Process for producing diamines

摘要

A process for producing diamines which comprises the steps of: (1) reacting a dialdehyde with ammonia and hydrogen in the presence of an alcohol and a hydrogenation catalyst to synthesize the corresponding diamine; (2) separating and recovering the alcohol by distilling the reaction mixture obtained by the step (1); (3) separating the diamine by purifying the distillation residue obtained by the step (2); and (4) feeding at least part of the alcohol recovered in the step (2) to step (1); said step (1) comprising maintaining the amount of ammonia at a level of at least 200 moles per mole of the primary amine that has formed in the step (1) and accumulated in the reaction vessel for step (1). The process can produce diamines commercially advantageously and in high yields, the diamines having little impurities.