Behaviors of southern red oak hemicelluloses and lignin in a mild sulfuric acid hydrolysis

Abstract

Removal and modification of southern red oak hemicelluloses and lignin in a 0.05%(w/v) sulfuric acid hydrolysis were investigated. The hydrolysis profile was to raise the reaction from room temperature to 150 degrees C for in 38 min and to extend the hydrolysis at 150 degrees C for 1 h. At the end of the hydrolysis, 25.5% of red oak components were dissolved, of which 58% was xylose and 17% lignin. As the hydrolysis proceeded from room temperature to 150 degrees C, a part of red oak xylan was removed to yield an oligomer fraction having maximal yield and average molecular weight of 3460 at 150 degrees C. This fraction and the bulk xylan extracted during the first 30 min at 150 degrees C were further degraded to give a lower molecular weight oligomer fraction, of which the yield and average molecular weight (2610) were highest at the end of the bulk removal of xylan. Red oak lignin, syringyl and guaiacyl units in particular, was increasingly removed with the progress of the hydrolysis. Lignin derivatives and a part of red oak extractives soluble in the hydrolysate were identified.

Batch Aqueous-Phase Reforming of Woody Biomass

“…In general, because of its branched structure and lower degree of polymerization, hemicelluloses are more susceptible to hydrolysis than cellulose. ,,− It is to be expected then that the hemicellulose fraction of biomass is degraded faster than the cellulose fraction. This was observed by Tran and Chambers during mild sulfuric acid hydrolysis of southern red oak at 150 °C as well as in the hydrothermal processing of lignocellulosic materials between 150−230 °C in the study made by Garrote and others . In a study reported by Karagoz et al on biomass liquefaction, it was shown that mainly phenolic compounds are found in the bio-oil of wood biomass when it is treated with different bases and their salts at 280 °C for 15 min.…”

Exploring Nonspecific Protein Adsorption on Lignocellulosic Amphiphilic Bicomponent Films

“…It is clear that the investigated systems only address very specific cases where cellulose and fatty acid esters of lignin are physically mixed, while in real systems the lignin is covalently attached to, for example, hemicelluloses. Although a wide range of acetylated lignins has been reported, , fatty acid esters involving lignins account for a rather low proportion of the total lignin and it is not sure whether they exist in nature at all. , However, there are other aromatic compounds such as suberins and urushiols where phenolic fatty acid esters are major constituents determining the structure and the function of cell wall components (e.g., cork). Moreover, it is assumed by some authors that suberins may be linked covalently to polyaromatic compounds such as lignins. , …”

Carbon Quality of Four-Year-Old Woodchips in a Denitrification Bed Treating Agricultural Drainage Water

“…The mean lignin concentration of the four-year-old woodchips at each location along the length of the bed ranged from 26.9% ± 0.75 (at 79.6 m) to 31.0% ± 0.78 (at 0 m) (table 1). As the woodchips were identified as hardwood (i.e., White Elm, Cottonwood, and Red Oak), we expect that the initial lignin concentration ranged from 22% to 24% (Pettersen, 1984;Rowell, 2013;Tran and Chambers, 1986).…”