Kraft lignin reaction with paraformaldehyde
نویسندگان
چکیده
منابع مشابه
The effect of metal ions on the reaction of hydrogen peroxide with Kraft lignin model compounds
Peroxide bleaching is significantly affected by transition and alkaline earth metals. Isolating the effects of different transition and alkaline earth metals on the reactions of peroxide with different representative lignin structures allows the separation of the positive from the negative contributions of these metal ions. In this work, five monomeric or dimeric phenolic lignin model compounds...
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Laboratory-obtained kraft lignins have been studied via elemental analysis (EA), 1H-NMR, FTIR, GPC to analyse the chemical structure. The kraft lignins were subjected to oxidation with H2O2 using Co(salen) as a biomimetic catalyst at mild condition (80oC, 240 min). The kraft lignins isolated from eucalyptus (EKL) and bamboo (BKL) had a low hydroxyl (oxygen) contents, a low molecular weights (~3...
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Linear hydrophilic derivatives are expected to soften lignin and improve its utilization in composite applications. Oxidation by means of laccase in the presence of oxygen was employed in an attempt to functionalize commercial kraft lignin by vanillic acid-PEG ester and ether derivatives. Thielavia arenaria and Melanocarpus albomyces laccases at pH 6 and 8 were used. According to O2 consumption...
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I n chemical pulping a large part of the wood is dissolved during digestion. The dry matter content of the generated black liquor is typically 12 to 18 wt% [1, 2]. In the case of kraft black liquors four main groups of organic constituents are present, 30-45 wt% ligneous material, 25-35 wt% saccharinic acids, about 10 wt% formic and acetic acid, and 3-5 wt% extractives. It also contains about 1...
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A series of activated carbons (ACs) were prepared by K2CO3 activation from kraft lignin (KL) that was recovered from papermaking black liquor. The effects of process parameters such as the activation temperature (AT), activated period, K2CO3 to KL mass ratio, and N2 flow rate on the characteristics of the final product were determined. The ACs were characterized using nitrogen adsorption, morph...
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ژورنال
عنوان ژورنال: Holzforschung
سال: 2019
ISSN: 1437-434X,0018-3830
DOI: 10.1515/hf-2019-0147