Screening And Experimental Study On Ionic Liquids For Extraction And Separation Of Thioglycolic Acid And Water

Thioglycolic acid(TGA)has a wide range of applications such as functional cosmetics,organic synthetic materials,corrosion inhibitor dressing agent etc.At present,the extractant used for separation of thioglycolic acid and water is mainly conventional organic solvents,such as ethers,ketones,lipids and so on.And there are many problems,such as low extraction capacity,environmental pollution,and recovering difficulties.Thus,it is necessary to investigate the green separation method of the thioglycolic acid reasonably and efficiently.This thesis aims at the efficient separation of thioglycolic acid and water.And the design and selection method of ILs extracted and separated by TGA and water were established.At the same time,the liquid-liquid equilibrium(LLE)data for the systems containing ILs,TGA and water were determined.The NRTL model was used to calculate the phase equilibrium and the binary interaction parameters.Then,the separation mechanism was explored.The main research contents are listed as follows:(1)Based on the conductor like screening segment activity coefficient(COSMO-SAC)model,the structure database of 30 kinds of cations and 30 kinds of anions were established for the separation of TGA and water.Based on the analysis of the ?-profile,the effects of the main structure of the cations,the carbon chain structure of cationic alkyl substituent,and different types of anions to the influence of extraction were explored.On the basis of the analysis of the ?-profile,12 kinds of anions and 5 cations were selected as the extractants for the separation of TGA and water.Then,the distribution selectivity(S),capacity(C)and performance index(PI)of the above 60 ionic liquids composed of 12 anions and 5 cations at room temperature(298.15K)were predicted as the screening standard.(2)The liquid-liquid phase equilibrium for the ILs,TGA and water were studied experimentally,the separation ability of these ILs were investigated by calculating the selectivity and distribution coefficient of the corresponding systems.Meanwhile,the parameters of the models were obtained by using the NRTL model.(3)The bond energy calculation and interaction energy calculation between the ILs/TGA and ILs/water were explored by molecular simulation and quantum chemistry calculation,and the hydrogen bonding between ILs/TGA and ILs/water was determined.