431-47-0Relevant articles and documents
Rosall,Robertson
, p. 869,870-872 (1975)
Protolytic Catalysis of Anilide Methanolysis. Spectator Catalysis of Leaving-Group Departure
Venkatasubban, K. S.,Schowen, Richard L.
, p. 653 - 655 (1984)
Substituted phenols serve as general-acid catalysts of leaving-group departure from the adduct of methoxide ion with m-NO2C6H4N(CH3)COCF3 in methanol at 25 deg C.Sufficiently high concentrations of general acid convert methoxide addition to the rate-limiting step, allowing determination of rate constants for methoxide addition to substrate carbonyl (ka = 300 M-1 s-1), for overall solvent-assisted leaving-group departure (ke = kake'/k-a = 5.9 M-1 s-1) and for overall general-acid-catalyzed leaving-group departure (kBH = kakBH'/k-a = 2400 +/- 1200 M-2 s-1 for five substituted phenols with pKa's from 12.7 to 14.6).Thus the Broensted α ca. 0.It is suggested that the general acid is a spectator at spontaneous expulsion of the leaving group, producing catalysis by fast subsequent trapping of CH3NAr-.The Jencks clock shows the tetrahedral intermediate to have a minimum characteristic lifetime of 1-10 ns.
Direct and remarkably efficient conversion of methane into acetic acid catalyzed by amavadine and related vanadium complexes. A synthetic and a theoretical DFT mechanistic study
Kirillova, Marina V.,Kuznetsov, Maxim L.,Reis, Patricia M.,Da Silva, Jose A. L.,Frausto Da Silva, Joao J. R.,Pombeiro, Armando J. L.
, p. 10531 - 10545 (2007)
Vanadium(IV or V) complexes with N,O- or O,O-ligands, i.e., [VO{N(CH 2CH2O)3}], Ca[V(HIDPA)2] (synthetic amavadine), Ca[V(HIDA)2], or [Bu4N]2[V(HIDA) 2] [HIDPA, HIDA = basic form of 2,2′-(hydroxyimino)dipropionic or -diacetic acid, respectively], [VO(CF3SO3) 2], Ba[VO(nta)(H2O)]2 (nta = nitrilotriacetate), [VO(ada)(H2O)] (ada = N-2- acetamidoiminodiacetate), [VO(Hheida)(H2O)] (Hheida = 2-hydroxyethyliminodiacetate), [VO(bicine)] [bicine = basic form of N,N-bis(2-hydroxyethyl)glycine], and [VO(dipic)(OCH2-CH3)] (dipic = pyridine-2,6-dicarboxylate), are catalyst precursors for the efficient single-pot conversion of methane into acetic acid, in trifluoroacetic acid (TFA) under moderate conditions, using peroxodisulfate as oxidant. Effects on the yields and TONs of various factors are reported. TFA acts as a carbonylating agent and CO is an inhibitor for some systems, although for others there is an optimum CO pressure. The most effective catalysts (as amavadine) bear triethanolaminate or (hydroxyimino)dicarboxylates and lead, in a single batch, to CH3COOH yields > 50% (based on CH4) or remarkably high TONs up to 5.6 × 103. The catalyst can remain active upon multiple recycling of its solution. Carboxylation proceeds via free radical mechanisms (CH3? can be trapped by CBrCl 3), and theoretical calculations disclose a particularly favorable process involving the sequential formation of CH3?, CH3CO?, and CH3COO? which, upon H-abstraction (from TFA or CH4), yields acetic acid. The CH3COO? radical is formed by oxygenation of CH 3CO? by a peroxo-V complex via a V{η1- OOC(O)CH3} intermediate. Less favorable processes involve the oxidation of CH3CO? by the protonated (hydroperoxo) form of that peroxo-V complex or by peroxodisulfate. The calculations also indicate that (i) peroxodisulfate behaves as a source of sulfate radicals which are methane H-abstractors, as a peroxidative and oxidizing agent for vanadium, and as an oxidizing and coupling agent for CH3CO? and that (ii) TFA is involved in the formation of CH3COOH (by carbonylating CH3?, acting as an H-source to CH 3COO?, and enhancing on protonation the oxidizing power of a peroxo-VV complex) and of CF3-COOCH3 (minor product in the absence of CO).
REACTION OF DIMETHYL SULFITE WITH DIMETHYLAMINOMETHYL DERIVATIVES
Baires, S. V.,Ivanov, V. B.,Ivanov, B. E.,Krokhina, S. S.,Efremov, Yu. Ya.,Korshunov, R. L.
, p. 203 - 206 (1986)
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Low-Temperature, Palladium(II)-Catalyzed, Solution-Phase Oxidation of Methane to a Methanol Derivative
Kao, Lien-Chung,Hutson, Alan C.,Sen, Ayusman
, p. 700 - 701 (1991)
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CH-activation of methane - Synthesis of an intermediate?
