| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4514637 | Industrial Crops and Products | 2012 | 8 Pages |
Miscanthus × giganteus bark was subjected to mild fractionation with peroxyformic acid by a two stage process. A factorial experimental design was used to study and quantify the effect of the variables (formic acid concentration (80–90%), hydrogen peroxide concentration (0.2–0.4%), temperature of the first stage (60–80 °C), and treatment time of the second stage (60–120 min)) on the main parameters of fractionation: pulp yield, remaining lignin and total polysaccharides in pulp. The dependence of lignin precipitation rate on hydrogen peroxide concentration in liquor was also studied. Hydrogen peroxide concentrations inferior to 0.5% seems to be suitable to recover high percentages of lignin. The isolated lignin was analysed by 2D-HSQC, 13C- and 31P NMR spectroscopy, FTIR spectroscopy, size-exclusion chromatography and chemical analysis. The most important chemical modifications taken place in the lignin during the fractionation were identified: β-O-4′ cleavage and hydrolysis of LC-bond structures. The C9-formula was also determined: C9H6.81O2.90(OCH3)0.68(COOH)0.07(OHPh)0.38(OHAl)0.33.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Mild peroxyformic acid fractionation of Miscanthus × giganteus was modeled. ► Formic acid concentration and temperature were the most influential variables. ► %H2O2 < 0.5 must be used to recover enough quantity of lignin from black liquors. ► The recovered lignin was characterized. ► β-O-4′ cleavage and hydrolysis of LC-bond structures were important modifications.
