Effect of (n)SiO2/(n)B2O3 in the precursor on chemical–physics properties of Ti-ZSM-5 synthesized by gas–solid method

Ti-ZSM-5 samples were successfully synthesized by using B-ZSM-5 with different molar ratios of (n)SiO2/(n)B2O3 as the precursors. The gas–solid synthesis included two steps which were deboronation in HCl solution and titanation with TiCl4. The effect of (n)SiO2/(n)B2O3 on the incorporation of titanium into the framework was investigated. The synthesized titanium containing samples were thoroughly characterized by XRD, FT-IR, XRF, UV–Vis, Raman, ICP-AES and NH3 TPD. Propylene epoxidation and phenol hydroxylation properties were also investigated. The results showed that (n)SiO2/(n)TiO2 in the samples increased with an increase in the (n)SiO2/(n)B2O3 in the precursors. The conversion of H2O2 increased with the decreasing of (n)SiO2/(n)B2O3 or (n)SiO2/(n)TiO2, and the selectivity to propylene oxide (PO) decreased. Anatase appeared in Ti-ZSM-5 sample synthesized by using B-ZSM-5 with a (n)SiO2/(n)B2O3 ratio 100 as the precursor.