ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

The Effect of Microwave and Ultrasonic Irradiation on the Reactivity of Benzaldehydes under Al₂O₃, Ba(OH)₂ , and K₂CO₃ Catalysis

M. Mečiarová, V. Poláčková, and Š. Toma

Department of Organic Chemistry, Faculty of Natural Sciences, Comenius University, SK-842 15 Bratislava

E-mail: toma@fns.uniba.sk

Received: 30 November 2001

Abstract: The solventless microwave reactions of substituted benzaldehydes with imidazole and piperidine on Al₂O₃ as an inorganic support resulted in the Cannizzaro reaction. The products of Cannizzaro reactions were also the main products at the attempted condensation reactions of benzaldehydes with vinyl acetate using barium hydroxide as the catalyst under microwave irradiation, but corresponding cinnamaldehydes were formed only under ultrasonic irradiation. 4-Chloro- and 4- bromobenzaldehydes proved to be unreactive at sonochemical S_NAr substitutions, but afforded S_NAr reactions under microwave irradiation.

Full paper in Portable Document Format: 563a208.pdf

Chemical Papers 56 (3) 208–213 (2002)