Hydrogen fluoride saccharification of wood: lignin fluoride content, isolation of. cap alpha. -D-glucopyranosyl fluoride and posthydrolysis of reversion products
Wood chips from bigtooth aspen (Populus grandidentata Michx.) were saccharified by reaction with 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 an 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/sup 0/C with 100mN sulfuric acid or 225mN hydrofluoric acid resulting in monomer yields of > 90% for 0.5% sugar solutions and > 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 ..cap alpha..-D-glucopyranosylfluride was isolated with a maximal yield of 0.2 g/g paper. Upon purification via paper chromatography glucosyfluoride was identified by its specific rotation and also by gas chromotography-mass spectrometer of its tetra-O-trimethylsilyl derivative.
- Research Organization:
- Michigan State Univ., East Lansing
- DOE Contract Number:
- AC02-76ER01338
- OSTI ID:
- 7152008
- Journal Information:
- Biotechnol. Bioeng.; (United States), Vol. 24:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACID HYDROLYSIS
REACTION INTERMEDIATES
WOOD
SACCHARIFICATION
ASPENS
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
GAS CHROMATOGRAPHY
HYDROFLUORIC ACID
LIGNIN
CARBOHYDRATES
CHROMATOGRAPHY
DECOMPOSITION
HYDROGEN COMPOUNDS
HYDROLYSIS
INORGANIC ACIDS
LYSIS
ORGANIC COMPOUNDS
PLANTS
POLYSACCHARIDES
SACCHARIDES
SEPARATION PROCESSES
SOLVOLYSIS
TREES
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