The Separation Of Ethyl Acetate-methanol Using Ethyl Methyl Imidazoles Ionic Liquid By Extractive Distillation

Ethyl acetate and methanol are important organic chemical raw materials which have been widely used in the process of chemical and pharmaceutical industry.Ethyl acetate and methanol are often used as solvents in pharmaceutical processes.As they can form binary azeotrope at 101.3kPa,which is difficult to obtain high-purity products by conventional distillation methods.Extractive distillation is more and more widely concerned.For extractive distillation,the selection of entrainers is the key point.In recent years,as a new kind of green solvent,ionic liquids(ILs)gradually show the tendency of replacing the traditional entrainers for its advantages of negligible vapor pressure,outstanding designability and so on.In this work,the ILs were used as entrainers and the effects of them on the ethyl acetate-methanol system were studied.The main work of this paper are as follows: 1-ethyl-3-methylimidazolium bromide([EMIM][Br])and 1-ethyl-3-methylimidazolium acetate([EMIM][Ac])ionic liquids were firstly synthesized by one step method and two step method,respectively.The structure,purity and water content of the three ILs([EMIM][Br]?[EMIM][Cl]?[EMIM][Ac])used in future experiment were measured.Isobaric vapor-liquid equilibrium(VLE)data for ethyl acetate-methanol binary system and ethyl acetate-methanol-ILs ternary systems were measured by a VLE still.The NRTL model was used to correlate the experimental data and the binary interaction parameters of the model were regressed.Aspen Plus was used to conduct the process simulation on the basis of the experimental data containing ILs.The effect of equipment parameters and process parameters on the purity of ethyl acetate was discussed by sensitivity analysis.The results indicated that the three ILs could satisfy the requirements of future experiment and could eliminate the azeotrope.As the addition of ILs,the azeotropic point was shifted and the relative volatility of ethyl acetate to methanol were improved.The separation abilities of three ILs follow: [EMIM][Ac]>[EMIM][Cl]>[EMIM][Br].The experimental VLE data were well correlated using the NRTL model,indicating that NRTL model could be used to fit the VLE data for the ternary system of ethyl acetate-methanol-ILs.The operation conditions that can complete the separation task were got through the Aspen Plus simulation.The better equipment parameters and process parameters were got by sensitivity analysis.