Catalytic oxidation of carbazole using t-butyl hydroperoxide over molybdenum catalysts

Zhou, Xinrui; Ma, Hong; Fu, Xing; Yao, Cheng-bin; Xiao, Jinqiu

doi:10.1016/s1872-5813(10)60021-7

Cited by 12 publications

(7 citation statements)

References 16 publications

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“…Moreover, these oxidations are known to produce polymeric or oligomeric forms but not to give monomeric biquinone/semiquinone (with two benzene rings oxidized to carbonyls) or monomeric monoquinone/semiquinone (with only one benzene ring oxidized to carbonyl) compounds. For example, oxidation of carbazole using t -butyl hydroperoxide oxidant and Mo(VI) complex as the catalyst has been shown to give dimeric or trimeric products at high temperatures . On the other hand, biooxidation by enzymes such as naphthalene-1,2-dioxygenasse, biphenyl-2,3-dioxygenase, laccase, and biphenyl utilizing bacteria have been reported to favor oxidation of carbazole to mono hydroxycarbazole at neutral pH.…”

Section: Introductionmentioning

confidence: 96%

“…For example, oxidation of carbazole using t-butyl hydroperoxide oxidant and Mo(VI) complex as the catalyst has been shown to give dimeric or trimeric products at high temperatures. 15 On the other hand, biooxidation by enzymes such as naphthalene-1,2-dioxygenasse, biphenyl-2,3-dioxygenase, 16 laccase, 17 and biphenyl utilizing bacteria 18 have been reported to favor oxidation of carbazole to mono hydroxycarbazole at neutral pH. Similarly, several electrochemical methods for oxidation of carbazoles have been reported to yield polycarbazoles.…”

Section: Introductionmentioning

confidence: 99%

“…But, on the other hand, the parent compounds, carbazole and their derivatives, themselves are not very reactive toward redox reactions because of their rigid structure. Literature reports show that oxidation of carbazoles, either by chemical, − biochemical, − or electrochemical − methods occurs only under severe experimental conditions. Moreover, these oxidations are known to produce polymeric or oligomeric forms but not to give monomeric biquinone/semiquinone (with two benzene rings oxidized to carbonyls) or monomeric monoquinone/semiquinone (with only one benzene ring oxidized to carbonyl) compounds.…”

Section: Introductionmentioning

confidence: 99%

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Regioselective Electrochemical Oxidation of One of the Identical Benzene Rings of Carbazole to 1,4-Quinone on the MWCNT Surface and Its Electrocatalytic Activity

Gayathri¹,

Pillai

Kumar³

2019

J. Phys. Chem. C

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Carbazole-1,4-quinone is a key structural unit of naturally occurring carbazole-quinone alkaloids, for instance, 3-methyl carbazole-1,4-quinone (Murrayaquinone), that are widely used in pharmaceutics and medicine. These compounds are generally synthesized from tetrahydro ketone derivatives by multistep synthetic routes. Until now, there is no direct method reported for the partial oxidation of carbazole to carbazole-1,4-quinone by chemical, biochemical, or electrochemical reaction routes. Literature survey on the oxidation of carbazole and its derivatives suggests that polymeric or oligomeric forms are the sole products, but not, monomeric carbazole-1,4-quinone. Herein, we report a simple electrochemical oxidation of surface-confined carbazole to a highly redox active carbazole-mono-1,4-quinone, where only one of the identical benzene rings of carbazole gets selectively oxidized, on a cathodically activated multiwalled carbon nanotube (MWCNT) surface anchored to a glassy carbon electrode (GCE/MWCNT*@Car-Qn; * = cathodically activated, Car-Qn = carbazole-1,4-quinone) in pH 7 phosphate buffer solution, unlike the time consuming conventional multistep synthetic routes. The GCE/MWCNT*@Car-Qn showed a well-defined surface-confined peak at E 1/2 = 215 ± 5 mV versus Ag/AgCl with a Nertisan pH dependence in character. This new hybrid system showed efficient electrocatalytic oxidation and sensing of hydrazine in a neutral pH solution. No such electrochemical features were noticed for carbazole on the GCE surface. Collective physico-chemical (scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, HRMS, and NMR) and electrochemical characterizations of the MWCNT*@Car-Qn formation process revealed that in situ formed H2O2 at cathodic potentials and iron impurity in MWCNT, forming electro-Fenton species, are responsible for the selective electrochemical oxidation of carbazole to carbazole-1,4-quinone on the MWCNT surface.

