There is provided a sulfated layered titanium oxide catalyst. Relatively long chain alkyl aromatic compounds are prepared by alkylating an alkylatable aromatic compound with a relatively long chain alkylating agent under alkylation reaction conditions in the presence of this sulfated layered material as alkylation catalyst. The layered material contains titanium oxide in the layers and oxide pillars separating the layers. The alkylation activity of the catalyst is increased by including sulfate ions in the layered material. This increased alkylation activity may be obtained by contacting the layered material with an aqueous solution of a sulfate compound such as sulfuric acid.