Ionic liquid mediated esterification of alcohol with acetic acid

Highly efficient esterification of alcohols with acetic acid by using a Brønsted acidic ionic liquid, i.e., 1-methyl-2-pyrrolidonium hydrogen sulfate ([Hnmp]HSO4), as catalyst has been realized. The turnover numbers (TON) were able to reach up to 11000 and turnover frequency (TOF) was 846. The catalytic system is suitable for the esterification of long chain aliphatic alcohols, benzyl alcohol and cyclohexanol with good yields of esters. The procedure of separating the product and catalyst is simple, and the catalyst could be reused. [Hnmp]HSO4 had much weaker corrosiveness than H2 SO4. The corrosive rate of H2SO4 was 400 times more than that of [Hnmp]HSO4 to stainless steel. © Higher Education Press and Springer-Verlag GmbH 2009.