加盐萃取精馏分离苯中低含量正庚烷的实验研究  

Experimentation study on low content of n-heptane from benzene by extractive distillation with salt

作　　者：董红星 刘剑[1] 李占双 侯智尧 裴健[1] 

机构地区：[1]哈尔滨工程大学化工学院,黑龙江哈尔滨150001

出　　处：《哈尔滨工程大学学报》2004年第6期728-731,共4页Journal of Harbin Engineering University

摘　　要：为获得高纯度苯,须除去粗苯中正庚烷等杂质,在正庚烷质量分数较低时,苯与正庚烷之间的相对挥发度趋近于1,采用萃取精馏进行分离存在萃取剂耗量过大等缺点,溶剂加盐萃取精馏克服了萃取精馏的缺点,该技术是目前学术界高度关注的方法,其在分离醇—水、酯—水等极性体系得到了广泛的应用.但该技术应用于非极性体系的研究刚刚起步.这里采用加盐萃取精馏方法对苯-正庚烷非极性体系进行了实验研究,考察了盐的类型、盐的质量分数、溶剂体积比等因素对分离苯-正庚烷两组分的分离效果影响,并分析了上述因素对其相对挥发度影响的规律.结果表明:采用DMF为溶剂(溶剂与原料液体积比为1∶1)加KSCN(质量分数为13%)分离苯中低含量正庚烷取得了令人满意的结果,其相对挥发度在全组成范围内有较大提高.To obtain purer benzene, n-heptane and other impurities must be removed from coarse benzene . Relative volatility of benzene and n-heptane is nearly to 1 for low concentration of n-heptane. There are many disadvantages of extractive distillation, such as consuming too much extractant.However, the disadvantages can be overcome by means of extractive distillation with salt .The technology has attracted much attention by researchers. It is generally used to separate ethanol-water and ester-water polar systems,but only applied to non-polar systems. Separation of n-heptane and benzene( non-polar systems ) was studied with extractive distillation with salt. Influence of the type of salt, quality percent of salt and solvent volume percent ratio on the separation effect of benzene and n-heptane is investigated. Then the factors which affect relative volatility were analyzed. The results show that DMF (vol. Proportion 1:1) with KSCN (quality content 13%)can separate low content n-heptane from benzene effectively and relative volatility can be increased in the whole range of concentration.

关 键 词：加盐萃取精馏 DMF+KSCN 非极性体 苯和正庚烷 

分 类 号：TQ028[化学工程]