Photoinduced Carbon Tetrabromide Initiated Aerobic Oxidation of Substituted Toluenes to Carboxylic Acids

Zheng, Kun; Yan, Xiaoyu; Zhang, Guofu; Yan, Xinhuan; Li, Xiaoqing; Xu, Xiangsheng

doi:10.1055/s-0039-1691534

Cited by 3 publications

(4 citation statements)

References 15 publications

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“…Deuteration of 3-methoxybenzoic acid. (17) Procedure B to afford 17-d as white solid (116.4 mg, 77%) with D-incorporation 89% for 2-position and 93% for 6-position by NMR and 1.83D by GC-MS. Rf 0.40 (Petroleum ether/EtOAc =6/1 with 1% CH3COOH).…”

Section: S36mentioning

confidence: 99%

Palladium-Catalyzed Ligand-Free ortho-Deuteration of Aromatic Carboxylic Acids with D2O

et al. 2022

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A ligand-free, palladium-catalyzed ortho-deuteration of aromatic carboxylic acid was developed using D2O as deuterium-source. Compared to their meta-substituted analogues, an unusually lower reactivity in para- and ortho-substituted benzoic acids toward hydrogen isotope exchange was observed. Further investigation revealed that the reaction temperature is a critical parameter for the reactivity, and the modified condition can afford deuterated products with good to excellent deuterium-incorporation.

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Section: S36mentioning

confidence: 99%

Palladium-Catalyzed Ligand-Free ortho-Deuteration of Aromatic Carboxylic Acids with D2O

et al. 2022

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“…Terephthalic acid was obtained in 96% yield after 6 h at 110 °C. The use of light in the photoinduced oxygenation of substituted toluene in the presence of catalyst systems containing bromine compounds, such as LiBr or HBr ( hv 400 W), CBr 4 –Ph 3 P (fluorescent lamp), or CBr 4 (400 nm LED), has also been described. − …”

Section: Introductionmentioning

confidence: 99%

Selective Aerobic Oxidation of Toluene in the Presence of Co²⁺ and Task-Specific Organic Salts, Including Ionic Liquids

Lisicki

Maciej

Orlińska

2021

Ind. Eng. Chem. Res.

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This paper presents research on the catalytic activity of systems composed of transition-metal compounds and organic bromide salts, [X][Br] or [X][Br 3 ], in the oxidation of toluene and its derivatives with oxygen using acetic acid as a solvent. Salts containing imidazolium, tetraalkylammonium, bromoalkylammonium, phenylalkylammonium, or benzylalkylammonium cations in combination with Co 2+ compounds were used. It was found that the [X][Br] and [X][Br 3 ] systems with Co 2+ compounds enabled the oxidation of toluene and its derivatives to the corresponding carboxylic acids with high selectivities and reaction rates. Moreover, long-term corrosion studies on three selected stainless steels showed that the organic salts that contained nitrogen atoms had an inhibitory effect on the corrosion caused by the Br − ions present in the reaction system. For the first time, the possibility of replacing inorganic bromides, used on an industrial scale in the Amoco process, by organic bromide salts, including ionic liquids, with corrosion-inhibiting properties was demonstrated.

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“…In order to reduce the induction period and facilitate the radical propagation, numerous metal (Au, Pd, Cu, Co et al) or metal free (g-C 3 N 4 , N-hydroxyphthalimide, carbon materials et al) based catalysts have been developed. [15,17,[20][21][22][23][24][25][26][27][28][29][30][31][32][33] However, these metal or metal-free catalysts are expensive, complexly prepared or harmful to the environment.…”

Section: Introductionmentioning

confidence: 99%

“…or metal free (g‐C 3 N 4 , N‐hydroxyphthalimide, carbon materials et al.) based catalysts have been developed [15,17,20–33] . However, these metal or metal‐free catalysts are expensive, complexly prepared or harmful to the environment.…”

Section: Introductionmentioning

confidence: 99%

Radical Propagation Facilitating Aerobic Oxidation of Substituted Aromatics Promoted by Tert‐Butyl Hydroperoxide

et al. 2021

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The selective oxidation of aromatics to synthesize valuedadded products is of great significance for chemical industry. Molecule oxygen as oxidant is the priority for this process, however, low efficiency was usually obtained. In this work, a new strategy for aromatics oxidation using O 2 and Tert-butyl hydroperoxide (TBHP) as dual oxidants without catalyst was proposed. Typical radical process was observed when Toluene was used as the substrate. As high as 47.1 % conversion and 87.6 % selectivity of benzol acid were obtained, while a negligible or low activity were observed under O 2 or TBHP oxidative systems. Detailed investigation shows that the distribution of products was almost the same between TBHP + N 2 and TBHP + O 2 processes, in which the very close active energies were obtained (46.0 and 46.3 kJ/mol). These results indicated that TBHP + N 2 or TBHP + O 2 involved reactions underwent the same reaction process. The mechanism study demonstrated that the decomposition of TBHP could produce abundance of t-BuO * and * OH radicals, which significantly enhanced the αH abstraction from toluene and formed alkyl radicals. The alkyl radicals then react with O 2 to produce peroxides, which started the radical propagation cycle. The overall rate would be enhanced subsequently. Furthermore, an extension application of other aromatic substrates was investigated and displayed a great promising future to produce aromatic products.

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Photoinduced Carbon Tetrabromide Initiated Aerobic Oxidation of Substituted Toluenes to Carboxylic Acids

Abstract: A mild and metal-free procedure is reported for the aerobic oxidation of substituted toluenes to carboxylic acids by using CBr4 as initiator under irradiation from a 400 nm blue light-emitting diode.

Cited by 3 publications

References 15 publications

Palladium-Catalyzed Ligand-Free ortho-Deuteration of Aromatic Carboxylic Acids with D2O

Palladium-Catalyzed Ligand-Free ortho-Deuteration of Aromatic Carboxylic Acids with D2O

Selective Aerobic Oxidation of Toluene in the Presence of Co²⁺ and Task-Specific Organic Salts, Including Ionic Liquids

Radical Propagation Facilitating Aerobic Oxidation of Substituted Aromatics Promoted by Tert‐Butyl Hydroperoxide

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Photoinduced Carbon Tetrabromide Initiated Aerobic Oxidation of Substituted Toluenes to Carboxylic Acids

Abstract: A mild and metal-free procedure is reported for the aerobic oxidation of substituted toluenes to carboxylic acids by using CBr4 as initiator under irradiation from a 400 nm blue light-emitting diode.

Cited by 3 publications

References 15 publications

Palladium-Catalyzed Ligand-Free ortho-Deuteration of Aromatic Carboxylic Acids with D2O

Palladium-Catalyzed Ligand-Free ortho-Deuteration of Aromatic Carboxylic Acids with D2O

Selective Aerobic Oxidation of Toluene in the Presence of Co2+ and Task-Specific Organic Salts, Including Ionic Liquids

Radical Propagation Facilitating Aerobic Oxidation of Substituted Aromatics Promoted by Tert‐Butyl Hydroperoxide

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Selective Aerobic Oxidation of Toluene in the Presence of Co²⁺ and Task-Specific Organic Salts, Including Ionic Liquids