Meyer, Dirk,Strassner, Thomas
, p. 84 - 87 (2015)
Abstract A dimeric methyl palladium(II) biscarbene complex with a bridging μ-chloro ligand was prepared by transmetalation from 1,1'-dimethyl-3,3'-methylenediimidazolium dichloride, silver(I) oxide and chloridomethyl(cycloctadiene)palladium(II). The complex was fully characterized and shows good activity in the CH-activation of methane. The solid state structure confirms a symmetrical dimeric structure with a μ-coordinated chlorido ligand.
Atmosphere-Pressure Methane Oxidation to Methyl Trifluoroacetate Enabled by a Porous Organic Polymer-Supported Single-Site Palladium Catalyst
Zhang, Yiwen,Zhang, Min,Han, Zhengbo,Huang, Shijun,Yuan, Daqiang,Su, Weiping
, p. 1008 - 1013 (2021)
The efficient conversion of methane into methanol at low temperature under low pressure remains a great challenge largely because of the inertness and poor solubility of methane. Herein, we report that a porous organic polymer-supported Pd catalyst, which was constructed via Friedel-Crafts type polymerization between 4,6-dichloropyrimidine and 1,3,5-triphenyl benzene and subsequent metalation, enabled the conversion of methane to methyl trifluoroacetate, a precursor to methanol, under atmosphere pressure (1 atm) at 80 °C to afford a 51% yield relative to methane with a TON of 664 over 20 h. On increasing the pressure to 30 bar, this palladium catalyst offered a TON of 1276 for a run and could be reused for at least five runs without a notable loss of activity. The characterization of this Pd catalyst revealed its good affinity for methane uptake that would increase the concentration of methane in the local space around the Pd center and the homogeneous distribution of Pd2+ on support that would protect the catalytically active metal species, shedding light on the high catalytic activity of this Pd catalyst toward methane conversion.
KF-Promoted copper-catalyzed highly efficient and selective oxidation of methane and other alkanes with a dramatic additive effect
Chen, Wei,Chen, Xiaoyan,Fan, Wu,Li, Suhua,Liu, Luyao
, p. 4962 - 4968 (2021/07/26)
Highly efficient oxidation of methane to methyl trifluoroacetate mediated by CuCl/KF/K2S2O8in trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) is described. The additive effect has been systematically evaluated and potassium fluoride (KF) was identified as the most effective promoter among the salts screened. KF is conjectured to exhibit the salt effect to promote the [SO4˙]?radical to escape the solvent cage based on control experiments. Cyclohexane and adamantane could also be efficiently oxidized into benzene or corresponding trifluoroacetates.
Functionalization of RhIII-Me Bonds: Use of capping Arene Ligands to Facilitate Me-X Reductive Elimination
Gu, Shunyan,Chen, Junqi,Musgrave, Charles B.,Gehman, Zo? M.,Habgood, Laurel G.,Jia, Xiaofan,Dickie, Diane A.,Goddard, William A.,Gunnoe, T. Brent
, p. 1889 - 1906 (2021/05/29)
We show how to improve the yield of MeX from CH4 activation catalysts from 12% to 90% through the use of capping arene ligands. Four (FP)RhIII(Me)(TFA)2 {FP = capping arene ligands, including 8,8′-(1,2-phenylene)diquinoline (6-FP), 8,8′-(1,2-naphthalene)diquinoline (6-NPFP), 1,2-bis(N-7-azaindolyl)benzene (5-FP), and 1,2-bis(N-7-azaindolyl)naphthalene (5-NPFP)} complexes. These complexes and (dpe)RhIII(Me)(TFA)2 (dpe = 1,2-di-2-pyridylethane) were synthesized and tested for their performance in reductive elimination of MeX (X = TFA or halide). The FP ligands were used with the goal of blocking a coordination site to destabilize the RhIII complexes and facilitate MeX reductive elimination. On the basis of single-crystal X-ray diffraction studies, the 6-FP and 6-NPFP ligated Rh complexes have Rh-arene distances shorter than those of the 5-FP and 5-NPFP Rh complexes; thus, it is expected that the Rh-arene interactions are weaker for the 5-FP complexes than for the 6-FP complexes. Consistent with our hypothesis, the 5-FP and 5-NPFP RhIII complexes demonstrate improved performance (from 12% to ～60% yield) in the reductive elimination of MeX. The reductive elimination of MeX from (FP)RhIII(Me)(TFA)2 can be further improved by the use of chemical oxidants. For example, the addition of 2 equiv of AgOTf leads to 87(2)% yield of MeTFA and can be achieved in CD3CN at 90 °C using (5-FP)Rh(Me)(TFA)2.
