Crossed intergrowth triggered TS-2 microsphere: Formation mechanism, modification and catalytic performance

TS-2 microspheres, consisting of intergrown primary nanocrystals, was prepared by controlling the synthetic parameters. The effects of the amount of quaternary ammonium cations as structure-directing agent, H2O/Si ratio, the presence of alcohol and the temperature were carefully investigated on the crystallization process. The high alkalinity was proved to be highly important for the preservation of the microsphere morphology initially formed, due to the unique intergrown stacking style. An alkali treatment with the aqueous solution of structure-directing agent, organic amine and ammonium salt and subsequent Na+ ion-exchange were performed to enhance the catalytic activity of TS-2 microsphere in the cyclohexanone ammoximation reactions, with both the conversion and selectivity higher than 99%. In the continuous reaction, the TS-2 microspheres exhibited to be durable catalyst with potential application in industrial ammoximation processes. (C) 2020, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.