A green template-assisted synthesis of hierarchical TS-1 with excellent catalytic activity and recyclability for the oxidation of 2,3,6-trimethylphenol

Abstract

A simple one-step hydrothermal synthetic strategy to nano-sized hierarchical TS-1 zeolite with randomly arranged mesopores of 26 nm in diameter and uniform crystal size of 200–300 nm has been developed by utilizing the green and cheap ammonium-modified chitosan (HTCC) as the mesopore directing agent. The obtained hierarchical TS-1 samples were comprehensively characterized by XRD, SEM, TEM, BET, XPS, and other techniques. It is demonstrated that the physicochemical and texural properties of the resultant hierarchical TS-1 can be tailored by simply adjusting the HTCC amounts. Furthermore, the catalytic activity was measured on the oxidation of large molecules 2,3,6-trimethylphenol to 2,3,5-p-benzoquinone with hydrogen peroxide as oxidant under the mild conditions. Due to the introduction of the mesoporosity into the crystals, the hierarchical TS-1 zeolite exhibits enhanced catalytic capability, 62.22% conversion of 2,3,6-trimethylphenol and 96.97% selectivity to 2,3,5-p-benzoquinone with excellent recyclability. This provides an efficient and green route to construct hierarchical TS-1 zeolites with potential applications on the catalytic oxidation of bulky organic molecules.