Structural effects on the rates of formation of amic acids and imides

Abstract

The reaction of amines with maleic anhydride (MA), pyromellitic anhydride (PMDA), dimethylmaleic anhydride (DMMA), and cyclo-octa-1,5-diene- 1,2,5,6-tetracarboxylic dianhydride (CODA) was followed by titration. MA and PMDA give the amic acids very readily and cyclize to the imides only at high temperatures, while DMMA and CODA react slowly to yield a mixture of the amic acids and imides even at ambient temperatures. The structural factors affecting the reaction are discussed.