Synthesis of cenosphere supported heterogeneous catalyst and its performance in esterification reaction

A heterogeneous catalyst has been developed from cenosphere, a byproduct generated in thermal power plant. The performance of catalyst was investigated in the esterification of propionic acid and ethanol. The catalyst was characterized by FTIR, X-ray diffraction, field emission scanning electron microscope, and Brunauer-Emmett-Teller surface area and surface acidity analysis. The response surface methodology (RSM) with the Box-Behnken design was employed to design the experiments as well as to optimize the various process parameters such as catalyst loading, alcohol/acid molar ratio, and reaction temperature. The characterization revealed that the cenosphere supported catalyst possessed increased amounts of silica content, surface hydroxyl groups, surface area as well as surface acidity as compared with that of pristine cenosphere. The catalyst showed an excellent activity in the esterification reaction with a maximum conversion up to 91%. The RSM model well fitted the experimental data and predicted optimal conditions which were validated experimentally with a good agreement. The recyclability study showed a significant catalytic stability up to three reaction cycles. This study reveals that the cenosphere supported catalyst can be used as a potential catalyst in the esterification reaction may replace the conventional homogeneous acid catalyst.