RT info:eu-repo/semantics/article T1 Governing Chemistry of Cellulose Hydrolysis in Supercritical Water A1 Cantero Sposetti, Danilo Alberto A1 Bermejo Roda, Maria Dolores A1 Cocero Alonso, María José AB At extremely low reaction times (0.02 s), cellulose was hydrolyzed in supercritical water (T=400 °C and P=25 MPa) to obtain a sugar yield higher than 95 wt %, whereas the 5-hydroxymethylfurfural (5-HMF) yield was lower than 0.01 wt %. If the reaction time was increased to 1 s, the main product was glycolaldehyde (60 wt %). Independently of the reaction time, the yield of 5-HMF was always lower than 0.01 wt %. To evaluate the reaction mechanism of biomass hydrolysis in pressurized water, several parameters (temperature, pressure, reaction time, and reaction medium) were studied for different biomasses (cellulose, glucose, fructose, and wheat bran). It was found that the H+ and OH− ion concentration in the reaction medium as a result of water dissociation is the determining factor in the selectivity. The reaction of glucose isomerization to fructose and the further dehydration to 5-HMF are highly dependent on the ion concentration. By an increase in the pOH/pH value, these reactions were minimized to allow control of 5-HMF production. Under these conditions, the retroaldol condensation pathway was enhanced, instead of the isomerization/dehydration pathway. PB Wiley YR 2015 FD 2015 LK http://uvadoc.uva.es/handle/10324/28439 UL http://uvadoc.uva.es/handle/10324/28439 LA eng NO ChemSusChem, Volume 8, Issue 6, 2015, Pages 1026–1033 NO Producción Científica DS UVaDOC RD 27-dic-2024