The formation of aromatic end group structures in O-alkyl substituted celluloses under alkaline pulping conditions

Abstract

Abstract UV resonance Raman (UVRR) spectroscopy was used to study changes in the structure of reducing end groups of O-alkyl substituted celluloses under conditions simulating the initial phase of soda pulping. The derivatives studied were carboxymethyl cellulose (CMC) with a degree of substitution (DS) of 0.58 and methyl cellulose (MC) with DS of 1.64–1.95. Hot alkaline treatments were carried out in solutions of sodium hydroxide (0.1–1 M) at 95°C in the presence of creosol as a lignin model compound. Alkali-stable aromatic end groups were generated in both cellulose ethers. Moreover, the end groups of methyl cellulose were extensively condensed with creosol. The results demonstrate that aromatisation and condensation depend on the pH and reaction time.