A homogeneous transition metal complex for clean hydrogen production from methanol–water mixtures

Abstract

The development of an efficient catalytic process that mimics the enzymatic function of alcohol dehydrogenase is critical for using biomass alcohols for both the production of H2 as a chemical energy carrier and fine chemicals under waste-free conditions. Dehydrogenation of alcohol-water mixtures into their corresponding acids with molecular hydrogen as the sole by-product from the reaction can be catalysed by a ruthenium complex with a chelating bis(olefin) diazadiene ligand. This complex, [K(dme)2][Ru(H)(trop2dad)], stores up to two equivalents of hydrogen intramolecularly, and catalyses the production of H2 from alcohols in the presence of water and a base under homogeneous conditions. The conversion of a MeOH-H2O mixture proceeds selectively to CO2/H2 gas formation under neutral conditions, thereby allowing the use of the entire hydrogen content (12% by weight). Isolation and characterization of the ruthenium complexes from these reactions suggested a mechanistic scenario in which the trop2dad ligand behaves as a chemically 'non-innocent' co-operative ligand.

Square‐Planar Ruthenium(II) Complexes: Control of Spin State by Pincer Ligand Functionalization

“…IR spectra were recorded as Nujol mulls between KBr plates. NMR spectra were recorded on a Bruker Avance III 400 spectrometer and calibrated to the residual proton resonance and the natural abundance 13 , T = 100(2) K, F(000) = 516; q range = 1. …”

Rhodium‐Catalyzed Ketone Methylation Using Methanol Under Mild Conditions: Formation of α‐Branched Products

“…The use of methanol in catalytic alcohol dehydrogenation reactions is a worthwhile and challenging goal, with fundamental developments made by the groups of Beller[12] and Milstein[13] and demonstrated further with methanol by the groups of Tincado/Grützmacher[14] and Glorius. [15] However, methods that utilize methanol as an alkylating reagent with C–C bond formation (reported on PhCH 2 CN[2e, 16]) or as a substrate for formal C–H functionalization (such as the work by Krische et al[17]) are extremely rare and represent an important area in need of development.…”

Novel Options and Limitations of Methanol‐Based Production and Storage for Mobile Applications

“…If the applied voltage could be reduced even more this would change the picture dramatically, considering that electro-reforming is far less complex than steam reforming. Recently, promising novel, efficient homogeneous ruthenium complex catalysts have been developed for aqueous phase methanol dehydrogenation to hydrogen and carbon dioxide [25,26]. It remains to be seen whether they can also be used as electrocatalysts in the above electro-reforming process, marking the next step towards a methanol economy.…”