nickel catalyst
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2022 ◽  
Pragnesh N. Dave ◽  
Ruksana Sirach ◽  
Riddhi Thakkar ◽  
Shalini Chaturvedi

Abstract Nanosize Nickel ferrite (NiF) was synthesized by the co-precipitation methods and its effect as a 5 % by mass additive was studied on the thermal decomposition of micrometer and nanometer size NTO. In the presence of 5 % NiF additive, the thermal decomposition peak temperature of NTO was decreased from 276.36 to 260.18 oC and that of nano NTO was decreased from 261.38 to 258.89 oC (β=10 oC min-1). The kinetics parameters confirms the catalytic activity of NiF for the thermal decomposition of NTO, and nNTO as the parameters such as activation energy (NTO=~25.45 % and nNTO=~45.94 % decrement), and pre-exponential factor (NTO=~21.94 % and nNTO=~43.12 % decrement) were decreased when 5 % NiF additive was added to NTO, and nNTO. The rate of the decomposition process was increased in the presence of 5 % NiF catalyst, indicating the faster thermal decomposition of both NTO, and nNTO in the presence of nickel catalyst.

ChemSusChem ◽  
2022 ◽  
David K. Leonard ◽  
Pavel Ryabchuk ◽  
Muhammad Anwar ◽  
Sarim Dastgir ◽  
Kathrin Junge ◽  

Yuan Zhu ◽  
Weisai Zu ◽  
Qing Tian ◽  
Zifeng Cao ◽  
Yu Wei ◽  

Herein, an organoboron photocatalyst, aminoquinolate diarylboron (AQDAB), is utilized collaboratively with nickel catalyst in metallaphotoredox catalyzed C(sp2)–P and C(sp2)–S cross-coupling reactions. This strategy effectively couples aryl halides with diarylphosphine oxides...

Ahmed Sadeq Al-Fatesh ◽  
Rawesh Kumar ◽  
Samsudeen Olajide Kasim ◽  
Ahmed Aidid Ibrahim ◽  
Anis Hamza Fakeeha ◽  

V. M. Mokhov ◽  
A. O. Panov ◽  
D. N. Nebykov ◽  
Yu. V. Popov

Reductive alkylation of nitriles with aldehydes and ketones using nickel nanoparticles supported on NaX zeolite as catalyst proceeds at 140-200 °C with the formation of the corresponding secondary and tertiary amines in 46-80 % yields.

D. N. Nebykov ◽  
Yu. V. Popov ◽  
V. M. Mokhov ◽  
E. V. Shepotko ◽  
D. S. Kos'yanenko

The process of mesityl oxide hydrogenation in the presence of a nickel catalyst prepared by impregnating a support with an aqueous solution of the corresponding salt in a displacement reactor in a gas-liquid-solid catalyst system has been studied. It has been established that the use of the catalyst used in the work makes it possible to selectively obtain methyl isobutyl ketone with complete conversion of mesityl oxide in the temperature range 70-100 ºС.

2021 ◽  
Jichao Xiao ◽  
John Montgomery

A simple procedure is reported for the nickel-catalyzed defluorinative alkylation of unactivated aliphatic aldehydes. The process involves the catalytic reductive union of trifluoromethyl styrenes with aldehydes using a nickel complex of a 6,6’-disubstituted bipyridine ligand with zinc metal as the terminal reductant. The protocol is distinguished by its broad substrate scope, mild conditions, and simple catalytic setup. Reaction outcomes are consistent with the intermediacy of an alpha-silyloxy(alkyl)nickel intermediate generated by a low-valent nickel catalyst, silyl electrophile, and the aldehyde substrate. Mechanistic findings with cyclopropanecarboxaldehyde provide insights into nature of the reactive intermediates and illustrate fundamental reactivity differences that are governed by subtle changes in ligand and substrate structure.

