Supported Catalytic θ-ring Packing with Ionic Liquid: Preparation and Application in Ethyl Lactate Reaction Distillation

The metal wire mesh was utilized as a support to prepare θ-ring packings with a porous epoxy resin layer firstly. Then, phosphotungstic acid ionic liquid was synthesized by 1-vinyl-3-propylsulfonic acid imidazolium salt and phosphotungstic acid, and it was loaded onto the porous epoxy resin layer of the θ-ring packing so that the supported catalytic θ-ring packing for reactive distillation was acquired finally. This supported catalytic θ-ring packing was evaluated by the esterification of ethyl lactate in a laboratory-scale reaction distillation column and its catalyst kinetics were determined. Experimental results demonstrated that this packing exhibited good catalytic ability and stability. With 2.65   g phosphotungstic acid ionic liquid catalyst, the conversion rate of lactic acid surpassed that of the tea bag packing containing 8.94   g Amberlyst-15 ion exchange resin catalyst. In addition, a reactive distillation production process for 99   wt% ethyl lactate was established and simulated, and results showed that in comparison with the KATAPAK-SP12 structured catalytic packing, this supported catalytic θ-ring packing can reduce the total annual costs of the reaction distillation column by 46.0% and the overall process by 29.1%.