Nanocrystalline Lithium Ion Impregnated Calcium Oxide As Heterogeneous Catalyst for Transesterification of High Moisture Containing Cotton Seed Oil

The present work demonstrates the application of nanocrystalline Li+ impregnated CaO as a heterogeneous catalyst for transesterification of used cottonseed oil with a higher amount of moisture. Catalysts with different alkali metal ions were prepared by the wet impregnation method, and their basic strengths were measured by Hammett indicators and a maximum was found in the case of lithium carbonate impregnated CaO. Further characterization of the lithium impregnated catalyst by powder X-ray diffraction and transmission electron microscopy studies supports the formation of a nanosized catalyst with a particle size of about 50 nm. The same catalyst has been chosen for studying the transesterification reaction of used cotton seed oil with methanol. The variables used for the transesterification were impregnated alkali metal ion, percentage of Li+ impregnation, catalyst concentration, reaction temperature (35-65 degrees C), oil to methanol molar ratio, reaction time (0.5-8 h), free fatty acid content (up to 6 wt %), moisture content (up to 15 wt %), and mixture of free fatty acid and moisture content. Reaction parameters have been optimized to achieve the least reaction period for the completion of the reaction. Complete transesterification of used cotton seed oil with methanol required 45 min in the presence of lithium carbonate impregnated CaO nanocatalyst at 65 degrees C when moisture and free fatty acid contents present in oil were 0.26 and 0.31 wt %, respectively. The same catalyst was found to be effective for the transesterification of cotton seed oil even in the presence of 15 wt % water though it took 2.5 h for the completion of the reaction.