摘要 |
<p>A process for preparing a rylenetetracarboxylic dianhydride, or a salt thereof having application formula Ib by subjecting a rylenetetracarboximide of application formula II to a hydrolysis under alkaline conditions in the presence of a polar organic solvent and removing the rylenetetracarboxylic dianhydride Ib from any rylenetetracarboxylic monoimide monoanhydride of application formula Ia which is formed to form the rylenetetracarboxylic dianhydride, or the salt thereof having formula Ib; or hydrolyzing the rylenetetracarboximide of application formula II under conditions that form the compound of application formula Ib and substantially no rylenetetracarboxylic monoimide monoanhydride of application formula Ia.</p> |