Synthesis and characterization of novel chlorinated SnO2 nanomaterials for biodiesel production via stearic acid esterification with methanol

Abstract

Up to now the chlorinated SnO2 (xClSnOAmmonia) as solid acid catalysts for stearic acid esterification have not been reported in the literature. Non-chlorinated SnO2 catalysts were prepared by precipitation method using different precipitating agents (ammonium hydroxide, SnOAmmonia, sodium carbonate, SnOCarbonate, and urea, SnOUrea). The impact of different precipitation agents and chloride ion (Cl¯) doping on physicochemical properties of SnO2 were studied by XRD, HR-TEM, BET and NH3-TPD analyses. The surface parameters of SnO2 catalyst were varied with changing the precipitant agent and Cl¯ ion doping. The total acidity of SnOAmmonia was about 32 % and 64 % larger than SnOCarbonate and SnOUrea, respectively. Furthermore, the chlorinated SnO2 with the highest Cl¯ ion loading (0.30ClSnOAmmonia) exhibited a noteworthy increase in total acidity as compared to non-chlorinated SnO2.The catalytic activity of the non-chlorinated catalysts increased gradually as a following order SnOUrea < SnOCarbonate < SnOAmmonia. Noteworthy, the chlorinated catalysts demonstrated progressively enhancements in the activity as increasing Cl¯ ion loadings.