Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/100073
Type: Artigo de periódico
Title: Pyrolysis-gas Chromatography Of The Macromolecular Fractions Of Oxidized Organocell Lignins
Author: Goncalves A.R.
Schuchardt U.
Meier D.
Faix O.
Abstract: Spruce Organocell lignin has been oxidized by O2 under pressure in acetic acid and in the presence of NaBr or NH4Br and Co(OAc)2 as catalyst in order to obtain chelating agents. The reaction time, O2 pressure, and the Co(OAc)2/bromide ratios were varied and the product quality was monitored by analytical pyrolysis-gas chromatography. The main pyrolysis products were phenol, guaiacol, 4-methyl-and 4-ethylguaiacol, catechol, isoeugenol, vanillin, and vanillic acid. In the oxidized lignins the moiety of demethoxylated, demethylated and oxidized guaiacyl units was increased. Vanillin and vanillic acid were used as marker for determination of the oxidation increments. The longer the reaction time and the more bromide as promoter was used the higher oxidation increments between 2 and 9 were observed. The oxidation increments correlate with the severity of oxidation. The yield of degradation products with low molecular weight was low. Bromides promote mainly the oxidation and not the depolymerisation of lignins. © 1997 Published by Elsevier Science B.V.
Editor: 
Rights: fechado
Identifier DOI: 
Address: http://www.scopus.com/inward/record.url?eid=2-s2.0-0031141810&partnerID=40&md5=2f904b4c387596dc40eaaaa487b33d7a
Date Issue: 1997
Appears in Collections:Unicamp - Artigos e Outros Documentos

Files in This Item:
File Description SizeFormat 
2-s2.0-0031141810.pdf551.29 kBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.