Benzofuranone stabilization of phosphate esters
A method for decolorizing and stabilizing alkylphenyl esters of phosphoric acid which comprises contacting the esters with an effective amount of a benzofuranone (e.g., is 5,7-di-t-butyl-3-(3,4 di-methylphenyl)3H-benzofuran-2-one) for a sufficient length of time to decolorize and stabilize the esters against subsequent color formation.
1. A method for decolorizing alkylphenyl esters of phosphoric acid which comprises contacting said esters with an effective amount of 5,7-di-t-butyl-3-(3,4 di-methylphenyl) 3H-benzofuran-2-one for a period of time sufficient to reduce the color to the desired level whereby said esters are decolorized and stabilized against subsequent color formation.
2. The method of claim 1 wherein said alkylphenyl esters correspond to the formula:
wherein R is alkaryl and R 1 and R 2 are selected from the group consisting of alkyl, aralkyl, alkaryl and aryl, and wherein the alkyl groups contain from about 1 to about 20 carbon atoms.
3. The method of claim 2 wherein said alkyl groups contain from 1 to about 12 carbon atoms.
4. The method of claim 1 wherein the alkylphenyl esters contain unreacted substituted and unsubstituted phenols.
5. The method of claim 2 wherein said decolorizing and stabilizing is conducted under an inert atmosphere.
6. The method of claim 5 wherein said inert atmosphere comprises nitrogen.
7. The method of claim 1 wherein the alkyl phenyl ester of phosphoric acid is an isopropylphenyl phenyl phosphate.