Catalytic, Oxidative Condensation of CH
            <sub>4</sub>
            to CH
            <sub>3</sub>
            COOH in One Step via CH Activation

Periana, Roy A.; Mironov, O. A.; Taube, Doug; Bhalla, Gaurav; Jones, Celina

doi:10.1126/science.1086466

Cited by 381 publications

(195 citation statements)

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“…14,[16][17][18] Practical application for C-H bond activation do not only implies that a C-H bond has to be broken, but also the functionalization of the resulting carbon entity by introduction of a heteroatom or formation of a new C-C bond. Systems involving transition metal complexes have proven to be good candidate and a few promising homogeneous systems have been developed 3,[19][20][21][22][23][24][25][26][27][28][29][30] with a particular interest for Pt(II) square planar metal complexes that will be addressed further. Extensive research has been aimed at studying the details of the selective functionalization of hydrocarbons.…”

Section: Methodsmentioning

confidence: 99%

“…Methane is used industrially as the principal starting material for the production of hydrogen, methanol, and acetic acid. 3 When used to produce any of these chemicals, methane is first converted to Synthesis Gas, a mixture of carbon monoxide and hydrogen, by a process termed steam reforming, Scheme 1. This process is heterogeneous in nature and requires high temperature.…”

Section: Introductionmentioning

confidence: 99%

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Combined Low Temperature Rapid Scan and¹H NMR Mechanistic Study of the Protonation and Subsequent Benzene Elimination from a (Diimine)platinum(II) Diphenyl Complex Relevant to Arene C−H Activation

et al. 2009

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A detailed kinetic study of the protonation and subsequent benzene elimination reactions of a (diimine)Pt II diphenyl complex (denoted as (N-N)PtPh 2 ) has been undertaken in dichloromethane solution with and without acetonitrile as a cosolvent. Spectroscopic monitoring of the reactions by UV-vis stopped-flow and NMR techniques over the temperature range -80 to +27 °C allowed the assessment of the effects of acid concentration, coordinating solvent (MeCN) concentration, temperature, and pressure. Protonation of (N-N)PtPh 2 with HBF 4 3 Et 2 O in CH 2 Cl 2 /MeCN occurs with a kinetic preference for protonation at the metal, rather than at a phenyl ligand, and rapidly produces (N-N)PtPh 2 H(NCMe) + (ΔH q = 29 ( 1 kJ mol -1 , ΔS q = -47 ( 4 J K -1 mol -1 ). At higher temperatures, (N-N)PtPh 2 H(NCMe) + eliminates benzene to furnish (N-N)PtPh(NCMe) + . This reaction proceeds by rate-limiting MeCN dissociation (ΔH q = 88 ( 2 kJ mol -1 , ΔS q = +62 ( 6 J K -1 mol -1 , ΔV q = +16 ( 2 cm 3 mol -1 ). Protonation of (N-N)PtPh 2 in dichloromethane in the absence of MeCN cleanly produces the Pt(II) π-benzene complex (N-N)PtPh(η 2 -C 6 H 6 ) + at low temperatures. Addition of MeCN to a solution of the π-benzene complex causes an associative substitution of benzene by acetonitrile, the kinetics of which were monitored by 1 H NMR (ΔH q = 39 ( 2 kJ mol -1 , ΔS q = -126 ( 11 J K -1 mol -1 ). When the stronger triflic acid is employed in dichloromethane/acetonitrile, a second protonation-induced reaction also occurs. Thus, (N-N)PtPh(NCMe) + produces (N-N)Pt(NCMe) 2 2+ and benzene with no detectable intermediates (ΔH q = 69 ( 1 kJ mol -1 , ΔS q = -43 ( 3 J K -1 mol -1 ). The mechanisms for all steps are discussed in view of the accumulated data. Interestingly, the data allow a reinterpretation of a previous report on proton exchange between the phenyl and benzene ligands in (N-N)PtPh(η 2 -C 6 H 6 ) + . It appears that the exchange occurs by a direct σ-bond metathesis pathway, rather than by the oxidative cleavage/reductive coupling sequence that was proposed.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Combined Low Temperature Rapid Scan and¹H NMR Mechanistic Study of the Protonation and Subsequent Benzene Elimination from a (Diimine)platinum(II) Diphenyl Complex Relevant to Arene C−H Activation

et al. 2009

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“…Using Shilov-type chemistry (Figure 2), Periana and co-workers have developed catalytic systems based on mercury (13), platinum (14) or gold (15) that convert methane into methyl bisulfate, usually in sulphuric acid media and at high temperature. Subsequently, Periana (16) and Pombeiro (17) independently reported conversion of methane into acetic acid, respectively using palladium-and vanadium-based catalysts.…”

mentioning

confidence: 99%

Silver-Catalyzed C-C Bond Formation Between Methane and Ethyl Diazoacetate in Supercritical CO ₂

Caballero

Despagnet-Ayoub

Díaz‐Requejo

et al. 2011

Science

237

163

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The use of methane, the lightest hydrocarbon and primary component of natural gas, as a source for fine chemicals production remains an appealing goal on scientific, economic and environmental grounds (1-4). Transition metal catalyzed C-H bond activation is a promising approach to achieve functionalization of the strong and relatively inert C-H bonds of alkanes more generally. In one possible scenario, these reactions proceed by metal-promoted C-H bond oxidative cleavage followed by insertion of a suitable X group into the M-C bond and release of the functionalized product by means of reductive elimination of the C-X-H unit (5). Individual reaction steps for this and related catalytic cycles have been widely reported (6), but a major challenge has been that removal of the functionalized fragments from the metal coordination sphere is often unfavorable, due to the robustness of the M-C bonds. Only FINAL VERSION ACCEPTED

