Synthesis of isoamyl acetate using Lewis acid ionic liquid bmimPF_6 as catalyst

The acidity of Lewis acid ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate(bmimPF6) was determined by using pyridine as IR spectroscopic probe,and isoamyl acetate was synthesized with bmimPF6 as catalyst.The influencing factors on yield of isoamyl acetate such as molar ratio of isoamyl alcohol to acetic acid,dosage of the catalyst,reaction time,and times of recycling use of the catalyst on the yield of isoamyl acetate were examined.Optimal conditions was obtained as:n(acetic acid)∶n(isoamyl alcohol)=1.2∶1,with the dosage of bmimPF6 12.5%(w) of total reactants,at 110 ℃ and reaction for 2.0 h.Yield of isoamyl acetate achieves 72.2%.The catalyst can be conveniently separated from the reaction mixture by decantation and can be reused for 4 times without significant decline of the activity.