Magnetic TEMPO Catalyst for Oxidation Reactions
Allows for oxidation of biomass and easy reuse of catalyst
- Reusable TEMPO catalyst
- Excellent conversion rates
- High stability (temperature, pH)
- Suitable for oxidation of woody biomass
2,2,6,6-Tetramethyl-1-piperidinyloxyl (TEMPO) is a classical homogeneous catalyst in chemical and biochemical oxidation reactions. While TEMPO delivers excellent reaction rates and product conversion, it is also toxic to the aquatic environment and among the more expensive commercial catalysts. Especially, in large-scale biomass functionalization processes, greater amounts of TEMPO are often lost during the reaction, in waste water effluent. For environmental and economical reasons, preventing the loss of TEMPO catalyst after the oxidation reaction is critical.
Researchers at The University of British Columbia have now developed a green and cost effective process to prevent the loss of TEMPO. The team under the leadership of Dr. Renneckar linked TEMPO to magnetic nanoparticles. Their Co@MagTEMPO and Fe@MagTEMPO catalysts demonstrated complete conversion of alcohols to carboxylic acids during the oxidation of woody biomass, such as cellulose pulp and Kraft lignin. These magnetic TEMPO catalysts are not only stable over a wide pH and temperature range but also are easily and fully recovered from the oxidized woody biomass simply by using magnetic force, a feature that further enables their recycling. The catalysts may be reused several times without losing their catalytic activity, as even with low catalyst loadings (0.2 mg.cm-3) fast reaction rates (0.25 mmol.g-1.h-1) were achieved.