Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Formate radical

In the last two decades a number of phenomena found many years ago in azo coupling and other substitution reactions have been elucidated with regard to their structural and mechanistic basis. These include charge-transfer complex formation, radical pairs as transient intermediates, and changes in product ratios due to mixing effects — a phenomenon which was not understandable at all only a few years ago (see Secs. 12.8 and 12.9). [Pg.305]

Scheme 2.160. Imin-formation/radical-cyclization for the synthesis of pyrrolidines. Scheme 2.160. Imin-formation/radical-cyclization for the synthesis of pyrrolidines.
Mundy CJ, Colvin ME, Quong AA (2002) Irradiated guanine a Car-Parinello molecular dynamics study of dehydrogenation in the presence of an OH radical. J Phys Chem A 106 10063-10071 Murata-Kamiya N, Kamiya H, Muraoka M, Kaji H, Kasai H (1998) Comparison of oxidation products from DNA components byy-irradiation and Fenton-type reactions. J Radiat Res 38 121-131 Nabben FJ, van der Stroom HA, Loman H (1983) Inactivation of biologically active DNA by isopropanol and formate radicals. Int J Radiat Biol 43 495-504 Nakashima M, Hayon E (1979) Rates of reaction of inorganic phosphate radicals in solution. J Phys Chem 74 3290-3291... [Pg.325]

For the formate radical HCOO, we use Eq. (10b) with DAB =110 kcal/ mol for the 171 coordination and Eq. (20b) with DAX = 166 kcal/mol for the rj1 coordination. We have calculated the relevant values of (2hcoo f°r Ag(lll), Ni(lll), Fe(110), and W(110). Because no direct experimental data are available, we shall discuss our projections later in the general context of HCOOH decomposition on metal surfaces. Here we shall only mention that for HCOO the 172 coordination was found to be always preferred over the 17 coordination, in full agreement with experiment (see Section IV,C). [Pg.127]

Cu (100) hco2 disordered The formate radical is in a plane 1 to the surface with the two oxygens closest to the surface, and a formate O-C-O bond angle of 125 ° is assumed. The 0 atoms are slightly off-center above two adjacent 4-fold hollow sites. The 0 atoms are 1.54 A above the Cu surface and separated by 2.17 A. The C atom is 2.11 A above the surface. NEXAFS/1/... [Pg.168]

No other experimental data exist for any QOOH homolysis. Benson estimated A 10 s and = 63 kJ moP for the decomposition of QOOH (1,5 formation) radicals into oxetanes. As solvent effects are unlikely to influence the liquid-phase homolysis, the kinetic parameters for the formation of oxetanes are taken to be consistent and relatively reliable. [Pg.62]

Single-Electron Transfer Grignard Formation Radical Anions Radical Cations... [Pg.326]

The kinetics of emulsion polymerization is complex, involving a large number of species and at least two phases. The first quantitative approach to emulsion polymerization kinetics led to extensions by many others.The important events to consider are 1) the free-radical reactions of chain formation initiation, propagation, chain transfer, and termination and 2) the phase transfer events that control particle formation radical entry into particles from the aqueous phase, radical exit into the aqueous phase, radical entry into micelles, and the aqueous phase coil-globule transition. In free-radical emulsion polymerization, the fundamental steps are shown schematically in Fig. 1... [Pg.865]

CH rate at very low pH suggests that undissociated CO is not a major adsorbed species. If CO dissociation was necessary for the formation of surface carbon for CH formation, then it is very difficult to accept the lower CH rate at low pH because it is unlikely that a hydrogen would displace a chemisorbed CO molecule. The effect of low pH may be due to blocking the formation of an intermediate more weakly bound than hydrogen, perhaps formate radicals. [Pg.168]

In spite of uncertainties about how CH4 is produced and whether or not a methyl radical is generated as a primary photochemical step, the complex Me-W(CO)3Cp has been utilized by Mohler in photoinduced DNA cleavage.60 The mechanism shown in Equation 10.43 has been proposed61 for the production of a formate radical under these conditions ... [Pg.445]

The proposed inactivation mechanism in Scheme 39 predicts that the normal reverse reaction, i.e., hydrogen abstraction from formate, may lead to a formate radical anion intermediate. Consistent with this idea, a isotope effect of... [Pg.374]

