Subcritical Water as Reaction Environment: Fundamentals of Hydrothermal Biomass Transformation
- 14 February 2011
- journal article
- review article
- Published by Wiley in ChemSusChem
- Vol. 4 (5), 566-579
- https://doi.org/10.1002/cssc.201000341
Abstract
Subcritical water, that is, water above the boiling and below critical point, is a unique and sustainable reaction medium. Based on its solvent properties, in combination with the often considerable intrinsic water content of natural biomass, it is often considered as a potential solvent for biomass processing. Current knowledge on biomass transformation in subcritical water is, however, still rather scattered without providing a consistent picture. Concentrating on fundamental physical and chemical aspects, this review summarizes the current state of knowledge of hydrothermal biomass conversion in subcritical water. After briefly introducing subcritical water as a reaction medium, its advantages for biomass processing compared to other thermal processes are highlighted. Subsequently, the physical‐chemical properties of subcritical water are discussed in the light of their impact on the occurring chemical reactions. The influence of major operational parameters, including temperature, pressure, and reactant concentration on hydrothermal biomass transformation processes are illustrated for selected carbohydrates. Major emphasis is put on the nature of the carbohydrate monomers, since the conversion of the respective polymers is analogous with the additional prior step of hydrolytic depolymerization.Keywords
This publication has 102 references indexed in Scilit:
- Fructose decomposition kinetics in organic acids-enriched high temperature liquid waterBiomass and Bioenergy, 2009
- Hydrothermal upgrading of wood biomass: Influence of the addition of K2CO3 and cellulose/lignin ratioFuel, 2008
- Biodiesel from microalgaeBiotechnology Advances, 2007
- An overview of dehydration, aldol-condensation and hydrogenation processes for production of liquid alkanes from biomass-derived carbohydratesCatalysis Today, 2007
- Kinetics of Levulinic Acid Formation from Glucose Decomposition at High TemperatureChinese Journal of Chemical Engineering, 2006
- Decomposition behavior of cellulose in supercritical water, subcritical water, and their combined treatmentsJournal of Wood Science, 2005
- Chemical Reactions of C1 Compounds in Near-Critical and Supercritical WaterChemical Reviews, 2004
- Pyrolysis of biomass to produce fuels and chemical feedstocksEnergy Conversion and Management, 2004
- Chemie in überkritischem WasserAngewandte Chemie, 1999
- Dehydration of d-fructose to levulinic acid over LZY zeolite catalystBiomass, 1987