Preparation of N,Ní»-dicyclohexylurea

Abstract

The invention discloses a method to prepare N,N`-dicyclohexylurea. The method takes carbamide and cyclohexane as material and water as solvent; a stirring device, a heating device, a reflux device and a water separating apparatus are arranged inside a reactor; the mixture is stirred and heated to flow back and the phegma flows into the water segregator; the azeotropic liquid in the water segregator is gradually discharged; with the reduction of the water, the temperature of the reaction gradually rises and when the temperature rises to 180-240 DEG C, the reaction will be continued for 10-30 min at this temperature, producing N,N`-dicyclohexylurea. The method greatly shortens preparation period with a yield over 95%, and meanwhile the method requires no organic solvent.

Description

technical field [0001] The invention relates to a preparation method of N, N'-dicyclohexylurea, an intermediate of N, N'-dicyclohexylcarbodiimide. Background technique [0002] N,N'-dicyclohexylurea is an intermediate for the preparation of N,N'-dicyclohexylcarbodiimide. Due to the cumulative diene structure in the N,N'-dicyclohexylcarbodiimide molecule, it has strong chemical activity and can not only react with many acidic compounds such as carboxylic acid, hydrocyanic acid and hydrogen sulfide, but also It can react with alcohols, amines and a class of compounds containing active hydrogen such as active methylene, so it has been paid more and more attention by people. However, the disadvantage of the previous preparation method of the intermediate N,N'-dicyclohexyl urea is that the reaction time is long, usually more than 20 hours, which increases the production cost of the product. [0003] The current preparation method of N, N'-dicyclohexyl urea is to prepare N, N'-d...

AI Technical Summary

Problems solved by technology

However, due to the poor miscibility between urea, cyclohexylamine and solvent isoamyl alcohol, urea and cyclohexylamine are not easy to react.