Methane exchange reactions with ethane

Similar results have been obtained for methane 12) and for ethane 19). The values quoted in Table II also illustrate the point that the distribution of deuterium between hydrogen and propane differs from the value expected for a random distribution. With the ratio of pressures used, the expected percentage for the mean deuterium content of the hydrocarbon would be 33.3, which is substantially less than the experimental value of 40.9 %. This type of deviation is also found with other hydrocarbons, but it does not affect the validity of using classical theory for the calculation of the interconversion equilibrium constants in studies of mechanism of exchange reactions. More accurate values for these equilibrium constants are necessary, however, if one is interested in the separation of isotopes by chemical processes. 

R H) is much faster than alkylation, so that alkylation products are also derived from the new alkanes and carbocations formed in the exchange reaction. Furthermore, the carbo-cations present are subject to rearrangement (Chapter 18), giving rise to new carbocations. Products result from all the hydrocarbons and carbocations present in the system. As expected from their relative stabilities, secondary alkyl cations alkylate alkanes more Teadily than tertiary alkyl cations (the r-butyl cation does not alkylate methane or ethane). Stable primary alkyl cations are not available, but alkylation has been achieved with complexes formed between CH3F or C2H5F and SbFs-212 The mechanism of alkylation can be formulated (similar to that shown in hydrogen exchange with super acids, 2-1) as... 

Most of the investigations into disproportionation reactions have mainly concentrated on chlorofiuoro derivatives of methane and ethane. When trichlorofluoromethane is refluxed with aluminum trichloride or aluminum tribromide, dichlorodifluoromethane and carbon tetrachloride are obtained. Dichlorofluoromethane yields chlorodifiuoromethane and chloroform chlorofiuoro derivatives of ethane and longer chain homologs exhibit a tendency towards isomerization as well as disproportionation, i.e. intramolecular halogen atom exchange. In this case, both types of reaction take place simultaneously. In other words, disproportionation of l,l,2-triehloro-1.2,2-trifiuoroethane (1) forms l,l,1.2-tetrachloro-2,2-difluoroethane (2) and... 

There is no doubt that total oxidation of hydrocarbons can occur at certain electrode surfaces in acidic media. ° Early research by Schlatter on the electrochemical oxidation of saturated and unsaturated hydrocarbons (such as propane and ethylene) in a 5 N H2SO4 electrolyte was found to result in complete or almost complete oxidation to CO2 and H2O. These tests were made in a two electrode cell equipped with an anion exchange membrane which served to separate the catholyte and anolyte. The oxidation half-reactions of a number of aliphatic hydrocarbons, including methane, ethane, and propane, being converted directly to carbon dioxide is listed below. 

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