In a process for the production of dialkylphosphinic acids, especially branched,
dialkylphosphinic acids in high purity via the reaction of an alpha olefin with
a hypophosphorous acid or a salt thereof, the improvement comprising conducting
the reaction in the presence of a stoichiometric excess of the olefin and isolating
and purifying the desired dialkylphosphinic acid product by neutralizing the monoalkylphosphinic
acid by-product with an aqueous base; removing the aqueous phase in which the neutralized
monoalkylphosphinic acid is preferentially solubilized; acidifying the dialkyl
product in the organic phase; and isolating the purified product.