Effect of support nature on WO3/SiO2 structure and butene-1 metathesis

Tungsten Oxides-Containing Titanium Silicalite for Liquid Phase Epoxidation of 1-octene with Aqueous Hydrogen Peroxide

“…The table shows that the area increases as WO 3 loading increases up to 7 wt%. Wang et al [15] reported that the height of ammonia desorption peak increased with the increased of WO 3 loading up to 6 wt%. It means that the total amount of acid sites increases up to monolayer coverage.…”

“…The result demonstrates that crystalline WO 3 appears only in samples with high loading while the WO 3 exists as highly dispersed species in the low loading samples. Wang et al [15] reported that the characteristic peaks of crystalline WO 3 were clearly seen for the samples with high loading amount of WO 3 , ca. [6% and 10%, depending on the nature of silica support.…”

“…The peak intensities of the crystalline WO 3 in the WO 3 /TS-1 samples increase with the increase of WO 3 loading, due to the increase of the WO 3 concentration on the surface of the TS-1 support. The surface concentration of metal dispersed in the support can be calculated quantitatively based on the amount of metal oxide loading [15]. Based on the graph of the surface concentration of the tungsten versus the ratio of the diffraction peak intensity of WO 3 to that of TS-1 (I WO 3 =I TSÀ1 ; 2h: 34.17°/23.04°) in various WO 3 loading, the dispersion capacity of tungsten on the titanium silicalite support was evaluated to be 0.35 W 6?…”

On the Product Formation in 1-Butene Metathesis over Supported Tungsten Catalysts

“…Tungsten supported on silica-alumina also results in an increase in number of acid sites and in particular to sites desorbing at temperatures larger than 430 K. Silica does virtually not adsorb ammonia, whereas WO 3 /SiO 2 shows acidity [4] through ammonia desorption with a peak FTIR of adsorbed pyridine was used to study the Brønsted and Lewis acidity of the range of supports and the corresponding supported tungsten catalysts (see Fig. 3).…”

“…For instance, the Fischer-Tropsch synthesis produces a large amount of relatively low value butenes [1], which can be converted into higher value propene [2][3][4]. In particular, the crossmetathesis of butenes [4] is of interest, since it negates the loss of the valuable ethene in the production of propene. The cross-metathesis of 1-butene with 2-butene yields propene (with 2-pentene as a co-product) and the 1-butene metathesis yields ethene and hexenes.…”