321. The addition of free radicals to unsaturated systems. Part III. Chlorotrifluoroethylene

Abstract

The product readily liberates iodine on exposure to light, and photochemical chlorination gives a high yield of the dichloride (111) : (11) would have given (IV) by this procedure. Compounds (111) (b. p. 35", n z , O 1-305) and (IV) (b. p. 34-7", ng 1-3029) cannot be distinguished by boiling point or refractive index, but comparison of the infra-red spectrum of (111) with that of a known sample of (IV), prepared from hexafluoropropene and chlorine, readily distinguishes the two isomers.* Further, with zinc and ethanol (IV) readily yields hexafluoropropene, whereas (111) does not (see below).

Use of Iodocompounds in Radical Polymerization

“…In contrast to the telomerization of TFE with R F Is, the addition of these telogens to CTFE has not been fully investigated. This may be explained by the fact that the R F (CF 2 CFCl) n I telomers produced are more efficient telogens than the starting R F I transfer agents (as seen in the previous When CF 3 I is used as the telogen, two isomers can be produced since the addition of • CF 3 radical onto CTFE 103,119 led to CF 3 CF 2 CFClI (mainly, 90%) and CF 3 CFClCF 2 I. Interestingly, Gumbrech and Dettre 120 used a mixture of (C 2 F 5 CO 2 ) 2 and CHI 3 (as a iodine donor) to obtain of C 2 F 5 (C 2 F 3 Cl) n I telomers, although a rather high DP n (ca. 13) was observed.…”

“…Whatever the ways of initiation, successful results have been obtained involving all kinds of telogens . A summary of the literature is listed in Table corresponding to photochemical, thermal, radical, redox, and miscellaneous initiations. ,,,,,,− …”

“…When CF 3 I is used as the telogen, two isomers can be produced since the addition of • CF 3 radical onto CTFE , led to CF 3 CF 2 CFClI (mainly, 90%) and CF 3 CFClCF 2 I. Interestingly, Gumbrech and Dettre used a mixture of (C 2 F 5 CO 2 ) 2 and CHI 3 (as a iodine donor) to obtain of C 2 F 5 (C 2 F 3 Cl) n I telomers, although a rather high (ca. 13) was observed.…”

“…53 A summary of the literature is listed in Table 4 corresponding to photochemical, thermal, radical, redox, and miscellaneous initiations. 20,23,27,49,51,85,[100][101][102][103][104][105][106][107][108][109][110][111][112][113][114][115][116] For the industrial scale, thermal telomerization appears the most widely used, probably because of the thermal stability of the fluorinated telomers produced. Moreover, it is wellrecognized that the good reactivity with redox catalysts leads to low molar mass telomers, as for thermal initiation at high temperature.…”

(Co)polymers of Chlorotrifluoroethylene: Synthesis, Properties, and Applications

“…This can be explained by the fact that the CFCl–I end groups borne by R F (CF 2 CFCl) n I in the resulting telomers are more reactive than the CF 2 –I end groups of R F I CTA. ,− For example, the use of CF 3 I as the CTA for the telomerization of CTFE led to the formation of two isomers. , Interestingly, Gumbrech and Dettre used a mixture of (C 2 F 5 CO 2 ) 2 and CHI 3 (as the iodine donor) to obtain C 2 F 5 (CF 2 CFCl) n I telomers with n ≅ 13. Elemental iodine was used to prepare I(CTFE) n I telomers that were subsequently used as interesting telogens in other telomerization reactions .…”