Methyl acetate hydrolysis reaction intensified by extractive distillation in dividing wall column

Abstract

The conventional fixed bed hydrolysis process of methyl acetate is a heavy energy consuming, low hydrolysis ratio and complex process. For complete hydrolysis of methyl acetate, an extractive distillation intensified hydrolysis process was proposed. In this study, the influence of hydrolysates on the reaction was investigated. And it was found that methanol exhibited much stronger inhibitory relatively to acetic acid. Further research revealed that acetic acid could break the methyl acetate/methanol azeotrope. Based on these two discoveries, the process employed product acetic acid as extractant with the benefit of not introducing impurity components and simplifying the process. Moreover, the process integrated with dividing-wall column technology for further energy-saving. The optimum plate numbers, reflux ratio of main column, feedstock feed plate, extractant feed plate and the ratio of extractant to feed are 55, 2.7, 20, 10 and 1.1, respectively. Under the optimum conditions, methyl acetate was almost completely hydrolyzed. The produced crude acetic acid and methanol had increased from 68.0% and 35.0% in conventional process to 71.7% and 90.4% in purity, respectively. This caused an 18% reduction in energy consumption for the whole process including hydrolysis and followed refining.