The direct esterification of α-pinene and acetic acid was investigated in the presence of acidic ionic liquids (ILs). The results show that acidic ILs, (3-sulfonic acid)-propyltriethylamine hydrosulfate ([HSO 3 –(CH 2 ) 3 –NEt 3 ]HSO 4 ) and (3-sulfonic acid)propyltriethylamine dihydrogen phosphate ([HSO 3 –(CH 2 ) 3 –NEt 3 ]H 2 PO 4 ), were of good catalytic property. The product could be easily separated from the reaction mixture and the ILs catalysts were of good reusability. Hence, a clean and environmentally friendly strategy for synthesizing bornyl acetate and α-terpinyl acetate is provided.
