Synthesis of Mesoporous Titanium Silicalite-1 with High Stability in Cyclohexanone Ammoximation

Mesoporous titanium silicalite-1（TS-1）was hydrothermally synthesized with the addition of triethanolamine（TEA）in the conventional process, and used in the cyclohexanone ammoximation in a continuous slurry reactor. The as-prepared TS-1 was characterized with X-ray diffraction（XRD）, scanning electron microcopy（SEM）, N2 adsorption-desorption, Fourier transform infrared（FT-IR）spectroscopy, UV-Visible（UV-Vis）diffuse reflectance spectra and UV Raman spectroscopy. The results indicated that the addition of TEA resulted in the formation of mesopores and the slight increase of framework titanium in TS-1. TS-1 synthesized with the addition of TEA exhibited a higher stability in the cyclohexanone ammoximation than that without the addition of TEA, attributing to the increase of mesopore volumes and the slight increase of the framework titanium in TS-1. However, when the addition of TEA was up to TEA/SiO2 ratio of 0.24, the crystallinity and framework titanium of TS-1 decreased markedly, and the average crystal sizes of TS-1 increased, with the catalyst stability becoming poor.