This persuasive evidence for homolytic chemistry occurring in the PFL reaction has led Kozarich and co-workers to propose a working hypothesis for the overall enzymic reaction (787). A chemical precedent exists in the H202/Fe(II)-mediated homolytic cleavage of ethyl pyruvate to ethyl formate radical and acetate. This is the Minisci reaction, which has been employed in the selective carboxylation of heteroaromatic bases (Scheme 40) (796-798). The initial step in this process is the formation of a hydroperoxy hemiketal with ethyl pyruvate and H2O2, followed by Fe(II) reduction of the hemiketal to the alkoxy radical. [Pg.374]

This is then followed by homolytie )8-scission to form acetate and the ethyl formate radical synthon. [Pg.375]

Weiss (18), Kevan, Davis, and Libby (3, 9) proposed ion-molecule reactions to explain dimer formation. Radical scavenging studies have lead Falconer and Salovey (4, 5, 12) to the conclusion that radical reactions produce at least 40% of the dimer. Other authors (17, 19) give much more importance to radical processes. [Pg.306]

The oxidation of formate radical ion, C02", previously postulated from steady-state studies (23), is less than diffusion controlled. The rate is influenced, presumably by the charge factor,... [Pg.297]

Rhus vernicifera stellacyanin has been labeled with asRu + at both exposed histidines, His-32 and 100 (38, 39). A pulse radiolysis study was carried out, and both the Ru(III) and Cu(II) sites were reduced by formate radicals on the order of 1 x 10 A/ s", in 55 and 45% proportions. A slower reduction of Cu(II) also was found this was attributed to Ru(II) to Cu(II) ET, with a rate constant of 0.05 s. Since a crystal structure of stellacyanin is not available, the ET distances were estimated from a computer model to be —16.1 A (39). The relatively low ET rate is in line with the slow ET reactions observed for azurin and plastocyanin. [Pg.306]


See other pages where Formate radical is mentioned: [Pg.277]    [Pg.333]    [Pg.247]    [Pg.23]    [Pg.646]    [Pg.165]    [Pg.172]    [Pg.116]    [Pg.212]    [Pg.791]    [Pg.304]    [Pg.192]    [Pg.47]    [Pg.21]    [Pg.160]    [Pg.646]    [Pg.66]    [Pg.520]    [Pg.520]    [Pg.192]    [Pg.36]    [Pg.374]    [Pg.376]    [Pg.376]    [Pg.301]    [Pg.392]   
See also in sourсe #XX -- [ Pg.413 ]




