Magnetic NiO nanoparticles confined within open ends MWCNTs: a novel and highly active catalyst for hydrogenation and synthesis of imines

Abstract

A new nanocatalyst has been synthesized by confining magnetic nickel nanoparticles within carbon nanotubes (CNTs) and characterized by XRD, TEM, Raman and VSM. The character of the nanocatalyst passivated with a gas mixture was that it can be stored safely in air below 150 C and needs no activation prior to use. In the catalytic test, a nickel oxide nanocatalyst confined inside the Multi-walled carbon nanotubes nanochannels (NiO/MWCNTs-in) was found to be a highly efficient and reusable catalyst for the reduction of various aromatic nitro compounds to various aromatic amines, the conversion and selectivity of which were almost up to 100% and exceed 80%. The prominent merit of the catalyst is that the overall formation rate of product inside the nanotubes exceeds that outside. Moreover, it is inexpensive, and could be prepared and scaled up easily. Besides, it can be simply separated from the reaction mixtures by an external magnetic field As a result of the possible confinement effect of CNTs, the employment of the CNTs channels as nanoreactors for catalysis may provide opportunities for the development of new heterogeneous catalysts.

CO2-Catalyzed Efficient Dehydrogenation of Amines with Detailed Mechanistic and Kinetic Studies

“…N-Phenyl-1-(4(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) [21] ; 72% yield. N-(4-fluorophenyl) [24] ; 99% yield. [27] ; 99% yield.…”

Selective Hydrogenation of Aromatic Nitro Compounds Using Unsupported Nickel Catalysts

“…The performance of the unsupported Ni‐acac catalyst was compared with previously reported Ni‐based supported catalysts and Raney‐Ni (Table S1). We found that our system shows better results when comparing the reaction conditions, yield and selectivity [17,18,44,22,37–43] . Moreover, the stability of the Ni‐acac catalyst is superior to those Ni‐based systems since it maintained great yield and selectivity even using it up to the fifth cycle.…”

“…We found that our system shows better results when comparing the reaction conditions, yield and selectivity. [17,18,44,22,[37][38][39][40][41][42][43] Moreover, the stability of the Ni-acac catalyst is superior to those Ni-based systems since it maintained great yield and selectivity even using it up to the fifth cycle. Most of the other supported catalysts showed good performance just for one catalytic run.…”

“…On the other hand, first-row transition metal-based catalysts have many advantages from an economic point of view due to their great earth-abundance, making them an attractive option compared to their noble counterparts. In this context, chemoselective non-noble nanoparticle catalysts such as Fe, [10,11] Co, [12][13][14] Cu, [15,16] and Ni [17][18][19][20][21][22] have been developed in recent years for the reduction of nitroarenes. The group of Beller has thoroughly studied supported Fe 2 O 3 [10,11] and Co 3 O 4based [12] nanoparticle catalysts, showing a remarkable conversion rate towards the reduction of functionalized nitroarenes, and high chemoselectivity by yielding substituted anilines with easily reducible groups such as C=O, C=C, C�C, C�N.…”

Platinum Nanoparticle Based Dip‐Catalyst for Facile Hydrogenation of Quinoline, Unfunctionalized Olefins, and Imines

“…[29] Furthermore, increasing restrictions imposed by governments and the United Nations protocols with the aim of eliminating toxic chemical processes require adopting safer procedures. In this context, researchers have studied systems with metals, such as Mn, [30] Ni, [31][32][33] Ru, [34,35] Co, [36][37][38] Rh, [39][40][41] Ir, [42][43][44][45] Pd, [46,47] and Pt [48] immobilized on zeolite, [49,50] silica, [50,51] polymers, [52][53][54] alumina, [55] magnetite, [39,[56][57][58][59] and carbon. [60] These systems exhibit moderate to excellent conversion and selectivity, especially in the hydrogenation reactions.…”