Quantification of muconic acid-type structures in high molecular weight material from bleach plant effluents

Effluents from the chlorine dioxide bleaching of chemical pulps were characterized with respect to high and low molecular weight material, GOD, TOC, elemental composition, and carboxylic acid and methyl ester content. A technique was developed for the quantitative estimation of muconic acid-type structures as moities of the high molecular weight material. The method is based on the use of quantitative C-13 NMR and the pH-dependent cyclization of muconic acids in aqueous solution. 20-40 % of the carboxylic acids in the high molecular weight material isolated from bleach plant effluents from three softwood kraft mills were found to exhibit muconic acid-type behaviour.