SEARCH



2- Thienyl radical, formation

Acyl radicals formation

Addition reactions, equilibria and alkyl radical heats of formation

Aldehyde formation, phenoxyl radical

Alkenes radical formation from

Alkoxy radical, formation

Alkyl formates, radical

Alkyl formates, radical reactions

Alkyl radicals carbocycle formation via cyclization

Alkyl radicals heterocyclic formation

Alkyl radicals preferential formation

Allyl radical formation

Amino acids free radical formation

Aminoxyl radicals Formation

Aminyl radicals, formation

Ammonia radical formation from

And free radical formation

And radical formation

Anion radicals formation

Anthryl radical, formation

Aromatic compounds radical formation from

Ascorbate radical formation

Bicyclic radical formation

Carbonyl radical anions, formation

Carboxylic acids radical formation from

Cation radicals formation during radiolysis

Cation radicals in solution, formation, properties and reactions

Cation radicals, in solution, formation

Coenzyme radical formation

Cyanine radical formation

Cycloheptatriene radical cation formation

Direct catalysis radical formations

Electron spin resonance radical formation

Esters radical formation from

Ethane formation from methyl radicals

Flavin radicals formation constant

Formate radical scavenger

Formation and Simple Reactions of Radicals

Formation of Diatomic Molecules and Radicals in the Gas Phase

Formation of Inorganic Radicals and Their Dimeric Radical Anions

Formation of Organic Ion-Radicals in Living Organisms

Formation of Radical Cations

Formation of Radicals in the Gas Phase

Formation of Silyl Radical Adducts

Formation of Unstable Radicals in the Liquid Phase

Formation of XO Radicals and Concentration Measurements

Formation of free radicals

Formation of initiating free-radicals

Formation of peroxy radicals

Formation of primary radicals

Formation of propagating radical

Formation of radical-ions and their reaction with monomers

Formation of radicals

Formation of the peroxy polymer radical

Fragmentation free radical formation

Free radical formation

Free radical formation effects from

Free radical formation mechanism

Free radical formation membrane lipid peroxidation

Free radical formation pathways

Free radical formation quantum yield

Free radical formation reducing substances

Free radical initiators homopolymer formation

Free radical peroxynitrite formation

Free radical, formation during cellulose

Free radicals formation with carbonyl

Free radicals in pyruvate formate-lyase

Free-radical formation during melt processing

Free-radical formation in the presence of oxygen

Hole Transfer through the Intermediate Formation of Hydroxyl Radicals

Homolytic bond cleavage, radical formation

Hydrazines radical formation from

Hydrogen abstraction radical formation

Hydrogen bonding and the formation of free radicals

Hydroxyl radical formation

Hydroxyl radical formation from peroxynitrite

Hydroxyl radical oxidation, formation

Hydroxyl radicals tropospheric formation

Intermediate formation of radical

Intermediate radicals, formation

Ion radical formation

Iron-catalysed reductive radical formation

Ketone formation, phenoxyl radical

Ketones radical formation from

Lipoxygenases free radical formation

Living radical formation, efficiency

Macroalkyl radicals formation

Mass spectrometry radical cation formation

Melt processing, radical formation

Metal-catalyzed free-radical formation

Metal-catalyzed free-radical formation preventing

Methyl radical, formation

Methyl thiyl radical formation

Methylcyclopentane, radical formation

Methylene radical formation

Mixing free-radical formation

Network formation in free-radical

Nickel complexes radical formation

Nitrate radical, formation

Nitroxide radicals formation in spin trapping experiments

OH radical formation yield

Oxidation free radicals formation

Oxygen radical formation

Oxygen, adsorbed anion radical formation

Perhydroxyl radical, formation

Peroxy compounds, radical formation

Peroxy radical formation

Peroxyl oxyl radical formation from

Peroxynitrite radical formation

Phenalenyl radical formation

Phenol 118 Radical formation

Photodissociation, free radical formation

Photolysis involving hydroxyl radical formation

Photolysis, radical formation

Polyethylene sample, radical formation

Protein radical, formation

Quantum free-radical formation

Radical Additions Anti-Markovnikov Product Formation

Radical Formation in Thermoplastics

Radical Processes Carbon-Heteroatom Bond Formation

Radical anion formation relative reactivities

Radical anion formation transition state

Radical bond formation from

Radical cations, formation

Radical cations, formation from

Radical cations, formation from alkynes

Radical formation

Radical formation

Radical formation and chain

Radical formation and cyclization

Radical formation during photodegradation

Radical formation from

Radical formation hydrocarbon cracking

Radical formation kinetics, square-planar

Radical formation pyrolysis

Radical formation using hypervalent

Radical formation, mechanism

Radical formation, rate

Radical mechanisms Grignard reagent formation

Radical pair formation

Radical peroxide, explosive, formation

Radical polymerisation polymer particle formation

Radical polymerization formation

Radical polymerization kinetics particle formation

Radical precursor, intermediate formation

Radical reactions carbon-sulfur bond formation

Radicals enthalpies of formation

Radicals formation during irradiation

Radicals formation/production

Radicals protein hydroperoxide formation

Radicals pyrrolidine formation from

Radicals trioxide formation mechanism

Radicals, anti-Markovnikov formation

Radicals, formation continued)

Radicals, formation during radiolysi

Radicals, formation intermediates initiators

Reaction Mechanism for Alkyl Radical Formation

Reactions Leading to Formation of Initiating Free Radicals

Reversible Radical Formation

Silicon-centered radicals formation

Square-planar complexes radical formation

Square-planar structures radical formation

Sterilization radical formation during

Studies on Radical Formation

Sugar fragmentation and free radical formation

Sugar radical formation

Sulphonyl radicals formation

Superoxide anion radical formation

The Mechanism of Formation via Radical Reactions

Thianthrene radical cations formation

Trifluoromethyl group radical formations

Tyrosyl radical formation, ribonucleotide reductase

Ultrasound radicals formation

Vitamin oxidation, radical formation

Vitamin oxygen radical formation

© 2024 chempedia.info