Selective Hydrogen Production from Glycerol over Ruthenium Catalyst

Abstract

Glycerol – one of the prominent by‐products of biodiesel is also an important source of hydrogen gas. Herein, the efficient and selective production of hydrogen gas from glycerol in water at 90–120 °C over a ruthenium nanoparticle (∼2.7 nm) catalyst is demonstrated. Notably, high yield of hydrogen gas (n(H2)/n(glycerol); 0.96–1.61) was achieved from the glycerol‐water solution, where the reaction temperature and base concentration played crucial role in achieving high yield of H2. Advantageously, under the studied reaction conditions, the ruthenium catalyst also exhibited appreciably high long‐term stability for over 36 h while generating ca. 70 L H2 per gram of Ru with H2 yield of 350 L per L of glycerol. Moreover, high yield for lactic acid is also achieved during the production of hydrogen gas from glycerol.

Ir(tri-N-Heterocyclic Carbene)-Catalyzed Production of Hydrogen and Cn Acids from Ethylene Glycol

“…The aldol product of dehydrogenated EG, intermediate I, can isomerize to intermediate II which undergoes retro-aldol reaction to afford C 3 and C 1 acids. 33 For C 3 acid, an alternative route via the C−C cleavage of C 6 aldohexose was considered because the aldol reaction of dehydrogenated EG with intermediate I afforded C 6 aldohexose, and the bond cleavage of C 6 aldohexose afforded lactic acid (C 3 acid). 12,31 However, we did not observe any C 6 a The mixture of catalysts (2.5 μmol), base (18.0 mmol), and EG (35.9 mmol) in water (2 mL) was heated at 180 °C for 3 h. The yields of H 2 were determined by measuring the volume of H 2 .…”

Ruthenium-Catalyzed Transformation of Ethylene Glycol for Selective Hydrogen Gas Production in Water

“…At the industrial scale, hydrogen is produced by methane reforming, aqueous-phase reforming, and steam reforming of fossil fuels, which are highly energy-intensive processes with the emissions of greenhouse gases. On the other hand, with the intervention of a suitable catalyst, hydrogen can be produced from several promising and potential small organic molecules such as methanol, − formic acid, − formaldehyde, ,− and other polyols. − …”

“…Recently, Maji et al employed a Mn-PNP complex for EG reforming to GA and H 2 as a byproduct at 140 °C in t AmOH in 12 h. 53 Therefore, it is evident from these reports that most heterogeneous catalysts work well at high temperature, while homogeneous catalysts are primarily explored in nonaqueous solvents. Recently, we also developed and explored several efficient catalysts for lowtemperature hydrogen production from methanol, 16 formic acid, 20,21 formaldehyde, 25 glycerol, 27 and others under water-based conditions. We envisioned that the dehydrogenation of EG may lead to the selective production of hydrogen gas along with the generation of formic acid as a valuable byproduct.…”