The Separation Of 2-butanone-ethanol System Using Phosphate Ionic Liquids By Extraction Distillation

2-Butanone and methanol are important organic chemical materials.In the production process of pyroligneous acid by the destructive distillation of wood,the distillate contains the mixture of 2-butanone and ethanol.2-Butanone and ethanol can form azeotrope at 101.3 kPa,which cannot be separated by conventional distillation.Extractive distillation is used to separate azeotropic or close-boiling systems.For extractive distillation,the selection of entrainers plays an important role.In recent years,ionic liquid(ILs)shows the tendency of replacing the traditional organic solvents gradually for its advantages of negligible vapor pressure,outstanding designability,high solubility and so on.The major work of this paper are as follow:(1)[EMIM][DEP] and [BMIM][DBP] were synthesized in our laboratory.The structure,purity and water content of ILs were measured.(2)At 101.3 kPa,the isobaric vapor-liquid equilibrium(VLE)data for the ternary system of 2-butanone-ethanol containing different ILs were measured.And the effect of the ILs on the VLE behavior of the 2-butanone and ethanol system was discussed.(3)Nonrandom two-liquid(NRTL)model was used to correlate the measured data and the binary interaction parameters of the model were regressed.(4)The extractive distillation process was simulated and optimized by Aspen Plus software through taking 2-butanone-ethanol-[EMIM][DEP] system as an instance.The results showed that:(1)Two synthetic ILs are completely satisfied for experimental requirement.The synthesis method is reliable and the technology is reasonable.(2)Three phosphate-based ILs could be completely eliminated the azeotropic phenomenon of 2-butanone-ethanol system.(3)The shorter alkyl chain length of anion and cation in ILs is,the stronger separation ability it has.The separation ability of the three ILs follows this order: [EMIM][DEP]> [BMIM][DEP]> [BMIM][DBP].(4)The VLE data were well correlated with the NRTL model,indicating that NRTL model could be applied to this system.(5)We let the mole fraction of 99.9% on the top act as the standard,and get the feasible operating conditions through the analysis of the sensitivity.