14548-46-0Relevant academic research and scientific papers
Rapid formation of nitrogen-doped carbon foams by self-foaming as metal-free catalysts for selective oxidation of aromatic alkanes
Qin, Guo-Xin,Hao, Yan,Wang, Shuai,Dong, Yu-Bin
, (2020)
Porous carbon materials have attracted considerable interest as metal-free catalysts. In this study, we report a nitrogen-doped and nanofiber-based porous carbon foam produced via an efficient and facile self-foaming approach and its subsequent pyrolysis; in this approach, carbon dioxide-rich ethanolamine serves as the foaming agent, N source and polymerization catalyst. Meanwhile resorcinol and formaldehyde are used as carbon sources. Carbon dioxide-rich ethanolamine plays a crucial role in the release of gas as well as initiating polymerization on the interfaces of bubbles, which directs the formation of polymer foam. The N-doped carbon foam can be a highly active metal-free heterogeneous catalyst to promote selective oxidation of the benzyl group to the corresponding phenone. In addition, the carbon foams are easily cast with different morphologies. Notably, the prepared carbon foam is fabricated as a monolithic reactor for the oxidation reaction, which also exhibits good catalytic performances in the scale-up experiment.
Fluorescent pH sensor constructed from a heteroatom-containing luminogen with tunable AIE and ICT characteristics
Yang, Zhiyong,Qin, Wei,Lam, Jacky W. Y.,Chen, Sijie,Sung, Herman H. Y.,Williams, Ian D.,Tang, Ben Zhong
, p. 3725 - 3730 (2013)
A heteroatom-containing organic fluorophore 1-(4-pyridinyl)-1-phenyl-2-(9- carbazolyl)ethene (CP3E) was designed and synthesized. CP 3E exhibits the effect of intramolecular charge transfer (ICT) caused by the donor-acceptor interaction between its carbazole and pyridine units. Whereas it emits faintly in solution, it becomes a strong emitter in the aggregated state, demonstrating the phenomenon of aggregation-induced emission (AIE). Its emission can be reversibly switched between blue and dark states by repeated protonation and deprotonation. Such behaviour enables it to work as a fluorescent pH sensor in both solution and the solid state and as a chemosensor for detecting acidic and basic organic vapors. Analyses by NMR spectroscopy, single-crystal X-ray diffraction and computational calculations suggest that the change in electron affinity of the pyridinyl unit and molecular conformation of CP3E upon protonation and deprotonation is responsible for such sensing processes.
Direct oxidation of the Csp3–H bonds of N-heterocyclic compounds to give the corresponding ketones using a reusable heterogeneous MnOx-N@C catalyst
Ren, Lanhui,Wang, Lianyue,Lü, Ying,Li, Guosong,Gao, Shuang
, p. 1216 - 1221 (2016)
Novel reusable MnOx-N@C catalyst has been developed for the direct oxidation of N-heterocycles under solvent-free conditions using TBHP as benign oxidant to give the corresponding N-heterocyclic ketones. The catalytic system exhibited a broad substrate scope and excellent regioselectivity, as well as being amenable to gram-scale synthesis. This MnOx-N@C catalyst also showed good reusability and was successfully recycled six times without any significant loss of activity.
Kinetics and mechanism of the reaction of Cr(II) aqua ions with benzoylpyridine N-oxide
Cheng, Mingming,Bakac, Andreja
, p. 2077 - 2082 (2007)
Aqueous chromium(II) ions, Craq2+, react with benzoylpyridine oxide (BPO) much more rapidly than with other pyridine N-oxides previously explored. The kinetics were studied under pseudo-first order conditions with either reagent in excess. Under both sets of conditions, the major kinetic term exhibits first order dependence on limiting reagent, and second order dependence on excess reagent, i.e. kCr = k2Cr[BPO][Craq2+]2 (excess Craq2+), and kBPO = k2BPO[Craq2+][BPO]2 (excess BPO), where k2Cr = (6.90 +/- 0.27) x 104 M-2s-1 and k2BPO = (3.32 +/- 0.28) x 105 M-2s-1 in 0.10 M HClO4. The rate constant k2Cr contains terms corresponding to [H+]-independent and [H+]-catalyzed paths. In the proposed mechanism, the initially formed Craq(BPO)2+ engages in parallel oxidation of Craq2+ and reduction of BPO. The latter reaction provides the basis for a convenient new preparative route for the BPO complex of Cr(III).
An efficient and practical aerobic oxidation of benzylic methylenes by recyclable: N -hydroxyimide
Wang, Jian,Zhang, Cheng,Ye, Xiao-Qing,Du, Wenting,Zeng, Shenxin,Xu, Jian-Hong,Yin, Hong
, p. 3003 - 3011 (2021/01/28)
An efficient and practical benzylic aerobic oxidation catalyzed by cheap and simple N-hydroxyimide organocatalyst has been achieved with high yields and broad substrate scope. The organocatalyst used can be recycled and reused by simple workup and only minute amount (1 mol% in most cases) of simple iron salt is used as promoter. Phenyl substrates with mild and strong electron-withdrawing group could also be oxygenated in high yields as well as other benzylic methylenes. Influence of substituents, gram-scale application, catalysts decay and general mechanism of this methodology has also been discussed. This journal is
Selective electrochemical oxidation of aromatic hydrocarbons and preparation of mono/multi-carbonyl compounds
Li, Zhibin,Zhang, Yan,Li, Kuiliang,Zhou, Zhenghong,Zha, Zhenggen,Wang, Zhiyong
, p. 2134 - 2141 (2021/09/29)
A selective electrochemical oxidation was developed under mild condition. Various mono-carbonyl and multi-carbonyl compounds can be prepared from different aromatic hydrocarbons with moderate to excellent yield and selectivity by virtue of this electrochemical oxidation. The produced carbonyl compounds can be further transformed into α-ketoamides, homoallylic alcohols and oximes in a one-pot reaction. In particular, a series of α-ketoamides were prepared in a one-pot continuous electrolysis. Mechanistic studies showed that 2,2,2-trifluoroethan-1-ol (TFE) can interact with catalyst species and generate the corresponding hydrogen-bonding complex to enhance the electrochemical oxidation performance. [Figure not available: see fulltext.]
