Synthesis of Ag-loaded 4A-zeolite composite catalyst via supercritical CO2 fluid for styrene epoxidation

In this paper, the silver nanoparticles (Ag NPs) were uniformly distributed to the 4A-zeolite via super-critical carbon dioxide (scCO(2)), and polyvinylpyrrolidone (PVP) was used as the capping agents. The transmission electron microscopy (TEM) detection of composite catalyst displayed that the Ag NPs had a narrow size distribution (3-6 nm). Catalytic property evaluation resulting showed the excellent catalytic activity of the Ag NPs/4A-zeolite samples. The high conversion of styrene and the superior selectivity of styrene oxide (SO) were shown to us when tert-butyl hydroperoxide (TBHP) was used as the oxidant in short reaction time. Solvents effects played a important role in the reaction, and acetonitrile was the optimal solvent for the styrene epoxidation via the investigation of solvents. (C) 2016 Elsevier Inc. All rights reserved.