Jump to main content
Jump to site search

Issue 23, 2015
Previous Article Next Article

Role of pentahedrally coordinated titanium in titanium silicalite-1 in propene epoxidation

Author affiliations

Abstract

Two titanium silicalite-1 samples with different crystal sizes were synthesized in the tetrapropylammonium bromide (TPABr) and tetrapropylammonium hydroxide (TPAOH) hydrothermal systems. The small-crystal TS-1 with a size of 600 nm was then treated with different organic bases. These TS-1 samples were evaluated in the epoxidation of propene, and characterized by ultraviolet-visible diffuse reflectance (UV-vis), X-ray absorption near edge structure (XANES) and Raman spectroscopies. The Ti L-edge absorption spectra show that a new Ti species, pentahedrally coordinated Ti, appears in some of the samples. This pentahedrally coordinated Ti species is correlated with the catalytic oxidation activity of TS-1, closely. Tetrahedrally coordinated Ti in TS-1 is the primary active center for selective oxidation reactions, but the existence of a small amount of pentahedrally coordinated Ti can further improve the catalytic activity. A high molar ratio of Si/Ti (n(Si/Ti)) in the synthesis process (n(Si/Ti) = 92.78) was beneficial for the generation of pentahedrally coordinated Ti. The improved catalytic activity of the TPAOH treated TS-1 is mainly due to the increasing amount of pentahedrally coordinated Ti, besides the elimination of diffusion limitation. Slowing down the crystallization rate can also increase the content of pentahedrally coordinated Ti.

Graphical abstract: Role of pentahedrally coordinated titanium in titanium silicalite-1 in propene epoxidation

Back to tab navigation

Supplementary files

Publication details

The article was received on 06 Jan 2015, accepted on 05 Feb 2015 and first published on 06 Feb 2015


Article type: Paper
DOI: 10.1039/C5RA00194C
Citation: RSC Adv., 2015,5, 17897-17904
  •   Request permissions

    Role of pentahedrally coordinated titanium in titanium silicalite-1 in propene epoxidation

    Y. Zuo, M. Liu, T. Zhang, L. Hong, X. Guo, C. Song, Y. Chen, P. Zhu, C. Jaye and D. Fischer, RSC Adv., 2015, 5, 17897
    DOI: 10.1039/C5RA00194C

Search articles by author

Spotlight

Advertisements