The effect of process parameters and catalyst support preparation methods on the catalytic efficiency in transesterification of sunflower oil over heterogeneous KI/Al2O3-based catalysts for biodiesel production

The essence of this study is synthesis of a newly developed and efficient heterogeneous catalyst based on aluminum oxide support promoted with potassium iodide (KI) as active dopant responsible for pronounced catalyst activity. Modified sol-gel, reflux and hydrothermal method were used for synthesis of aluminum-oxide support using aluminum isopropoxide as a precursor. The gamma-Al2O3 support and KI/gamma-Al2O3 catalyst samples were examined by various experimental techniques. Effects of several operational parameters were considered and those are: methanol to sunflower oil molar ratio, catalyst loadings, reaction time and reaction stirring rate. The obtained results indicated that modified sol-gel method for synthesis of gamma-Al2O3 catalyst support is the most favorable for obtaining the catalyst with superior catalytic performances in transesterification of sunflower oil. A maximum conversion (triglycerides to methyl esters) of 99.99% was achieved using the SG-KI/gamma-Al2O3-770 catalyst under following optimal process parameters: 15:1 methanol to sunflower oil molar ratio, 2.5 wt% catalysts loading, 600 rpm stirring rate and 4 h of the reaction run.

Automated summary

This study presents the synthesis of a highly efficient heterogeneous catalyst based on aluminum oxide support. The catalyst is promoted with potassium iodide as an active dopant, resulting in enhanced catalyst activity. The modified sol-gel method was found to be the most favorable for synthesizing the catalyst support, which showed superior catalytic performances in the transesterification of sunflower oil. The optimal process parameters resulted in a maximum conversion rate of 99.99%.