Immobilization of 12-Tungstophosphoric acid in alumina-grafted mesoporous LaSBA-15 and its catalytic activity for alkylation of o-xylene with styrene

This paper dealed with the immobilization of 12-Tungstophosphoric acid (HPW) in alumina-grafted mesoporous LaSBA-15 and its catalytic activity for alkylation of o-xylene with styrene were also studied. All the samples were characterized by elemental analysis, nitrogen adsorption, FT-IR spectra, diffuse reflectance UV–vis spectra, XPS, 27Al MAS NMR and NH3-TPD. Results showed that the mesopore structure of LaSBA-15 was maintained well even after the surface modification and the subsequent immobilization step of HPW. It was demonstrated that grafting of silica with small alumina clusters at partial to full surface coverage could produce isolated basic sites to anchor the molecular HPW. Among the catalysts investigated, when the content of alumina was suitable (20 wt.%), it exhibited the best catalytic performances in terms of yield and stability. This behavior may be owing to high dispersion of the HPW species on the surface modified LaSBA-15 and the strong interaction between the HPW and the support in the presence of alumina, thus prevent HPW leaching from the support.

Graphical abstractAfter grafting the silica surface with alumina, the interaction between the HPW and the support increased obviously, thus could prevent HPW leaching from the support. When the content of alumina was suitable (20 wt.%), it had the best catalytic performances in terms of yield and stability.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Alumina on mesoporous LaSBA-15 surface was studied by means of analytic techniques. ► Catalysts were effective for alkylation of o-xylene with styrene. ► Presence of alumina can increase the catalysts stability. ► Catalysts show superior stability to the HPW/LaSBA-15 catalyst.