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Vapor-liquid Equilibrium Separation Of Simulation Studies And 3,5-dichloro-aniline Distillation System

Posted on:2014-08-07Degree:MasterType:Thesis
Country:ChinaCandidate:Y X LiFull Text:PDF
GTID:2261330425956440Subject:Applied Chemistry
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3,5-Dichloroaniline (3,5-DCA, CAS NO.626-43-7) is an important organic intermediate for the synthesis of agricultural fungicides, herbicides, insecticides and plant growth adjusting agents, it is also used for the synthesis of quinoline derivatives in medicine. In recent years, more and more attention has been given to the use of3,5-DCA. Research on3,5-DCA have great significance for the development of ring phthalimide agricultural fungicide.The reduction of3,5-dichlorobenzene which now still an important way to manufacture3,5-DCA is the earliest method reported in literature. However, during the production process of3,5-DCA, there are some reactants and by-products remained in the objective product. In order to obtain the high purity of3,5-DCA, it should be separated from its mixture. The method of purification of3,5-DCA commonly used is distillation, and the saturated vapor pressure data is a fundamental data in distillation process. However no reports were made for the saturated vapor pressure data of pure3,5-DCA and binary vapor-liquid phase equilibrium. In order to enrich the basic data of distillation and provide the detailed fundamental data for engineering fields, the saturated vapor pressure ranging from (10.25to95.81) kPa and binary vapor-liquid phase equilibrium for two systems were measured in the present work.(1) The saturated vapor pressure of3,5-dichloroaniline was measured from10.25to95.81kPa with an inclined ebulliometer, the results were fitted by an Antoine equation using a nonlinear least-squares regression method with three Antoine constants A=15.5360, B=5722.3960, and C=-12.1273K, respectively. The ideal gas vaporization enthalpy, ideal gas molar vaporization entropy, average molar vaporization enthalpy as well as average molar vaporization entropy of3,5-dichloroaniline was calculated. The average molar vaporization enthalpy was50.00kJ·mol-1, average molar vaporization entropy was101.76J·mol-1. The relative error of vapor pressure between the experimental values and calculated values of3,5-dichloroaniline was from-0.96%to0.89%. the relative error between literature values and calculated values by Antoine constants obtained from the equation of3,5-dichloroaniline at normal pressure was from0.64%to1.27%, which indicated that the regressed Antoine constants of3,5-dichloroaniline can meet the needs of engineering design. (2) The vapor-liquid equilibrium data for two binary systems of3,5-dichloroaniline (1)+1,3,5-trichlorobenzene (2),3-chloroaniline (1)+3,5-dichloroaniline (2) under the pressure of20kPa,60kPa and101kPa were measured respectively by inclined ebulliometer. The quantitative analysis of components was determined by Agilent Technologies7890A with a FID hydrogen flame ionization detector using the area normalization method. Herington area test method was used to check the thermodynamic consistency for all the experimental data. According to Herington method, the measured vapor-liquid phase equilibrium data for the two systems all passed the thermodynamically consistency test. Based on the obtained Antoine parameters of3,5-dichloroaniline, the data of vapor-liquid equilibrium were correlated by UNIQUAC model, NRTL model and Wilson model with interaction parameters, and the model parameters were acquired. The calculated results have good agreement with the experimental values for the two systems of1,3,5-trichlorobenzene (1)+3,5-dichloroaniline (2) and3-chloroaniline (1)+3,5-dichloroaniline (2) under pressure of20kPa,60kPa and the lOlkPa, the correlation results are satisfactory. As for the1,3,5-trichlorobenzene (1)+3,5-dichloroaniline (2) system, the regression results under20kPa by the Wilson model were better; however for the vapor-liquid phase equilibrium data under60kPa and101kPa, the regression results by the UNIQUAC model were better. As for the3-chloroaniline (1)+3,5-dichloroaniline (2) system, the regression results of the three models under20kPa were about the same, the results under60kPa and101kPa were better with the UNIQUAC model. In conclusion, the regression results of the two binary systems under three pressures with UNIQUAC model were better than those with the NRTL and Wilson models.(3) The separation process of3,5-dichloroaniline via distillation was designed and simulated using Chemcad software. The influence of the reflux ratio, the theoretical stage, the feed stage, the feed temperature, the operating pressure of the top column, the distillate heat duty and the bottom heat duty on the distillation process of3,5-dichloroaniline were studied and the optimum process conditions were obtained. The distribution of temperature, the total vapor flow rate and total liquid flow rate, the composition distribution of each component in the liquid phase as well as the vapor phase in every tower stage were obtained under the optimum operation conditions. The composition of3,5-dichloroaniline exceed99.4%in mass fraction.
Keywords/Search Tags:3,5-dichloroaniline, saturated vapor pressure, vapor-liquid equilibrium, UNIQUAC model, NRTL model, Wilson model, distillation simulation
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