Ethane reaction with hydroxyl

In Example 4.10, a Gaussian plume model was used to estimate the rate of release of some hydrocarbon gases from a natural gas well installed using hydrofracking. Chemical transformations were neglected. Should the loss of ethane (C2H6) by reaction with hydroxyl radical be ignored in the calculation ... 

Wallington, T.J., Neuman, D.M., Kurylo, M.J. (1987) Kinetics of the gas phase reaction of hydroxyl radicals with ethane, benzene, and a series of halogenated benzenes over the temperature range 234 -38 K. Int. J. Chem. Kinet. 19, 725-739. 

Of course, all the appropriate higher-temperature reaction paths for H2 and CO discussed in the previous sections must be included. Again, note that when X is an H atom or OH radical, molecular hydrogen (H2) or water forms from reaction (3.84). As previously stated, the system is not complete because sufficient ethane forms so that its oxidation path must be a consideration. For example, in atmospheric-pressure methane-air flames, Wamatz [24, 25] has estimated that for lean stoichiometric systems about 30% of methyl radicals recombine to form ethane, and for fuel-rich systems the percentage can rise as high as 80%. Essentially, then, there are two parallel oxidation paths in the methane system one via the oxidation of methyl radicals and the other via the oxidation of ethane. Again, it is worthy of note that reaction (3.84) with hydroxyl is faster than reaction (3.44), so that early in the methane system CO accumulates later, when the CO concentration rises, it effectively competes with methane for hydroxyl radicals and the fuel consumption rate is slowed. 

Hsu, K. J., and W. B. DeMore, Rate Constants and Temperature Dependences for the Reactions of Hydroxyl Radical with Several Halogenated Methanes, Ethanes, and Propanes by Relative Rate Measurements, J. Phys. Chem., 99, 1235-1244 (1995). 

In comparing the activation energies for reactions of hydroxyl with ethane, ethylene, and acetylene it may be concluded that a similar reaction occurs in all three cases, namely, H atom abstraction. The activation energy increases from ethane to acetylene depending upon the C-H bond energy. 

From Hexa-chlor Ethane.—It may also be prepared by oxidizing a derivative of ethane, viz., hexa-chlor ethane, CCle, with potassium hydroxide. This reaction may be considered as yielding the complete oxidation product of ethane by the replacement of the six chlorine atoms by six hydroxyl groups. This then loses water, as in the case of all compounds which contain more than one hydroxyl group linked to one carbon atom, and di-carboxyl, or oxalic acid results, as follows. 

The hydroxylation of small alkanes, such as propane and ethane, is particularly attractive to the chemical industry. However, monooxygenation of carbon centers is a reaction that is difficult to achieve chemically as it requires extreme temperatures. An attractive alternative is the use of cytochrome P-450 enzymes (P-450s) that can catalyze such reactions with a high degree of regio- and stereoselectivity. Thus, there has been much work directed toward evolving P-450s with altered substrate specificities that can catalyze hydroxylation of Cl-ClO alkanes. 

Howard CJ, Evenson KM. 1976. Rate constants for the reactions of hydroxyl with ethane and some halogen substituted ethanes at 296 K. J Chem Phys 64 4303-4306. 

Jeong KM, Hsu KJ, Jeffries JB, et al. 1984. Kinetics of the reactions of hydroxyl with ethane,... 

There are few reports of alkene-deuterium reactions on bimetallic catalysts, but those few contain some points of interest. On very dilute solutions of nickel in copper (as foil), the only product of the reaction with ethene was ethene-di it is not clear whether the scarcity of deuterium atoms close to the presumably isolated nickels inhibits ethane formation, so that alkyl reversal is the only option, or whether (as with nickel film, see above) the exchange occurs by dissociative adsorption of the ethene. Problems also arise in the use of bimetallic powders containing copper plus either nickel, palladium or platinum. Activation energies for the exchange of propene were similar to those for the pure metals (33-43 kJ mol ) and rates were faster than for copper, but the distribution of deuterium atoms in the propene-di clearly resembled that shown by copper. It was suggested that the active centre comprised atoms of both kinds. On Cu/ZnO, the reaction of ethene with deuterium gave only ethane-d2. as hydrogens in the hydroxylated zinc oxide surface did not participate by reverse spillover. ... 

Jeong KM, Hsu KJ, Jeffries JB, et al. 1984. Kinetics of the reactions of hydroxyl with ethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1-difluoro-1,2-dichloroethane, and 1,1,1,2-tetrafluoroethane. J Phys Chem 88 1222-1226. 

J. H. Lee and I. N. Tang, Absolute rate constants for the hydroxyl radical reactions with ethane, furan, and thiophene at room temperature, J. Chem. Phys. 77(9), 4459-4463 (1982). 

Dual-level direct dynamics of the hydroxyl radical reaction with ethane and haloethanes Toward a general reaction parameter method ... 

Give a sequence of reactions leading to the formation of acetaldehyde from ethane starting with the reaction of hydroxyl radical. 

If hydroxyl were to react by H atom abstraction in the case of ethane, and by addition with ethylene, an inverse dependence would be observed for the activation energy, namely, a decrease from ethane to ethylene, as is the case for hydrogen atom reactions. The activation energies for reactions of oxygen atoms with ethane and ethylene decrease from ethane... 

Solutions of dipositive lanthanide cations have been obtained in liquid ammonia, ethanol, THF, acetonitrile and hexamethylphosphoramide. Ions stabilized, or for which there is evidence for stabilization, include Nd2+, Dy2+ and Tm2+ as well as Eu2+, Yb2+ and Sm2+. The non-hydroxylic solvents are best at stabilizing M2+ ions. Thus NdCl2(THF)2 has been reported from the reduction of NdCl3 in THF by Na(naphthalene),657 and corresponding reductions of MC13 (M = Eu, Yb or Sm) have also been achieved.658 Solutions of solvated MI2 (M = Sm or Yb) in THF may easily be made by the quantitative reaction of the metal with 1,2-diiodoethane, producing ethane. The solid THF adducts may be isolated.659... 

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