Manufacture of anthraquinone

Claim 1

AS AN IMPROVEMENT IN THE MANUFACTURE OF ANTHROQUINONE FROM PHTHALIC ANHYDRIDE AND BENZENE BY THE FRIEDEL-CRAFTS METHOD WHEREIN ALL REACTIONS ARE EFFECTED UNDER ANHYDROUS CONDITIONS AND THE SOLID REACTION PRODUCTS ARE OBTAINED AS FREE-FLOWING, DRY MATERIALS, THE IMPROVED PROCESS WHICH COMPRISES REACTING PHTHALIC ANHYDRIDE WITH BENZENE AND ALUMINIUM CHLORIDE UNDER ANHYDROUS CONDITIONS WHILE MECHANICALLY AGITATING THE REACTION MIXTURE MIXTURE TO FORM A CHEMICAL COMPLEX OF ALUMINUM CHLORIDE AND O-BENZOYL BENZOIC ACID AND REMOVING THE BY-PRODUCT HYDROGEN CHLORIDE AND UNREACTED BENZENE UNDER ANHYDROUS CONDITIONS WHILE CONTINUING THE AGITATION TO OBTAIN THE SAID COMPLEX AS A DRY, FREEFLOWING MATERIAL, AND THEN CONVERTING THE SAID DRY COMPLEX INTO ANTHRAQUINONE UNDER ANHYDROUS CONDITIONS BY REACTING IT WITH FROM 0.9 TO 1.3 PARTS OF OLEUM OF 5% TO 20% STRENGTH AT TEMPERATURES BETWEEN 105*C. AND 150*C. WHILE MECHANICALLY AGITATING THE REACTION MIXTURE UNTIL SAID COMPLEX IS DECOMPOSED AND CONVERTED INTO ANTHRAQUINONE, ALUMINIUM SULFATE AND HYDROGEN CHLORIDE AND REMOVING THE BY-PRODUCT HYDROGEN CHLORIDE UNDER ANHYDROUS CONDITIONS WHILE CONTINUING THE AGITATION TO OBTAIN A DRY, FREEFLOWING MIXTURE CONTAINING THE ANTHRAQUINONE ADMIXED WITH ANHYDROUS ALUMINIUM SULFATE AS A BY-PRODUCT, THE AMOUNT OF OLEUM BEING SUFFICIENT TO DECOMPOSE SAID COMPLEX AND FIX THE ALUMINUM AND CHLORINE CONSTITUENTS THEREOF AS ALUMINUM SULFATE AND HYDROGEN CHLORIDE, RESPECTIVELY, AND SUFFICIENT TO EFFECT COMPLETE RING CLOSURE OF THE O-BENZOYL BENZOIC ACID CONSTITUENT THEREOF AT THE REACTION TEMPERATURES EMPLOYED IN SAID REACTION, BUT INSUFFICIENT TO CONVERT THE SAID DRY MIXTURE OF SOLID REACTION PRODUCTS INTO A PASTY COMPOSITION.