Hydrogen fluoride saccharification of wood: lignin fluoride content, isolation of alpha-delta-glucopyranosylfluoride and posthydrolysis of reversion products
Wood chips from bigtooth aspen (Populus grandidentata Michx.) were saccharified by reaction with liquid hydrogen fluoride either anhydrous or containing up to 10% v/v water. The reaction products were separated into a solid lignin fraction and a water-soluble saccharide fraction. The fluoride content of the lignin (determined after alkaline fusion) was initially about 1 mg/g wood, but was lowered to 0.1 mg/g wood by grinding and washing. Thus little or no chemical binding of fluoride to lignin occurred during hydrogen fluoride (HF) solvolysis. Analysis of the water-soluble fraction by gel filtration on Biogel P2 columns showed a range of low-molecular-weight oligosaccharides and only 10-20% sugar monomers. Thus considerable reversion occurred during HF evacuation. Posthydrolysis conditions were optimized for these reversion products by varying temperature and acid concentration. Optimal conditions at 1 h were 140 degrees C with 100mN sulfuric acid or 225 mN hydrofluoric acid resulting in monomer yields of more than 90% for 0.5% sugar solutions and more than 80% for 10% sugar solutions. After reaction of pure cellulose (filter paper) with hydrogen fluoride in the absence of water, and terminating the reaction with calcium carbonate, the reaction intermediate alpha-D-glucopyranosylfluoride was isolated with a maximal yield of 0.2 g/g paper. Upon purification via paper chromatography glucosylfluoride was identified by its specific rotation and also by gas chromatography-mass spectrometry of its tetra-O-trimethylsilyl derivative. (Refs. 32).
- Research Organization:
- Plant Research Lab, Michigan State Univ, East Lansing, MI 48824
- OSTI ID:
- 6742440
- Journal Information:
- Biotechnol. Bioeng.; (United States), Vol. 24:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
WOOD
ACID HYDROLYSIS
CELLULOSE
CHROMATOGRAPHY
FILTRATION
GLUCOSE
HYDROFLUORIC ACID
LIGNIN
ORGANIC FLUORINE COMPOUNDS
POPLARS
REACTION INTERMEDIATES
SACCHARIFICATION
ALDEHYDES
CARBOHYDRATES
CHEMICAL REACTIONS
DECOMPOSITION
HEXOSES
HYDROGEN COMPOUNDS
HYDROLYSIS
INORGANIC ACIDS
LYSIS
MONOSACCHARIDES
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PLANTS
POLYSACCHARIDES
SACCHARIDES
SEPARATION PROCESSES
SOLVOLYSIS
TREES
140504* - Solar Energy Conversion- Biomass Production & Conversion- (-1989)