| Abstrakt: |
In this research, the process of alkalization of cotton cellulose with solutions of sodium hydroxide of different concentrations has been studied. It was found that the enthalpy of cellulose alkalization with 30-40% NaOH solutions is more exothermic than with 16- 20% alkalis. Thus, the cellulose treatment with 30-40% alkalis provides the formation of more reactive alkali cellulose. In addition, the determination of the formation enthalpy of alkali celluloses showed that this thermochemical characteristic is exothermic, and therefore, the process of cellulose alkalization is energetically favorable. A study of the methylation reaction of alkali cellulose with methyl chloride to a degree of substitution of 1.3-1.8 showed that the enthalpy of this reaction is quite exothermic and ranges from -184 to -287 kJ/mol. Since the exothermic value of the enthalpy of the chemical reaction is 7-11 times higher than the exothermic enthalpy of cellulose alkalization, the alkalization process of cellulose cannot be a chemical reaction of the alcoholate formation. It is most likely that alkalization is a physicochemical process of forming a molecular adduct of hydrated hydroxide ions with cellulose. [ABSTRACT FROM AUTHOR] |
