Purification of 2-Pyrrolidone by Falling Film Melt Crystallization

Industrial grade 2-pyrrolidone with a purity of 99.5% is produced by aminolysis of gamma-butyrolactone and subsequent fractional distillation, but it still contains trace amounts of gamma-butyrolactone and other impurities. Falling film melt crystallization was applied for further purification of 2-pyrrolidone from 99.5% to a very high purity. The effects of the precooling temperature, feed rate, cooling rate, final crystallization temperature, heating rate, and final sweating temperature on the purity and yield of 2-pyrrolidone were studied. 2-Pyrrolidone was purified by falling film melt crystallization to a purity and yield of more than 99.9 and 73.3%, respectively. The mathematical model of falling film crystallization was applied for simulation of the crystal layer growth of 2-pyrrolidone. The simulated average thickness of the crystal layer was in good agreement with the experimental values, demonstrating the applicability of the model to falling film crystallization of 2-pyrrolidone.

Automated summary

Industrial grade 2-pyrrolidone with a purity of 99.5% can be further purified to a very high level using falling film melt crystallization. Controlling factors such as precooling temperature, feed rate, and cooling rate can impact the purity and yield. Mathematical modeling of the crystallization process can accurately simulate the growth of the crystal layer, providing valuable insights for process optimization.