Separation of acetone–tetrahydrofuran azeotropic mixture by continuous extractive distillation

Abstract Background Acetone and tetrahydrofuran are commonly used as solvents in the chemical industry. The separation of acetone–tetrahydrofuran mixtures is often faced in the pharmaceutical and special chemical industries. As acetone and tetrahydrofuran can form a minimum azeotrope, they cannot be separated by conventional distillation. But acetone and tetrahydrofuran are important organic raw materials and solvents, so the mixture should be separated for reuse. Results The process of continuous extractive distillation was used to separate the mixture of acetone (62% mass fraction) and tetrahydrofuran (38% mass fraction) using butyl ether as solvent. The characteristics of the continuous extractive distillation were simulated via ASPEN and experiments also showed the feasibility of separating the acetone–tetrahydrofuran mixture. Effects of the reflux mass ratio (R), mixture feed stage (FS), the solvent feed stage (SFS) on the extractive distillation column and the volume ratio of solvent to mixture (S/F) on the distillate mass fraction of acetone and bottom product mass fraction of acetone were investigated. The results of the extractive distillation simulation were verified by experiment data. With the following operation conditions for the extractive distillation column: number of theoretical plates 53; mixture feed at 24th plate; solvent feed at 7th plate, solvent to mixture ratio 3 and reflux mass ratio 3, the mass fraction of acetone in the distillate can reach 99%. Conclusions The process of continuous extractive distillation using butyl ether as solvent can separate the acetone–tetrahydrofuran mixture. The solvent to mixture ratio and reflux mass ratio are important factors that affect the mass fraction of the product. © 2013 Society of Chemical Industry