Synthesis and Application of Alumina Pillared Bentonite Catalyst for Esterification of Acetic Acid with Different Alcohols

Abstract

The synthesis of alumina pillared bentonite using Al₁₃ Keggin ion pillaring agent has been carried out. We studied their properties and catalysis application for esterification reaction. Characterization studied were performed by using X-ray fluorescence, X-ray diffraction, transmission electron microscopy, BET/N₂ gas sorption analysis methods besides the characterization on surface acidity by pyridine adsorptions and FTIR spectroscopy analysis. The experimental results indicated that significant improvement on bentonite physico-chemical characteristics was obtained by a pillarization process using oxide of aluminium. Catalytic activity test showed that Al₂O₃ pillared bentonite resulted in higher ethyl acetate percentage relative to the raw bentonite by value of 16.74 and 8.61 %, respectively, although raw bentonite surface acidity was higher than Al₂O₃ pillared bentonite. It was demonstrated also that catalytic activity of alumina pillared bentonite was not only affected by surface acidity but also was affected by physico-chemical character of surface i.e specific surface area and total pore volume. The effect of alcohols on catalytic activities in esterification reaction was measured using different alcohols consist of methanol, ethanol and n-propanol with similar reaction condition for all experiments. Analytical data showed that the conversions of acetic acid by using methanol, ethanol and n-propanol were 48.42, 57.89 and 64.20 %, respectively and their selectivities were 100 % for all alcohols.