A New Solid Acid-Based Route to Linear Alkylbenzenes

We have investigated the use of sulfated zirconia as a catalyst for the alkylation of benzene with long-chain linear alkenes. Optimum activity was obtained for SZ calcined between 500 to 550°C with subsequent cooling in a desiccator. Spectroscopic pyridine titration of the calcined catalyst shows that SZ is essentially Brønsted in nature under normal reaction conditions. Activity and selectivity are comparable to those of AlCl3. A relationship between catalyst reusability and the pore structure has been observed. Microporous sulfated zirconia was found to be deactivated after the initial reaction, whereas mesoporous sulfated zirconia was reusable. The deactivated catalysts can be regenerated by both solvent extraction and thermal treatment; the latter resulted in complete regeneration of catalyst activity.