An Environmentally Friendly Nb–P–Si Solid Catalyst for Acid-Demanding Reactions

5 years ago

An Environmentally Friendly Nb–P–Si Solid Catalyst for Acid-Demanding Reactions

Paolo Carniti, Rosa Vitiello, Martino Di Serio, Antonio Aronne, Antonella Gervasini, Luciana Minieri, Pasquale Pernice, Claudio Imparato, Alessandro Piccolo, Nigel J. Clayden

Here, we report the structural characteristics, the surface properties, and the catalytic performances of a Nb–P–Si ternary oxide material (2.5Nb₂O₅·2.5P₂O₅·95SiO₂, 2.5NbP) in two reactions of importance for biomass valorisation and green industrial production: hydrolysis of inulin and esterification of oleic acid with polyalcohol for biolubricant production. High dispersion of the Nb centers, ascertained by UV–vis–DRS, ²⁹Si, ³¹P, and ¹H solid-state NMR spectroscopy, is the key point for the successful activity of 2.5NbP. Intrinsic and effective acidities of the sample were studied by FT-IR of adsorbed pyridine in the absence and presence of water and by volumetric titrations of the acid sites in cyclohexane and in water, to enlighten the nature and amount of acid sites in different environments. For both studied reactions, 2.5NbP catalyst exhibits water-tolerant acidic sites, mainly Brønsted ones, giving higher activity and better stability in the reaction medium than well-known niobium oxophosphate catalyst, which is considered one of the best water-tolerant acid catalysts.

Publisher URL: http://dx.doi.org/10.1021/acs.jpcc.7b05886

DOI: 10.1021/acs.jpcc.7b05886