Recovery and Reuse of 1-Allyl-3-methylimidazolium Chloride in the Fractionation of Pinus radiata Wood

Abstract

Ionic liquids are expected to be potential solvents for biorefinery purposes. However, the high cost has limited widespread implementation, making their recycling essential to the process. Herein, the capacity to recover and reuse the ionic liquid 1-allyl-3-methylimidazolium chloride ([Amim][Cl]) in the fractionation of Pinus radiata wood using microwave heating was evaluated. In the proposed process, cellulose- and lignin-rich materials were obtained. The ionic liquid used was recovered and reused in the forthcoming cycles up to five times. Characterization of [Amim][Cl] recovered demonstrated that although the structure of the ionic liquid remained unaltered, some woody fractions were accumulated. As a consequence, a reduction of the fractionation yields was obtained, and variations of the composition and amorphicity of the fractions recovered were produced. Through a global mass balance, this study gives an overall approximation of the concentration of the main components and the characteristic streams involved in successive cycles.