Process for preparing 2-anilinoacridone
AssigneeCiba-Geigy Corporation
InventorWilfried G. Holtje
Life of this patent
Estimating the term…
Abstract
A process is disclosed wherein 2,5-di(phenylamino) terephthalic acid is half-cyclized by dissolving it in a mixture of polyphosphoric acid and phosphoric acid and heating at 100.degree.-120.degree. C. to form 2-(phenyl)amino-3-carboxy-9(10H)acridone (ACA). The ACA is decarboxylated to form 2-(phenyl)amino-9(10H)acridone, also known as 2-anilinoacridone, by dissolving it in tetramethylene sulfone and heating in the presence of a basic cupric carbonate catalyst.
Claims3
A process comprising dissolving at from about 40.degree. C. to about 60.degree. C. a compound of the formula ##STR6## wherein R and R.sup.1 are --H, --Cl, C.sub.1-4 alkyl or C.sub.1-4 alkoxy, in a mixture of 50 to 75 volume percent polyphosphoric acid and 50 to 25 volume percent phosphoric acid, calculated as 85% aqueous phosphoric acid, heating the solution to 100.degree. to 120.degree. C. for 5 to 90 minutes and recovering a compound of the formula ##STR7##
Dependencies are inferred from the claim text.