Synthesis of 32P labelled compounds using recoil-atoms

Using the reactions of recoil atoms and subsequent thin-layer chromatography, carrier-free tris (polyfluoroalkyl) phosphates labelled with 32P have been synthesized. To prepare samples with the activity 105-106 Bq, a mixture, containing 400 g, ClCl4, 0.02 mol of tetrafluoropropyl alcohol and 0.03x10-3 mol of imidazole was irradiated by a Po-Be source neutron flux (108 neutron/s) for 1-12 days at room temperature. The effect of temperature, exposure time, concentrations and alcohol-to-imidazole ratio on the yield of tris (polyfluoroalkyl) phosphate is studied. The optimum conditions are determined to be: 20-40 deg C, alcohol concentration = 0.69 molar percent, alcohol-to-imidazole ratio = 600. The 32P-labelled tris (tetrafluoropropyl) phosphate produced is used to study its reetherification with n-butanol in the 0-80 deg C range in the presence of the CsF catalyst. The reaction rate constants of consecutive substitution of butyl group for tetrafluoropropyl one at 40 deg C are evaluated to be: K1=(1.1+-0.1)x10-4 c-1, K2=(2.1+-0.1)x10-5 c-1, K3=(3.9+-0.1)x10-6 c-1, respectively