Method for preparing hexamethylenediamine

Abstract

This invention discloses a method for preparing hexamethylenediamine, comprising the following steps: (1) under ammoniation reaction conditions, optionally in the presence of a solvent, subjecting hexanediol and ammonia to an ammoniation reaction to obtain an ammoniation reaction product; (2) separating and obtaining from the ammoniation reaction product a stream containing hexamethyleneimine and water, dehydrating the stream containing hexamethyleneimine and water to obtain a dehydrated stream containing hexamethyleneimine, and returning at least part of the dehydrated stream containing hexamethyleneimine as a circulating stream to the step (1), wherein a water content in the dehydrated stream containing hexamethyleneimine is less than 3 wt %, preferably less than 1.5 wt %. The invention can not only improve the yield of hexamethylenediamine but can also prolong the service life of the catalyst.

Dependencies are inferred from the claim text.