Study On Extractant For Separating N-ethylethylenediamine And Ethylenediamine Azeotrope System By Extractive Distillation

Based on modified UNIFAC model and with MATLAB software,a program has been developed used to select extractant for separating azeotrope system by extractive distillation, analysis conditions of extractive distillation and calculate vapor-liquid equilibrium of multi-component system. According to the vapor-liquid equilibrium experimental data of binary systems and ternary systems such as ethanol-water system and cyclohexane - benzene - methylene chloride system in literature, the average relative error between calculated results and the data in literature are 1.70% and 6.59% respectively, while the average relative deviation of relative volatility for cyclohexane - benzene - dichloromethane ternary system is only 1.94%. These showed that the program has good reliability and applicability.By this program, through the calculation of relative volatility of ethylenediamine and N-ethylethylenediamine azeotropic system in different conditions with different extractants, we found that the suitable extractants are ethylene glycol, glycerol and nitrobenzene, in which glycerol is the best. At the same time, we discussed the effect of different raw material compositions and solvent ratio on the relative volatility. The results showed that solvent ratio was one of the most important factors. The bigger the solvent ratio was, the greater the relative volatility of separated system was, while the effect of raw material composition on relative volatility was weak. The relative volatility of system changed slightly while the content of hard component increased.In addition, different extractant had different characteristics in extractive distillation for ethylenediamine and N-ethylethylenediamine azeotropic system. When ethylene glycol and glycerol were extractans, the N-ethylethylenediamine was volatile component, while nitrobenzene was the extractant, the ethylenediamine was the volatile component. The solvent ratios below 15 had greater effects on ethylenediamine-N ethylethylenediamine azeotropic system...