Determinação da relação siringila/guaiacila de lignina de Eucalyptus spp. por pirólise analítica

• Autor(a) principal: Guimarães, Cleide de Castro Justino
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5931
• topic: Lignina; Pirólise analítica; Relação siringila/guaiacila; Lignin; Analytical pyrolysis; Syringyl/guaiacyl ratio; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::TECNOLOGIA E UTILIZACAO DE PRODUTOS FLORESTAIS::TECNOLOGIA DE CELULOSE E PAPEL

During Kraft pulping and subsequent pulp bleaching, almost all of the lignin is removed. Therefore, it is important to know about quantity and quality of lignin, cellulose and hemicellulose in the wood to predict the pulp extraction process and the final product s quality with good precision. It is known that the lignin composition concerning the amounts of syringyl units (S) and guaiacyl (G) can affect the efficiency of kraft pulping. Syringyl/guaiacyl ratio (S/L) was determined in Eucalyptus clones, grown in Guanhães region, Minas Gerais state, by pyrolysis coupled to gas chromatography and mass spectrometry (Py-GC/MS). Samples were pyrolyzed at 550 ° C and 39 compounds were identified - 14 derived from carbohydrates and 25 derived from lignin. Syringyl/guaiacyl ratio was calculated based on area values of the signals recorded in the pyrogram and compared with the results obtained by nitrobenzene alkaline oxidation method. Guaiacol,4-methyl- 1,2-Benzenediol, 4-vinyl guaiacol, vanillin, eugenol and Isoeugenol were used as guaiacyl type markers and Metoxyeugenol; cis-4-propenylsyringol, syringaldehyde, 4-vinylsiyringol and trans-4-propenylsyringol as syringyl type markers to perfom S/G ratio calculations. These markers were used in the analysis of the main componentes, which can separate the clones and identify the compounds responsible for the separation and observe the similarity of the peaks of the compounds for analysis by hierarchical clustering. The proposed methodology using lignin markers was proved useful in determining the S/G ratio in eucalyptus wood by Py-GC/MS, insofar as the analysis speed and the small amounts of samples consumption.