Catalytic distillation for simultaneous hydrolysis of methyl acetate and etherification of methanol

A catalytic distillation process was developed for the treatment of a methyl acetate/methanol byproduct stream typically encountered in polyvinyl alcohol manufacture. A two-step reaction scheme (hydrolysis + etherification) with separation is modeled in a catalytic distillation column to produce dimethyl ether (DME) and acetic acid. Simulations are performed using Aspen Plus® and assume both physical and reaction equilibrium. A batch catalytic distillation test with only methyl acetate and methanol as feed, showed DME to be the sole distillate product, whereas, the bottoms product contained acetic acid, water, methanol, and DME. Simulation results show that this “self-feeding” reaction sequence can be used to produce a high purity DME product with complete conversion of water and methanol. The effect of pressure, water, molar feed ratio of methyl acetate/methanol, and feed location were examined. Even with no additional water fed, the hydrolysis reaction proceeds to completion and is only dependent on the molar feed ratio of methyl acetate/methanol. All possible azeotropes (methyl acetate/water, methyl acetate/methanol) are eliminated by completely reacting away water and methanol.