SPIN-TRAPPING OF FLUOROALKYL RADICALS

The formation of fluoroalkyl radicals in liquid chlorofluorocarbons (C F2Cl-CFCl2, CFCl3, CFCl2-CH3, CHF2-CF2-CF2Cl, CF3-CFH-CF3 and CCl4) ha s been investigated by means of the spin trapping technique and ESR sp ectroscopy. It is shown that the primary fluoroalkyl radicals which we re generated in these compounds by ionising radiation are preferably f ormed by bond cleavage at carbon atoms attached to one fluorine atom. Besides the liberation of chlorine atoms in chlorine-containing compou nds, in CHF2-CF2-CF2Cl and CF3-CFH-CF3 fluorine atoms were also detect ed. By comparison of radicals formed from gamma-irradiated CF2Cl-CFCl2 (CFC-113) and from CF2Cl-CFClI or CF2I-CFCl2 by zinc reduction, it wa s demonstrated that in CFC-113 both .CF2-CFCl,(2) and .CFCl-CF2Cl radi cals are formed, whereas in iodine-containing homologues the formation of one species is favoured.