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High‐Surface‐Area SiO2–ZrO2 Mixed Oxides as Catalysts for the Friedel–Crafts‐Type Alkylation of Arenes with Alcohols and Tandem Cyclopropanation Reactions

“…The observation that the catalytic activity increases with decreasing Zr concentration suggests that the catalytic activity is related to the presence of isolated Zr species. Several authors have described the epoxidation activity of SiO 2 –ZrO 2 catalysts (prepared either by sol–gel methods15 or by the grafting of organometallic compounds16) for the formation of coordinatively unsaturated, isolated Zr species. Very recently, the catalytic activity of Zr‐SBA‐15 for the Friedel–Crafts‐alkylation reaction has been attributed to the Lewis acidity of the isolated Zr species 3c.…”

Enhancement of catalytic activity of titanosilicalite-1 - sulfated zirconia combination towards epoxidation of 1-octene with aqueous hydrogen peroxide

“…However, development of the catalysts in order to increase its catalytic activity towards epoxides is still in progress, such as in catalyst preparation and modification [3,4]. Meanwhile, zirconia-silica composite prepared by sol-gel method and zirconia supported on the silica aerosil have been shown to be an active catalyst in the epoxidation of 1-octene using t-butyl hydroperoxide (TBHP) as oxidant [5,6]. Its activity is related with the structure of zirconium in the materials, i.e.…”