STABILISATION EN COULEUR D'ANHYDRIDES D'ACIDES DICARBOXYLIQUES PURIFIE

摘要

1331853 Colour stabilization of dicarboxylic acids and anhydrides MONSANTO CO 26 May 1971 [27 May 1970] 17255/71 Heading C2C A method for improving the colour stability of a refined dicarboxylic acid or acid anhydride comprises incorporating therein a colourstabilizing amount of a molecular halogen or a compound containing an ionic or labile halogen to give a novel composition therewith provided that when the anhydride is maleic anhydride the colour-stabilizing agent is not an alkali metal chloride or bromide, alkaline earth metal chloride or bromide, silver chloride, hydrobromic acid or hydrochloric acid. Suitable colour - stabilizing agents include inorganic halides and organic compounds such as fumaryl chloride, acrylyl chloride and meso-α,α1-dichlorosuccinic acid, and is preferably present in an amount of from 0À01 to 5 p.p.m. Examples describe the stabilization of maleic anhydride.