Catalysis of vegetable oil transesterification by Sn(II)-exchanged Keggin heteropolyacids: bifunctional solid acid catalysts

• DOI: 10.1007/s11144-017-1258-z
• Publication Date: 2017-09-04T10:38:49Z
• Authors: Márcio José Da Silva; Castelo Bandane V...; Milena Galdino Te...; Armanda Aparecida...
• Keywords: Hydrodeoxygenation; Brønsted–Lowry acid–base theory

Keggin heteropolyacid protons (i.e., H3PW12O40, H3PMo12O40, H4SiW12O40) were partially exchanged with Sn(II) cations generating solid acid catalysts that were used for vegetable oil transesterification reactions. These catalysts have double acidity properties, i.e., Lewis acidity and Bronsted acidity that are suitable for the conversion of vegetable oil into biodiesel. The highest efficiency (ca. 100%) was achieved on the Sn1.2H0.6PW12O40-catalyzed transesterification reactions. The relationship between the catalytic activity and acidic properties was deeply discussed and the effects of main reaction parameters were assessed. The activity of the precursor HPA, tin salts and physical mixture were compared and confirmed a synergism between Sn(II) cations and PW12O40 3− anions. The reusability of catalyst was investigated.