Method for increasing yield of single stage crystallizing N-vinylpyrrolidone

N-vinylpyrrolidone (NVP) is a monomer used for making different grades of polypyrrolidones. The purity of NVP mostly affects the quality of produced polymer. Obtaining the pure NVP is done by crystallization. Multi stage crystallization process is costly and time consuming. Hence by controlling the concerned parameters in liquor freezing and consequently melting step can increase the yield of single stage crystallization and avoid the cost of continuous process. Experiments are done on the main involved parameters in crystallizing of produced NVP by HEP process, such as various impurities concentration in liquor, PH, added inhibitor, water percentage and the rate of cooling the liquor to prepare a method for increasing the yield of single stage crystallizing NVP. The experiments are done in pilot plant, and the final results are performed on scaled up crystallizer of RTC co.

کلیدواژه ها:

Crystallization ، NVP ، single stage ، temperature regime