Design Of Deep Eutectic Solvent And Vapor-Liquid Equilibrium Study For Separation Of Isopropanol-Water Azeotrope

Isopropanol(IPA)is widely used in the industry as chemicals and chemical intermediate.In the industrial production process,a large amount of a mixture of aqueous isopropanol is often produced,and the mixture generally has a high content of isopropyl alcohol and has a high recovery value.Since isopropanol can form an azeotrope with water,it is difficult to separate isopropanol from its aqueous solution by conventional distillation.In order to obtain isopropanol,a special distillation is usually used to separate the azeotrope.For example,extractive distillation,azeotropic distillation,salt distillation,pressure swing distillation and reactive distillation.In view of the insufficient research on vapor-liquid equilibrium of aqueous solution containing isopropanol in salt rectification,this paper establishes a design method for eutectic solvent separation of isopropanol and water.Vapor-liquid equilibrium data containing eutectic solvent,isopropanol and water were also determined.In addition,the experimental data were correlated using the NRTL model.At the same time,the binary interaction parameters of the NRTL model are obtained.The main research contents are as follows:(1)Based on the conductor like screening segment activity coefficient(COSMO-SAC)model,a database of choline chloride eutectic solvents for the separation of isopropanol from water was established.The influence of the deep eutectic solvents(DESs)with choline chloride on separation were explored by σ-profile analysis.On the basis of the analysis of the a-profile,2 kinds of DESs were selected as a good solvent for separating isopropyl alcohol and water.Then,the distribution selectivity(S),capacity(C)and performance index(PI)of the DESs at room temperature(298.15K)were predicted as the screening standard.(2)The isobaric vapor-liquid equilibrium(VLE)for the DESs,IPA and water were studied experimentally.The results indicated that the relative volatility of isopropanol to water increased by adding the DESs.With increasing the concentrations of the DESs,the azeotropic point of the system IPA+water moved.Meanwhile,correlation calculation the phase equilibrium data and the model parameters are obtained by using the NRTL model,which provides a basis for the separation process design.(3)The bond energy calculation and interaction energy calculation between the DESs/IPA and DESs/water were explored by molecular simulation and quantum chemistry calculation,and the hydrogen bonding between DESs/IPA and DESs/water was determined.