A rapid synthesis route for Sn-Beta zeolites by steam-assisted conversion and their catalytic performance in Baeyer-Villiger oxidation

Sn-Beta zeolites were prepared by a rapid and clean steam-assisted conversion (SAC) method from dry stannosilicate gel. The amorphous gel was converted to highly crystalline Sn-Beta within 5 h at mild reaction temperature of 453 K. The properties of the as-prepared samples were characterized by XRD, SEM, UV-Vis, UV-Raman, ICP and N-2 adsorption. A high gel conversion to BEA can be obtained with Sn4+ inserted in the zeolite framework. The SAC method was successfully used to produce pure silica Beta zeolite (Si/Sn = infinity) to Sn-Beta zeolite with 3.8 wt.% SnO2 (i.e., Si/Sn = 83). The Sn-Beta prepared by SAC method is an efficient catalyst for Baeyer-Villiger (B-V) reaction of cyclohexanone to epsilon-caprolactone. (C) 2012 Elsevier B.V. All rights reserved.