Hoechst Aktiengesellschaft

Paul Stutzke

Alexander Ohorodnik

Klaus Gehrmann

Eberhard Auer

Elmar Lohmar

Methyl-[2-(2,4,6-tribromophenylcarbamoyl-)ethyl-]phosphinic acid is made continuously. To this end, molten 2-methyl-2,5-dioxo-1-oxa-2-phospholane is reacted with molten 2,4,6-tribromoaniline at 210.degree. to 250.degree. C. in the absence of a solvent.

Production of

Production of N-substituted 2-carbamoyl phosphinic acids of the general formula: ##STR1## in which R.sup.1 stands for an alkyl group having 1 to 4 carbon atoms or an aryl group; R.sup.2 and R.sup.3 stand independently of each other for an alkyl group having 1 to 4 carbon atoms, an aryl group or a hydrogen atom; R.sup.4 stands for an alkyl group having 1 to 18 carbon atoms, an aryl group or a hydrogen atom; and R.sup.5 stands for an alkyl group having 1 to 18 carbon atoms or an aryl group. More specifically, a 2-chloroformyl phosphinic acid chloride of the general formula ##STR2## is reacted at 120.degree. to 170.degree. C with an amine of the general formula ##STR3## and resulting N-substituted 2-carbamoyl phosphinic acid chloride of the general formula ##STR4## the latter compound being obtained while hydrogen chloride is split off, is hydrolyzed with water.

Production of N-substituted 2-carbamoyl phosphinic acids

Continuous production of 2,5-dioxo-1-oxa-2-phospholanes of the general formula ##STR1## from a beta-halogenoformyl-ethyl phosphinic acid halide of the general formula

Continuous production of 2,5-dioxo-1-oxa-2-phospholanes

Beta-halogenoformyl-ethyl phosphinic acid halides of the general formula:

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Walberberg, Germany

Paul Stutzke