The Purification Of The N-Methyl Pyrrolidone

In this paper, it presents the application of ion exchange technology and batch distillation technology into the purification of NMP, using ion exchange resin to desalt, adsorbing impure ion in NMP, and separating water in NMP with batch distillation method. This paper optimizes operating conditions of the two experiments, confirms a better technological parameter, obtains NMP of higher quality and provides reference for industrial applications.Using cation exchange resin, strong acidic styrene(001×7), D001 strongly acidic styrene type macroreticular cation exchange resin, Amberjet 1200Na, strongly basic styrene type anion exchange resin 201×7, D202strongly basic styrene typeⅡmacroreticular anion exchange resin and Amberjet 4200C1 in ion-exchange adsorption, through the static, dynamic adsorption experiments and the desorption experiment, the optimum resin was selected and the amount of resin, adsorption time, sequence, the influence of flow for adsorption effect was studied. The experimental result shows that D001 macroreticular cation exchange resin and D202 macroreticular anion exchange resin are the optimal in the NMP system treatment. Actual exchange amount is 7.5×10-3g/ml, the ratio of cation resin to anion resin 2:1, the stirring rate 700 r/min. In the dynamic adsorption experiment,1LNMP needs 50g cation resin,25g anion resin, flow rate 60ml/min. First through the cation resin, then the anion resin, after 3 cycles, the reaction time is about 50min, and the conductivity of NMP drops from 2.67us/cm to 0.09us/cm.The distillation experiment first determines the Vapor-liguid equilibrium data for the NMP-H2O system, based on the Corresponding State Group Contribution, the NMP saturation vapor pressure data is estimated, and then with the thermodynamic calculation method, liquid activity coefficient of water and NMP can be educed. The experimental data is correlated with the Wilson model to obtain the Wilson binary interaction coefficient, conducting the thermodynamic consistency test, and the result meets the requirements of Herington thermodynamic consistency, which can attest the reliability of the Vapor-liguid equilibrium data. Then, using the Vapor-liguid equilibrium data to direct rectification design, the comprehensive separation effect and its yield, determines the optimum reflux ratio of this system is 2:1, and testing under this condition, the test result accords with the requirements of separation and theoretical calculation, which also proves the correctness of theoretical computation. The enhanced NMP is obtained, with conductivity less than 0.1 Ous/cm and water content less than 300ppm. Finally, I make industrial design for the whole purification process and lay a preliminary foundation for the realization of industrialization.