Doped Keggin heteropolyacids as catalysts in sulfide oxidation

VALERIA PALERMO, ANGEL G SATHICQ, PATRICIA G VÁZQUEZ, HORACIO J. THOMAS, GUSTAVO P. ROMANELLI

Reaction Kinetics, Mechanisms and Catalysis

Springler

Año: 2011 vol. 104 p. 181 - 195

1878-5204

In this research, we report the preparation of V, Bi and Bi-V Keggin structures where Mo ispartially replace by V, Bi, and Bi and V, respectively (H4PMo11VO40, (PMoV); H6PMo11BiO40, (PMoBi); and H5PMo11V0.5Bi0.5O40, (PMoVBi), in H3PMo12O40, (PMo)). These catalysts were characterized by means of ICP-AES analysis, 31P-NMR, UV-visible spectra, FT-IR spectra, thermal analysis, textural properties and potentiometric titration. In addition, the activities of the synthesized catalysts were evaluated in the selective oxidation of sulfides to sulfoxides/sulfones and in the solventfree multicomponent synthesis of dihydropyrimidinones by the Biginelli method. The incorporation of V, Bi and Bi-V into the structure of PMo increases the catalytic activity (acid and redox catalysts). The two most active catalysts (PMoV and PMoVBi) were supported on aminopropyl-functionalized silica (SiO2NH2) and they were found to be and efficient heterogeneous catalysts for the selective oxidation of diphenylsulfide to the corresponding sulfoxide/sulfone.