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Regioselective Electrochemical Oxidation of One of the Identical Benzene Rings of Carbazole to 1,4-Quinone on the MWCNT Surface and Its Electrocatalytic Activity

Gayathri¹,

Pillai

Kumar³

2019

J. Phys. Chem. C

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“…One of these compounds, indole, is containing nitrogen, which produces nitrogen oxides (NOX) when burned for industrial purposes, and is dispersed into the environment in different ways such as burning fossil fuels and some other industrial activities [3][4][5]. Furthermore, indole and its derivatives have been regarded as one of the most crucial obstacles for the oxidative desulfurization process for two main reasons [6,7]. First, since the nitrogen in indole is virtually free, it can interact easily with oxygen; however, that of sulfur due to being strongly bonded in the heterocycle resonance cannot do it with ease.…”

Section: Introductionmentioning

confidence: 99%

Cu(II)/Z4A as an Efficient Nanocomposite for Oxidative Degradation of Indole and Optimization of Effective Factors via RSM Procedure

et al. 2021

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One of the aromatic contaminants in the oil and fuel is indole, which is toxic even at low doses and is considered as air and water pollutant. In this research, the surface of Zeolite 4A (Z4A) was modified by Cu(II)nanoparticles to introduce a desirable nanocomposite (Cu(II)/Z4A) for indole oxidative degradation. The catalysts characterization was carried out by XRD, SEM, EDS, FTIR, and BET/BJH techniques. Response Surface Methodology (RSM) based on Box-Behnken Design (BBD) was employed for studying several effective factors influences in indole oxidation process, including pH, weight percentage of loaded copper (Cu(wt %)), mass of composite, and indole initial concentration (IND concentration). The obtained results by BBD revealed the solution pH was the most pivotal factor in indole oxidative degradation and predicted that under the optimum experimental conditions, the efficiency should be 98.91%. Moreover, GC-mass analysis was applied for evaluating side products, of which results led to some mechanisms and new productions to be found by using indole oxidative degradation. The results also demonstrated that due to indole oxidation and applying the proper solvent (ethanol), some side products were generated capable of acting as a fuel octane number enhancer, which may play a significant role in obtaining more valuable fuels.

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“…On the other hand, sulfur compounds are Benzothiophene (BT), Dibenzothiophene (DBT), 3‐methyl thiophen (3‐MT), Thiophen (T), 2‐methyl thiophene (2‐MT), 4,6‐dimethyl dibenzothiophene (4, 6‐DMDBT), Sulfone dibenzothiophene (DBTO), and 4‐methyl dibenzothiophene (4‐MDBT) . For removal, the most effective methods are oxidative denitrogenation (ODN) and oxidative desulfurization (ODS) by catalysts. Meanwhile, zeolite matrixes are a group of catalysts with a high selectivity and a desirable activity to break down the recently introduced C−N and C−S bonds .…”

Section: Introductionmentioning

confidence: 99%

Morphology‐Controlled Synthesis of CuO, CuO Rod/MWW Composite for Advanced Oxidation of Indole and Benzothiophene

et al. 2019

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Various morphologies of copper (II) oxide (CuO) such as dandelion, sea anemone, walnut, leaf, dendrite, rod, fiber, feather, and flake were synthesized and characterized by different methods. The oxidation of indole (IND) and benzothiophene (BT) in mild conditions was studied by various morphologies of CuO. Walnut with the lowest surface area 7.928 (m2g−1) and rod with a high surface area 41.237 (m2g−1) had efficiencies of 5.93% and 91.44% for IND and 0.53% and 88.29% for BT at 4 h, respectively. Zeolite MWW was synthesized by microwave and hydrothermal method on which CuO rod was loaded via wet impregnation method. The results indicated that CuO rod/MWW composite considerably outperformed CuO rod. The oxidations of IND and BT by CuO rod/MWW composite for 75 min was 99.99 and 97.67%, respectively. Based on the results across all experiments, the oxidation of the IND was higher than that of BT. CuO rod/MWW composite was shown to be an efficient catalyst for oxidation of nitrogen and sulfur heterocycles.

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Catalytic oxidation of carbazole using t-butyl hydroperoxide over molybdenum catalysts

Cited by 12 publications

References 16 publications

Regioselective Electrochemical Oxidation of One of the Identical Benzene Rings of Carbazole to 1,4-Quinone on the MWCNT Surface and Its Electrocatalytic Activity

Regioselective Electrochemical Oxidation of One of the Identical Benzene Rings of Carbazole to 1,4-Quinone on the MWCNT Surface and Its Electrocatalytic Activity

Cu(II)/Z4A as an Efficient Nanocomposite for Oxidative Degradation of Indole and Optimization of Effective Factors via RSM Procedure

Morphology‐Controlled Synthesis of CuO, CuO Rod/MWW Composite for Advanced Oxidation of Indole and Benzothiophene

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