Hydrogenolysis and Activation of Soda Lignin Using [BMIM]Cl as a Catalyst and Solvent
AbstractTo improve the reactivity of the soda lignin, an acid ionic liquid 1-butyl-3-mthylimidazolium chloride ([BMIM]Cl) was used as the catalyst and solvent to degrade the soda lignin through hydrogenolysis. Structural elucidation of the lignin samples was conducted by using a combination of analytical methods including chemical analysis, ultraviolet spectrophotometry (UV spectrophotometry), Fourier transform infrared spectroscopy (FT-IR spectra), two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance (2D-HSQC NMR) techniques, and gel permeation chromatography (GPC). The antioxidant activities of the lignin samples were evaluated using the diammonium 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS+) radical scavenging and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging methods. The degradation mechanism was proposed based on the characterization results. The optimal reaction condition was as follows: the concentration of [BMIM]Cl in the solution was 10 wt %, the hydrogen initial pressure was 3 MPa, and the solution was heated for 4 h at 90 °C. After the reaction, the total hydroxyl content of the soda lignin increased by 81.3%, while the phenolic hydroxyl content increased by 23.1%. At the same time, the weight-average molar mass of the soda lignin sample decreased from 8220 to 6450 g/mol with an improved antioxidant activity. In addition, approximately 56.7% of the β-O-4 linkages were degraded in the lreaction. The main effect of the acid ionic liquid [BMIM]C1 was related to the cleavage of β-O-4 linkages. This study has shown the potential of using the catalyzed soda lignin as a natural polymer antioxidant. View Full-Text
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Zhang, S.; Liu, L.; Fang, G.; Yan, N.; Ren, S.; Ma, Y. Hydrogenolysis and Activation of Soda Lignin Using [BMIM]Cl as a Catalyst and Solvent. Polymers 2017, 9, 279.
Zhang S, Liu L, Fang G, Yan N, Ren S, Ma Y. Hydrogenolysis and Activation of Soda Lignin Using [BMIM]Cl as a Catalyst and Solvent. Polymers. 2017; 9(7):279.Chicago/Turabian Style
Zhang, Shengming; Liu, Liang; Fang, Guizhen; Yan, Ning; Ren, Shixue; Ma, Yanli. 2017. "Hydrogenolysis and Activation of Soda Lignin Using [BMIM]Cl as a Catalyst and Solvent." Polymers 9, no. 7: 279.
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