Zirconium (IV) Molybdo Tungstate- Application as Catalyst for the Synthesis of an Ester

Abstract

Aims: The research work is based on the kinetic study of the esterification reaction of benzoic acid with alcohol by using zirconium molybdo tungstate and conventional catalyst (sulphuric acid). Study Design: The study was designed to compare the results of both the catalysts under similar conditions. Place and Duration of Study: Department of Chemistry, M. M. University, Mullana (Ambala) India during June – December, 2012. Methodology: An amorphous heteropolyacid salt named zirconium (IV) molybdo tungstate (ZrMoW), having 0.61 meq/g ion-exchange capacity was synthesized. Characterization ­­­as ion exchanger was done on the basis of physicochemical techniques.  Then the prepared sample was tried as catalyst for the esterification reaction of benzoic acid with 1-propanol and iso-propanol. The results were compared with the conventional acid catalysts under the similar conditions. Results: The synthesized material was examined in different acidic and basic media, certifying its long range chemical stability. The compound is thermally stable, as only 17.67% weight decreased up to 2000C. Increase in the concentration of the catalyst accelerated the rate of esterification. The esterification of the benzoic acid with iso-propanol didn’t give any appreciable yield. The catalyst can be regenerated and reused again and again without any significant loss in the % yield i.e. only 10-15% even after 5 regenerations. Conclusion: Esterification of benzoic acid with alcohol was carried out over ZrMoW catalyst and the results clearly demonstrated that zirconium (IV) molybdo tungstate represents a better catalytic system as compared to conventional acid catalysts. From the kinetic study, inference was drawn that ZrMoW has got higher initial rate. It has been found that ZrMoW is admirable catalyst for the above esterification reaction.