Carbonaceous radicals species

Endo et al. investigated the reductive decomposition of various electrolytes on graphite anode materials by electron spin resonance (ESR). In all of the electrolyte compositions investigated, which included LiC104, LiBF4, and LiPFe as salts and PC, DMC, and other esters or ethers as solvents, the solvent-related radical species, which were considered to be the intermediates of reductive decomposition, were detected only after prolonged cathodic electrolysis. With the aid of molecular orbital calculation, they found that the reduction of salt anion species is very difficult, as indicated by their positive reduction enthalpy and that of free solvent (A/4 — 1 kcal mol ). However, the coordination of lithium ions with these solvents dramatically reduces the corresponding reduction enthalpy (A/ —10 kcal mol ) and renders the reaction thermodynamically favored. In other words, if no kinetic factors were to be considered, the SEI formed on carbonaceous anodes... 

When benzene is depleted, the carbonaceous molecular species present in the system are mainly aromatic radicals and aliphatic species such as C H, etc. The question which arises... 

Examination and analysis of the eharring materials help to understand the carbonisation and intumescence process. It has been shown that the ehar resulting from PU eonsists of an aromatie carbonaceous structure that condenses and oxidises at high temperature. In the presence of APP, a reaction between the additive and the pol mier oeeurs, which leads to the formation of a phosphocarbonaceous polyaromatic stmcture. Moreover, this char is strongly paramagnetic. Large radical species present, such as polyaromatic macromolecules, can trap free radicals, and so enhance the fire retardant performance of the PU/APP formulations. 

The CsHe desorption was essentially inhibited in the presence of SO2 because sulfur species can react with Fe O radical to form a relatively stable Fe SOs Fe (see Eq. 23), resulting in a significant decline in the density of available adsorption sites for CsH . Simultaneously, the scarcity of a-02 surface species (Fe 02") due to a competitive SO2 adsorption (Eq. 22) leads to a decrease in both rates of propene oxidation and carbonaceous species (CO and CO2) formation. 

In addition to being oxidized by the hydroxyl radical, alkenes may react with the N03 radical as has been described by several investigators (52, 56, 66). Listed in Table I are some of the organic nitrates that have been predicted to be produced via reaction of OH and N03 with isoprene and pro-pene. Analogous compounds would be expected from other simple alkenes and from terpenes such as a- and (3-pinene. Other possible organic nitrates may be produced via the oxidation of aromatic compounds (53, 54) and the oxidation of carbonaceous aerosols (67). Quantitative determination of these species has not been made in the ambient atmosphere. 

Various forms of molecular carbon, from ions to radicals, have been detected in the diffuse interstellar medium (ISM) using electronic, rotational, and vibrational spectroscopies (Henning and Salama 1998 Snow and Witt 1995). Discrete absorption and emission bands seen toward diffuse interstellar clouds indicate the presence of numerous two-atom molecules such as CO, CN and C2. In addition to these interstellar features, a large family of spectral bands observed from the far-UV to the far-IR still defies explanation. Currently, it is the general consensus that many of the unidentified spectral features are formed by a complex, carbonaceous species that show rich chemistry in interstellar dust clouds (Ehrenfreund... 

We let a beam of atomic hydrogen and a beam of methyl radicals interact with the film surface simultaneously. This can be considered the simplest of all multi-species experiments first, H and CH3 are the simplest radicalic hydrocarbon species. Second, by restricting ourselves to radicals, the interaction of the beams with the film is purely chemical and expected to be limited to the very surface. Third, the effect of each species separately is already known the previous section described the temperature dependent interaction of CH3 radicals with the a-C H surface. The interaction of atomic hydrogen with carbonaceous materials has been studied extensively in the past by various groups [53,56,57]. A rate equation model describing chemical erosion by atomic hydrogen is well-established [53,58]. 

Carbonaceous residues could act as bridges for top-side addition to adsorbed cycloalkenes, or in solution adsorbed solvent molecules could perform the same role. (6) Finally - a possibility not previously considered, but one which follows logically from (5) - a hydrogen or deuterium atom from an alkyl radical may add top-side to a chemisorbed alkene as one step in the alkyl-alkene-alkyl chain shown in process 7.K, or by alkyl disproportionation. This is most likely to happen when species are packed closely together, i.e. when they are small or at low hydrogen pressure. 

The tin additives exert their fire-retardant action in both the condensed and vapour phases, by promoting the formation of a thermally stable carbonaceous char and (in halogen-containing polymer formulations) by generating volatile metal halide species which assist in free radical scavenging reactions in the flame. 

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