Isomerisation of n-hexane has been studied at industrially relevant conditions over sulphated zirconia promoted with Pt, Rh, Ir, and Ru. The Pt-promoted sample showed the highest activity, and it was considerably more active than a commercial, zeolite-based catalyst. The samples promoted with rhodium and iridium showed a lower, and similar activity, while ruthenium was less efficient and gave a less stable catalyst. The selectivities were similar for all the samples, with the methylpentanes and 2,3-dimethylbutane as main and primary products. Measured kinetic parameters for the reaction were in agreement with a conventional bifunctional mechanism: Positive order in n-hexane, negative in hydrogen and an activation energy around 90 kJ/mol. Prereduction of the samples was necessary to achieve a high activity, but if the activation temperature was too high the activity was lost, probably due to the loss of sulphate groups through excessive reduction. (c) 2005 Elsevier B.V. All rights reserved.