Application and Synthesis of [Ru(CH3P(CH2PPh2)3)(CH3CN)3](OTf-)3 as a Catalyst for the Selective Hydrodeoxygenation of Biomass-Derived Substrates in Aqueous Acidic Media

Abstract

The goal to replace chemicals from fossil resources and increased environmental consciousness has focused research on the development of green processes to obtain high value and low volume chemicals from biomass. The use of solvents such as water has necessitated the development of soluble and robust homogeneous catalysts to maintain activity in aqueous conditions. This work outlines the synthesis of a molecular ruthenium pre-catalyst with the cationic tridentate hetero-triphos ligand [CH3P(CH2PPh2)3](OTf-), first described by Guenther et al. in 2010. Comparison of bond distances is performed between previously synthesized triphos and hetero-triphos containing complexes to the novel complexes presented in this work, to identify possible predictors of reactivity. Furfuryl acetate, a non-edible biomass derived platform chemical, was chosen as the substrate to evaluate the catalytic activity of [Ru(CH3P(CH2PPh2)3)(CH3CN)3](OTf-)3 as this will also allow for comparison of activities between previous works. Valuable products were identified and their yields quantified, with the best reaction conditions (175 °C, 0.1 mol% catalyst, 250 mM substrate) giving 2-methylfuran (54%), 1,4-pentanediol (32%) and cyclopentanol (5%). The saturation concentration of the complex in D2O was found to be 0.001 mM, indicating that high solubility in water will continue to be a challenge for the triphos series of catalysts.