Half-sandwich ruthenium complex containing phenyl benzoxazole structure as well as preparation method and application of half-sandwich ruthenium complex
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Paragraph 0045-0048, (2021/04/14)
The invention relates to a half-sandwich ruthenium complex containing a phenyl benzoxazole structure as well as a preparation method and application of the half-sandwich ruthenium complex. The ruthenium complex has the following structure as shown in the specification. The preparation method comprises the steps of dissolving phenyl benzoxazole, [CymRuCl2] 2 and sodium acetate in methanol at room temperature, heating the system, and continuing to react; and after the reaction is finished, standing, filtering, carrying out reduced pressure pumping on the solvent, carrying out column chromatography separation on the obtained crude product to obtain the red half-sandwich ruthenium complex containing the phenyl benzoxazole structure, and applying the red half-sandwich ruthenium complex to catalysis of oxidation of alkyl pyridine compounds to prepare nitrogen heterocyclic ketone compounds. Compared with the prior art, the preparation method provided by the invention is simple and green, the catalytic oxidation reaction can be carried out under mild conditions, and the catalyst has high stability and is not sensitive to air and water.
Finely dispersed CuO on nitrogen-doped carbon hollow nanospheres for selective oxidation of sp3C-H bonds
Gupta, Shyam Sunder R.,Lakshmi Kantam, Mannepalli
, p. 16179 - 16186 (2021/09/22)
Hollow nanostructured materials are of great importance in heterogeneous catalysis owing to their improved mass transfer and diffusion properties. In this study, we have successfully prepared a novel nanocomposite, CuO supported nitrogen-doped carbon hollow nanospheres (denoted as CuO/N-C-HNSs), by a template protection-sacrifice method employing SiO2nanospheres as the sacrificial template. The diverse nitrogen species present in the support anchored the CuO nanoparticles firmly and stabilized them as fine particles having sizes below 10 nm. The as-prepared CuO/N-C-HNSs efficiently catalyze the selective oxidation of sp3C-H bonds under mild reaction conditions usingt-butyl hydroperoxide as the oxidant and water as the green solvent. The strong coordination between CuO and nitrogen species prevents the aggregation as well as leaching of CuO nanoparticles during the catalytic reaction. A wide range of aromatic hydrocarbons were smoothly oxidized into the corresponding products at 80 °C in 20 h affording both conversion and selectivity as high as 99%. The excellent catalytic activity and reusability of CuO/N-C-HNSs can be attributed to the uniformly dispersed CuO sites, hollow nanostructure and the synergistic effect between CuO and nitrogen-doped carbon hollow nanospheres.
Mn(III) active site in hydrotalcite efficiently catalyzes the oxidation of alkylarenes with molecular oxygen
Wang, Anwei,Zhou, WeiYou,Sun, Zhonghua,Zhang, Zhong,Zhang, Zhihui,He, MingYang,Chen, Qun
, (2020/12/07)
Developing efficient heterogeneous catalytic systems based on easily available materials and molecular oxygen for the selective oxidation of alkylarenes is highly desirable. In the present research, NiMn hydrotalcite (Ni2Mn-LDH) has been found as an efficient catalyst in the oxidation of alkylarenes using molecular oxygen as the sole oxidant without any additive. Impressive catalytic performance, excellent stability and recyclability, broad applicable scope and practical potential for the catalytic system have been observed. Mn3+ species was proposed to be the efficient active site, and Ni2+ played an important role in stabilizing the Mn3+ species in the hydrotalcite structure. The kinetic study showed that the aerobic oxidation of diphenylmethane is a first-order reaction over Ni2Mn-LDH with the activation energy (Ea) and pre-exponential factor (A0) being 85.7 kJ mol?1 and 1.8 × 109 min?1, respectively. The Gibbs free energy (ΔG≠) was determined to be -10.4 kJ mol-1 K-1 for the oxidation based on Eyring-Polanyi equation, indicating the reaction is exergonic. The mechanism study indicated that the reaction proceeded through both radical and carbocation intermediates. The two species were then trapped by molecular oxygen and H2O or hydroxyl species, respectively, to yield the corresponding products. The present research might provide information for constructing highly efficient and stable active site for the catalytic aerobic oxidation based on available and economic material.
Rapid, chemoselective and mild oxidation protocol for alcohols and ethers with recyclable N-chloro-N-(phenylsulfonyl)benzenesulfonamide
Badani, Purav,Chaturbhuj, Ganesh,Ganwir, Prerna,Misal, Balu,Palav, Amey
supporting information, (2021/06/03)
Chlorine is the 20th most abundant element on the earth compared to bromine, iodine, and fluorine, a sulfonimide reagent, N-chloro-N-(phenylsulfonyl)benzenesulfonamide (NCBSI) was identified as a mild and selective oxidant. Without activation, the reagent was proved to oxidize primary and secondary alcohols as well as their symmetrical and mixed ethers to corresponding aldehydes and ketones. With recoverable PS-TEMPO catalyst, selective oxidation over chlorination of primary and secondary alcohols and their ethers with electron-donating substituents was achieved. The reagent precursor of NCBSI was recovered quantitatively and can be reused for synthesizing NCBSI.
