The synthesis of NMP is described in detail

NMP mainly uses the BDO method to synthesize γ-butyrolactone, and then reacts with methylamine to generate NMP. This route is a relatively mature and reliable technical production route at present.

The industrialization of this method takes a long time, the technology continues to mature, and the output is large 1 methyl 2 pyrrolidone. The main research uses copper-based catalysts, adding zinc, aluminum, chromium, manganese and other co-catalysts to improve the activity and selectivity of student reactions. The catalyst can be used more conveniently and has a long life. , low cost, 1,4-butanediol conversion rate reaches 98%, selectivity 95%, yield > 90%, the economic market competitiveness analysis of this technology mainly depends on the raw material 1,4-butanediol of the enterprise price and source.

The biggest advantage is that it is not limited by the hydrogen source, and hydrogen is produced as a by-product nmp. The scale of the production enterprise can be large or small, and the basic organic food raw material 1,4-butanediol can be used for production. For manufacturers who need to further improve production and various fine chemicals using γ-butyrolactone as raw material more appropriate.

γ-butyrolactone process flow

Feed 1,4-butanediol is pumped into the 1,4-butanediol heater through a metering pump, heated to a certain temperature by heat conduction oil, and mixed with circulating hydrogen before entering the static mixer. After being fully mixed, it enters the mixing heater nmp solvent. After heating to a certain temperature, the 1,4-butanediol is completely vaporized, enters the heavy matter separator, and then enters the dehydrogenation reactor for dehydrogenation reaction. The temperature and pressure are controlled to a certain extent. After the reaction is completed, the product and the circulating hydrogen in the product hydrogen heat exchanger exchange heat. After the heat exchange is completed, the product enters the product cooler. After the circulating water is cooled, it enters the gas-liquid separator. There, the reaction product and hydrogen are separated, and the reaction product flows into the original product storage tank. The hydrogen separated by the gas-liquid separator, a small amount of high-altitude discharge or after purification treatment, enters the hydrogen device. After pressurization, the remaining large amount of hydrogen enters the hydrogen compressor. After pressure, it enters the product hydrogen heat exchanger, and the reaction product enters the hydrogen heater after heat exchange, and heats the 1,4-butanediol mixture to the static mixer for circulation. The crude product γ-butyrolactone is pumped into the azeotropic column to remove light impurities, and then into the product distillation column to obtain high-purity products.

NMP process flow

The γ-butyrolactone and 40% methylamine aqueous solution in the raw material are pumped into the steam preheater at a certain molar ratio by the metering pump at the same time, and then enter the static mixer. After being fully mixed, it enters the amination reactor. At a high temperature of 230 ~ 260 °C and a pressure of 7.0 ~ 8.0 mpa, the product is cooled by the product cooler and then enters the constant pressure box. The bottom of the constant pressure box is transformed into a positive pressure, and then enters the untreated nuclear waste storage tank, and then pumped into the deamination tower for deamination, and the monomethylamine aqueous solution with a concentration of about 30% is drawn from the top of the deamination tower into the recovery tank, reaching After a certain amount, it reacts in the amination synthesis section, the tower effluent enters the dehydration tower for dehydration, the tower top water enters the sewage treatment system, the tower kettle effluent enters the middle section tower for rectification, and the liquid from the middle fraction tower enters the product tower for rectification and extraction. The product is put into the product storage tank, enters the filling workshop for filling, and after the residual liquid is discharged from the bottom of the tank, it is recycled or incinerated by a qualified recycling company.

Foreign technical situation

NMP is mainly synthesized from γ-butyrolactone (GBL) and monomethylamine (MMA), and NMP is also synthesized from γ-butyrolactone and mixed methylamines. The catalyst-free synthesis of NMP from γ-butyrolactone and methylamine was developed by E. Spath et al. in 1936, and German companies, American companies, and Japanese companies have all established NMP production facilities. The production routes of Γ-butyrolactone are different. German and American companies use 1,4-butanediol to produce γ-butyrolactone, while Japanese companies use high-pressure hydrogenation of maleic anhydride to produce γ-butyrolactone.