Selective separation of benzene from hydrocarbon mixtures via liquid-liquid extraction method using aqueous solutions of substituted cyclodextrins

摘要

The selective separation of benzene from hydrocarbon mixtures was investigated by way of liquid-liquid extraction using aqueous solutions of unsubstituted alpha-cyclodextrin (alphaCD),betaCD and seven kinds of substituted CDs.Separation factor for benzene to cyclohexane was evaluated from the extraction of an equimolar mixture of benzene and cyclohexane.Hydroxypropyl-alphaCD showed the highest selectivity followed by 2,6-di-O-methyl-alphaCD,hydroxyethyl-betaCD,hydroxypropyl-betaCD and 2,6-di-O-methyl-betaCD.Then,separation selectivity for benzene was compared among the nine kinds of CDs carrying out the extraction from an equimolar mixture of 3-methylpentane,n-hexane,benzene and cyclohexane.Finally,the extraction method was applied to reformate using the aqueous solutions of hydroxypropyl-alphaCD and hydroxypropyl-betaCD.The results suggest that this method is effective for reducing the benzene content in reformate.