Highly selective and efficient solvent-free transformation of bio-derived levulinic acid to γ-valerolactone by Ru(II) arene catalyst precursors
dataset
posted on 2020-05-05, 08:07 authored by Novisi K. Oklu, Banothile C. E. MakhubelaThe selective and efficient solvent-free hydrogenation of bio-based levulinic acid (LA) to γ-valerolactone (GVL)
was achieved with new pyridylimine ruthenium(II) complexes as catalyst precursors. The hydrogenation reactions
were performed in the presence of formic acid as hydrogen source using a catalyst loading as low as 0.1 mol
% with potassium hydroxide or triethylamine (Et3N). 4-Hydroxyvaleric acid (HVA) was produced only when
KOH was used, whereas reactions involving Et3N were selective to GVL. At 150 °C,>96% LA conversions were
achieved with 100% GVL selectivity. Recyclability of catalyst precursors was demonstrated by running three
consecutive reactions where 100% conversion and selectivity was maintained. In-situ NMR studies show that
hydrogen gas is formed by the decomposition of formic acid to carbon dioxide and hydrogen. Ru-hydride species
have been detected, by 1H NMR, and are believed to be the catalytically active species, and a mechanism of the
reaction has been proposed.
was achieved with new pyridylimine ruthenium(II) complexes as catalyst precursors. The hydrogenation reactions
were performed in the presence of formic acid as hydrogen source using a catalyst loading as low as 0.1 mol
% with potassium hydroxide or triethylamine (Et3N). 4-Hydroxyvaleric acid (HVA) was produced only when
KOH was used, whereas reactions involving Et3N were selective to GVL. At 150 °C,>96% LA conversions were
achieved with 100% GVL selectivity. Recyclability of catalyst precursors was demonstrated by running three
consecutive reactions where 100% conversion and selectivity was maintained. In-situ NMR studies show that
hydrogen gas is formed by the decomposition of formic acid to carbon dioxide and hydrogen. Ru-hydride species
have been detected, by 1H NMR, and are believed to be the catalytically active species, and a mechanism of the
reaction has been proposed.
