Sodium periodate mediated oxidative extraction of polysaccharide-derived structures from wood biomass: Influence of reaction time and oxidation conditions in birch and spruce

Sodium periodate (NaIO4) oxidation was used as a direct method to recover soluble wood components, primarily hemicelluloses, from untreated birch and spruce biomass. Through monitoring the reaction over time and at different oxidant-to-biomass ratios, the study elucidated the relationship between periodate consumption, aldehyde formation, and polysaccharide solubilization. A rapid initial uptake of the oxidant led to aldehyde generation and the extraction of hemicellulosic fractions, mainly xylan-rich in birch and glucomannan-rich in spruce followed by a decreasing (detectable) oxidizing effect likely due to further conversions of introduced aldehydes. Fourier transform infrared and heteronuclear single quantum correlation nuclear magnetic resonance analyses confirmed structural modifications consistent with monosaccharide ring opening and further conversions of created aldehydes. Size-exclusion chromatography revealed the expected accompanying chain cleavage of the affected structures. Together, these findings demonstrate both the potential and complexity of using periodate oxidation for simultaneous extraction and functionalization of wood polysaccharides, emphasizing the need for proper optimization.