Reactions of phosphoric acid in the autoxidation of fats

Summary At the elevated temperatures used in accelerated stability tests phosphoric acid was shown to react with fatty peroxides in such a manner as to prevent their estimation by the usual iodometric methods. A dark, phosphorus‐containing precipitate formed, which was apparently polymeric in nature. Phosphoric acid also reacted with oxidized fat to form an undisassociated fat‐soluble complex but did not react with fresh unsaturated fatty esters. In addition to the well known sparing action of phosphoric acid on a ‐tocopherol, it was shown that a ‐tocopherol and quinone also exerted a marked sparing action on the phosphoric acid.