Synthesis of hierarchically porous zeolite TS-1 with small crystal size and its performance of 1-hexene epoxidation reaction

TS-1 is a typical microporous zeolite, which is hindering the timely diffusion of reaction products and is likely to cause secondary side reactions in heterogeneous catalytic reaction due to the micropore size. However, zeolite TS-1 with hierarchical pores of micropores and mesoporous/macropores can solve this problem to a great extent. In view of this, hierarchical zeolite TS-1 is synthesized by using tetrapropylammonium hydroxide (TPAOH) as structure directing agent and polyacrylamide (PAM) as a hierarchical pore-directing template. The texture property of hierarchical TS-1 can be optimized by changing the amount of PAM in the synthesis gel. With the increase of PAM content, the pore volume and specific surface area of the hierarchical zeolite TS-1 increases. Compared with the conventional TS-1, the hierarchical TS-1 samples have obvious pore size distribution in the range of 20–80 nm. It is interesting that the particle size of TS-1 decreases after adding PAM. When the hierarchical TS-1 is applied to the epoxidation reaction of 1-hexene with H2O2, the selectivity of the desired product 1,2-epoxyhexane is significantly increased.