Kinetics and reusability of Zr/CaO as heterogeneous catalyst for the ethanolysis and methanolysis of Jatropha crucas oil

Abstract

Zirconium impregnated (5–20wt.%) calcium oxide (Zr/CaO) was prepared by a simple wet chemical method followed by calcination up to 900°C. The prepared Zr/CaO was employed as a heterogeneous catalyst for the transesterification of Jatropha crucas oil with ethanol and methanol for the production of fatty acid ethyl and methyl esters, respectively. The catalysts were characterized by powder X-ray diffraction, Fourier transform-infrared spectroscopy, Brunauer–Emmett–Teller surface area measurement, scanning electron microscopy, transmission electron microscopy techniques and basic strength of the catalyst were established by acid–base titration. The catalytic activity was found to be a function of basic sites which in turn depend on calcination temperature and zirconium concentration. The catalyst with 15wt.% zirconium concentration and calcined at 700°C, showed the highest catalytic activity among the prepared catalysts. A pseudo first order kinetic equation was applied to evaluate the kinetic parameters of Zr/CaO catalyzed transesterification. The activation energy (Ea) for the Zr/CaO catalyzed methanolysis and ethanolysis was found to be 29.8kJmol−1 and 42.5kJmol−1, respectively. The Koras–Nowak test was performed to demonstrate that catalytic activity was independent from the mass transport phenomenon and follows the kinetic regime.