Views: 5 Author: Site Editor Publish Time: 2023-05-09 Origin: Site
N-Methylpyrrolidone (NMP) is a non-protonic solvent with the advantages of strong polarity, high boiling point, low viscosity, low volatility, thermal and chemical stability, etc. It is widely used as a solvent in many fields such as lithium-ion battery manufacturing, polymer synthesis, electronic chemicals, insulating paints, etc.
According to the source, NMP can be divided into two categories, synthetic NMP and recycled NMP. Synthetic NMP is a new product made by chemical synthesis. The condensation of γ-butyrolactone (GBL) with monomethylamine to make NMP is the current synthetic route for industrial production; recycled NMP is a recycled product after the recovery and refinement of NMP used as a solvent.
In the synthesis of NMP, the vast majority of manufacturers use the route of dehydrogenation of 1,4-butanediol (BDO) to GBL, followed by ammoniacal condensation to NMP, while only Mitsubishi Chemical uses the route of hydrogenation of maleic anhydride to GBL, followed by ammoniacal condensation to NMP globally.
There are two main modes of recycling NMP: one is for NMP users to recycle themselves, forming an internal cycle, and the other is to commission manufacturers to refine, or to purchase refined NMP products from manufacturers. Among the NMP producers, there are both those specialising in synthetic or recycled products, and those with both synthetic and recycling capabilities. As the recycling process of NMP requires simple equipment, the technical difficulty is low, easy to obtain and the investment amount is small.
NMP has been industrially produced earlier and the production process is technically mature. From the perspective of major NMP producers worldwide, the condensation of GBL with monomethylamine to produce NMP is currently the only industrialised technical route. According to the different reaction conditions, it can be divided into two types: non-catalytic reaction and catalytic reaction, of which the former is the production process adopted by most manufacturers.
The condensation of GBL with monomethylamine under catalyst-free conditions to produce NMP was first developed by E. Spath et al. in 1936 and then industrialised by BASF in Germany and GAF in the USA, and is the most widely used NMP production process to date. In 2008, Irisu Chemical was the first to develop a catalytic synthesis process using ZSM molecular sieves, which can moderate the reaction conditions to a certain extent.
On the domestic front, Sinopec has developed a process technology for the preparation of NMP from BDO dehydrogenation-ammoniation using Cu-Zn-Cr-Zr as the catalyst. Despite the obvious advantages of the catalytic process, there are few industrial applications due to some unresolved engineering issues (e.g. catalyst lifetime, etc.).
In 2022, the global synthetic NMP production capacity is 687,000 tonnes/year. The total overseas production capacity is 155,000 tonnes/year, accounting for 23% of the total global synthetic NMP production capacity. Major producers include BASF (70,000 tonnes/year), Ashland (25,000 tonnes/year), Mitsubishi Chemical (25,000 tonnes/year), Leander Basell (20,000 tonnes/year) and Balaji Amines India (15,000 tonnes/year).
In 2022, China's synthetic NMP production capacity will be 532,000 tonnes/year, accounting for 77% of the total global synthetic NMP production capacity. At present, there are 16 synthetic NMP producers in China, of which 8 have a synthetic capacity of 30,000 tonnes/year and above, with a total capacity of 427,000 tonnes/year, accounting for 80.3% of the total synthetic NMP capacity in China, and the industry is highly concentrated. The representative production enterprises include Changxin Chemical, Zhongrun Chemical, Binzhou Uneng, Mackie Chemical, Jingrui New Energy, etc.
Most of the synthetic NMP producers in China have NMP recycling and processing capacity, and the business model of recycling NMP is mainly incoming processing, supplemented by incoming processing. 2022, there are about 9 producers with both NMP synthesis and recycling processing capacity in China, and the total recycling capacity is 375,000 tons/year.
Driven by high growth in downstream consumption, the scale of production capacity for synthetic and recycled NMP in China will continue to expand at a high rate, with explosive growth in domestic NMP production by 2025.
