Long CARBON Chain ESTERS FROM Babassu Biodiesel USING Mesoporous Silica AS CATALYST

Long carbon chain esters can be used as lubricants, due to structural similarity with the petroleum derivative. These esters have been obtained using vegetable oil as feedstock and homogeneous catalysts based on pyridine and strong acids. However, such catalysts may not be adequate on industrial scale applications due to safety issues and also because they may require additional washing steps to eliminate reaction by-products and remaining catalyst material. In this study we evaluate the synthesis of long chain esters by transesterification of babassu methyl ester as source material using 2-ethyl-1-hexanol as the transesterifying alcohol and SBA-15 impregnated with CaO (16%wt) as catalyst. The supported catalyst was characterized by N₂ adsorption/desorption isotherms at 77K. The specific surface area was 500 m² /g, total pore volume of 0.3946 cc/g and average pore size of 3.14 nm. The reaction parameters were varied according to an experimental factorial design. In all experiments, the alcohol/oil molar ratio was 12:1 and the activation temperature of the catalyst was 783 K. The variable levels were: reaction temperature, 353K and 298K; catalyst concentration, 1.0 and 2.5 wt% relative to liquid phase mass; and magnetic stirring rate, 60 and 1000 rpm. The best performance was obtained at reaction temperature of 353 K, magnetic stirring of 1000 rpm and catalyst concentration of 2.5 wt%, showing conversion values in the order of 80%wt.