Sulfuric Acid → 3,4,9,10-Perylenetetracarboxylic dianhydride

Participants

Reaction Conditions

Reaction Steps

800 g of 95% strength sulfuric acid are initially taken and 200 g of 89.4% strength perylene-3,4,9,10-tetracarboxylic acid diimide are introduced at room temperature. The temperature of the mixture is then raised to 220° C. and is maintained at this level for two hours. The mixture is then allowed to cool to room temperature and the precipitate which has been formed is filtered off with suction and washed with water until it is neutral. 174.3 g of crude perylene-3,4,9,10-tetracarboxylic dianhydride are obtained after drying at 80° C. This is introduced, with exclusion of light, into a solution composed of 6 liters of water and 140 g of 85% strength potassium hydroxide. While blanketed with nitrogen, the solution is heated to 80°-90° C., and stirring is continued for a further 90 minutes at this temperature. The solution is then allowed to cool to 25° C., the pH is adjusted to a value of 8-9 and the solid residue is filtered off with suction and washed with 100 ml of water. (The residue is 38.8 g of perylene-3,4,9,10-tetracarboxylic acid diimide which has only been half-saponified, i.e. perylene-3,4,9,10-tetracarboxylic acid monoanhydride-monoimide, and this is expediently added to the next batch.) 60 g of 85% strength potassium hydroxide and 60 g of animal charcoal are introduced into the filtrate, with the exclusion of light, and the solution is then blanketed with nitrogen. After a further hour's stirring at 25° C., a solution of 60 g of iron(II) sulfate and 600 ml of water is added dropwise, the mixture is stirred for a further hour at 25° C. and is clarified and the filtrate is then added dropwise to 600 g of concentrated hydrochloric acid, the mixture is kept at 80°-90° C. for one hour and the precipitate is filtered off with suction, washed with water until it is neutral and dried at 80° C. 120.9 g of perylene-3,4,9,10-tetracarboxylic dianhydride are obtained.

Provenance & Evidence