Green and selective toluene oxidation–Knoevenagel-condensation domino reaction over Ce- and Bi-based CeBi mixed oxide mixtures.

• Synthesis and comprehensive characterization of Ce- and Bi-based CeBi mixed oxides. • The Ce-rich mixed oxide was active in the oxidation of toluene. • The Bi-rich mixed oxide was active in the Knoevenagel condensation. • Their mixture catalysed the oxidation-condensation reaction with full selectivity. • The domino reaction proceeded in aqueous environment. Both Bi- and Ce-based CeBi mixed oxides were prepared by a modified sol-gel process from their precursor salts. The mixed as well as the parent oxides were characterized by X-ray diffractometry, Raman, XPS, UV–DRS and X-ray photoelectron spectroscopies, ICP–OES method, scanning and transmission electron microscopies as well as BET surface area, CO 2 - and NH 3 -temperature-programmed desorption measurements. After characterizing the morphology, the acid-base properties, the oxidation states of the cationic components and the porosity of these structures, their catalytic activities were probed in the Koevenagel condensation of benzaldehyde and diethyl malonate and the toluene oxidation to benzaldehyde reactions. Based on the catalytic activities of the oxides in the individual reactions, a catalyst mixture from the Bi- and Ce-based mixed oxides was used successfully in the toluene to benzaldehyde oxidation and benzaldehyde to benzylidene malonate Knoevenagel condensation domino reaction under environmentally benign conditions. [ABSTRACT FROM AUTHOR]