Utilization of metal complexes as catalysts in the transesterification of Brazilian vegetable oils with different alcohols

This article reports the use of Sn(3-hydroxy-2-methyl-4-pyrone)2(H2O)(2) (1), Pb(3-hydroxy-2-methyl-4-pyrone)(2)(H2O)(2) (2), and Zn(3-hydroxy-2-methyl-4-pyrone)(2)(H2O)(2) (3) as catalysts in the transesterification reaction of different alkyl-chain triglycerides and alcohols. The methanolysis of native oils from Brazilian's Savannah and Amazonian regions, such as Andiroba (Carapa guianensis), Babassu (Orbignia sp.), Cumaru (Dipteryx odorata), Palm tree (Elaeis sp.), Piqui (Caryocar sp.), and Soybean oil as well as the alcoholysis of Soybean oil with several alcohols (ethanol, propanol, iso-propanol, n-butanol, terc-butanol and cyclo-hexanol) was studied. Activities of the tin and lead pyrone complexes were observed in all the alcohol studies. For linear alcohols, the reaction activities decrease with increasing carbonic chain length. It was also shown that the catalytic activities are higher when vegetable oil with short chain fatty acids or with a high unsaturated degree and short and linear chain alcohols are used. (C) 2003 Elsevier B.V. All rights reserved.