The controlled catalytic oxidation of furfural to furoic acid using AuPd/MgIJ(OH)2

© 2017 The Royal Society of Chemistry. The emphasis of modern chemistry is to satisfy the needs of consumers by using methods that are sustainable and economical. Using a 1% AuPd/Mg(OH) 2 catalyst in the presence of NaOH and under specific reaction conditions furfural; a platform chemical formed from lignocellulosic biomass, can be selectively oxidised to furoic acid, and the catalyst displays promising reusability for this reaction. The mechanism of this conversion is complex with multiple competing pathways possible. The experimental conditions and AuPd metal ratio can be fine-tuned to provide enhanced control of the reaction selectivity. Activation energies were derived for the homogeneous Cannizzaro pathway and the catalytic oxidation of furfural using the initial rates methodology. This work highlights the potential of using a heterogeneous catalyst for the oxidation of furfural to furoic acid that has potential for commercial application

Deoxygenation of Palmitic Acid on Unsupported Transition-Metal Phosphides

Highly active bulk transition-metal phosphides (WP, MoP, and Ni₂P) were synthesized for the catalytic hydrodeoxygenation of palmitic acid, hexadecanol, hexadecanal, and microalgae oil. The specific activities positively correlated with the concentration of exposed metal sites, although the relative rates changed with temperature due to activation energies varying from 57 kJ mol^–1 for MoP to 142 kJ mol^–1 for WP. The reduction of the fatty acid to the aldehyde occurs through a Langmuir–Hinshelwood mechanism, where the rate-determining step is the addition of the second H to the hydrocarbon. On WP, the conversion of palmitic acid proceeds via R-CH₂COOH → R-CH₂CHO → R-CH₂CH₂OH → R-CHCH₂ → R-CH₂CH₃ (hydrodeoxygenation). Decarbonylation of the intermediate aldehyde (R-CH₂COOH → R-CH₂CHO → R-CH₃) was an important pathway on MoP and Ni₂P. Conversion via dehydration to a ketene, followed by its decarbonylation, occurred only on Ni₂P. The rates of alcohol dehydration (R-CH₂CH₂OH → R-CHCH₂) correlate with the concentrations of Lewis acid sites of the phosphides