Enhanced stability and activity for solvent-free selective oxidation of cyclohexane over Cu2O/CuO fabricated by facile alkali etching method

Xie, Congjia; Wang, Wei; Yang, Yepeng; Jiang, Liang; Chen, Yongjuan; He, Jiao; Wang, Jiaqiang

doi:10.1016/j.mcat.2020.111134

Cited by 12 publications

(7 citation statements)

References 45 publications

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“…Because the addition of BHT, a radical scavenger, prevents the production of any products in the oxidation reaction, it is obvious that the oxidation of cyclohexane with tert -butyl hydroperoxide appears to be a radical process. As a consequence of the findings in this study and previous studies, 46 , 47 we proposed a probable reaction mechanism for the catalytic oxidation of cyclohexane with TBHP over CuNPs@LDH, as illustrated in Scheme 2 .…”

Section: Resultssupporting

confidence: 78%

Fabrication and Characterization of Cu Nanoparticles Dispersed on ZnAl-Layered Double Hydroxide Nanocatalysts for the Oxidation of Cyclohexane

Kirar¹,

Gupta²,

Chandra

et al. 2022

ACS Omega

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In the chemical industry, designing high-performance catalysts for the oxidation of cyclohexane into value-added products such as cyclohexanol and cyclohexanone (the combination is known as KA oil) is critical. The catalytic activity of copper nanoparticles supported on layered double hydroxide (LDH) for the liquid phase oxidation of cyclohexane was examined in this study. In this work, we have developed Cu nanoparticles supported on layered double hydroxide nanocatalysts, abbreviated as CuNPs@LDH, by the chemical reduction approach. Various physical methods were used to characterize the resulting material, including ICP-AES, XRD, FTIR, SEM, EDX, HRTEM, and BET surface area. The catalytic activity of copper nanoparticles supported on LDH was examined for the liquid phase oxidation of cyclohexane with tert-butyl hydroperoxide. CuNPs@ LDH nanocatalysts with an excellent 52.3% conversion of cyclohexane with 97.2% selectivity of KA oil was obtained after 6 h at 353 K. The hot filtration test further indicated that CuNPs@LDH was a heterogeneous catalyst that could be recycled at least six times without suffering a substantial reduction in its catalytic activity.

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Section: Resultssupporting

confidence: 78%

Fabrication and Characterization of Cu Nanoparticles Dispersed on ZnAl-Layered Double Hydroxide Nanocatalysts for the Oxidation of Cyclohexane

Kirar¹,

Gupta²,

Chandra

et al. 2022

ACS Omega

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“…The mechanism of C–H bond oxygenation through the synergistic catalysis of Co-TCPPNi is presented in Scheme 2 , with references to certain relevant studies [ 26 , 37 , 79 , 82 , 84 , 85 , 86 , 87 , 88 ] after determining the primary radical species, radical mechanism, and synergistic catalysis model. The oxygenation reaction pathway of hydrocarbons with oxygen catalyzed by Co-TCPPNi, as demonstrated in Scheme 2 , can be separated into four major sub-paths that are interconnected with each other.…”

Section: Resultsmentioning

confidence: 99%

Efficient and Selective Oxygenation of Cycloalkanes and Alkyl Aromatics with Oxygen through Synergistic Catalysis of Bimetallic Active Centers in Two-Dimensional Metal-Organic Frameworks Based on Metalloporphyrins

