| Ethylene glycol diacetate?EGDA?is not only a safe and efficient environmental protection organic solvent but also can be used as a new solvent plasticizer,which has a wide application prospect in industry.The synthesis of ethylene glycol diacetate is mainly by the direct esterification of ethylene glycol and acetic acid,so the current research on ethylene glycol diacetate is mainly focused on searching for and using"environment-friendly catalyst"to catalyze the esterification.However,the separation of ethylene glycol and ethylene glycol diacetate azeotrope in the product system was seldom studied,and toluene was often used as extractant to separate the azeotropic system.Because toluene is not suitable for large-scale use as extractant,the selection of new extractant is very important.In this paper,water is used as extractant to separate mixed solution of ethylene glycol and ethylene glycol diacetate.In this paper,the system of water-glycol diacetate and sodium chloride and calcium chloride with different contents are determined.The liquid-liquid equilibrium data of salt-containing potassium chloride system were studied.The liquid-liquid phase equilibrium relationship of water-ethylene glycol diacetate system and the effect of salt effect on the phase equilibrium relationship of the water-glycol glycol diacetate system were studied.In this paper,the liquid-liquid equilibrium data of water-glycol-ethylene glycol diacetate system and its salt containing system were determined by liquid-liquid equilibrium kettle method,and the triangular phase diagram of the system was plotted according to the measured experimental data.From the experimental results,the addition of salt can significantly increase the area of the two-phase region in the phase diagram.With the increase of the concentration of salt in the water phase,the area of the two-phase zone increases,and the effect on the area of the two-phase zone is NaCl>CaCl2>KCl.The liquid-liquid equilibrium data obtained from the experiment are verified by Othmer-Tobias equation hand equation and Bachman equation,and the correlation coefficient R 2 of the correlation between Othmer-Tobias equation and Hand equation is R 2?0.9890,which shows a good correlation.At the same time,NRTL model and UNIQUAC model are used to correlate the experimental data.The binary interaction parameters between the components of the system and the regression calculated values of the liquid-liquid equilibrium data.The RMSD absolute deviation of the NRTL model is not greater than 1.228%,while the RMSD absolute deviation of the UNIQUAC model is not greater than 2.598%.The model can be used to correlate the experimental data well,and NRTL model is more effective than UNIQUAC model. |
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