| N-vinylpyrrolidone (NVP) is an important chemical raw material that can be used as solvents or additives in the plastics, paper, wood, ink and other materials. The polyvinylpyrrolidone (PVP) which is synthesized by NVP is widely used in food, cosmetics and pharmaceutical industries with increasing need.Acetylene method is the most widely used in industry among varieties of synthesis methods of NVP which use 2-pyrrolidone reacting with acetylene under base catalyst to generate NVP at high temperature. Although the method has low cost and high yield, it is necessary to design production process conditions to optimize its security because of the generally low yield and the high reaction temperature. This article first explores the reaction conditions of acetylene method in lab level, followed by the relevant pilot design on its basis. The main contents are as follows:1. Use 2-pyrrolidone to react with acetylene by strong base catalyst to generate N-vinylpyrrolidone in laboratory. The influence of different catalysts and a small amount of water on reaction were investigated. The addition of polyether and purity of acetylene were also studied. The effect of reaction conditions on yield such as temperature and gas pressure was explored and optimized. Under the optimized conditions with 180℃ and 0.75MPa acetylene gas pressure, using pyrrolidone potash as catalyst and with vacuum dehydration, the yield of NVP can reach 84.7%. In addition, the cycle usage of system was also researched.2. The 100 tons N-vinylpyrrolidone pilot production process which includes purity of acetylene, preparation of the catalyst, synthesis of NVP, and refined of NVP four stages was designed according to the results of a small trial in former chapter. Process flow diagrams have also been given. And key equipment, such as the main reactor, distillation column was focused on to design and optimize. The purity of the produced NVP reached 99.8% and the yield was up to 68%, higher than the national average level. |
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