The kinetics of the heterogeneous gold-catalyzed aerobic epoxidation of stilbene in the liquid phase has been shown to be hindered by diffusion limitations, due to the use of supports which are unsuitable to apolar reaction media. The choice of these supports is generally dictated by the ability of standard methods of preparation to stabilize highly dispersed gold nanoparticles on them. Hence, new methods need to be designed in order to produce catalytically active gold nanoparticles on hydrophobic supports in general and on passivated silicas in particular. By investigating Tsukuda's method to produce colloidal solutions of gold nanoparticles upon reduction of the triphenylphosphine gold chloride complex in solution, we found that direct reduction of AuPPh3Cl in the presence of a commercially available silica support functionalized with dimethylsiloxane, Aerosil R972, leads, in a highly reproducible and potentially scalable way, to the best catalyst ever reported for this reaction. (C) 2011 Elsevier BM. All rights reserved.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: Funding of K.G. PhD fellowship by the French National Research Agency (ANR-08-KJC-0090-01-ACTOGREEN project) is gratefully acknowledged. This publication is based on work partly supported by Collaborative Travel Funds, made by King Abdullah University of Science and Technology (KAUST). The authors thank P. Mascunan and N. Cristin (IRCELYON) for elemental analyzes and P. Delichere (IRCELYON) for XPS experiments.