Catalytic activity for synthesis of isomerized products from benzene over platinum-supported sulfated zirconia

The catalytic activity of Pt/SO 4 2−/ZrO 2 in the benzene hydrogenation and isomerization reaction at 250°C is superior to that of other Pt/conventional solid acid catalysts such as Pt/HY-zeolite and Pt/H-mordenite. The catalytic activity of SO 4 2−/ZrO 2 for cyclohexane isomerization to methylcyclopentane at 250°C is higher than that of HY-zeolite and H-mordenite. SO 4 2−/ZrO 2 and HM10 have more Brönsted acid sites of the highest strength and show a higher percentage of isomerization conversion. In contrast, ZrO 2, which contains almost no Brönsted acid sites, and HY5.6, which contains almost no Brönsted acid sites of the highest strength, show a lower conversion percentage. Consequently, Brönsted acid sites of the highest strength are active sites responsible for cyclohexane isomerization. However, the isomerization conversion percentage does not completely correlate with the number of highest-strength Brönsted acid sites, suggesting that not all of these sites contribute to the reaction nor do only Brönsted acid sites influence cyclohexane isomerization. Neither the total number nor the number of highest-strength Lewis acid sites correlates with the isomerization conversion rate, indicating that Lewis acid sites are not responsible for cyclohexane isomerization.