Nanocrystalline potassium impregnated SiO2 as heterogeneous catalysts for the transesterification of karanja and jatropha oil

Abstract

Potassium impregnated SiO₂ having 1 : 1 to 1 : 6 atomic ratios of Si to K have been prepared by a sol–gel method and evaluated as heterogeneous catalysts for the transesterification of jatropha and karanja oil with methanol. These catalysts are characterized by powder XRD, TEM, SEM-EDX, Hammett indicators, soluble basicity and FT-IR studies. TEM images of the catalyst with a 1 : 6 atomic ratio of Si and K revealed uniform impregnation of 1.4–5.5 nm sized potassium nanoparticles over 50–72 nm sized spherical silica nanoparticles. This catalyst was found to be efficient for the transesterification of jatropha and karanja oil in 0.3 h and 0.75 h respectively.