118129-60-5

Example 1: 292.5 g (0.75 mol) of 3,4,9,10-tetracarboxylic dianhydride of >98% purity was stirred with 4420 g of 100% by weight sulfuric acid for 12 hours at room temperature. Subsequently 7 g of iodine was added and the mixture was heated to 85°C. 262.5 g (1.64 mol) of bromine was added slowly and dropwise over 8 hours. Upon completion of the reaction, the mixture was cooled to room temperature and purged with nitrogen to remove excess bromine. Next, the sulfuric acid concentration was diluted to 86 wt% by adding a total of 670 g of water in batches over a period of 1 hour. During this process, the reaction mixture was again heated to 85°C. After cooling, the precipitated product was filtered through a G4 glass filter and washed with 3 kg of 86 wt% sulfuric acid. The product was stirred in 5 liters of water and then filtered again, washed to neutrality and dried under reduced pressure at 120°C. 370 g of 1,7-dibromo-3,4,9,10-perylenetetracarboxylic acid dianhydride in the form of a bright red fine crystalline powder was finally obtained, with a melting point >360 °C, a purity of >98% and a yield of 90%. Analytical data: Elemental analysis (calculated value/measured value, wt%): C: 52.4/52.1; H: 1.1/1.1; O: 17.45/17.4; Br: 29.1/29.4. IR (KBr): ν=1782+1770 (strong, C=O), 1735+1723 (strong, C=O) cm^-1; UV/VIS ( H2SO4): λmax (ε) = 408 (10309), 520 (29410), 554 (43141) nm.

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