Air-Stable Efficient Nickel Catalyst for Hydrogenation of Organic Compounds

Abstract

A series of composites containing nanoparticles of NiO (from 1 to 10% by weight per Ni), deposited on NORIT charcoal, was prepared by the decomposition of the Ni0 complex Ni(cod)2 (cod = cis,cis-1,5-cyclooctadiene). Ni content in the composites was set by loading the appropriate quantities of the Ni(cod)2 precursor. The catalytic activity of the composites was associated with the in situ generation of active sites due to a reduction in NiO, hence the composites could be stored in air without a loss in their catalytic performance. The composites were analyzed by powder XRD, TEM, XPS, and adsorption methods. The hydrogenation of quinoline was used as a reference reaction for studies of the influence of temperature, P(H2), catalyst loading on the product yield, and for the selection of the composite possessing the highest performance. It was found that 3% Ni loading was the most optimal. This composite was used as an efficient catalyst for the hydrogenation of compounds with ethylene and acetylene bonds, nitro- and keto- groups as well as a series of substituted quinolines and analogs. The studied composites can be proposed as air-stable and efficient catalysts for the hydrogenation of a wide range of organic compounds.

Advances and Challenges in Development of Transition Metal Catalysts for Heterogeneous Hydrogenation of Organic Compounds

“…The hydrogenation of nitro-compounds bearing a nitrile function resulted in the transformation of the NO 2 group to NH 2 and the hydrolysis of nitrile to amide, instead of the expected reduction to benzylamine. [99] The productivity of the studied composites was superior to Raney nickel. The studied composites exhibited air-stability and represent effective catalysts for the hydrogenation of a broad range of organic compounds.…”

“…Similarly to decomposition of Ni(Cod) 2 , decomposition of Pd 2 (dba) 3 in solution in the presence of Norite activated carbon led to formation of a series of composites, where content of Pd varied from 1 to 10 %. [101] As in the case of Ni/ C, described above, the most relevant information on the size of Pd nanoparticles was obtained from CO chemisorption, and in all cases this value varied in range 2.5-6 nm. The performance of the obtained Pd/C catalysts was superior compared to a number of commercially available catalysts in all processes, tested by us, in particular, hydrogenation of quinoline could be performed with > 80 % yield at p(H 2 ) = 1 bar and T = 50 °C at 1 mol % Pd loading and 99 % yield at 2 mol % Pd loading (reaction time 24 h).…”

“…Decomposition of Ni(Cod) 2 was carried out in THF solution, containing suspended Norit charcoal, at room temperature (for 1-3 % Ni loading) or 60 °C (for 5-10 % Ni loading). [99] Though synthesis was carried out in Ar, the composites were stored in air and their catalytic activity was high. Importantly, no metallic Ni phase could be confidently detected in the composits by XRD or XPS.…”

“…The composites were also very efficient in hydrogenation of a wide range of organic compounds, such as alkenes, alkynes, dienes, carbonyl compounds and nitrocompounds. [101] Scale-up of the above mentioned Pd/C composites was not a trivial task, because uniform heating of the large volumes of the reaction mixtures could not be achieved. Non-uniform distribution of the active Pd nanoparticles on the support was one of the reasons, in particular, in many experiments increase of the volume of the reaction mixture and mass of the catalyst (prepared in 100 + g scale), keeping the same Pd/substrate ratio, improved the product yield.…”

Перспективи Зниження Вмісту Платинових Металів У Каталізаторах Гідрування Органічних Сполук

“…• гідрування алкенів, зокрема ненасичених сполук у складі жирів (виробництво моторного палива, лакофарбова, харчова промисловість) [13];…”