General procedure for the synthesis of 2-(cyclohexylimino)ethyl chloride hydrochloride from 1-(2-chloroethyl)azepane: 165.9 g of isopropanol was added to the reaction system, and dry hydrogen chloride gas was slowly vented under stirring until the pH of the reaction system was ≤2.5 when the venting was stopped. The reaction mixture was heated to a maximum of 80 °C with continuous stirring for 30 minutes. Subsequently, 2.8 g of activated carbon was added and stirring was continued for 30 minutes. Upon completion of the reaction, thermal filtration was performed to remove the activated carbon. The filtrate was cooled to 0-5°C and left to crystallize for 8 hours. Upon completion of crystallization, the solid product was collected by filtration and dried to give 53.1 g of N-(2-chloroethyl)hexamethyleneimine hydrochloride in 84.5% yield. The purity of the product N-(2-chloroethyl)hexamethyleneimine hydrochloride was tested to be 98.6%.
