Selective addition of isobutene over ZrSiO₄/SiO₂-SO₃H: Hydroacetoxylation versus dimerization

The acid-catalyzed Markovnikov addition of isobutene is affected by the concomitant isobutene oligomerization. Herein, a solid acid catalyst consisting of the sulfonated silica modified with crystalline ZrSiO₄ was prepared, and the ZrSiO₄/SiO₂-SO₃H catalyst went beyond conventional acid catalysts in the hydroacetoxylation of isobutene. The structure of the catalyst was well-characterized, and the role of ZrSiO₄ in suppressing the dimerization of isobutene was discussed in terms of both kinetic study and in-situ DRIFT analysis. Moreover, this catalyst also showed general applicability for a broad substrate scope, further highlighting the necessity of ZrSiO₄ in the solid acid catalyst.