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Vanadate ion-catalyzed oxidation of methane with hydrogen peroxide in an aqueous solution

2008

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The functionalization of saturated hydrocarbons, the "noble gases" of organic chemistry [1], is an important area of metal-complex catalysis [2][3][4][5][6][7][8][9]. Obtaining products of the partial oxidation of the most inert alkane methane is an especially challenging problem. It is known that vanadium derivatives catalyze the oxidation and oxidative functionalization of alkanes, including methane [10][11][12][13][14][15][16].Earlier, we found that a vanadate anion in an acetonitrile solution catalyzes the effective oxidation of saturated hydrocarbons with air oxygen in the presence of hydrogen peroxide at low temperatures ( 20-70° C) [17][18][19][20][21][22][23][24][25][26][27][28][29][30]. The presence of pyrazine-2-carboxylic acid (PCA) as a cocatalyst in concentrations that sometimes exceed the concentration of a vanadium complex is a necessary condition for the reaction. The primary product of the reaction is alkyl hydroperoxide, which decomposes during the process yielding the corresponding carbonyl compound (ketone or aldehyde) and alcohol.A study of the selectivity parameters in the oxidation of various alkanes showed that the oxidizing action of the test system is due to the formation of hydroxyl radicals, which attack C-H bonds in an alkane. It was assumed [26] that the PCA anion coordinated to vanadium facilitates the processes of the proton transfer between ligands in the vanadium coordination sphere and, thus, accelerates the reaction of the generation of hydroperoxyl and hydroxyl radicals. Bell et al. [31] performed a density functional theory (DFT) study of our reagent. They showed that the direct proton transfer from the H 2 O 2 molecule to the oxygen atom of a vanadium-containing species indeed has a substantially higher barrier as compared to that of proton migration first from hydrogen peroxide to the carboxyl group of the pyrazine-2-carboxylate anion coordinated to the vanadium ion through the nitrogen atom and only then to the V=O moiety. Recently, on the basis of the results of the study of the electronic absorption spectra of solutions and the kinetics of isopropanol oxidation with this system, it has been concluded [30] that the decomposition of vanadium(V) diperoxocomplex with the PCA anion is the rate-determining step of the process and the species that induces the oxidation of isopropanol is the hydroxyl radical.It was assumed [28] that H 2 O 2 degradation in an organic solvent proceeds as a radical nonchain process. Preliminary data [23,24] obtained earlier indicate that this system oxygenates alkanes in an aqueous solution as well. Since water is a quite attractive (inexpensive and environmentally friendly) solvent, it was interesting to investigate in more detail the methane oxidation in an aqueous solution.In the present work, we investigated the behavior of the vanadate ion and PCA during the oxidation of methane in an aqueous solution in the presence of hydrogen peroxide and air at a pressure ranging from atmospheric to 10 bar and a temperature ranging from ambient to 90°ë . ...

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Catalytic, Oxidative Condensation of CH ₄ to CH ₃ COOH in One Step via CH Activation

Cited by 381 publications

References 21 publications

Combined Low Temperature Rapid Scan and¹H NMR Mechanistic Study of the Protonation and Subsequent Benzene Elimination from a (Diimine)platinum(II) Diphenyl Complex Relevant to Arene C−H Activation

Combined Low Temperature Rapid Scan and¹H NMR Mechanistic Study of the Protonation and Subsequent Benzene Elimination from a (Diimine)platinum(II) Diphenyl Complex Relevant to Arene C−H Activation

Silver-Catalyzed C-C Bond Formation Between Methane and Ethyl Diazoacetate in Supercritical CO ₂

Vanadate ion-catalyzed oxidation of methane with hydrogen peroxide in an aqueous solution

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Catalytic, Oxidative Condensation of CH 4 to CH 3 COOH in One Step via CH Activation

Cited by 381 publications

References 21 publications

Combined Low Temperature Rapid Scan and1H NMR Mechanistic Study of the Protonation and Subsequent Benzene Elimination from a (Diimine)platinum(II) Diphenyl Complex Relevant to Arene C−H Activation

Combined Low Temperature Rapid Scan and1H NMR Mechanistic Study of the Protonation and Subsequent Benzene Elimination from a (Diimine)platinum(II) Diphenyl Complex Relevant to Arene C−H Activation

Silver-Catalyzed C-C Bond Formation Between Methane and Ethyl Diazoacetate in Supercritical CO 2

Vanadate ion-catalyzed oxidation of methane with hydrogen peroxide in an aqueous solution

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Product

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Catalytic, Oxidative Condensation of CH ₄ to CH ₃ COOH in One Step via CH Activation

Combined Low Temperature Rapid Scan and¹H NMR Mechanistic Study of the Protonation and Subsequent Benzene Elimination from a (Diimine)platinum(II) Diphenyl Complex Relevant to Arene C−H Activation

Combined Low Temperature Rapid Scan and¹H NMR Mechanistic Study of the Protonation and Subsequent Benzene Elimination from a (Diimine)platinum(II) Diphenyl Complex Relevant to Arene C−H Activation

Silver-Catalyzed C-C Bond Formation Between Methane and Ethyl Diazoacetate in Supercritical CO ₂