This invention provides a convenient process for the preparation of monoacylhydrazines from carboxylic acids or their salts and hydrazine or substituted hydrazine in the presence of a 1,3,5-triazine substituted with at least one chloro or fluoro. The resulting monoacylhydrazine can further be converted to a diacylhydrazine by effectively either repeating the reaction or through reaction with a carboxylic acid chloride.