The following is a description of the synthesis of n-vinylcaprolactam non-acetylene:
1. Alcoholamine dehydration method
The r-butyrolactone and ethanolamine are put into an autoclave, added with water and nitrogen, and reacted at 260 ° C and 30 MPa to obtain β-hydrocarbyl pyrrolidone, and then catalytically dehydrated to obtain vinyl pyrrolidone. The method has high yield, and the n-vinyl caprolactam product has high purity and has been industrialized abroad.
The method has the advantages of less waste, good selectivity and easy regeneration of the catalyst, and is an ideal synthetic method. The technical difficulty is the selection and production of high-efficiency catalysts.
2. Ether exchange and transesterification
The vinylated raw material is subjected to an ether exchange reaction with butyl vinyl ether or transesterified with vinyl acetate to obtain a vinylpyrrolidone. The yield of n-vinylcaprolactam is relatively high, and the reaction conditions are mild, but the separation and purification process of the product is complicated, and the by-products, butanol and acetic acid, are produced, and the industrialization cost is high, which is only suitable for theoretical research.
The above two methods are an overview of the content of the n-vinyl caprolactam non-acetylene synthesis method.