Electrophilic alkylation uses Lewis acids and Brønsted acids, sometimes both.  Classically, Lewis acids, e.g., aluminium trichloride, are employed when the alkyl halide are used.  Brønsted acids are used when alkylating with olefins.  Typical catalysts are zeolites, i.e. solid acid catalysts, and sulfuric acid.  Silicotungstic acid is used to manufacture ethyl acetate by the alkylation of acetic acid by ethylene: