Effects of crystal size and pore structure on catalytic performance of TS-1 in the isomerization of styrene oxide to phenyl acetaldehyde

In this study, isomerization of styrene oxide to phenyl acetaldehyde was investigated over a series of TS-1 catalysts with different crystal sizes and post-treatment methods under a gas-phase atmosphere free of solvents. The physicochemical properties of the samples were characterized by a combination of N2 adsorption, XRD, NH3-TPD, UV–vis, FT-IR and SEM. By the characterization of catalysts and investigation of their catalytic performances, results indicated that nano size TS-1 exhibited better anti-coking ability and phenyl acetaldehyde selectivity than micro size TS-1. Additionally, TPAOH treatment led to the development of considerable mesoporosity without significant destruction of its intrinsic zeolite properties. The results highlighted that the existence of well-developed hierarchical pore systems in TS-1-O could reduce diffusion path length and enhance transport of phenyl acetaldehyde out of the zeolite crystals, thus markedly improving catalytic stability and selectivity. However, upon NaOH treatment, the micropore structures were irreversibly destroyed accompaning with the amorphization of the zeolite crystals.