Solvent-free synthesis of chalcones catalyzed by aminopropylated silica sol-gel

G. ROMANELLI, G. PASQUALE, Á. SATHICQ, H. THOMAS, J. AUTINO, P. VÁZQUEZ

JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2011 vol. 340 p. 24 - 32

1381-1169

Aminopropylated nanosilica was prepared by a simple sol–gel process from tetraethyl orthosilicate(TEOS) and then it was functionalized with different amounts of 3-aminopropyltriethoxysilane (APS)under toluene reflux. The prepared solids were characterized by means of XRD, FT-IR, TGA–DTA,SEM–EDS, and TEM. Their textural properties were determined by adsorption–desorption isotherms ofN2 at 77 K. It was proved that the amount of APS used in the preparation process had a great influence onthe physicochemical properties of the hybrid organic–inorganic solid materials. The materials were usedas catalyst in the Claisen–Schmidt preparation of chalcones for the reaction of substituted acetophenonesand benzaldehydes under solvent-free conditions. The result showed that the presence of a high amountof aminopropyl groups was important for a very good performance of the catalyst in the substrate conversion.Also, the influence of different groups in the aromatic ring of acetophenones and benzaldehydeswas investigated. In all cases, coproduct formation was not observed; the catalysts were recovered andcan be recycled twice without appreciable loss of reactivity.