661-96-1

The ester group exhibits a strong directive effect in the photochemical reduction of a carbon-halogen bond and directs the reduction in perhalogenated chlorofluoropropanoates of the type CFXY-CClZ-COOR (X,Y,Z = Cl, F) to the α-position in the acyl part of an ester.The reduction takes place with the same regioselectivity even in esters CFCl2-CHCl-COOR (10).In esters containing an α -CCl2- group the reductions to the first and the second stages can be separated and the individual reduction products can be obtained preparatively.The α C-F bond is more difficult to reduce and therefore in the ester CFCl2-CHF-COOR (11) the β C-Cl bond was reduced specifically and in the ester CF2Cl-CHF-COOR (12) both the α C-F bond and the β C-Cl bond were reduced parallely.The relative reactivity of fluorinated halogenopropanoates with an α C-Cl bond showed only small differences in the reduction with 2-propanol in the presence of acetone as a sensitiser; the quantum yield Φ reached values of about 28-35 under kinetic measurements and thus proved the existence of a chain radical mechanism.

The acrylic ester F2CCFCO2CD3 is prepared from a mixture of difluorotetrachloroethanes CFCI2CFCI2 and CF2CICCI. The dehalogenation of these Freons, followed by the addition of CFCI3 by means of AICI3 leads to a mixture of chlorofluoropropanes. The hydrolysis with oleum gives the acid chlorides which are then esterified by CD3OD. The dehalogenation of the mixture by the zinc stirred in oxalic acid enables isolation of the expected ester by distillation. This compound, the refractive index of which n20D=1.3667 does not show a major absorption in the near infra-red between 0.6 and 1.4 μm. Thus the corresponding polymer is likely to provide a good material for the core of optical fibers.