促进剂甲醇对合成成核剂二亚苄基山梨糖醇的影响

研究了山梨糖醇与苯甲醛在酸性催化剂条件下脱水缩合制备成核剂二亚苄基山梨糖醇（DBS）的反应规律,筛选出较好的反应溶剂﹑反应催化剂﹑反应促进剂和产品后处理工艺,确定了最佳反应条件。促进剂甲醇的使用和加入方式,对缩合反应影响最大,甲醇的最佳加入方式是分批加入法,反应温度可以在最佳的范围内波动,有利缩合反应进行,副反应较少,反应收率高,DBS产物熔点高,甲醇的最佳加入量为溶剂环己烷质量的12%左右,过量的使用对后面的反应影响不大,反而延长了反应时间,造成促进剂浪费和回收成本的增加。

Effect of Promoter Methanol on Synthesis of Dibenzylidene Sorbitol

Condensation reaction of sorbitol with benzaldehyde using acid catalyst to prepare nacleating agent dibenzyline sorbitol（DBS） was studied. Suitable solvent, catalyst and reaction promoter was selected, and the best reaction conditions was determined. Promoter methanol had great effect on condensation reaction. The best feeding mode of methanol is batch feeding. Dibenzylidene Sorbitol （DBS） yield is higher, side reaction is less and melting point of DBS is high when reaction temperature is controlled in best range. The best adding quantity of methonal is 12%（wt） of the solvent cyclohexone. Over-addition of methanol has little effect on condensation reaction and extended reaction time, to cause the methanol wastes and recovery cost increases. 更