Carboxymethylcellulose obtained by ethanol/water organosolv process under acid ...

• Autor(es): Ruzene, Denise S. ; Gonçalves, A. R. ; Teixeira, J. A. ; Amorim, M. T. Pessoa de
• Data: 2007
• Identificador Persistente: http://hdl.handle.net/1822/7744
• Origem: RepositóriUM - Universidade do Minho
• Assunto(s): Acid and alkaline catalyzed ethanol pulping; Carboxymethylcellulose; Chemical bleaching; Infrared spectra; Sugarcane bagasse; Organosolv pulping
• Tipo de Documento: Artigo
• Idioma: Inglês

Descrição

Sugar cane bagasse pulps were obtained by ethanol/water organosolv process under acid and alkaline conditions. The best condition of acid pulping for the sugarcane bagasse was 0.02 mol/L sulfuric acid at 160°C, for 1 h, whereas the best condition for alkaline pulping was 5% sodium hydroxide (base pulp) at 160°C, for 3 h. For the residual lignin removal, the acid and alkaline pulps were submitted to a chemical bleaching using sodium chlorite. Pulps under acid and alkaline conditions bleached with sodium chlorite presented viscosities of 3.6 and 7.8 mPa·s, respectively, and μ-kappa numbers of 1.1 and 2.4, respectively. The pulp under acid condition, bleached with sodium chlorite was used to obtain carboxymethylcellulose (CMC). CMC yield was 35% (pulp based), showing mass gain after the carboxymethylation reaction corresponding to 23.6% of substitution or 0.70 groups −CH2 COONa per unit of glucose residue. The infrared spectra showed the CMC characteristic bands and by the infrared technique it was possible to obtain a substitution degree (0.63), similar to the substitution degree calculated by mass gain (0.70).