Separation of benzene and toluene from close boiling nonaromatics by extractive distillation

Abstract

Abstract Benzene and toluene are virtually impossible to separate from close boiling nonaromatic hydrocarbons by rectification. Benzene and toluene can be readily separated from similar boiling nonaromatics by using extractive distillation in which the extractive distillation agent is a proper mixture of organic compounds boiling higher than benzene or toluene. A typical extractive distillation agent for benzene is a mixture of phthalic anhydride, maleic anhydride, and adiponitrile; for toluene, phthalic anhydride, maleic anhydride, and glycerol triacetate.