水析结晶精制对二氯苯研究

Study on Refining P-DCB by Watering-Out Crystallization

水析结晶精制对二氯苯的新方法 ,即加水使溶解于有机溶剂里的混二氯苯 (对二氯苯、邻二氯苯 )中的对二氯苯优先结晶析出 ,达到分离提纯的目的。文中选用水溶性有机溶剂 ,研究了溶剂量、溶剂配比、结晶温度等因素对晶体产品的收率及纯度的影响 ,并提出在适宜的工艺条件下可将对二氯苯的纯度从 75%一次提高到 99.7%以上 ,收率可达到 67%以上。

The new method of the separation of the mixture of dichlorobenzene (DCB) isomers (namely,p DCB and o DCB) in organic solvent by watering out crystallization is concerned about the first crystallization and precipitation of pure p DCB from solution by the addition of water.The organic solvent that is soluble in water is selected.Several factors affecting the purity and rate of yield such as amount and composition of mixed solvent,temperature etc.are studied.It is also mentioned that purity of p DCB from 75% can reach over 99.7% by one stage crystallization and rate of yield over 67% under appropriate conditions.