Hydrolysis Of Methyl Acetate By Reactive And Extractive Distillation Using Ionic Liquids As Catalyst And Entrainer

The hydrolysis of methyl acetate is an important process in the manufacture of polyvinyl alcohol(PVA).The hydrolysis of methyl acetate is a reversible reaction,and it is required to be carried out by reactive distillation,but the hydrolysis process is complicated if traditional reactive distillation is used.In this paper,the reaction kinetics of the hydrolysis reaction using ionic liquid as catalyst was investigated,and the reactive and extractive distillation using ionic liquids as catalyst and entrainer(RED-IL)was simulated for the hydrolysis of methyl acetate.Ionic liquid catalyst was screened experimentally,and the reaction kinetics of hydrolysis was measured based on the selected catalyst.The catalytic activity of four ionic liquids was compared,and the optimal catalyst for the hydrolysis of methyl acetate is 1-butylsulfonic-3-methylimidazolium trifluoromethanesulfonate([BSO3HMIm][OTf]).The reaction kinetics for hydrolysis of methyl acetate catalyzed by [BSO3HMIm][OTf] was measured.The effects of agitation speed,catalyst concentration,reaction temperature and initial reactant molar ratio on the conversion of methyl acetate and reaction rate were investigated.Based on the reaction mechanism,the kinetic models of ideal pseudo-homogeneous(IPH)model and non-ideal pseudo-homogeneous(NIPH)model were deduced,and the parameters of the models were correlated by the experimental kinetics data.The results indicate that the reaction kinetics of the hydrolysis is well described by NIPH model.The reaction rate and chemical-phase equilibrium for the hydrolysis of methyl acetate were measured using mixed ionic liquid([BSO3HMIm][OTf] and1-octyl-2,3-dimethylimidazolium bis((trifluoromethyl)sulfonyl)imide([OMMIm][Tf2N]))as catalyst and entrainer.The results show that the reaction rate will decrease if the mole fraction of [OMMIm][Tf2N] in the mixed mixture increases,the reaction equilibrium is not affected by the entrainer [OMMIm][Tf2N],entrainer[OMMIm][Tf2N] can enhance the relative volatility of methanol to methyl acetate,but catalyst [BSO3HMIm][OTf] decreases the relative volatility of methanol to methyl acetate.The catalytic activity of mixed ionic liquid after recycling was tested experimentally,and the catalytic activity of [BSO3HMIm][OTf] is not significantly reduced after 6 recycles.RED-IL process for hydrolysis of methyl acetate was simulated,based on the reaction kinetics and chemical-phase equilibrium.The process flow diagram of the reactive and extractive distillation using [BSO3HMIm][OTf] as catalyst and[OMMIm][Tf2N] as entrainer was proposed for hydrolysis of methyl acetate.The effects of theoretical plate number,solvent ratio,ratio of catalyst flowrate to reactants flowrates,feed tray location of ionic liquids,feed tray location of reactant,liquid holdup and reflux ratio on reactive and extractive distillation were investigated.After RED-IL process was optimized,the purities of methanol and acetic acid are 0.9969 and 0.9958,respectively,and the conversion of methyl acetate is 0.9969.