Process for preparing ethylenedialkylphosphinic acids, esters and salts and use thereof

The invention relates to a method for producing ethylenedialkylphosphinic acids, esters and salts, and to the use thereof as flame retardants. The claimed method is characterised in that ⋅ a) a phosphinic acid source (I) is reacted with olefins (IV) in the presence of catalyst A so as to obtain an alkylphosphonous acid, salt or ester (II) thereof, and ⋅ b) the alkylphosphonous acid, salt or ester (II) thereof obtained in this manner is reacted with acetylenic compound (V) in the presence of catalyst B in order to obtain the ethylenedialkylphosphinic acid derivative (III), ⋅ catalyst A being transition metals and/or transition metal compounds and/or catalyst systems composed of a transition metal and/or a transition metal compound and at least one ligand ⋅ and catalyst B being electromagnetic radiation.