Method for preventing the discoloration of dihydric phenols
AssigneeSumitomo Chemical Company, Limited
InventorsMasaaki Takenaka, Haruhisa Harada, Hiroshi Maki, Shigeru Sasaki
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Abstract
Dihydric phenol is effectively prevented from discoloration by mixing the dihydric phenol with 0.00001 to 0.1% by weight of hydrocarboxylic acid on the basis of the dihydric phenol.
Claims7
A method of substantially preventing discoloration of a dihydric phenol represented by the general formula, ##STR2## wherein R is a hydrogen atom or an alkyl group having 1-6 carbon atoms, comprising mixing the dihydric phenol with a hydroxycarboxylic acid in an amount of 0.00001 to 0.1% by weight based on the weight of the dihydric phenol, said acid being selected from the group consisting of tartaric acid, malic acid, lactic acid, tartronic acid and esters of said acids.
Dependencies are inferred from the claim text.