Ultrasound-assisted improved synthesis of supported V2O5 catalyst and subsequent application for the production of n-hexyl acetate

• First depiction of the improved synthesis of supported V2O5 using ultrasound.
• Use of ultrasound and PVP helps in obtaining catalyst with smaller size.
• Application of the synthesized catalyst for esterification reaction.
• Use of ultrasound in the reaction also significantly intensifies the reaction.

The present work deals with synthesis of vanadium pentoxide supported on alumina as a heterogeneous catalyst using two approaches as conventional synthesis based on ozonation and intensified approach based on combination of ultrasound with ozonation. Commercially available vanadium sulfate hydrate has been used as a precursor for the catalyst synthesis. The catalyst characterization has been performed in details using particle size, FTIR, SEM, EDX and XRD analysis. It has been observed that the ultrasound assisted approach for catalyst synthesis resulted in reduced particle size and also increased the stability of the synthesized catalyst nanoparticles. The obtained catalyst was further used in the reaction for synthesis of n-hexyl acetate with detailed investigation into the effect of operating parameters. The optimum conditions established for the esterification were molar ratio of alcohol to acid as 6:1, catalyst concentration of 1.5% by weight, temperature as 70 °C and ultrasonic power dissipation as 100 W with duty cycle of 80% and an irradiation time of 150 min. The efficacy of the ultrasound assisted approach for the esterification has also been compared with the conventional approach. The ultrasound assisted operation improved the conversion from 53.33% obtained in the conventional processing to 80.38% with a reduction in operating temperature of the reaction from 100 °C for the conventional approach to 70 °C for the ultrasound assisted approach. The work has clearly elucidated the beneficial effects that can be obtained by the use of ultrasound in both catalyst synthesis as well as catalytic reactions.