New multi-phase catalytic systems based on tin compounds active for vegetable oil transesterificaton reaction

It is reported here about some attempts in order to develop a multi-phase catalytic system active for vegetable oil alcoholysis based upon tin compounds. The immobilization of Sn(3-hydroxy-2-methyl-4-pyrone)(2)(H2O)(2) by dissolving it in the 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid and supporting it in an ion-exchange resin, as well as the catalytic behavior of tin oxide was studied. By anchoring the tin complex in the ionic liquid, it was observed that its catalytic activity was maintained but it was not possible to reuse the catalytic system due to leaching of the catalyst from the ionic phase during each reaction. On the other hand, it was found that the tin complex lost its catalytic activity when supported in the organic resin. It was also shown that tin oxide was active for soybean oil methanolysis (conversion yields up to 93% in 3 h were achieved) and was also possible to recycle it without any loss in its catalytic activity. (C) 2004 Elsevier B.V. All rights reserved.