SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2022, Vol. 48 ›› Issue (8): 191-201.DOI: 10.1016/j.cjche.2021.07.018

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Insights into depolymerization pathways and mechanism of alkali lignin over a Ni1.2–ZrO2/WO3/γ-Al2O3 catalyst

Xinyu Lu1, Dandan Wang1, Haoquan Guo1, Pengcheng Xiu1, Jiajia Chen1, Yu Qin1, Hossain Mahmud Robin1, Chaozhong Xu1, Xingguang Zhang2, Xiaoli Gu1   

  1. 1. Co–Innovation Center for Efficient Processing and Utilization of Forest Products, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China;
    2. Department of Chemistry, School of Science, University of Shanghai for Science and Technology, Shanghai 200093, China
  • Received:2021-04-28 Revised:2021-07-18 Online:2022-09-30 Published:2022-08-28
  • Contact: Xingguang Zhang,E-mail:x.g.zhang@usst.edu.cn;Xiaoli Gu,E-mail:guxiaoli@njfu.edu.cn
  • Supported by:
    This research was financially supported by the National Natural Science Foundation of China ( 21774059), the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions.

Insights into depolymerization pathways and mechanism of alkali lignin over a Ni1.2–ZrO2/WO3/γ-Al2O3 catalyst

Xinyu Lu1, Dandan Wang1, Haoquan Guo1, Pengcheng Xiu1, Jiajia Chen1, Yu Qin1, Hossain Mahmud Robin1, Chaozhong Xu1, Xingguang Zhang2, Xiaoli Gu1   

  1. 1. Co–Innovation Center for Efficient Processing and Utilization of Forest Products, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China;
    2. Department of Chemistry, School of Science, University of Shanghai for Science and Technology, Shanghai 200093, China
  • 通讯作者: Xingguang Zhang,E-mail:x.g.zhang@usst.edu.cn;Xiaoli Gu,E-mail:guxiaoli@njfu.edu.cn
  • 基金资助:
    This research was financially supported by the National Natural Science Foundation of China ( 21774059), the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions.

Abstract: This study performed catalytic depolymerization of alkali lignin over Ni-based catalysts. Effects of different promoters (Zr and W), Ni loadings, reaction temperatures, and the addition of formic acid and catalyst on lignin conversion and products distribution were all investigated. The result showed that the highest oil yield (40.1% (mass)) was obtained at 240?℃ over Ni1.2/γ-Al2O3 promoted by Zr and W species. Quantitative analysis indicates that Zr and W species prefer to lignin depolymerization while Ni active phase prefer to hydrodeoxygenation and hydrogenation. The interconversion of products derived from lignin depolymerization was determined by gas chromatography-mass spectrometer, which demonstrated that phenolic compounds were dominant products in all lignin derived bio-oils, wherein the proportion of vanillin was highest (65.7%) at 180?℃, while that of alkyl guaiacols increased with the increase of temperature (from 12.45% at 180?℃ to 66.67% at 240?℃). Residual lignin obtained after lignin depolymerization was also investigated for detecting differences on functional groups, wherein the disappearing peaks at 1511?cm?1 (stretching of aromatic rings), 1267, 1215 and 1035?cm?1 (vibrations of guaiacyl and syringyl units) were detected by Fourier transform infrared spectrometry. Additionally, the higher O/C ratio measured by elemental analysis also confirmed that alkali lignin was depolymerized effectively under mild conditions.

Key words: Alkali lignin, Formic acid, Chemical reduction, Phenolic compounds

摘要: This study performed catalytic depolymerization of alkali lignin over Ni-based catalysts. Effects of different promoters (Zr and W), Ni loadings, reaction temperatures, and the addition of formic acid and catalyst on lignin conversion and products distribution were all investigated. The result showed that the highest oil yield (40.1% (mass)) was obtained at 240?℃ over Ni1.2/γ-Al2O3 promoted by Zr and W species. Quantitative analysis indicates that Zr and W species prefer to lignin depolymerization while Ni active phase prefer to hydrodeoxygenation and hydrogenation. The interconversion of products derived from lignin depolymerization was determined by gas chromatography-mass spectrometer, which demonstrated that phenolic compounds were dominant products in all lignin derived bio-oils, wherein the proportion of vanillin was highest (65.7%) at 180?℃, while that of alkyl guaiacols increased with the increase of temperature (from 12.45% at 180?℃ to 66.67% at 240?℃). Residual lignin obtained after lignin depolymerization was also investigated for detecting differences on functional groups, wherein the disappearing peaks at 1511?cm?1 (stretching of aromatic rings), 1267, 1215 and 1035?cm?1 (vibrations of guaiacyl and syringyl units) were detected by Fourier transform infrared spectrometry. Additionally, the higher O/C ratio measured by elemental analysis also confirmed that alkali lignin was depolymerized effectively under mild conditions.

关键词: Alkali lignin, Formic acid, Chemical reduction, Phenolic compounds