title: Trapping of p-coumaryl and coniferyl alcohol during soda-anthraquinone treatment: a means of estimating uncondensed β-O-4 structures in native lignin.
abstract: In most native lignins, at least 50% of the phenylpropane (C(9)) units are involved in β-O-4 linkages. It was recently observed that ethylguaiacol (EG) was efficient at trapping coniferyl alcohol generated from the cleavage of uncondensed β-O-4 dimeric structures during soda-anthraquinone (AQ) or SAQ delignification of sugar maple wood meal. Some of the coniferyl alcohol was transformed to vinylguaiacol and isoeugenol, and the α-carbon atom in all three monomers formed C-C bonds with the C-5 position of EG. In the present research, eucalyptus and sugar cane bagasse meals were also investigated, and the yields of uncondensed β-O-4 structures in the nonsyringyl fraction were quantitated. The estimates of the uncondensed fraction of the lignin in the three samples (assuming S units are 90-95% uncondensed) were in close agreement with results from traditional but more tedious methods such as permanganate oxidation or spectroscopic methods requiring a sample representative of native lignin.
authors.affiliation: Department of Paper and Bioprocess Engineering (PBE), SUNY College of Environmental Science & Forestry (ESF), 1 Forestry Drive, Syracuse, New York 13210, USA.
authors.forename: Ericka F
authors.initials: EF
authors.lastname: Alves
authors.forename: Samar K
authors.initials: SK
authors.lastname: Bose
authors.forename: Raymond C
authors.initials: RC
authors.lastname: Francis
authors.forename: Mohammed
authors.initials: M
authors.lastname: El Moussaouiti
mesh_terms: D031002:Acer / Q000737:chemistry; D000880:Anthraquinones / Q000737:chemistry*; D005052:Eucalyptus / Q000737:chemistry; D008031:Lignin / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010636:Phenols; D031786:Saccharum / Q000737:chemistry; D014934:Wood / Q000737:chemistry*
chemical_list: D000880:Anthraquinones; D010636:Phenols; D008031:Lignin; C010559:coniferyl alcohol