2021 ◽  
Taeho Kang ◽  
José Manuel González ◽  
Zi-Qi Li ◽  
Klement Foo ◽  
Peter Cheng ◽  

A versatile method to access differentially substituted 1,3- and 1,4-diamines via a nickel-catalyzed three-component 1,2-carboamination of alkenyl amines with aryl/alkenylboronic ester nucleophiles and N–O electrophiles is reported. The reaction proceeds efficiently with free primary and secondary amines without needing a directing auxiliary or protecting group, and is enabled by fine-tuning the leaving group on the N–O reagent. The transformation is highly regioselective and compatible with a wide range of coupling partners and alkenyl amine substrates, all performed at room temperature. A series of kinetic studies support a mechanism in which alkene coordination to the nickel catalyst is turnover-limiting.

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7581
Mateusz Zakrzewski ◽  
Oleksandr Shtyka ◽  
Radoslaw Ciesielski ◽  
Adam Kedziora ◽  
Waldemar Maniukiewicz ◽  

This work investigates the effect of the addition of Ru and CeO2 on the process of gasification of carbon deposits formed on the surface of a nickel catalyst during the mixed methane reforming process. Activity studies of the mixed methane reforming process were carried out on (Ru)-Ni/CeO2-Al2O3 catalysts at the temperature of 650–750 °C. The ruthenium-promoted catalyst exhibited the highest activity. Carbonized post-reaction catalyst samples were tested with the TOC technique to investigate the carbonization state of the samples. The bimetallic catalyst had the lowest amount of carbon deposit (1.5%) after reaction at 750 °C. The reactivity of the carbon species was assessed in mixtures of oxygen, hydrogen, carbon dioxide, and water. Regardless of the gasifying agent used, the carbon deposit was removed from the surface of the catalytic system. The overall mechanism of mixed methane reforming over Ru and CeO2 was shown.

2021 ◽  
Jonathan Mark Tailby

<p>One of the major challenges to be overcome before hydrogen fuelled vehicles can become commonplace is to store hydrogen with sufficient storage density to be practical. One approach to overcoming this challenge involves converting the hydrogen into a secondary fuel that can be stored more easily, such as ammonia. This introduces the challenge of efficiently retrieving the hydrogen from the secondary fuel with sufficient purity to be used in a polymer electrolyte membrane fuel cell. Putting the hydrogen producing reaction inside a membrane which is capable of filtering out hydrogen creates a membrane reactor which can increase hydrogen purity and can accelerate the reaction both kinetically and thermodynamically. The most effective materials currently known for hydrogen membranes are high palladium alloys of copper and silver. These are able to absorb hydrogen on the side with high hydrogen partial pressure and desorb that hydrogen on the side with low hydrogen pressure. Palladium metal is also able to interact with some catalysts by hydrogen spillover. Hydrogen is transported from the surface of the catalyst to the palladium surface more quickly than the hydrogen can desorb from the catalyst, this potentially accelerates both the catalysis and the hydrogen filtration. This research aimed to create a catalytic spillover membrane to extend the possibility of ammonia as a secondary fuel for hydrogen transport. In this research, several methods to produce a nickel catalyst on the surface of the palladium were explored: electrodeposition with and without a lithographic template; spray coating with nanoparticles; and preshaped nickel mesh and nickel foam. These potential catalysts were tested for ammonia decomposition. Templated electrodeposition created the most effective catalyst, but the nickel foam was most easily applied to the next stage of the research. The nickel foam catalyst was subsequently retested for ammonia decomposition in three scenarios: in contact with palladium foil; in a reactor with a palladium membrane; and in contact with a palladium membrane. The presence of a palladium membrane improved decomposition more than spillover contact between nickel foam catalyst and palladium, however, the combination of spillover contact with a palladium membrane increased the ammonia decomposition further. The rate of hydrogen flux through the palladium membranes was calculated for the experimental results. These were compared to flux values predicted by a model equation. The results showed that spillover contact between nickel catalyst and palladium membrane increased the hydrogen flux through the membrane.. The research outcomes have generated new knowledge and improved understanding of the morphology and role of nickel catalysts in accelerating ammonia decomposition. The research highlights the complex relationship between reactor design, gas flow paths, catalyst presentation and catalysis chemistry, suggesting promising areas for future research.</p>

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