Stereo-preference in the degradation of the erythro and threo isomers of β-O-4-type lignin model compounds in oxidation processes III: in the reaction with chlorine- and manganese-based oxidants

We examined which isomer, the erythro or threo, of a non-phenolic β-O-4-type lignin model compound is stereo-preferentially oxidized in hypochlorite, chlorite, manganese dioxide, or permanganate systems. No clear stereo-preference was observed in the hypochlorite or chlorite systems at alkaline, neutral, or acidic pH except for a slight threo stereo-preference that appeared after the step-wise addition of the oxidizing reagent had been terminated in the neutral or acidic chlorite systems. A clear threo stereo-preference was observed in the manganese dioxide or permanganate systems.