Influence of acidity of modified chloroaluminate based ionic liquid catalysts on alkylation of iso-butene with butene-2

► Some new catalytic systems composed ionic liquids and additives were synthesized. ► These systems showed a high activity for alkylation of iso-butane with butene-2. ► FT-IR spectrum showed to be an efficient method to evaluate the acidity of Ils. ► This is a valuable guide to explain the mechanism and to select the catalysts.