LIGNOCELLULOSIC COMPOUNDS DECOMPOSITION IN SUBCRITICAL AND SUPERCRITICAL WATER
Liquefaction of lignocellulosic compounds by thermochemical treatment is being investigated in order to produce renewable chemicals and biofuels. However, reactivity of lignocellulosic materials is not completely elucidated yet because of the complex chemical composition of hydroliquefaction products (polydispersity of oxygenated functional groups and wide range of molecular weights). In this work, hydrothermal degradations of model compounds representative of lignocellulosic biomass are studied in sub-and supercritical water which have been selected for the singular solvent (i.e. dielectric constant equivalent to acetone) and acido-basic catalytic properties of water under those intense conditions (2030MPa and 300-400℃). Hydrothermal liquefaction products are characterized by a multitechnique analytical approach which combines chromatographic, spectrometric and spectroscopic methods, aiming to define conversion pathways of lignocellulosic compounds. Characterizations of hydrothermal conversion products from lignocellulosic monomers reveal that molecular weight ranges of products resulting from liquefaction of lignocelluloses are higher than the ones of starting materials, showing that condensation reactions occur with significance. Chemical formulae of products and MS-MS study reveal that condensation reactions come partly from alkylation of aromatic rings which are generated by hydrolysis of ether bonding in lignin and aromatization of monosaccharides. By this experimental approach, we show that thermochemical liquefaction of lignocellulosic compounds produce a polydisperse mixture of oxygenated chemicals coming from a complex pathway occurring with competitive reactions. We focus on hydrothermal liquefaction pathway investigation, and more particularly, on the condensation reactions which are involved in the formation of heavy products during the thermal conversion of biomass. The knowledge of these condensation reactions leads to a better understanding of secondary reactions supported during thermochemical liquefaction of lignocellulosic biomass, which is necessary for the further development of efficient and selective catalytic processes.
Lignocellulose Subcritical water Analytical characterization Condensation reactions Pathway
J. BARBIER N. CHARON N. DUPASSIEUX A. LOPPINET-SERANI M.COURTIADE A. DUCROZET A. FONVERNE J. PONTHUS F. CANSELL
IFP, BP3, 69360 Vernaison, France CNRS, Université de Bordeaux, ICMCB site de lENSCPB, 87 avenue du Dr. Schweitzer,33608 Pessac, Fran
国际会议
北京
英文
967-972
2010-05-17（万方平台首次上网日期，不代表论文的发表时间）