VERFAHREN ZUR VERRINGERUNG DES KALIUMS IN EINEM INTEGRIERTEN PROZESS ZUR HERSTELLUNG VON 2,6- NAPHTHALENEDICARBONSÄURE

摘要

Disclosed is a method for reducing alkali metals in aromatic dicarboxylic acids produced by disproportionation or rearrangement of an alkali salt of a mono- or dicarboxylic acid to levels acceptable for polymerization which comprises: a) Washing the aromatic dicarboxylic acid with water in a ratio of about 4-8:1 water to acid at a temperature of about 70 - 200 DEG 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 - 200 DEG 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 of about 5:1 at a temperature of about 100 - 200 DEG C to further reduce levels of alkali metals.