Production of 5-Hydroxymethylfurfural from pine wood via biorefinery technologies based on fractionation and reaction in ionic liquids

Abstract

Pine wood is mainly composed of extractives, lignin, cellulose, and hemicelluloses (which include pentosans and hexosans). In the scope of biorefineries, the utilization of pine wood entails the selective separation of its major components. A sequence of aqueous and delignification treatments enables the selective separation of hemicelluloses (as soluble products from the aqueous fractionation step), lignin (as soluble products from the delignification stage), and cellulose (accumulated in the solid phase leaving the delignification stage). Delignification was done in media containing acetic acid or the ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate. Both the soluble hemicellulose-derived saccharides and the cellulose-containing solids were found to be suitable substrates for 5-hydroxymethylfurfural production in reaction media containing the ionic liquid 1-butyl-3-methylimidazolium chloride in the presence of Brønsted and/or Lewis acidic catalysts. The processing schemes considered in this work allowed an efficient utilization of the feedstock using environmentally friendly technologies.

Advances of Ionic Liquids and Deep Eutectic Solvents in Green Processes of Biomass‐Derived 5‐Hydroxymethylfurfural

“…Pine wood mainly composed of lignin, cellulose, and hemicelluloses was performed in [BMIm]HSO 4 at 170 °C for 1.5 h to obtain a solid phase (77.6 % glucan, 2.6 % hemicelluloses, and 13.2 % klason lignin), which was reacted in the media containing [BMIm]Cl and catalyst CrCl 3 • 6H 2 O, achieving 51 % HMF yield at 160 °C for 1.08 h. [87] [BMIm]Cl was also used as solvent for direct transformation of wood chops and rice straw into HMF with 41 and 35 % yields, respectively, in the presence of CrCl 3 • 6H 2 O at 120 °C for 2 h. After an alkaline pretreatment under the conditions of 60 °C for 24 h, the HMF yields increased to 79 and 76 % for wood chops and rice straw, respectively, because alkaline pretreatment could cause structural alteration of lignin, solvation of hemicellulose, and swelling and decrystallization of cellulose. [88] Process intensifications are favorable for carbonate degradation and transformation.…”

Ultrasound-Assisted Cold Alkaline Extraction: Increasing Hemicellulose Extraction and Energy Production from Populus Wood

“…Additionally, this helps prevent excessive degradation of cellulose fibers. The second step involves oxidative delignification or organosolv treatment to remove the lignin fraction [18]. Among the various pretreatment methods available, alkaline pretreatment offers significant advantages, including the use of environmentally friendly and non-corrosive chemicals, as well as milder operating conditions [19].…”