Acid Strength of Sulfated Zirconia Inferred from Catalytic Isobutane Conversion

The kinetics of the catalytic conversion of isobutane under gas-phase fixed-bed flow conditions over sulfated zirconia (SZ), when compared with those of other strong solid acids of known acidity, suggests that SZ may be a very strong solid superacid; this conclusion disagrees with recent reports claiming that SZ is not a superacid, and supports older claims, based on acidity tests with Hammett indicators, that SZ may have H0 of < -16.