The effects of pH on the inorganic products formed during the reaction of chlorine dioxide with an etherified lignin model compound have been studied. Analyses of the inorganic species produced during the reaction at pH 8 revealed that 2 mol of chlorite are liberated for every 1 mol of oxidized nonphenolic lignin model compound formed, consistent with two consecutive one-electron-transfer processes. In contrast, the low-pH reactions produced mostly ring oxidation products and chlorinated organic material, accompanied by increased levels of hypochlorous acid. The transient hypochlorous acid rapidly reacted with chlorite to generate chloride ions, with a maximum chloride formation at pH 4. Chlorate formation was shown to increase with increasing reaction pH. These results are in contrast to those previously reported for reactions with wood pulps and are explained on the basis of the slow reaction kinetics of nonphenolic lignin moieties as compared to phenolic ones, thereby enabling hypochlorous acid to react with chlorine dioxide to produce chlorate.