The n-vinyl caprolactam (NVCL) product can be used as a monomer unit in oligomers, polymers and copolymers. It has thus been found to be useful, for example, in the production of paper coatings, adhesives, printing inks, detergents, engine oil additives, textile auxiliaries, radiant solid surface coatings, cosmetics, pharmaceuticals, auxiliaries for oil production or chemicals for photographic use.
Poly n-vinylcaprolactam is a temperature sensitive polymer having a low critical phase transition temperature (LCST). Its LCST is just in the physiological temperature range (30-40 ° C), which makes its research on the application of biological and medical herbs gradually developed. Therefore, a reasonable and feasible production process route, and ultimately the production of quality products, and occupy the market is very important.
There are many reports on the synthesis of n-vinyl caprolactam in tunnels, but the current mature industrial production method is: acetylene liquid phase addition.
According to the research, it was found that in the vacuum nitrogen reflux reductive step, the effect of dehydration is difficult to control. During the purification process of the product, this part of the distillation column has a large investment, and the product needs to be crystallized and purified. There are patent protections in the United States and Japan, so there are related problems when industrializing.
According to the actual conditions of the n-vinylcaprolactam engineering, the method of crystallization is used in the purification process of the product by means of solvent dehydration in the dehydration step. The synthetic route is as follows: