Ethylene photolysis vinyl radical

The main difficulty in obtaining the vinyl radical is that the species easily loses the hydrogen atom and is converted into acetylene. Nevertheless, a very low concentration of the radical H2C=CH has been achieved (Shepherd et al., 1988) by vacuum UV photolysis of ethylene frozen in an argon matrix, and a Fourier transform IR study of this intermediate has been carried out. A variety of and deuterium-substituted ethylene parent molecules were used to form various isotopomers of vinyl radical. On the basis of its isotopic behaviour and by comparison with ab initio... 

The flash-photolysis study revealed that the vinyl radicals produced in process (3) can be stabilized at higher pressures. Butene-1 and propylene, which are attributed to the combination of vinyl radicals with ethyl and methyl radicals respectively, were found to be absent at low ethylene pressure but became significant at 10-20 torr. Furthermore the addition of 600 torr N2 sharply increased the butene-1... 

For ethylene-carbon monoxide copolymers, the formation of the free radical type I prcxlucts is suppressed to only about 10% of the total reactkms because both radicals are polymeric and hardly ever escape from the iimnediate environment On the other hand, for ethylene-methyl vinyl ketone copolymers, photolysis yields one polymeric and one small acetyl radical, with the effknency of type I reaction eight times as... 

The initially formed adduct radicals were scavenged by an excess of methyl iodide. A study of the addition of methyl radicals, from the photolysis of biacetyl in the presence of isobutane, to hexafluoropropene has indicated that it is rather unselective, reacting at a rate similar to that with tetrafluoro-ethylene, but a further study, employing octane as scavenger, has indicated that tetrafluoroethylene is some six times as reactive (in the latter work the vinyl ethers CFa O CFiCFs and n-C8F, O CF CF2 were also studied). 

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