Sulfated Zirconia

Introduction

Zirconia, when modified with anions such as sulfate, forms a highly acidic or super-acidic catalyst that exhibits superior catalytic activity in many reactions. [1] Sulfated ­zirconia (SO₄ ^²- /ZrO₂, SZ) is a crystalline solid acid that has monoclinic and tetragonal phases with a super acidity of -16.04 (Hammett acidity), which is responsible for its ­enhanced catalytic activity. [2]

A variety of organic reactions that are normally catalyzed by Brønsted or Lewis acids have been shown to take place more efficiently in the presence of sulfated oxides, especially sulfated zirconia even under milder reaction conditions. The reactions can take place in shorter time and with greater selectivity, and better yields. The range of ­reactions that have been successfully performed on SZ catalysts include alkylation, condensation, esterification, transesterification, nitration, cyclization and isomerization. [3]

References

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