N,N-二甲基乙酰胺+硫氰酸钾复合溶剂萃取分离苯-环己烷的选择性

采用N,N-二甲基乙酰胺+硫氰酸钾(KSCN)复合溶剂萃取分离苯-环己烷混合物,考察了复合溶剂中KSCN的质量分数、原料液组成、温度和复合溶剂与原料液的体积比(溶剂比)对苯的选择性系数(β)的影响。实验结果表明,在原料液组成一定时,β随复合溶剂中KSCN含量的增加先增大后减小;当复合溶剂中KSCN含量一定时,β随原料液中苯含量的增大而减小;在25～35℃,温度及溶剂比对β影响不大;在25℃、溶剂比为1.0、复合溶剂中KSCN质量分数为8%、原料液中苯体积分数不超过30%时,苯-环己烷混合物可达到较好的分离效果,β最大可达7.5。

Selectivity of Extraction Separation of Benzene-Cyclohexane with Dimethylacetamide+Potassium Thiocyanate Composite Solvent

A novel composite solvent was prepared through adding potassium thiocyanate(KSCN) to dimethylacetamide,which was used as extractant in extraction separation of benzene and cyclohexane.Effects of KSCN mass fraction in the composite solvent,volume fraction of benzene in the feed,temperature and volume ratio of the composite solvent to the feed on selectivity coefficient(β) of benzene to cyclohexane were investigated.With increase of the KSCN content,the β first increased and then decreased,and the β increased with decrease of the benzene content in the feed.The temperature and the volume ratio of the composite solvent to the feed had a little influence on the β in 25-35 ℃.Under the conditions of 25 ℃,mass fraction of KSCN in composite solvent 8% and volume ratio of the composite solvent to the feed 1.0,effect of the extraction separation could be satisfied and the β could reach 7.5.