Competitive study of the reactions Br + RFI → IBr + RF and determination of bond dissociation energies D(RF−I) where RF = CF3, C2F5, n-;C3F7, i-C3F7, and n-C4F9 |
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Authors: | Ernest N Okafo Eric Whittle |
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Abstract: | The overall photobromination reactions have been studied using a competitive technique. Relative Arrhenius parameters were obtained for the rate-determining step These were placed on an absolute basis using previous-absolute values of A and E for RFI=CF3I. The activation energies were used to calculate bond dissociation energies D(R? I) with the following results: RF? | E16 | D(RF?I)(kcal/mole) | CF3I a a E16 from 1] | 10.8 | 52.6 | C2F5I | 8.8 | 50.6 | n-C3F7I | 7.4 | 49.2 | i-C3F7I | 7.5 | 49.2 | n-C4F9I | 6.7 | 48.4 | The D(RI) are compared with related D(R? I) and it is concluded that for a given alkyl group RH and the corresponding perfuloroalkyl group RF, D(RI) > D(RI) whereas it has previously been found that D(RX;) < D(RX) where X is not iodine. |
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