Phosphorus oxide (P4O10) → 4,6-Diaminoresorcinol

Participants

Reaction Conditions

Reaction Steps

4,6-Diamino-1,3-benzenediol dihydrochloride (2.1279 g, 10.0 mmol), 2-benzothiazole terephthalic acid (2.9891 g, 10.0 mmol) and 9.96 g of polyphosphoric acid (77% P2O5) were placed in a resin flask equipped with a mechanical stirrer, nitrogen inlet/outlet tubes, a vacuum connector and a side opening on the resin flask. The solution was heated at 90° C. in vacuo for 20 hours for dehydrochlorination. The reaction mixture was cooled to 50° C., then 6.04 g of P2O5 was added, in vacuo, thereby raising the polymer concentration to 18%. After adding the P2O5, heating was resumed. The mixture was heated at 174° C. for 16 hours, then at 190° C. for 24 hours. Work-up, as in the preceeding Example, gave 3.2 g of polymer with [N]=4.1 dl/g, methanesulfonic acid at 30° C.

Provenance & Evidence