One-step highly selective catalytic oxidation of cyclohexane to KA-oil over functional CeMn0.5Co0.5Ox composite oxide: Synergistic effects between Mn and Co species with different valences and metal ion ratios

Fu, Shangjun; You, Kuiyi; Ni, Wenjin; Chen, Zhenpan; Zhao, Fu‐Gang; Yan, Dejian; Zhang, Xiaowen; Luo, He’an

doi:10.1016/j.ces.2023.118878

Cited by 11 publications

(3 citation statements)

References 72 publications

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“…To explore in greater detail the radical species in this work, electron paramagnetic resonance (EPR) measurement was also carried out utilizing 5,5-dimethyl-1-pyrroline N-Oxide (DMPO) as a radical capture reagent. It is demonstrated in Figure 12 that when cyclohexane was utilized as a model substrate possessing C-H bonds, the main radical species were carbon-centered radicals (cyclohexyl radical, C 6 H 11 •), peroxide-centered radicals (cyclohexyl peroxide radical, C 6 H 11 OO•), and oxygen-centered radicals (cyclohexyl oxygen radical, C 6 H 11 O• and hydroxyl HO•), which is in good agreement with the radical species reported in relevant documents [1,11,22,66,67]. Secondly, in the determination of the major radical species, the activation of O 2 and the corresponding key intermediates were explored and verified, too.…”

Section: Mechanism Studysupporting

confidence: 87%

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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Section: Mechanism Studysupporting

confidence: 87%

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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“…When increasing the reaction time from 0 to 3 min, a weak signal at 1130 cm –1 appeared and gradually strengthened as the reaction time further prolonged from 6 to 16 min but then gradually weakened and almost disappeared between 16 and 31 min. Since the signal at 1130 cm –1 indicates the stretching vibration of the C–O–O bonds in alkyl peroxides, it supports the mechanism that C 6 H 11 OO· is initially generated at the catalyst surface by the reaction of activated oxygen species (O 2 ·) (or O 2 ) with C 6 H 12 (or C 6 H 11 ·), and it will further abstract H from the surface of the catalyst or C 6 H 12 molecule to form C 6 H 11 OOH, which is subsequently reduced/decomposed into KA oil …”

Section: Resultsmentioning

confidence: 64%

“…66 Then, the activated oxygen species (O 2 •) (or O 2 ) will react with C 6 H 12 (or C 6 H 11 •) to produce a cyclohexyl peroxide radical (C 6 H 11 OO•), which is further transformed into cyclohexyl hydroperoxide (CHHP) by abstracting the H atom from the surface of the catalyst or C 6 H 12 molecule (Figure 5). 61 Finally, CHHP is reduced/decomposed into KA oil under the synergistic catalysis of Co 2+ /Co 3+ redox pairs and acidic sites. Due to the creation of more oxygen vacancies and altered acidity after introducing the Ca dopant, the electron transfer between radicals and La 0.5 Ca 0.5 CoO 3 at the solid−liquid interface cage is further facilitated, leading to an enhanced cage reaction with a higher KA oil selectivity.…”

Section: Optimization Of Reaction Conditionsmentioning

confidence: 99%

Roles of the A-Site Ca Dopant in Modifying Surface Properties of a Co-Based Perovskite Catalyst for Selective Oxidation of Cyclohexane

Li,

Hao,

Chen

et al. 2024

Ind. Eng. Chem. Res.

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Selective catalytic oxidation of cyclohexane into cyclohexanol and cyclohexanone (KA oil) is an important but challenging reaction in the modern chemistry industry, which is characterized by a low KA oil selectivity under high conversion of cyclohexane. To solve the contradictory issue between cyclohexane conversion and KA oil selectivity, A-site-doped Co-based perovskite oxides (La 1−x A x CoO 3 , A = Mg, Ca, Sr, and Ba) as catalysts are used for solvent-free cyclohexane oxidation using molecular oxygen as an oxidant. Among all selected perovskite catalysts, Ca element-modified La 0.5 Ca 0.5 CoO 3 exhibits the best catalytic performance with a cyclohexane conversion of 7.7% and a KA oil selectivity of 86.5% under optimal reaction conditions. The characterization results show that doping the Ca element into the A-site can effectively regulate the surface properties of LaCoO 3 by changing the molar ratio of Co 2+ /Co 3+ ions, creating more oxygen vacancies, and altering the acidity and basicity, which play essential roles in promoting the activation of O 2 and the reduction/ decomposition of cyclohexyl hydroperoxide (CHHP). This work demonstrates that the catalytic performance of LaCoO 3 in the aerobic oxidation of cyclohexane can be further modified by optimizing its A-site compositions, which opens a large space for the design of highly active and selective perovskite-type catalysts for partial oxidation of saturated alkanes.

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Insight into the Better Collaboration of NiO and MnO_x in NiMn₂O₄ Spinel for Enhanced the Catalytic Oxidation Performance of Toluene

Zhang,

Xin,

Deng

et al. 2024

ChemCatChem

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NiMn oxides with different ratios (NixMnyOz) as well as spinel‐type NiMn2O4 oxides were synthesized and utilized in the catalytic oxidation of toluene. The results indicate that NiMn2Ox synthesized by the oxygen‐only roasting method exhibits superior catalytic activity due to the appropriate metal valence distribution. The catalytic activity is strongly related with the crystalline phase structures, NiMn2O4 spinel oxides catalyst shows the best low‐temperature performance with 90% conversion (T90) at 230 °C. Characterization results reveal that the superb catalytic performance of NiMn2O4 spinel oxide is mainly profit by the larger surface area, more abundant surface fugacious oxygen, stronger toluene adsorption capacity than that of the other NixMnyOz catalysts, which in favor of the speedy conversion of benzoic acid, improving the toluene catalytic performance. This finding provides a novel design strategy of NiMn composite oxides for synthesis of high‐efficiency performance toluene catalysts.

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One-step highly selective catalytic oxidation of cyclohexane to KA-oil over functional CeMn0.5Co0.5Ox composite oxide: Synergistic effects between Mn and Co species with different valences and metal ion ratios

Cited by 11 publications

References 72 publications

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

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

Roles of the A-Site Ca Dopant in Modifying Surface Properties of a Co-Based Perovskite Catalyst for Selective Oxidation of Cyclohexane

Insight into the Better Collaboration of NiO and MnO_x in NiMn₂O₄ Spinel for Enhanced the Catalytic Oxidation Performance of Toluene

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One-step highly selective catalytic oxidation of cyclohexane to KA-oil over functional CeMn0.5Co0.5Ox composite oxide: Synergistic effects between Mn and Co species with different valences and metal ion ratios

Cited by 11 publications

References 72 publications

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

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

Roles of the A-Site Ca Dopant in Modifying Surface Properties of a Co-Based Perovskite Catalyst for Selective Oxidation of Cyclohexane

Insight into the Better Collaboration of NiO and MnOx in NiMn2O4 Spinel for Enhanced the Catalytic Oxidation Performance of Toluene

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Insight into the Better Collaboration of NiO and MnO_x in NiMn₂O₄ Spinel for Enhanced the Catalytic Oxidation Performance of Toluene