One-pot Eucalyptus globulus wood fractionation in acid-catalyzed mixtures of water and 1-pentanol: an optimization study

Samples of Eucalyptus globulus wood were processed in a reaction media made up of 1-pentanol, water, and diluted acid catalyst. The effects of selected variables (proportion of 1-pentanol in the reaction media, catalyst charge and temperature) on wood solubilization and on the composition of the various phases from treatments (solids containing cellulose, pentanol-rich phase containing depolymerized lignin, and the aqueous phase concentrating the hemicellulose-derived products) were assessed by Response Surface Methodology. Numerical optimization based on the statistical models allowed the identification of the best operational conditions, under which extensive removal of both lignin and hemicelluloses was reached at good selectivity toward cellulose solubilization. The treated solids achieved near stoichiometric conversion upon enzymatic hydrolysis performed under diverse operational conditions, and the lignin structural analysis provided data typical for hardwoods. The experimental results confirmed the potential of 1-pentanol as a solvent for Eucalyptus globulus wood-based biorefineries.