Separation Of Sec-Butyl Alcohol + Sec-Butyl Acetate By Batch Extractive Distillation

Sec-butyl alcohol and sec-butyl acetate are important chemical materials. The mixture of sec-butyl alcohol and sec-butyl acetate is produced during the ester exchange reaction of sec-butyl acetate and alcohols. The binary mixture forms a pseudo-azeotrope at nomal atmosphere when the content of sec-butyl alcohol is more than 85%(wt), which is difficult to be separated by common distillation. Extractive distillation is an effective method of separating the mixture. So far there are few reports about the separation of sec-butyl alcohol and sec-butyl acetate using extractive distillation. And the Vapor – liquid equilibrium(VLE) data of the systems of sec-butyl alcohol + sec-butyl acetate + extractive agent have not been reported in the open literature, which leads to the blindness in simulation, design and industrialization of the process. Thus, investigations of the vapor-liquid equilibrium and the influence of some factors on the process are significant.In this work, DMF, DMAC, DMSO and DMF + DMSO were chosen as extractive agent by literature and experience. The isobaric VLE data for the binary, ternary and quaternary systems of sec-butyl alcohol + sec-butyl acetate + solvents(DMF, DMAC, DMSO and DMF + DMSO) were measured. The thermodynamic models NRTL, Wilson and UNIQUAC were used to correlate the binary VLE data. And the binary interaction parameters for the models were obtained. The predicted binary, ternary and quaternary VLE data by the obtained n parameters fit with experimental data well. Meanwhile, the VLE experiments show that the separation efficiency of mixture solvent is better than thatof single solvent.The experiment on separating sec-butyl alcohol and sec-butyl acetate by batch extractive distillation using the mixture solvent DMF + DMSO as extractive agent was operated in this paper. It is demonstrated that the mixture solvent DMF + DMSO is feasible in separation of sec-butyl alcohol and sec-butyl acetate by batch extractive distillation. The comercial software PROII 7.1 was used to simulate the experimental process. The simulation results agree well with experimental ones. The influences of some parameters on the batch extractive distillation process were investigated using PROII 7.1. And the appropriate operating conditions were determined, under which the yield of sec-butyl acetate is 85.66%.