Gl. Rorrer et Mc. Hawley, VAPOR-PHASE HF SOLVOLYSIS OF CELLULOSE - MODIFICATION OF THE REVERSION OLIGOSACCHARIDE DISTRIBUTION BY IN-SITU METHANOLYSIS, Carbohydrate polymers, 22(1), 1993, pp. 9-13
The solvolysis of cellulose by anhydrous hydrogen fluoride (HF) vapor
produces water-soluble oligosaccharides generated by repolymerization
of the primary solvolysis product, glucosyl fluoride. In-situ methanol
ysis of glucosyl fluoride in the HF-reacting cellulose substrate reduc
ed the extent of this reversion reaction and increased the recovery of
monomers (as glucose and 1-0-methyl glucose) in the water-soluble rea
ction products. Single cellulose filter paper wafers both with and wit
hout absorbed methanol were reacted with an HF vapor stream at 30-degr
ees-C and 1.0 atm for reaction times varying from 2 to 12 min. The oli
gosaccharide product distribution in the water-soluble reaction produc
ts was then profiled by HPLC. The cellulose substrate was completely c
onverted to water-soluble products within 4 min exposure to HF vapor,
but the oligosaccharide product distribution did not reach equilibrium
until 10 min exposure to HF vapor. Absorbed methanol (5 mole methanol
to 1 mole glucan) in the cellulose substrate increased the monomer re
covery of the water-soluble reaction products from 30 mole % to 60 mol
e %.