The alkylation of isobutane/isobutene to produce alkylate was investigated in the presence of Bronsted-Lewis acidic ionic liquids (ILs). The results show that the IL (3-sulfonic acid)-propyltriethylammonium chlorozincinate [HO3SC3NEt3] Cl-ZnCl2 (molar fraction of ZnCl2, x = 0.83) was an efficient catalyst for the alkylation reaction. The conversion of isobutene was about 100% and the selectivity for the C-8-alkylate reached 91.7%, in which the mass ratio of trimethylpentane to dimethylhexane was more than 75. The IL reusability was good and its catalytic performance did not significantly decrease after ten reaction cycles. It was also found that a synergetic effect of Bronsted and Lewis acid sites enhanced the catalytic performance of ILs. (C) 2015 Elsevier Ltd. All rights reserved.