Ethyl radicals, disproportionation recombination

Butenyl (C4H7) mainly disappears by reacting with ethyl radicals. The leftover ethyl radicals either recombine (faster process) or undergo disproportionation (slower process) ... 

For example, in the case of ethyl radicals, the recombination and disproportionation reactions may produce n-butane, ethylene, and ethane ... 

If other possible termination steps are considered, then it can be inferred that recombination or disproportionation of ethyl radicals, c,H5 is more likely than recombination of C and. Step 5... 

The study of the recombination (kc) and the disproportionation (/tdis) of ethyl radicals proved the dependence of the ratio kdis/kc on the solvent [230-232], Stefani [231] found that log( dis/ c) is a linear function of the solubility 8S, which is equal to the square root of the cohesive energy density of the solvents (Dce) ... 

The recombination and disproportionation of ethyl-radicals are considered to be the main termination processes, viz. 

Subsequently the usual recombination and disproportionation reactions of ethyl radicals occur [52]. The thermal decomposition of a mixture of Pb(C2H5)4 and Pb2(C2H5)e was studied [58] in this case also, the concentration of Pb2(C2H5)6 initially increased [59]. 

Recombination of alkyl radicals, as that of atoms, occurs practically without an activation energy. In the gas phase at a sufficiently high pressure the recombination of methyl radicals is bimolecular with the rate constant close to (l/4)Zo (where Zo is the frequency factor of bimolecular collisions, and the factor 1/4 reflects the probability of collisions of particles with the antiparallel orientation of s ins). The theoretical estimation of the constant at a collision diameter of 3.5-10 m agrees with the experimental value = 2-10 ° l/(mol-s) (300 K). This k value agrees with the estimation by the theory of absolute reaction rates under the assumption that the free rotation of methyl groups is retained in the transition state. In the liquid the recombination of meth)d radicals is bimolecular with the rate constant of difiiision collisions (see Qiapter 5). For example, in water 2k = 3.2-10 l/(mol s) (298 K). Ethyl radicals react with each other by two methods recombine and disproportionate... 

An increase of disproportionation at the expense of recombination when ing from primary to secondary and tertiary alkyl radicals may be expressed by the ratio 1 5 25. An almost equal ratio for disproportionation and recombination has been found for reactions of the methyl radical with ethyl, isopropyl and rer/.butyl radicals [13]. 

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