BackgroundIn order to replace petrochemicals by bio-based lignin products in high value-added applications, a formic/acetic acid treatment was adapted to beech wood (Fagus sylvatica L.) for lignin extraction. ResultsBeech wood particles were delignified at atmospheric pressure by a formic acid/acetic acid/water mixture. Cooking time and temperature were optimized for delignification, pulp yield and 2-furfural concentration. Response surface design analysis revealed that delignification yield increased with cooking time and temperature. ConclusionThe multi-criteria optimization of delignification was used to find the ideal cooking conditions (5 h 07 min, 104.2 degrees C) to maximize delignification (70.5%) and pulp yield (58.7%) and, to a lesser extent, minimize 2-furfural production. Treatment conditions were found to influence the chemical structure of extracted lignins. Cooking time and temperature inversely influenced lignin molecular weights. (c) 2013 Society of Chemical Industry