Hydrocarbon oxidizability

Latimer, 1952). Therefore all applied oxidants are, in thermodynamic terms, able to oxidize or to dehydrogenate all hydrocarbons and all oxidizable functional groups of organic molecules. 

Acetylene has a low solubiHty in Hquid oxygen. Excessive concentrations can lead to separation of soHd acetylene and produce accumulations that, once initiated, can decompose violently, detonating other oxidizable materials. Acetylene is monitored routinely when individual hydrocarbons are determined by gas chromatography, but one of the wet classical methods may be more convenient. These use the unique reaction of acetylene with Ilosvay s reagent (monovalent copper solution). The resulting brick-red copper acetyHde may be estimated colorimetricaHy or volumetricaHy with good sensitivity (30). 

In cell culture, lycopene is a highly oxidizable nonpolar hydrocarbon supplied in an aqueous medium and is incubated at body temperature for 12-72 h. The amount of intact lycopene or its oxidation products delivered to and absorbed by various cell types is an important factor to keep in mind when evaluating the effects of lycopene on various cellular processes. Before reviewing cell culture studies designed to characterize the effects of lycopene on prostate cell biology, the characteristics of prominent prostate cell lines, and the stability and uptake of lycopene by various prostate cell lines are reviewed. 

Calcium nitrate is a strong oxidizing agent. Mixing with organic substances such as fuel oil or hydrocarbons or other oxidizable compounds can cause explosion. 

Both in situ and ex situ chemical oxidation technologies are commercially available for the treatment of liquids, soils, and sludges containing hydrocarbons and other oxidizable contaminants. 

Carbanions derived from hydrocarbons or substituted hydrocarbons with pKa values in the range of 10 may—e.g., 2-nitropropane—or may not (diethyl malonate) be oxidizable. When oxidation does occur, it is generally solely by the radical-chain mechanism. 

Like benzenoid hydrocarbons, pyridine-like heterocycles give well-developed two-electron waves on reduction at the dropping mercury electrode. The latter are polarographically much more reducible than the former. This can be explained easily in terms of the HMO theory It is assumed (cf. ref. 3) that the value of the half-wave potential is determined essentially by the energy of the lowest free 7r-molecular orbital (LFMO) of the compound to be reduced, and for models of hetero analogues this quantity is always lower than that for the parent hydrocarbons. Introduction of an additional heteroatom into the molecule leads to a further enhancement of the ease of polarographic reducibility.95 On the other hand, anodic oxidation of the heterocyclic compounds is so much more difficult in comparison with benzenoid hydrocarbons that they are not oxidizable under the usual polarographic conditions. An explanation in terms of the HMO theory is obvious. 

Restriction of hydrocarbon chains to small rings is known to significantly enhance their oxidizability, either in the gas phase or in solution (95), so that photooxidative generation of radical cations from small rings should occur readily. Because... 

Single oxidation processes have, however, also become important. Besides the oxidability of easily oxidizahle substances, for instance aniline, or easily oxidizable groups like methyl, the peculiar reaction which seems to occur very frequently in the electrical oxidation in sulphuric acid, and which consists of the entrance of oxygen into the benzene nucleus, must be emphasized. Hydrocarbons, phenols, quin-ones, and azo-compounds seem to behave alike in this respect. 

Oxidation of hydrocarbons with dioxygen is more facile when the C-H bond is activated through aromatic or vinylic groups adjacent to it. The homolytic C-H bond dissociation energy decreases from ca. 100 kcal mol-1 (alkyl C-H) to ca. 85 kcal mol-1 (allylic and benzylic C-H), which makes a number of autoxidation processes feasible. The relative oxidizability is further increased by the presence of alkyl substituents on the benzylic carbon (see Table 4.6). The autoxidation of isopropylbenzene (Hock process, Fig. 4.49) accounts for the majority of the world production of phenol [131] ... 

In our study of the aromatic aldehydes we have also stated that they are synthesized by the oxidation of benzene hydrocarbons containing an unsaturated side chain, in which the double bond is between the first and second carbons from the benzene ring. The aldehydes then being oxidizable to the acids gives us a second class of hydrocarbons from which the acids may be obtained by oxidation. 

Supercritical fluid chromatography (SFC) with ELD, using CO2 or C02-MeOH as mobile phase, was applied to simultaneous determination of 11 priority phenols and 13 polycyclic aromatic hydrocarbons. Voltammetric measurements allow low-nanogram detection limits of reducible and oxidizable analytes, even if they elute simultaneously from the chromatographic column . SFC with MeOH-modified CO2 was performed under isobaric and pressure-programmed conditions, combined with ELD. LOD was 250 p,g of 2,6-dimethylphenol for oxidative ELD and 100 pg of 1,3-dinitrobenzene for reductive ELD . Various sorbents were investigated for SPE preconcentration prior to SFC 20 . 

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