Abstract: The present invention relates to phosphorus compounds of the formula ##STR1## in the (RS), (R) and (S) forms, in which Ar.sup.1 --Ar.sup.1 is a bipheny1 radical, 1-phenylnaphthyl radical or 1,1'-binaphthyl radical, each R', if present, independently of the others, is F, an alkyl or alkoxy radical each having 1 to 8 carbon atoms, m is an integer from 0 to 4, k is an integer from I to 4, Ar.sup.2 is a phenyl radical, each R", if present, is, independently of the others, F, Cl, CF.sub.3, SO.sub.3 H, SO.sub.3, SO.sub.3 Me (Me is Li, Na, K), a dialkylamino radical having 2 to 8 carbon atoms, an alkyl or alkoxy radical each having 1 to 8 carbon atoms and n is an integer from 0 to 5, and to a process for their preparation.

Abstract: Aryl phosphinites of the formula (I) ##STR1## can be prepared in a simple manner and in high yields by reacting 2,4-di-tert.-butylphenylphosphonous dihalides with alkyl- or arylmagnesium bromides or alkyl- or arylmagnesium chlorides.Aryl phosphinites serve for the preparation of secondary phosphine oxides which are used as starting materials for the preparation of phosphine ligands in catalyst systems.

Abstract: Diarylphosphinous acid aryl esters are made by the disclosed process. These compounds are useful for stabilizing plastics, in particular polymerization plastics, and hence can be incorporated into a plastic molding composition.