Metal-free catalysis of nitrogen-doped nanocarbons for the ammoxidation of alcohols to nitriles

Shang, Sensen; Dai, Wen; Wang, Lianyue; Lv, Ying; Gao, Shuang

doi:10.1039/c6cc09151b

Cited by 41 publications

(30 citation statements)

References 39 publications

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“…Our recent investigations on the use of noble-metal-free nanoparticles deposited on nitrogen-doped carbon materials for various organic transformations led us to study the application of a promising heterogeneous catalyst for the oxidative cleavage of 1,2-diols [21][22][23][24] .…”

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confidence: 99%

Aerobic oxidative cleavage of 1,2-diols catalyzed by atomic-scale cobalt-based heterogeneous catalyst

et al. 2019

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The oxidative cleavage of the CC bonds in 1,2-diols is an important transformation in synthetic organic chemistry. The challenge for this reaction is to develop a recyclable catalyst and an efficient catalytic system that operates under mild conditions. Here we report an atomically dispersed cobalt (3.8 wt% Co) on N-doped carbon catalyst, which exhibits improved catalytic activity toward the oxidative cleavage of a variety of 1,2-diols into esters, ketones or aldehydes using molecular oxygen under mild conditions. For example, the oxidative cleavage of internal diols is achieved at ambient temperature and air pressure. The robust catalyst can be reused at least seven times without regeneration treatment. The formation of highly dispersed active CoN x sites is demonstrated by catalyst characterization and potassium thiocyanate poisoning experiment. Mechanistic insights into monosubstituted diols indicate a sequence reaction including stepwise oxidation/nucleophilic addition/C-C bond cleavage, and reveal two reaction pathways.

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confidence: 99%

Aerobic oxidative cleavage of 1,2-diols catalyzed by atomic-scale cobalt-based heterogeneous catalyst

et al. 2019

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“…Our group designed and prepared mesoporous N-doped nanocarbon materials of high BET surface area (denoted as meso-N/ C) derived from via pyrolysis of polypyridyl ligand 4,5-diazafluoren-9-one azine (DAA) using template assisted synthesis. [74] For the first time, the resulting meso-N/C can act as a metal-free catalyst exhibiting good performance in aerobic ammoxidation of alcohols to nitriles with aqueous ammonia as ammonia resource (92 % conversion, 90 % benzonitrile yield). The authors presented that both pyridinic and pyrrolic-N has a linear relationship with the initial reaction rate.…”

Section: Ammoxidation Of Alcoholsmentioning

confidence: 99%

“…Relationship between benzyl alcohol conversion rate and (pyridinic N1/pyrrolic N2)/C atomic ratio of meso-N/C-x. Reproduced with permission from Ref [74]…”

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Heteroatom‐Enhanced Metal‐Free Catalytic Performance of Carbocatalysts for Organic Transformations

Shang

Gao

2019

ChemCatChem

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The exploitation and design of metal‐free catalysts for chemical transformation is always a fascinating theme from the prospective of fundamental and applied research. In addition to their distinct advantages such as lower cost, higher biocompatibility and reliability and thus higher sustainability, metal‐free materials often unexpectedly render different reaction pathway or mechanism from conventional metal catalysts. As a consequence, metal‐free catalysts have revolutionized and expanded the platform of catalysis. Among them, carbons are a typical class of nonmetallic materials. To date, a series of elements (e. g., B, N, P or S) as heteroatom dopants have equipped pristine carbons with enhanced performance and even new chemical functionality. It was proposed to attribute to modulated electrical properties and surface physicochemical features originated from structural distortions and changes of charge densities. In this minireview, we overviewed the catalytic application of heteroatom‐doped carbocatalysts in oxidation, oxidative coupling, reduction and hydrogenation reactions with special emphasis on the role of heteroatoms and consequently enhanced performance. This minireview highlights the structure‐activity correlations, thereby directing the rational design of advanced metal‐free catalysts for organic synthesis. Some controversies about active sites and challenges in catalyst design are also discussed here.

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“…Recently, BCN nanotubes showed a notable activity improvement for methanol conversion (29 %) with excellent selectivity to formaldehyde (54 %) [18] . To date, many macrocycle compounds such as phthalocyanine, porphyrin, polypyridine ligands have been used to prepare N‐doped carbon [15b,19] . Such complicated carbon precursors are usually difficult to be synthesized and quite expensive.…”

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confidence: 99%

Defect‐Rich Core‐Shell Carbon Derived from Ionic Liquid for Direct Synthesis of Imines

Shang

et al. 2021

ChemistrySelect

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Development of metal-free catalysis in chemical transformation is highly desirable due to its significant inherent advantages compared with conventional metal or metal oxide catalysts but challenging. Herein, ionic liquid 1-ethyl-3-methylimidazolium dicyanamide and sodium tetraphenylborate were employed as joint precursors to facilely prepare micro-mesoporous coreshell carbon with specific surface area up to 2870 m 2 g À 1 , consisting of smooth unpenetrated shell and secondary hollow spherical carbon core. The as-obtained core-shell carbon as metal-free catalyst exhibited good performance for selfcoupling and cross-coupling of amines to achieve the corresponding symmetry and asymmetry imines under mild and neat conditions. Excitingly, for the challenging aliphatic amines, the desired imines were achieved in our case in 55.9 % yield. The nearly linearly correlation between imine yield and I D /I G indicated that the resulting defects from departure of heteroatoms during pyrolysis may be active site.

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Metal-free catalysis of nitrogen-doped nanocarbons for the ammoxidation of alcohols to nitriles

Cited by 41 publications

References 39 publications

Aerobic oxidative cleavage of 1,2-diols catalyzed by atomic-scale cobalt-based heterogeneous catalyst

Aerobic oxidative cleavage of 1,2-diols catalyzed by atomic-scale cobalt-based heterogeneous catalyst

Heteroatom‐Enhanced Metal‐Free Catalytic Performance of Carbocatalysts for Organic Transformations

Defect‐Rich Core‐Shell Carbon Derived from Ionic Liquid for Direct Synthesis of Imines

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