Abstract
Dicarboxylic acid dihydrazides are widely used as pharmaceutical intermediates, plant growth regulators, water-based coating additives, epoxy crosslinking agents. Dihydrazides are prepared by adding hydrazine hydrate to an acid halides and diesters. In this work the hydrazinolysis of succinic acid was studied using various ion exchange resins as catalysts, and the optimum conditions and the reaction mechanism were identified. Analysis of the initial reagents and the target product were performed out using photocolorimetric and IR spectroscopic methods, the composition of the target product was determined by elemental analysis. Hydrazinolysis of succinic acid were performed in aqueous medium in the temperature 90 °C for 3 h. Succinic acid conversion was 82–95 %, and the succiniyldihydrazide yield 61–93 %. It has been shown the efficient catalysts for the hydrazinolysis of succinic acid are AV-17-8, AN-31 and AN-1 anion exchangers. The highest succinyldihydrazide yield (93 %) was obtained with anion exchanger AV-17-8. On the basis of IR spectroscopic studies, a plausible process mechanism was suggested. A probable mechanism of the process with the formation of supramolecular complexes with the participation of substrates and fixed polymer-bound quaternary ammonium and hydroxyl ions of the anion exchanger was proposed. Thus, the most efficient method of succinic acid dihydrazide preparation has been proposed in comparison with known methods.