Patent ID: 6426430
Filing Date: 2002-07-30
Classification: B01J,C07C,C08G,Y02P

Abstract:
A method for reducing alkali metals in aromatic dicarboxylic acids produced by disproportionation or rearrangement of an alkali salt of a monocarboxylic acid which comprises:a) Washing the aromatic dicarboxylic acid with water in a ratio (grams:grams) of about 4-8:1 water to acid at a temperature of about 70-200Â° C., b) Introducing the aromatic dicarboxylic acid in water into a reactor characterized by minimal backmixing and reacting the aromatic dicarboxylic acid in water in said reactor at a temperature of about 100-200Â° C.; c) Directing the aromatic dicarboxylic acid in water exiting said reactor to a centrifuge to separate the solid aromatic dicarboxylic acid from water containing contaminants; d) Optionally, combining the solid aromatic dicarboxylic acid again with water in a ratio (grams:grams) of about 5:1 at a temperature of about 100-200Â° C. to further reduce levels of alkali metals.