Potential of hydrocarbons

Opeida [46] compared the values of the rate constants of peroxyl radical reactions with hydrocarbons with the BDE of the oxidized hydrocarbon, electron affinity of peroxyl radical, EA(R02 ) ionization potential of hydrocarbon (/Rn), and steric hindrance of a-substituent R(Fr). They had drawn out the following empirical equation ... 

The anions originate from the attachment of an electron to whatever electron acceptors are available in the system in bulk hydrocarbon monomer this results in the formation of radical anions. Because the electron affinities of alkenes are much lower than the ionization potentials of hydrocarbon radicals, the neutralization reaction between the cations and the anions, one possible version of which is... 

Exposure of various invertebrate species to high concentrations of petroleum did not induce mixed function oxidase activity. Enzyme activity was stimulated, however, in a number of fish tissues by petroleum. Different permutations can be addressed as to the significance of basal or induced levels of mixed function oxidases and hydrocarbon toxicity. AHH may have a physiological role in enhancing hydrocarbon clearance but may also increase the mutagenic-carcinogenic potential of hydrocarbons. Both of these concepts have been demonstrated in studies with fish (29,30). Induced AHH levels may permit a more rapid oxidative transformation with concomitant "disappearance" of parent hydrocarbons, but potentially toxic metabolites could be retained in tissues for longer periods (31). It is likely that at the enzymic level the... 

Rather surprisingly, the differences in half-wave potentials of hydrocarbons from one solvent to another are very small. This constancy in energy values as well as slopes of correlation lines in widely varying solvents and supporting electrolytes implies that solvation energies, provided they are not small, change in the same way from system to system. 

These energy values are calculated from thermochemical tables (11) and the ionization potentials of hydrocarbons obtained by Stevenson (15) using mass spectrometric methods. The union of an olefin and a proton from an acid catalyst leads to the formation of a positively charged radical, called a carbonium ion. The two shown above are sec-propyl and fer -butyl, respectively. [For addition to the other side of the double bond, A 298 = —151.5 and —146 kg.-cal. per mole, respectively. For comparison, reference is made to the older (4) values of Evans and Polanyi, which show differences of —7 and —21 kg.-cal. per mole between the resultant n- and s-propyl and iso-and tert-butyl ions, respectively, against —29.5 and —49 kg.-cal. per mole here. These energy differences control the carbonium ion isomerization reactions discussed below.]... 

Hydrocarbon (or petroleum) solvents are also used for dry cleaning. From the original Stoddard solvent to Exxon s latest DF 2000 offering, the main drawback has been the fuel potential of hydrocarbon solvents. It was the flammability of Stoddard solvent that turned the industry away from petroleum solvents to the nonflammable halogenated solvents, such as perc, in the first place. Other barriers to the widespread use of petroleum arise over zoning restrictions, taxation, and inevitable regulation related to its use. 

Loosely bound aggregates (chemical effects) are formed with the hydrocarbons acting as electron donors (Lewis base) and the solvents acting as electron acceptors (Lewis acid). The hydrocarbon that forms the most stable complex with the solvent experiences a decrease in volatility. Electron donors are rated by ionization potential, and electron acceptors are rated by their electron affinities. The selectivity will be higher, the larger the difference in ionization potential between the hydrocarbons and the larger the electron affinity of the solvent (9). While data on ionization potentials of hydrocarbons can be found (15, 16), electron affinities data are rare because of difficulties in their experimental determination. Prausnitz and Anderson (8) recommend that the sigma scale, proposed by Hammett (17), be used to determine approximately the solvents relative ability to form complexes with the two hydrocarbons. Attempts by this author, however, to use this scale were not conclusive. Prausnitz and Anderson (8) should be consulted to understand better the physical and chemical effects. 

