Synthesis of mesoporous silica-included heteropolyacids materials and the utilization for the alkylation of phenol with cyclohexene

Abstract

Mesoporous silica-included heteropolyacids materials were synthesized and characterized by nitrogen sorption, XRD, FT-IR, TEM and NH3-TPD. Characterization results show that silica included heteropolyacids is a kind of Bronsted acid catalyst possessing large surface area, suitable pore structure, appropriate acid strength and high acid density. These materials are used as solid catalysts for the alkylation of phenol with cyclohexene. The mesoporous channel facilitates not only the dispersion of Bronsted acidity centers but also the transport of reactant and product molecules, thus leading to a significantly improved catalytic performance. Through adjusting the interaction between the support pore channel surface and heteropolyacid acive species, different acidity amount and strength can be obtained, leading to the tunable selectivity to the alkylation of phenol with cyclohexene. The improvement of reusability of silica-included HPA catalyst was related to the uniform dispersion of HPA and the enhanced interaction between HPA and the support. In six cycles of the catalyst, a stable activity could be mainttained.