Carboxymethylcellulose obtained by ethanol/water organosolv process under acid conditions.
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 degrees C, for 1 h, whereas the best condition for alkaline pulping was 5% sodium hydroxide (base pulp) at 160 degrees 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 x s, respectively, and mu-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 -CH(2) 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).
Ruzene
Denise S
DS
Departamento de Biotecnologia, Escola de Engenharia de Lorena-USP, CxPostal 116, CEP 12.600-970, Lorena SP, Brazil.
Gonçalves
Adilson R
AR
Teixeira
José A
JA
de Amorim
Maria T Pessoa
MT
D000143:Acids / Q000737:chemistry*; D000468:Alkalies / Q000737:chemistry; D002266:Carboxymethylcellulose Sodium / Q000138:chemical synthesis*; D000431:Ethanol / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals / Q000737:chemistry*; D035261:Plant Components, Aerial / Q000737:chemistry*; D031786:Saccharum / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D000143:Acids; D000468:Alkalies; D009930:Organic Chemicals; D012997:Solvents; D014867:Water; D000431:Ethanol; D002266:Carboxymethylcellulose Sodium