Although the present major use of these hydrocarbons is as fuel, the tremendous possibilities offered for conversion to valuable chemicals makes it interesting to consider the research work which has been done and some of the results that have been attained. By oxidation these gases may be converted to methyl, ethyl, propyl, and butyl alcohols formaldehyde. acetaldehyde, propionaldehyde, and butryaldehyde formic, acetic, propionic, and butyric acids resins etc. An idea of the potentialities of hydrocarbon oxidation may be obtained by considering the theoretical yields of alcohols... 

Hall correlated the ionization potentials of hydrocarbons, ethane to decane, assuming xmchanged localized orbitals and energies c, and y. ... 

Many studies on hydrocarbon as the carbon source for cultivating yeasts and bacteria to produce cellular proteins and various substances have been published by a number of investigators since 1960. Especially various findings on hydrocarbon fermentation such as pathway, cellular component, growth rate, respiration, and so forth have been reported (Humphrey, 1967 Sharpley, 1966 Miller and Johnson, 1966). However, many engineering problems remain to be solved before the microbial potential of hydrocarbon fermentation can be exploited on an industrial scale with an understanding of the physical properties of hydrocarbon fermentations. 

Reactivity is a measure of the smog-forming potential of hydrocarbons. Aromatics and olefins are the exhaust hydrocarbons that react most readily with nitric oxide (NO) in the atmosphere in the presence of sunlight to form nitrogen dioxide (NO2), a key initiator in the formation of ozone, oxidants, and eye irritants. 

The lifeblood of modern society is found in petroleum products. Cars, planes, trains, ships, and farm equipment all require petroleum products to operate. Approximately 85% of all hydrocarbons manufactured are converted into gasoline. Jet fuel, diesel, heating oils, and liquefied petroleum. The remaining 15% provides the foundation (feedstock) for fertilizers, pesticides, pharmaceuticals, solvents, plastics, and many other products. It is difficult to look around our world and not see the results of modern petroleum manufacturing. Before 1800, though, few people recognized the value or potential of hydrocarbon processing. 

Fig. 2. Relationship between the ionization potential of hydrocarbons and the peak wavenumber of the CT absorption and CT fluorescence bands in PMDA-hydrocarbons CT complexes in nonpolar solvents.

The ionization potential and electron affinity of a molecule in solution are measured by the corresponding oxidation and reduction potentials (see Section 4.4). It has been shown that the oxidation potentials of even AHs run parallel to their gas-phase ionization potentials and the same seems to be true of the reduction potentials and electron affinities. The PMO method can therefore be used to estimate the relative reduction potentials of hydrocarbons in solution and hence the ease with which they react with alkali metals. One can also observe reversible electron transfer reactions between hydrocarbons and radical anions, e.g.,... 

Due to the symmetry, observed in the classical L.C.A.O. molecular orbital calculations, of the h.o.m.o. (related to the ionization potential) and of the l.e.m.o. (related to the ease of acceptance of an electron in reduction) in certain types of compounds, e.g., conjugated hydrocarbons (complete symmetry when overlap is neglected, less complete when it is included), any property related, i.e., proportional, to one will be proportional to the other (this will not hold in more refined treatments). Thus, the theoretical r-ionization potentials of hydrocarbons are linearly proportional to the values for diphenyl, naphthalene, phenanthrene and anthracene the point for butadiene deviates slightly from the straig[ht line relation, while that for st5nrene deviates markedly. Such incidental correlations, due primarily to mathematical S3munetry rather than to fundamental physical significance, must be watched for carefully. The same remark is valid for a proposed correlation" between absorption spectra and half-wave potentials (cf. reference 21). 

Improved estimates of thin-section porosity and a quantitative measure of pore space quality can be obtained by the methods described in this paper. Accurate measurement of porosity and interrelated parameters such as pore size, geometry, distribution, quality, and interconnectivity will be useful aids in assessing the production potential of hydrocarbon-bearing formations. Pore quality and identification of microporosity and its distribution by epifluorescence microscopy are also likely to be of value in interpretation of formation resistivity measurements, connate water retention in the reservoir, and capillary pressure behavior. 

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