Use of hydroxycarboxylic acids as stabilizers for bisphenols.

摘要

Lactic, malic and glyceric acids have been found to be superior to the hydroxy carboxylic acids heretofore employed for stabilizing bisphenols. The hydroxy carboxylic acids of the present invention or their ammonium or alkali metal salts can be added to the feed reactants used to make a bisphenol or to the reaction mixture after the reaction is complete or at any point in between. Lactic, malic and glyceric acids are particularly useful when the bisphenol is exposed to high temperatures, e.g. during the separation of the bisphenol from the reaction mixture or in a melt.