| 摘要 |
<p>Aromatic polycarboxylic acids and their anhydrides such as bisphenol A dianhydride are prepared from the corresponding polycarboximides, such as bisphenol A bisimide, by an exchange reaction with phthalic acid or phthalic anhydride and water in the presence of dimethyl-n-butylamine as an exchange catalyst. The use of this amine results in the formation of a product of decreased color, as compared with the use of triethylamine.</p> |
