INVESTIGATION OF HYDROGEN ABSTRACTION FROM METHYL GLUCOSIDE BY ACTIVE OXYGEN SPECIES UNDER OXYGEN BLEACHING CONDITIONS
Two carbohydrate model compounds, methyl β- D-glucopyranoside (MGP) and its deuterated derivative, methyl β-D-(1-2H)glucopyranoside (MGP- 1D) or methyl β-D-(2-2H)glucopyranoside (MGP-2D), were subjected together to reactions with active oxygen species (AOS) under oxygen bleaching conditions (0.5 mol/L NaOH, 0.36 mmol/L Fe3+, 1.1 MPa O2, 95OC). In this system, AOS were in situ generated by reactions of O2 with a co-existing phenolic compound, 2,4,6-trimethylphenol (TMPh) or 4-hydroxy-3-methoxybenzyl alcohol (vanillyl alcohol, VA). When the origin of AOS was TMPh, kinetic isotope effects were observed in the oxygen-alkali treatments of both MGP-1D and MGP-2D. Hence, the anomeric and C-2 hydrogens of MGP were confirmed to be abstracted by AOS generated from TMPh. However, no clear kinetic isotope effects were observed in both cases when the origin of AOS was VA. Contrary, it is too early to conclude that the hydrogens are not abstracted by AOS originated from VA because the AOS are possibly such species that do not show any clear kinetic isotope effect even when the AOS abstract the hydrogens. This possibility is now being investigated.
active oxygen species bleaching carbohydrate kinetic isotope effect lignin
Tomoya Yokoyama Fumiko Konishi Akihiko Nakagawa Yuji Matsumoto
Laboratory of Wood Chemistry, Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo,113-8657, Japan
国际会议
广州
英文
434-437
2010-11-08（万方平台首次上网日期，不代表论文的发表时间）