Commercial manufacture of swep is based on a straightforward carbamate forming sequence: producers first generate the key aromatic amine, 3,4 dichloroaniline, then react it with methyl chloroformate (or an equivalent carbamoylating agent) under controlled, typically alkaline, conditions to form the carbamate linkage. The process is optimised to minimise side reactions such as over acylation or hydrolysis, and the resulting crude product is purified by standard solvent based processes and crystallisation to yield technical grade swep.
