Process for separating lignin from lignocellulosic materials

The present invention provides a process for separating lignin from a lignocellulosic material in order to obtain cellulose free or substantially free of lignin, the process comprising the steps of (a) preparing a CO 2 -triggered switchable solvent by mixing water, a water-insoluble amine which is a secondary amine, a tertiary amine, or a combination thereof, and CO 2 ; (b) mixing the lignocellulosic material with the CO 2 -triggered switchable solvent obtained in step (a), thereby the lignin is dissolved in the solvent and the cellulose is not dissolved; and (c) separating the cellulose.