The synthesis of biscitraconimides and polybiscitraconimides

A series of N-alkylene biscitraconimides was synthesized from the corresponding N-alkylene-biscitraconamic acids or directly from itaconic anhydride and a homologous series of aliphatic diamines, H₂N(CH₂)_nNH₂, where n = 2 through 12. The biscitraconamic acids were synthesized from the α,ω-diamino-alkanes and itaconic anhydride. Isomerization of itaconic anhydride to citraconic anhydride occurs in the presence of the diamines to yield biscitraconamic acids instead of bisitaconamic acids expected and observed in similar studies. The intermediate biscitraconamic acids or the biscitraconimides were polymerized thermally between 175 and 225°C to tough ambered-colored films of polybiscitraconimides that exhibit good thermal stability.