Delignification of autohydrolyzed wood in media containing water and a protic ionic liquid

Eucalyptus nitenswood samples were treated with hot, compressed water (autohydrolysis) to solubilize the hemicellulosic fraction, and the resulting solid (autohydrolyzed wood) was delignified in media containing water and an acidic ionic liquid (either 1-butyl-3-methylimidazolium hydrogen sulfate or triethylammonium hydrogen sulfate). The solid yields and the compositional changes caused by delignification were studied using empirical modeling of data. The effects of selected variables (water content of the reaction media, temperature and reaction time) were assessed on a quantitative basis, enabling the selection of optimal reaction conditions. Aspects regarding the selectivity of the separation of the diverse components are discussed, and the results are compared with data reported in related studies.