Periodate oxidation of 4-O-methylglucuronoxylans: Influence of the reaction conditions

• 4-O-Methylglucuronoxylans were oxidized to obtain aldehyde functionalized xylans.
• Periodate content and xylan concentration have a limited effect on aldehyde contents.
• Reaction temperature and xylan molar mass have a drastically impact on aldehyde content.
• MGX chain length drastically impacts the reaction rate for a constant amount of periodate consumed.

This work aims at studying the sodium periodate oxidation of 4-O-methylglucuronoxylans (MGX) in different experimental conditions for a control of the oxidation degree. A series of sodium periodate oxidation reactions were conducted at three NaIO4/xylose molar ratios: 0.05, 0.20 and 1.00. The effects of xylan molar mass, xylan concentration and reaction temperature on the reaction rate have been evaluated by UV/visible spectroscopy at 0.20 NaIO4/xylose ratio. No depolymerization is observed at 0.05 ratio while depolymerization occurs at 0.20 and is even complete at 1.00 NaIO4/xylose ratio. An increase of the reaction temperature – up to 80 °C – leads to an increase of the oxidation rate with no effect on the depolymerization. At high xylan concentrations, the oxidation rate increases but promotes chains aggregation.