title: Solvent-free catalytic depolymerization of cellulose to water-soluble oligosaccharides.
abstract: The use of cellulose is hampered by difficulties with breaking up the biopolymer into soluble products. Herein, we show that the impregnation of cellulosic substrates with catalytic amounts of a strong acid (e.g., H(2)SO(4), HCl) is a highly effective strategy for minimizing the contact problem commonly experienced in mechanically assisted, solid-state reactions. Milling the acid-impregnated cellulose fully converts the substrate into water-soluble oligosaccharides within 2 h. In aqueous solution, soluble products are easily hydrolyzed at 130 °C in 1 h, leading to 91 % conversion of the glucan fraction of α-cellulose into glucose, and 96 % of the xylans into xylose. Minor products are glucose dimers (8 %), 5-hydroxymethylfurfural (1 %) and furfural (4 %). Milling practical feedstocks (e.g., wood, sugarcane bagasse, and switchgrass) also results to water-soluble products (oligosaccharides and lignin fragments). The integrated approach (solid-state depolymerization in combination with liquid-phase hydrolysis) could well hold the key to a highly efficient "entry process" in biorefinery schemes.
authors.affiliation: Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Niklas
authors.initials: N
authors.lastname: Meine
authors.forename: Roberto
authors.initials: R
authors.lastname: Rinaldi
authors.forename: Ferdi
authors.initials: F
authors.lastname: Schüth
mesh_terms: D002384:Catalysis; D002482:Cellulose / Q000737:chemistry*; D005285:Fermentation; D008031:Lignin / Q000737:chemistry; D009844:Oligosaccharides / Q000737:chemistry*; D058105:Polymerization; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D009844:Oligosaccharides; D012997:Solvents; D014867:Water; C036909:lignocellulose; D002482:Cellulose; D008031:Lignin