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首页> 外文期刊>RSC Advances >Zinc-based deep eutectic solvent-mediated hydroxylation and demethoxylation of lignin for the production of wood adhesive
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Zinc-based deep eutectic solvent-mediated hydroxylation and demethoxylation of lignin for the production of wood adhesive

机译：基于锌的深度共晶溶剂介导的木质素的羟基化和木质素去甲氧化物生产木材粘合剂

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Choline chloride-ZnCl2 deep-eutectic solvent (ChCl-ZnCl2 DES), mole ratio 1 : 2, was used to improve the chemical reactivity of wheat straw alkali lignin under different temperatures and times of pretreatment. The chemical structure of the resulting modified lignin was studied by UV, FT-IR, H-1, C-13 and P-31-NMR spectroscopies, TGA, NALDI-TOF MS and ICP. Interestingly up to 10 wt% of lignin can be readily dissolved in ChCl-ZnCl2 DES under the optimized pretreatment conditions (80 degrees C, 1 h) yielding ca. 65% of modified lignin upon precipitation using water as an antisolvent. As a result of the chemical modification of lignin occurring during its dissolution in DES, the total phenolic hydroxyl of the fraction precipitated increased ca. 1.9-fold while methoxyl moieties were reduced between 1.6 and 2.2-fold when compared with untreated lignin. Thus, in the fraction of lignin precipitated, phenolic hydroxyl formation took place at the expense of selective methoxyl cleavage from the aromatic ring, judging by the decrease of S units, whereas beta-O-4' linkages and molecular weight remain unchanged. Finally modified lignin was used as a phenol replacement in the synthesis of phenol-formaldehyde (PF) adhesives. Remarkably, the strength of the modified resin (1.3 MPa) compared with PF resin was practically the same when 40 wt% of the phenol was replaced by the modified lignin. This work shows that lignin can be readily modified in a DES-improving its reactivity-further advancing its prospective use in the wood industry.
机译：胆碱氯化叔锌深 - 共晶溶剂（CHCl-ZnCl2 DES），摩尔比1：2用于改善小麦秸秆碱木质素的化学反应性，不同温度和预处理的时间。通过UV，FT-IR，H-1，C-13和P-31-NMR谱，TGA，NALDI-TOF MS和ICP研究得到的改性木质素的化学结构。有趣的是，在优化的预处理条件下，可以很容易地溶解在CHCl-ZnCl2 DE中（80摄氏度，1小时）的CA.使用水作为抗溶剂沉淀的65％改性木质素。由于在DES溶解期间发生木质素的化学改性，馏分的总酚羟基沉淀出来。 1.9倍，而与未经处理的木质素相比，甲氧基部分在1.6和2.2倍之间。因此，在木质素的沉淀部分中，酚醛羟基形成以芳香环的选择性甲氧基切割的牺牲，通过减少单位的降低来判断，而β-O-4'连杆和分子量保持不变。最后改性木质素用作合成酚醛（PF）粘合剂的苯酚替代品。值得注意的是，当通过改性木质素替换40wt％的苯酚时，与PF树脂相比的改性树脂（1.3MPa）的强度几乎相同。这项工作表明，木质素可以在DES改善其反应性的情况下容易地修改 - 进一步推动其在木业的前瞻性用途。

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  • 来源
    《RSC Advances》 |2016年第92期|共10页
  • 作者

    Hong Shu; Lian Hailan; Sun Xiang; Pan Dong; Carranza Arturo; Pojman John A.; Mota-Morales Josue D.;

  • 作者单位

    Nanjing Forestry Univ Coll Mat Sci &

    Technol Nanjing 210037 Jiangsu Peoples R China;

    Nanjing Forestry Univ Coll Mat Sci &

    Technol Nanjing 210037 Jiangsu Peoples R China;

    Nanjing Forestry Univ Coll Mat Sci &

    Technol Nanjing 210037 Jiangsu Peoples R China;

    Nanjing Forestry Univ Coll Mat Sci &

    Technol Nanjing 210037 Jiangsu Peoples R China;

    Louisiana State Univ Dept Chem Baton Rouge LA 70820 USA;

    Louisiana State Univ Dept Chem Baton Rouge LA 70820 USA;

    UNAM CONACYT Ctr Nanociencias &

    Nanotecnol CNyN Ensenada 22860 BC Mexico;

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  • 正文语种 eng
  • 中图分类 化学;
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