Study Of New Technology In Synthesis Of N-Vinylpyrrolidone

N-vinylpyrrolidone(NVP) is an organic synthetic raw material which is mainly applied in preparation of Poly-vinlypyrrolidone(PVP). PVP is a water soluble high molecular weight polymer. It has solubility, membranous form property and protective -glue actions. PVP is widely used as medicine binding agents, cosmetic additives and foodstuff additives.So far, the ways of synthesizing NVP manly include acetylene method and nonacetylene method. A world widely used method of producing NVP is Peppe method in which raw meterial acetylene is treated at high temperature and high pressure. Not only is the reaction condition harsh, the equipments in investment and the energy consumption large, but also exists the danger of acetylene explosion, so the Reppe method suits large-scale production only.The nonacetylene method includes the method of y -butyrolactone, mellow exchange, aether exchange and so on. This subject is mainly about the most prospective Y -butyrolactone method, in which first N-hydroxyethyl-2-pyrrolidone (NHP) is prepared by ammonolysis of r-butyrolactone and ethanol amine, then NVP is gained by direct or indirect dehydration of NHP. This technology has virtues of fower reaction steps and mild operation condition.In this study, first the technology of ammonolysis is studied and improved by using HY molecular sieves as catalyst, and then NVP is gained by direct or indirect dehydration of ammonolysis product NHP. In the indirect dehydration, hydrochloric acid first reacts with NHP, and then sodium hydroxide and its alcohol solution are used to get NVP; In the direct method, NHP is dehydrated directly in gas-phase on HY molecular sieves to get NVP; at the same time, IR, GC, XRD, DSC are adopted to token the reactive intermediates and products and the reactive mechanisms are studied.From the results, the best technology conditions is as follows:(1) The synthesis of NHP: general pressure, HY molecular sieves as catalyst, reaction temperature 185℃, reaction time 12h, molar ratio of Y -butyrolactone and ethanolamine 1:1. The yield of NHP is 88.2% and the selectivity is 96.5%.(2) The indirect dehydration of NHP: a Halide : general pressure, hydrochloric acid as halide, ACl3 as catalyst, heater temperature 150℃, reaction time 4h, molar ratio of NHP and HC1 1:1.2, the yield of NC1P is 87.5%, and the selectivity is 95.3%. b ethylenation: isopropanol as solvent, reaction temperature 65℃, reaction time 3h,molar ratio of NC1P and NaOH 1:1.2, the quantity of solvent NC1P and isopropanol 1:1.5, the yield of NVP is 85.0% and its selectivity is 90.7.(3) The direct method of NHP: At a lower drop rate 6mL/min and a higher vacuum degree 0.092Mpa, HY molecular sieves as catalyst, the size of the catalyst is 80~100mu,reaction temperature 350℃ ±+ 10℃, the yield of NVP is 41.2% and the selectivity is 75.2%.