In Situ Hydrogen Activation Inspiring Efficient One-Pot Hydrogenation of Halogenated Nitrobenzenes over Ni–Co-Based Composites

Abstract

Selective hydrogenation of halogenated nitrobenzenes (XNBs) to halogenated amines (XANs) is of great importance for practical applications. Non-noble metal-based catalysts have shown prominent advantages in price and reserves accompanying low activity and selectivity toward the hydrogenation of halogenated nitrobenzenes (XNBs) even under harsh conditions. In this work, inexpensive Ni−Co-based composites (N x CC) were prepared for in situ tandem hydrogenation of XNBs to XANs by using hydrogen released from ammonia borane (AB) hydrolysis under ambient pressure. The results show these N x CC samples exhibited superior catalytic performance against Co 3 O 4 or NiO samples. A selected N 0.2 CC catalyst as the mainly screened one can quantitatively convert XNBs to XANs with unprecedented activity with 100% XAN conversion. This catalyst can completely convert m-chloronitrobenzene (m-CNB) to m-chloroaniline (m-CAN), suggesting N 0.2 CC efficiently suppresses the further dichlorination of m-CAN. Recycling test shows the N 0.2 CC possesses higher stability and recyclability. The N 0.2 CC catalyst was found to be a dual catalyst that synergistically catalyzes both the AB dehydrogenation (about 1735 mL min −1 g −1 of hydrogen generation rate) and the subsequent hydrogenation (almost 100% conversion) of XNBs. Notably, it is the first time that the rapid in situ hydrogen activation (IHA) which facilely arouses the efficient hydrogenation of adsorbed substrate on the surface of catalyst has been elaborated. From a unique perspective, distinctive and simple control experiments were innovatively designed for testifying the advantage of tandem hydrogenation in contrast with traditional hydrogenation. This work presents an efficient and environmental strategy to selectively produce XANs from XNBs using highperformance non-noble metal composites.

Bicomponent CuO/NiCo2O4 nanocomposites for the dehydrogenation of ammonia borane and the tandem hydrogenation of halogenated nitroaromatics

“…To some extent, this can also be confirmed by the elemental content determined by XPS (Table S1†). As mentioned above, it is indicated that the NiCo 2 O 4 component is relatively stable throughout the tandem hydrogenation process, coinciding with the results of our previous work, 42 while CuO underwent partial loss and agglomeration during hydrogenation reduction.…”

“…The bicomponent CuO/NiCo 2 O 4 catalyst demonstrated dual catalytic performances for catalyzing AB dehydrogenation and m -CNB hydrogenation. Owing to possible positive factors, 42 this tandem hydrogenation displays attractive performance under mild conditions in contrast with traditional hydrogenation.…”

“…The CuO/NiCo 2 O 4 nanocomposites was prepared using a previous method. 42 CoSO 4 ·7H 2 O (10 mmol), Ni(NO 3 ) 2 ·6H 2 O (10 mmol), and CuSO 4 ·5H 2 O (10 mmol) were dissolved in 150 mL high purity water, respectively. After the above solution was uniformly mixed by mechanical stirring, ammonia water was added to the mixed solution for adjusting the pH of the solution to 9–10.…”

Attractive Tandem Hydrogenation of Nitroaromatics Using AB as a Hydrogen Source over Pomelo Peel-Templated Bimetallic CuO–NiO/PP Nanocomposites

“…In general, the bimetallic synergistic effect improves the catalytic efficiency of AB activation and hydrogenation reaction. 69,70 In the cases of CuO−NiO/PP, the bimetallic synergy between Cu and Ni components benefits the electron transfer, activation, and hydrogenation of the substrate, which contributes to the remarkable reactivity of CuO−NiO/PP.…”

Pre-Coking Strategy Strengthening Stability Performance of Supported Nickel Catalysts in Chloronitrobenzene Hydrogenation

“…For this reason, the development of replacing heterogeneous catalysts is necessary to overcome this drawback. In this context, different catalytic systems have been reported, including precious metals (Pt [5][6][7][8][9][10], Pd [11][12][13], Ru [14,15], Ir [16], Au [17]), nonprecious metals (Co [18][19][20], Ni [21,22], Fe [22][23][24]), and metal-free catalysts [25,26]. Among these, Pt-based precious metal catalysts have been widely studied, mainly owing to their superb hydrogenating ability and extremely high chemoselectivity, the latter representing one of the main challenges in this field [1].…”