furthermore,the adding proportion of solvent could be furtherly decreased.The product from sealed process was separated and purified by vacuum distillation while vacuum rectification for product from atmospheric process,the results showed that the separation and purification time of vacuum distillation was reduced by 7/8,solvent was recovered by 5.3 percentage point and could be reused,and the product yield was improved by 55.7 percentage point to 85.6% with the purity of 96.51%.