Synthesis and characterization of copper and aluminum salts of H3PMo12O40 for their use as catalysts in the eco-friendly synthesis of chromanes

DANIELA S. MANSILLA; M. ROSARIO TORVISO; ELBA N. ALESSO; PATRICIA G. VÁZQUEZ; CARMEN V. CÁCERES

APPLIED CATALYSIS A-GENERAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam - Holanda; Año: 2010 vol. 375 p. 196 - 204

0926-860X

Acid catalysts based on aluminum (or copper) salts of molybdophosphoric acid (H3PMo12O40) were prepared. They were synthesized from a heteropolyacid solution to which Al2(SO4)3, Al2O(CH3COO)4 or CuSO4 wasadded. The obtained saltswere texturally characterized and a low specific surface area, between 1 and 9 m2/g, was observed. The analysis of the prepared salts by ICP-AES spectrometry indicated that the molar content ofMoand P was that corresponding to the anion [PMo12O40]3. The presence of undegraded Keggin structure was confirmedbyXRD, FT-IR, DRS and 31PMAS-NMR. The catalyst aciditywasmeasured by means of potentiometric titration with a solution of n-butylamine in acetonitrile and by temperature-programmed desorption of pyridine. The AlPMo12O40 salt (from sulfate), which at 5 h of reaction showed the highest conversion of m-cresol (98%) and 75% and 25% selectivity to chromane 4 reaction showed the highest conversion of m-cresol (98%) and 75% and 25% selectivity to chromane 4