Synthesis of cationic hemicellulosic derivatives with a low degree of substitution in dimethyl sulfoxide media

Abstract

A series of water-soluble cationic 2-hydroxylpropyltrimethylammonium hemicellulosic derivatives with low average degrees of substitution (DS's) were prepared by the incorporation of the cationic moiety 2,3-epoxypropyltrimethylammonium chloride (ETA) onto the backbone of hemicelluloses in the presence of NaOH as a nucleophilic catalyst in homogeneous dimethyl sulfoxide (DMSO) media. The dependence of the homogeneous reaction on the different affecting factors was investigated. The average DS was calculated from the N/C ratio in the products and from the weight gain. The degree of substitution determined by the nitrogen content (DS N ) values up to 0.25 in a one-step synthesis of the etherified hemicelluloses could be controlled by the adjustment of the amount of solvent used and the molar ratio of NaOH or ETA to the anhydromonomer units in the hemicelluloses. The structure of the cationic hemicellulosic derivatives formed was determined by Fourier transform infrared spectroscopy and further confirmed with solution-state 13 C-NMR spectroscopy. In comparison, no significant degradation of the hemicellulosic derivatives occurred during the etherification of the polymers in the homogeneous DMSO system.

Effect of Cationic Hemicellulosic Fractions from Corncob Obtained by Graded Ethanol Precipitation on Recycled Paper Strength

“…The absorption at 3468 cm -1 is attributed to the stretching of -OH groups (Ren et al 2007a). The C-H stretching vibration gave signals at 2920 cm -1 (Ren et al 2008). The band at 1646 cm -1 is attributed to the bending mode of the absorbed water.…”

Application of cationic hemicelluloses produced from corn husk as polyelectrolytes in sewage treatment

“…The cationic hemicelluloses were produced according to the procedure described by Ren et al (2008) [9] , as follows: Hemicelluloses (0.5 g) and distilled water (5 mL) were stirred for 30 min at 60 °C; NaOH (0.7 g) was added to the system, which was stirred for 20 min; ETA (3.46 g) was added to the system, which was stirred for 30 min; NaOH (1.1 g) was added to the system, which was stirred for 5 h at 60 °C. The mixture was cooled in ice bath and neutralized with HCl solution.…”

“…The amorphous character and low molecular weight of hemicellulose allow a better accessibility of the polymeric chain and, consequently, lead to better reactivity when compared to other lignocellulosic compounds, such as cellulose. Also, cationic hemicellulose derivatives usually present high solubility in water, which is an important aspect of polyelectrolytes used for effluent treatment [8][9][10] . Considering the abundance of hemicelluloses in lignocellulosic biomass, the production and application of their derivatives are very important.…”

“…Cationic hemicellulose can be prepared by various methods [8][9][10][11][12] . In this paper, hemicelluloses obtained from corn husk were converted into cationic hemicelluloses by quaternization with 2,3-epoxypropyltrimethylamonium chloride (ETA), and then used for sewage treatment at the …”

Incorporation of carboxyl groups into xylan for improved absorbency

“…A number of attempts have been made to modify hemicelluloses using different types of vinyl monomers to improve properties (Ren et al 2008a;Lindblad et al 2005). A few efforts were made to increase the hydrophobicity which is an issue when introducing the hemicellulose into water (Hettrich et al 2006;Ren et al 2008b;Natanya andPlackett 2008 andVoepel et al 2009).…”