Kinetics of ultrasound‐assisted esterification of maleic acid and butanol using heterogeneous catalyst

Abstract

The present research investigates the kinetics of ultrasound-assisted synthesis of dibutyl maleate using a heterogeneous catalyst (Amberlyst-15) in solvent-free system. Reaction parameters were optimized based on conversion by varying the various parameters such as n-butanol to maleic acid mole ratio, temperature, molecular sieves, catalyst loading, power, and duty cycle. Optimization of parameters resulted in 56.2% yield at 343 K, alcohol to acid mole ratio as 4:1, catalyst loading of 4%, molecular sieves of 4% with an ultrasound power input of 100 W with 60% duty cycle and 22 kHz frequency. In the presence of ultrasound, the reaction time reduced to 120 min in comparison with 240 min of the conventional process. The experimental kinetic data were correlated using Pseudo-Homogeneous model as well as heterogeneous models like Eley-Rideal model and Langmuir-Hinshelwood-Hougen-Watson (LHHW) model based on single as well as dual-site mechanisms. LHHW (reactants and products) model was found to be the best fit. The results proved that the reaction follows second-order kinetics. The activation energy of the reaction was calculated as 14.64 kJ/mol.

Ultrasound Induced Intensified Synthesis of Tricaprin Using the Homogeneous Acid Catalyst para-Toluene Sulfonic Acid

“…The researchers achieved 89% conversion in 40 min at 45 °C with an optimum power of 200 W, above which the extent of conversion reduced, explained by the fact that the cushioning effect is typically seen at higher power levels, which reduces energy transfer and consequently the cavitational activity . Mulay and Rathod studied the ultrasound-assisted esterification of dibutylmaleate using a heterogeneous catalyst Amberlyst-15, where the researchers achieved maximum conversion at 100 W as the ultrasonic power when the power was varied between 70 and 130 W. A decrease in conversion was recorded above 100 W of ultrasonic power, elucidating the existence of optimum power. Wen et al illustrated a direct and linear relationship between ultrasonic power and the esterification rate between palmitic acid and vitamin C catalyzed by sulfuric acid.…”

Dual Frequency Ultrasound-Assisted Esterification of Palm Empty Fruit Bunch Oil with Zeolite Heterogeneous Acid Catalyst

“…The ultrasound waves could improve the mixing between alcohol and oil due to cavitation effect. Mulay et al [4] Comparison of esterification of maleic acid using mechanical stirring and 22 kHz 100 W ultrasound waves assisted reaction. Recently, dual frequency ultrasound waves have shown better enhancement than single frequency waves [11].…”