Zhou

Jin

et al. 2023

Biomimetics

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Confined catalytic realms and synergistic catalysis sites were constructed using bimetallic active centers in two-dimensional metal-organic frameworks (MOFs) to achieve highly selective oxygenation of cycloalkanes and alkyl aromatics with oxygen towards partly oxygenated products. Every necessary characterization was carried out for all the two-dimensional MOFs. The selective oxygenation of cycloalkanes and alkyl aromatics with oxygen was accomplished with exceptional catalytic performance using two-dimensional MOF Co-TCPPNi as a catalyst. Employing Co-TCPPNi as a catalyst, both the conversion and selectivity were improved for all the hydrocarbons investigated. Less disordered autoxidation at mild conditions, inhibited free-radical diffusion by confined catalytic realms, and synergistic C–H bond oxygenation catalyzed by second metal center Ni employing oxygenation intermediate R–OOH as oxidant were the factors for the satisfying result of Co-TCPPNi as a catalyst. When homogeneous metalloporphyrin T(4-COOCH3)PPCo was replaced by Co-TCPPNi, the conversion in cyclohexane oxygenation was enhanced from 4.4% to 5.6%, and the selectivity of partly oxygenated products increased from 85.4% to 92.9%. The synergistic catalytic mechanisms were studied using EPR research, and a catalysis model was obtained for the oxygenation of C–H bonds with O2. This research offered a novel and essential reference for both the efficient and selective oxygenation of C–H bonds and other key chemical reactions involving free radicals.

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“…The reaction mechanism of C-H bonds' oxidation utilizing O2 by means of the relay catalysis of Si@Porp. Co&Cu was investigated systematically in this work, too, and it is demonstrated in Scheme 4 in referencing some of the relevant literature [12,22,[55][56][57][58][59][60][61][62]. To confirm the speculated mechanism, the nature of the free radical process in C-H bonds' oxidation utilizing O2 in this work and the major reactive species were explored in detail.…”

Section: Mechanism Studymentioning

confidence: 97%

Efficient Inhibition of Deep Conversion of Partial Oxidation Products in C-H Bonds’ Functionalization Utilizing O2 via Relay Catalysis of Dual Metalloporphyrins on Surface of Hybrid Silica Possessing Capacity for Product Exclusion

Zhang,

Feng,

et al. 2024

Biomimetics

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To inhibit the deep conversion of partial oxidation products (POX-products) in C-H bonds’ functionalization utilizing O2, 5-(4-(chloromethyl)phenyl)-10,15,20-tris(perfluorophenyl)porphyrin cobalt(II) and 5-(4-(chloromethyl)phenyl)-10,15,20-tris(perfluorophenyl)porphyrin copper(II) were immobilized on the surface of hybrid silica to conduct relay catalysis on the surface. Fluorocarbons with low polarity and heterogeneous catalysis were devised to decrease the convenient accessibility of polar POX-products to catalytic centers on the lower polar surface. Relay catalysis between Co and Cu was designed to utilize the oxidation intermediates alkyl hydroperoxides to transform more C-H bonds. Systematic characterizations were conducted to investigate the structure of catalytic materials and confirm their successful syntheses. Applied to C-H bond oxidation, not only deep conversion of POX-products was inhibited but also substrate conversion and POX-product selectivity were improved simultaneously. For cyclohexane oxidation, conversion was improved from 3.87% to 5.27% with selectivity from 84.8% to 92.3%, which was mainly attributed to the relay catalysis on the surface excluding products. The effects of the catalytic materials, product exclusion, relay catalysis, kinetic study, substrate scope, and reaction mechanism were also investigated. To our knowledge, a practical and novel strategy was presented to inhibit the deep conversion of POX-products and to achieve efficient and accurate oxidative functionalization of hydrocarbons. Also, a valuable protocol was provided to avoid over-reaction in other chemical transformations requiring high selectivity.

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Enhanced stability and activity for solvent-free selective oxidation of cyclohexane over Cu2O/CuO fabricated by facile alkali etching method

Cited by 12 publications

References 45 publications

Fabrication and Characterization of Cu Nanoparticles Dispersed on ZnAl-Layered Double Hydroxide Nanocatalysts for the Oxidation of Cyclohexane

Fabrication and Characterization of Cu Nanoparticles Dispersed on ZnAl-Layered Double Hydroxide Nanocatalysts for the Oxidation of Cyclohexane

Efficient and Selective Oxygenation of Cycloalkanes and Alkyl Aromatics with Oxygen through Synergistic Catalysis of Bimetallic Active Centers in Two-Dimensional Metal-Organic Frameworks Based on Metalloporphyrins

Efficient Inhibition of Deep Conversion of Partial Oxidation Products in C-H Bonds’ Functionalization Utilizing O2 via Relay Catalysis of Dual Metalloporphyrins on Surface of Hybrid Silica Possessing Capacity for Product Exclusion

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