Study On The Separation Of Acetophenone And α-phenylethanol By Extractive Distillation

Acetophenone is an important organic chemical raw material which is widely used in soap, spices and pharmaceutical industry. Alpha-phenylethanol is also an important chemical raw material with wide application in spices and pharmaceutical industry. The boiling points of acetophenone and alpha-phenylethanol are respectively202℃and203.5℃under the atmospheric pressure which are very close. It is difficult to separate the mixture effectively by normal distillation methods. Extractive distillation method was used to separate the mixture and its process and effect were studied.First, triethylene glycol(TEG) was selected as the proper solvent to separate acetophenone and alpha-phenylethanol by extractive distillation method through qualitative analysis and quantitative estimation by UNIFAC group contribution method as well as the overall consideration of the properties of solvents such as dissolubility, boiling point, viscosity, et al. Then batch distillation experiments were conducted fully demonstrating that the solvent selected can effectively promote the separation of acetophenone and alpha-phenylethanol.Based on experiments, the process of extractive distillation to separate the mixture using TEG as solvent was simulated with Aspen plus software. The effect of some operation parameters including distillate rate, number of stages, solvent ratio, reflux ratio, solvent feed stage, feed stage, solvent feed temperature on separation was studied and then those operation parameters were optimized. With the optimum parameters, simulation results indicated that it was able to obtain the qualified acetophenone product of purity of99.70%with a recovery rate of99.81%and the bottom product had barely acetophenone. The results were satisfactory. And the influence of operating pressure on the separation was also investigated. The result indicated that the separation process gets easier with lower operating pressure.