Produção Nacional
Revisado por pares
Evaluation of the Kinetics of Xylose Formation from Dilute Sulfuric Acid Hydrolysis of Forest Residues of Eucalyptus grandis
2007; American Chemical Society; Volume: 46; Issue: 7 Linguagem: Inglês
10.1021/ie0607494
ISSN1520-5045
AutoresEliana Vieira Canettieri, George J. M. Rocha, João Andrade de Carvalho, João Batista de Almeida e Silva,
Tópico(s)Advanced Cellulose Research Studies
ResumoDilute acid hydrolysis studies were performed on forest residues of Eucalyptus grandis, in a cylindrical reactor of stainless steel. The kinetics of this hydrolysis reaction was investigated employing 0.65% sulfuric acid, a residue/acid solution ratio of 1/9 (w/w), temperatures of 130, 140, 150, and 160 °C, and reaction times in the range 20−100 min. The results showed that, under the optimized conditions of acid hydrolysis employed in this study, the variables temperature and reaction time had a strong influence on hemicellulose removal and a small influence on the degree of lignin and cellulose removal. The highest xylose extraction yield was 87.6% attained at 160 °C, after 70 min reaction time, simultaneously with the formation of decomposition products, namely 2.8% acetic acid, 0.6% furfural, and 0.06% 5-hydroxymethylfurfural. A similar xylose extraction yield (82.8%) was observed at 150 °C after 100 min, with the formation of 3.2% acetic acid, 1.0% furfural, and 0.07% 5-hydroxymethylfurfural. The kinetic parameters determined at 130, 140, 150, and 160 °C for degradation of xylan present in the hemicellulose of the eucalyptus forest residue during the formation of xylose were the first-order reaction rate constants (k) for each temperature, 1.22 × 10-4, 2.12 × 10-4, 5.43 × 10-4, and 9.05 × 10-4 s-1, respectively, and an activation energy (Ea) of 101.3 kJ mol-1.
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