Keggin-type phosphotungstic acid supported on mesoporous SiO2-Al2O3 aerogel like beads and their application in the isopropylation of naphthalene

Spherical mesoporous silica-alumina aerogel like beads based on sol-gel technology and the drop wise addition have been synthesized and used as catalyst support for phosphotungstic acid (PWA). Their catalytic performances in the isopropylation of naphthalene with isopropanol were investigated in a batch reactor. It was found that PWA was highly dispersed on the silica-alumina support and their Keggin structure can be retained. In addition, PWA/SiO2-Al2O3 catalyst showed high surface area, both of Lewis acid sites and Bronsted acid sites. Because of having more Bronsted acid sites, silica-alumina supported acid catalysts showed much higher conversion (87.97 %) and selectivity to diisopropylnaphthalenes (41.41 %) and beta, beta-products (59.82 %) than pure acid and reactive supports in the isopropylation of naphthalene. The catalytic behavior has been discussed in relation with the physical chemical properties of catalysts, reaction and activation temperature and reaction time.