To date, effective nickel-catalyzed enantioselective cross-couplings of alkyl electrophiles that bear oxygen leaving groups have been limited to reactions of allylic alcohol derivatives with Grignard reagents. In this Communication, we establish that, in the presence of a nickel/pybox catalyst, a variety of racemic propargylic carbonates are suitable partners for asymmetric couplings with organ...

Chiral trivalent phosphorus species are the dominant class of ligands and the key controlling element in asymmetric homogeneous transition-metal catalysis. Here, novel chiral diaminophosphine oxide ligands are described. The arising catalyst system with nickel(0) and trimethylaluminum efficiently activates formamide C-H bonds under mild conditions providing pyrrolidones via intramolecular hydro...

Nickel(0)-catalyzed cross-coupling of heteroaryl-containing diarylmethanes with both aryl bromides and chlorides has been achieved. The success of this reaction relies on the introduction of a unique nickel/NIXANTPHOS-based catalyst system, which provides a direct route to triarylmethanes from heteroaryl-containing diarylmethanes. Reactivity studies indicate the Ni(NIXANTPHOS)-based catalyst ex...

A stainless-steel mesh loaded with nickel catalyst was produced and used for the pyrolysis-catalysis of waste high-density polyethylene with the aim of producing high-value carbon products, including carbon nanotubes (CNTs). The catalysis temperature and plastic-to-catalyst ratio were investigated to determine the influence on the formation of different types of carbon deposited on the nickel-s...

Deactivation of cobalt and nickel catalysts in Fischer-Tropsch synthesis and methanation JAVIER BARRIENTOS Akademisk avhandling som med tillstånd av KTH i Stockholm framlägges till offentlig granskning för avläggande av teknologie doktorsexamen fredagen den 23 september kl. " True wisdom comes to each of us when we realize how little we understand about life, ourselves, and the world around us....

The partial oxidation of methane to syngas was studied in this work over Ni-containing ceria catalysts with nickel content of 5, 10 and 20 at.% at atmospheric pressure. All catalysts, in the as prepared state, showed similar activity and CO selectivity at T ≥ 550◦C. Catalyst pre-reduction was not required. Reaction mixtures were dilute, containing 3 mol% CH4 and 1.5 mol% O2. Methane conversion ...

Efficient oxygen-evolution reaction catalysts are required for the cost-effective generation of solar fuels. Metal selenides have been reported as promising oxygen-evolution catalysts; however, their active forms are yet to be elucidated. Here we show that a representative selenide catalyst, nickel selenide, is entirely converted into nickel hydroxide under oxygen-evolution conditions. This res...

the role of nickel as catalyst on the conversion of methane and ethylene in a gas phase flow reactor in the absence of oxygen is studied. in this study, nickel in its different forms is used as catalyst. the role of pressure, flow rate, and temperature on the conversion of feed gases is investigated. the experiments have been carried out in the presence and absence of the catalysts to measure t...

The low activity of the oxygen reduction reaction in polymer electrolyte membrane fuel cells is a major barrier for electrocatalysis, and hence needs to be optimized. Tuning the surface electronic structure of platinum-based bimetallic alloys, a promising oxygen reduction reaction catalyst, plays a key role in controlling its interaction with reactants, and thus affects the efficiency. Here we ...

A two-stage pyrolysis−catalytic steam reforming process was used with mesoporous MCM-41 supported iron and nickel bimetallic catalysts for hydrogen-rich syngas production from a simulated mixture of waste plastics. Different Fe/Ni weight ratios (00:20, 05:15, 10:10, 05:15, and 20:00) have been investigated to determine the influence on hydrogen production. The results showed that the presence o...