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

• Published in: Reaction kinetics, mechanisms and catalysis Vol. 122; no. 2; pp. 1011 - 1030
• Main Authors: Da Silva, Márcio José, Vilanculo, Castelo Bandane, Teixeira, Milena Galdino, Julio, Armanda Aparecida
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-12-2017
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Physical Chemistry; Transesterification; Biodiesel; Solid acids; Tin(II) heteropolyacid salt catalysts
• ISSN: 1878-5190; 1878-5204
• DOI: 10.1007/s11144-017-1258-z

Keggin heteropolyacid protons (i.e., H
3
PW
12
O
40
, H
3
PMo
12
O
40
, H
4
SiW
12
O
40
) 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 Brønsted acidity that are suitable for the conversion of vegetable oil into biodiesel. The highest efficiency (ca. 100%) was achieved on the Sn
1.2
H
0.6
PW
12
O
40
-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 PW
12
O
40
3−
anions. The reusability of catalyst was investigated.