Hoechst Aktiengesellschaft

Klaus Hestermann

Bernd Lippsmeier

Hubert Neumaier

Production of halogen-containing tertiary phosphine oxides of the general formula (I) ##STR1## in which R.sub.1 stands for an alkyl, halogenoalkyl, alkenyl, halogenoalkenyl, alkinyl or halogenoalkinyl radical, each of these radicals containing from 1 to 18 carbon atoms, or stands for a cycloalkyl, a halogenated cycloalkyl, an aryl, a halogenated aryl, an aralkyl or a halogenated aralkyl radical, and X stands for halogen. The oxides are made by subjecting a compound of the general formula (II) ##STR2## in which R has the same meaning as R.sub.1 and X stands for halogen, to thermal treatment in the presence of hydrogen halide at atmospheric or at elevated pressure so as to split off water and formaldehyde in vapor form therefrom; by continuously freeing the resulting reaction mixture from the said components in vapor form; by terminating the reaction and thereafter stripping off the hydrogen halide from the reaction mixture by introducing an inert gas thereinto; and by purifying the remaining crude product by distillation or recrystallization.

Production of halogen-containing tertiary phosphine oxides

Production of tertiary phosphine oxides of the general formula (I): ##STR1## in which the substituents R.sub.1 and R.sub.2, being identical or different, each stand for an alkyl, alkenyl, alkinyl, cycloalkyl, aralkyl or aryl radical having from 1 to 18 carbon atoms. The phosphine oxides are made by splitting off formaldehyde and hydrogen halide at temperatures within the range about 150.degree. and 350.degree. C, in the presence of hydrogen halide, from a molten compound of the general formula (II): ##STR2## in which R.sub.1 and R.sub.2 have the meanings given above and X stands for halogen; separating the formaldehyde and hydrogen split off from the reaction mixture, and treating the resulting crude product so as to separate the compound of general formula (I) therefrom.

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Munich, Georgia

Klaus Hestermann