Effect of s/g ratio on kraft pulping and ecf bleaching of some poplars and eucalyptus
Contribuinte(s) |
Universidade Estadual Paulista (UNESP) |
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Data(s) |
03/12/2014
03/12/2014
01/03/2014
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Resumo |
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The effect of syringyl:guaiacyl (S/G) ratio on kraft pulping and kraft pulping followed by O-2 delignification was investigated with six poplars grown on the same site. The results showed an improvement in the ease of delignification (EOD) when the S/G ratio was increased from a low to a moderately high value. However, above that moderately high value there was no further improvement in EOD with increasing S/G ratio. Kraft pulping followed by elemental chlorine-free (ECF) bleaching was then investigated with three Brazilian eucalypti with S/G ratio of 2.69, 2.46 and 2.41. The chips with S/G = 2.69 had superior EOD compared to the chips with S/G = 2.41. However, pulps from the S/G = 2.69 chips also contained less lignin-carbohydrate complexes (LCC) than corresponding pulps from the chips with S/G = 2.41. LCC are known to retard delignification in both alkaline pulping and ECF bleaching. The S/G ratio of eucalyptus pulp lignins was estimated by nitrobenzene oxidation (NBO) of the pulps and H-1 NMR or their isolated lignins. The S/G ratio decreased from a value of >= 2.46 for the lignin in two eucalyptus chip samples to <= 1.21 for the lignin in their kraft pulps. In general, S units appear to solubilize at a much higher rate than G units during kraft pulping. |
Formato |
365-373 |
Identificador |
http://www.cellulosechemtechnol.ro/pdf/CCT3-4%282014%29/p.365-373.pdf Cellulose Chemistry and Technology. Bucuresti: Editura Acad Romane, v. 48, n. 3-4, p. 365-373, 2014. 0576-9787 http://hdl.handle.net/11449/111469 WOS:000339139600020 |
Idioma(s) |
eng |
Publicador |
Editura Acad Romane |
Relação |
Cellulose Chemistry And Technology |
Direitos |
closedAccess |
Palavras-Chave | #Hardwood #S/G ratio #lignin-carbohydrate complexes #kraft pulping #ECF bleaching |
Tipo |
info:eu-repo/semantics/article |