Verfahren zur Reinigung von Pyromellithsaeuredianhydrid

摘要

Pyromellitic dianhydride is purified by washing with, or recrystallizing from, an aliphatic or cycloaliphatic ketone. The starting material may be that obtained by gas phase oxidation of, e.g. 1,4-dimethyl-2,5-diisopropylbenzene.