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Biomass Chemical Engineering ›› 2022, Vol. 56 ›› Issue (2): 9-13.doi: 10.3969/j.issn.1673-5854.2022.02.002

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Demethylation/Hydroxyethylation Combined Modification of Corn Straw Lignin

Kaixin ZHANG, Yalan YU, Yuting DUAN, Changwei WU, Lei XUE, Pengfei HUO()   

  1. Material Science and Engineering College, Northeast Forestry University, Harbin 150040, China
  • Received:2021-02-02 Online:2022-03-30 Published:2022-03-25
  • Contact: Pengfei HUO E-mail:huopengfei@nefu.edu.cn

Abstract:

The corn straw lignin was modified by demethylation/hydroxyethylation with sodium sulfite and glyoxal, to further improve the hydroxyl content and activity of lignin. The combined modification effect on lignin was characterized by Fourier transform infrared spectroscopic(FT-IR), thermogravimetric, differential scanning calorimetry(DSC) and acetylation titration. The results showed that the corn straw lignin modified by demethylation/hydroxyethylation had excellent activity. The total hydroxyl mass fraction of the modified lignin was 88.33% higher than that of the original lignin, and the phenolic hydroxyl group increased by 14.70%, which indicated that the reaction activity was significantly enhanced. Microscopic characterization by Fourier tansform infrared spectroscopy showed that the hydroxyl content of lignin was increased in many ways by combined modification, which had a significant effect on the increase of hydroxyl content. It was found by thermogravimetric and differential scanning calorimetry (DSC) analysis characterization that compared with the original lignin, the combined modified lignin(G-DL) degraded more thoroughly, with an exothermic peak at 77 ℃ and an exothermic value of 459.82 J/g. The activity of the reaction was higher than that of demethylated lignin(DL) and raw lignin.

Key words: corn straw lignin, combined modification, hydroxyl content, reactivity

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