The catalyst-free synthesis of NMP from 1.17-butyrolactone and methylamine was developed by E. Space in 1936. 2. At present, NMP production enterprises in China also adopt the process of synthesizing NMP without catalyst from 7-butyrolactone and methylamine. The catalytic synthesis of NMP from y-butyrolactone and methylamine was carried out in two steps. In the first step, 7-butyrolactone and methylamine were ammonolysed to form 4-hydroxy-1-N-methylbutyramide at 115 C. In the second step, the product was dehydrated to form NMP at 250 C and pressure of 5.88 MPa for 3 h. The final product was obtained by concentration, decompression, dehydration and distillation. P, the yield was 90%. The two reactions can be carried out intermittently in an autoclave reactor or or in a tubular reactor with a yield of 94% when the reaction time is 2 h. The gas-phase catalytic synthesis of NMP can be carried out at atmospheric pressure, and the reaction time is shortened. The requirement for equipment is greatly reduced, and the energy consumption is greatly reduced. It has good development value. 7. The process of synthesizing NMP from monobutyrolactone and methylamine without catalyst requires higher temperature, pressure and longer residence time. The selection of equipment, operation and control of the process all put forward higher requirements, thus increasing investment. 1.2 Gas-phase catalytic synthesis of NMP4J has developed a process for synthesis of NMP under atmospheric pressure using solid acid Mgo-SiO as catalyst, 7-butyrolactone and methylamine as raw materials. The reactor is a 430 glass tubular reactor made by ourselves. It can be heated by resistance wire. The mixture of 7-butyrolactone and methylamine aqueous solution filled with catalyst is controlled by a micro metering pump. It enters the reactor in the form of liquid phase. Nitrogen is used as inert gas for dilution, and the reaction is measured by a micro-gas metering meter. Device. Ceramic materials were filled in both upper and lower stages of the reactor, and the upper filling stage was long enough to serve as a preheating stage to ensure that the reaction proceeded in the gas phase. After the reaction, the product was collected by condensation, and the uncooled methylamine was absorbed by hydrochloric acid aqueous solution. When the molar ratio of methylamine to butyrolactone is 1.35, the reaction temperature is 260-270 (?) 1.3 NMP was synthesized by electrolysis using N-methylsuccinimide as raw material, trichloromethane as extractant, 20% (mass) sulfuric acid as medium, and lead as electrode. The process of electrolytic synthesis of NMP is as follows: adding 20% sulfuric acid in cathode pool, adding raw material N-methyl succinimide (white crystallization), and pouring 20% sulfuric acid into anode barrel, so that the liquid level of cathode and anode is basically the same. Condensate water is introduced and ice bath is added to maintain a certain reaction temperature. Start the magnet agitator, connect the anode plate to the DC regulated power supply, and electrolyse for 2 hours with the current of 0.03A/m2. The electrolyte was poured into the separating funnel and extracted three times with equal volume of trichloromethane. The electrolyte was fully stationary and separated. The filtrate was distilled at atmospheric pressure and the solvent was basically evaporated and then changed to vacuum distillation. The yield of NMP is over 70% and the purity of the product is over 97%. The essence of the electrolytic synthesis of NMP from N-methylsuccinimide is the catalytic reaction on the surface of the electrode. The negative electrode of the electrolytic cell undergoes reduction reaction to form atomic hydrogen: H+e-H and then reduces organic compounds by atomic hydrogen. The chemical reaction formula is as follows: N-methylsuccinimide is used as raw material to synthesize NMP by electrolysis in