Patent ID: 7049463
Filing Date: 2006-05-23
Classification: C07F

Abstract:
1. An improved process for the production of dialkylphosphinic acid in high yield and purity by the reaction of a hypophosphorous acid or salt with a stoichiometric excess of an alpha olefin in the presence of a free radical initiator and optionally a transition metal catalyst to form a reaction product composition comprising monoalkylphosphinic acid and dialkylphosphinic acid; the improvement comprising: a) adding sufficient aqueous base to the reaction product composition to i) form the salts of the phosphinic acids, and ii) establish an aqueous phase and an organic phase, wherein the monoalkylphosphinic acid preferentially solubilizes into the aqueous phase; b) separating the organic phase from the aqueous phase; c) acidifying the organic phase; and d) removing the olefin from the organic phase; and e) isolating the purified dialkylphosphinic acid product.