Organobromine compounds in reactions of homolytic addition and telomerization

Random and sequential radical cotelomerizations of 3,3,3‐trifluoropropene (H2CCHCF3) with vinylidene fluoride (F2CCH2)

“…The product was filtered and dried under vacuum (0.1 mm Hg/40 °C) overnight (Y = 13 wt. %), and characterized by 19 F and 1 H NMR spectroscopy. The molar ratio of TFP/VDF in the product was found to be 90.5/9.5 mole %.…”

“…The signal centered at -39 ppm on the 19 F NMR spectra is characteristic of the normal addition of the chain transfer agent onto -CH 2 CF 2  radical yielding (CF 3 ) 2 CF-CH 2 -CF 2 -I, while for the reverse adduct (CF 3 ) 2 CF-CF 2 -CH 2 -I, the perfluoromethylene appears at -109 ppm. 3 From these 19 F NMR signals, it was possible to assess the percentage of normal and reverse addition that was found to be 96.6 % normal.…”

“…3 From these 19 F NMR signals, it was possible to assess the percentage of normal and reverse addition that was found to be 96.6 % normal. This was expected due to the electronwithdrawing character of the fluorine atom, that makes the methylene of VDF electronpoor, and consequently more prompt to the addition of the electron-rich radicals.…”

“…This was expected due to the electronwithdrawing character of the fluorine atom, that makes the methylene of VDF electronpoor, and consequently more prompt to the addition of the electron-rich radicals. Also the signals from both CF 3 -and >CF-groups of the telogen can be used as a label to assess the molecular weight by 19 F NMR spectroscopy. …”

“…[7][8][9][10][11][12][13][14][15][16][17][18][19] In addition, Vasil'eva's team 13 even proposed mechanisms of formation of unexpected telomers and determined various chain transfer constants of telogens showing that, in some cases, the transfer to the telogen is more efficient than the radical chain growth. 10,16,17 Other transfer agents have been used such as silanes, phosphonates, disulfides or hydrogen bromide yielding the monoadduct.…”