Facile synthesis of hierarchical manganese-containing TS-1 and its application on the oxidation of cyclohexanone with molecular oxygen

Abstract

Abstract Herein, we report a one-step hydrothermal approach to synthesize hierarchical manganese-containing TS-1 zeolite (HMTS) with mesopores of 2–4 nm in diameter and uniform crystal size of 150–200 nm by employing manganese (III)-acetylacetonate and tetrabutyl titanate as manganese and titanium sources, respectively. It is demonstrated that Mn and Ti species in designed ratios have been successfully incorporated into the framework of HMTS zeolites during the hydrothermal treating processes. Moreover, the physicochemical and textural properties of HMTS can be easily tailored by simply altering the amounts of the template agents. The as-synthesized HMTS catalyst exhibits superior catalytic activity, excellent structural stability and recyclability on the selective oxidation of cyclohexanone to adipic acid under mild solvent-free conditions via a non-nitric acid route, which avoids the high energy consumption and emission of greenhouse gas (N2O). This work demonstrates a facile route to the direct synthesis of Mn-containing, hierarchical meso/microporous TS-1 with economized energy and time, presenting potential prospects in the field of aerobic oxidations of bulky organic compounds.