Ti/SiO2 as a Nanosized Solid Catalyst for the Epoxidation of Fatty Acid Methyl Esters and Triglycerides

The chemical method has been employed to prepare a series of titanium-loaded silica (1.7 wt 96 Ti on SiO2), followed by calcination in the temperature range of 550-950 degrees C. Diffuse reflectance solid-state ultraviolet-visible spectroscopy supported the incorporation of TiO2 on the silica support and existence of titanium in distorted tetrahedral and octahedral environments. The surface morphology and particle size of Ti/SiO2 were observed by field emission scanning electron microscopic and transmission electron microscopic techniques and later support the formation of 20-100 nm sized Ti/SiO2 particles. Prepared Ti/SiO2 has been employed as a solid catalyst for the epoxidation of fatty acid methyl esters, derived from used cotton seed oil, under two different reaction conditions, viz., (i) H2O2 and formic acid and (ii) H2O2, acetonitrile, and butyronitrile in the presence of ultraviolet radiation. To demonstrate the versatility of the prepared Ti/SiO2 catalyst, it was also successfully employed for the epoxidation of a variety of substrates, viz., methyl oleate, used cotton seed oil, and fatty acid methyl esters obtained from soybean, Karanja, and Jatropha oils. Under optimized reaction conditions in both methods, the prepared Ti/SiO2 catalyst afforded a high epoxide yield (100%) even at room temperature (35 degrees C). The catalyst was amenable to recovery and recycling for at least five consecutive reaction cycles with the partial loss of activity after every successive run. Finally, the synthesized epoxidized fatty acid methyl esters have been tested as lubricity improver additives for diesel fuel.