γ-strahlenchemische Reaktionen des weißen Phosphors in Cyclohexan- und Cyclohexan-Tetrachlorkohlenstoff-Lösung

Abstract

Red phosphorus, soluble phosphorus organic compounds and small amounts of phosphine are formed when white phosphorus in cyclohexane solution is exposed to γ-rays. The red phosphorus contains one C6H11-group per 4 — 5 P-atoms. It reacts with chlorine to give cyclohexylphosphorusdichloride. Its reactivity towards oxygen can be decreased by high temperatures during irradiation or by high γ-doses. It is concluded from quantitative studies of this “annealing” process that phosphorus atoms carrying C6H11-endgroups are especially reactive in the polymeric form of phosphorus. The low molecular weight products of the reaction between white phosphorus and cyclohexane undergo typical reactions of tertiary phosphines. They can readily be oxidized and chlorinated to yield cyclohexyl-phosphinic-acid or cyclohexyl-phosphorus-dichloride, respectively. White phosphorus acts as a scavenger for free H-atoms and C6H11-radicals from the radiolysis of cyclohexane. This reaction, however, does generally not lead to the complete cracking of all PP-bonds of the P4-molecule. The following products are formed in the γ-irradiation of white phosphorus in cyclohexane in the presence of carbon tetrachloride: Red phosphorus containing C6H11- and CCl3-endgroups, cyclohexylphosphorus-dichloride, trichloromethyl-phosphorus-dichloride, chloroform, cyclohexyl-chloride, hexachloroethane and trichloromethyl-cyclohexane. The yields of these products at various doses, dose rates, temperatures and compositions of the solutions are described. Several products such as C6H11PCl2 are produced with high G-values at temperatures above 100°C. The results are explained by a reaction scheme in which three chain reactions simultaneously occur. They are linked together since they have a common intermediate in the form of the CCl3-radical. At high doses, the reaction products of phosphorus mentioned above (including the red phosphorus) are transformed into soluble organic phosphorus compounds of high boiling points the structure of which has not yet been recognized.