Insight into the effect of mass transfer channels and intrinsic reactivity in titanium silicalite catalyst for one-step epoxidation of propylene

One-step epoxidation of propylene to propylene oxide (PO) in TS-1/H2O2 system is a promising green and sustainable formation route. However, the TS-1 catalyst is limited by the small pore channels and inadequate intrinsic reactivity. Herein, tetrapropylammonium hydroxide (TPAOH) is used to modify the TS-1 skeleton structures to improve the mass transfer and intrinsic reactivity. Comparative catalytic performance tests indicate that the optimized temperature for TPAOH treatment to modify TS-1 was 90 degrees C, and the achieved H(2)O2 utilization efficiency and the PO selectivity can be over 80%. Different TPAOH treatment temperatures significantly influenced the dissolution and recrystallization behavior of TS-1, which altered the composition and microstructure in terms of the pore volume and size, surface properties, and active sites. Our findings indicated that the enlarged pore channels for favorable mass transfer, improved hydrophobic surfaces, enriched framework titanium, and reduced acid strength of titanium silicalite zeolite should be the primary reasons for the enhanced conversion and yields.

Automated summary

In this study, the one-step epoxidation of propylene to propylene oxide using the TS-1/H2O2 system was optimized by modifying the TS-1 catalyst with tetrapropylammonium hydroxide (TPAOH). The results showed that the highest H(2)O2 utilization efficiency and PO selectivity were achieved at a TPAOH treatment temperature of 90 degrees C. TPAOH treatment significantly altered the composition and microstructure of TS-1, leading to improved mass transfer and intrinsic reactivity, resulting in enhanced propylene conversion and yields.