title: Behaviour of xyloisosaccharinic acid and xyloisosaccharino-1,4-lactone in aqueous solutions at varying pHs.
abstract: Xyloisosaccharinic acid is one of the major degradation products formed during the alkali catalysed hydrolysis of hemicelluloses. In acidic solution xyloisosaccharinic acid undergoes an acid catalysed lactonisation to generate xyloisosaccharino-1,4-lactone. We report here the solution phase properties of xyloisosaccharinic including measurement of its aqueous pK(a) (3.00 ± 0.05) using (13)C NMR methods. We also report rate constants for the acid catalysed lactonisation, k(lact(D20)), of xyloisosaccharinic acid and the results of our investigations of the kinetics of hydrolysis of xyloisosaccharino-1,4-lactone at acidic and basic pHs. The second-order rate constants for the hydrolysis reactions k(HO-) (25 M(-1)s(-1)) and k(D+) (4.13 E-4M(-1)s(-1)).
authors.affiliation: Department of Chemical and Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Almond
authors.forename: Paul B
authors.initials: PB
authors.lastname: Shaw
authors.forename: Paul N
authors.initials: PN
authors.lastname: Humphreys
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Chadha
authors.forename: Klaus
authors.initials: K
authors.lastname: Niemelä
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Laws
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D012996:Solutions; D013400:Sugar Acids / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D012996:Solutions; D013400:Sugar Acids; D014867:Water; D015107:4-Butyrolactone