The effect of acoustic irradiation has been studied in several hydrogenation reactions (1-phenyl-1,2-propanedione, ethyl-pyruvate and D-fructose hydrogenation) as well as in an esterification reaction over various heterogeneous catalysts. The reaction rate and selectivity were significantly improved under sonification in 1-phenyl-1,2-propanedione hydrogenation over Pt/SF (silica fiber) catalyst. Acoustic irradiation enhanced the reaction rate in esterification of propionic acid with ethyl alcohol over functionalized polymer fiber Smopex-101 catalyst compared to identical silent conditions. Furthermore, ultrasound remarkably suppressed catalyst deactivation in D-fructose hydrogenation over Raney-Ni catalyst. The spent catalysts used in the hydrogenation reactions either in presence or absence of acoustic irradiation were intensively studied by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). (c) 2006 Elsevier B.V. All rights reserved.