| 摘要 |
Process for the preparation of perylene-3,4,9,10-tetracarboxylic dianhydride of high purity and in a very good yield in an ecologically unobjectionable manner, which comprises saponifying perylene-3,4,9,10-tetracarboxylic acid diimide with a 2.5-fold to 6-fold amount by weight of 92.5% to 97.5% strength sulfuric acid at temperatures of 210 DEG to 230 DEG C., washing the resulting mixture of perylene-3,4,9,10-tetracarboxylic dianhydride and perylene-3,4,9,10-tetracarboxylic acid monoanhydride-monoimide with a 0-fold to 4-fold amount by weight of 80-95% strength sulfuric acid, and then washing it with water until it is neutral, converting the compounds present in the mixture into their potassium salts by means of potassium hydroxide, after removing the perylene-3,4,9,10-tetracarboxylic acid monoanhydride-monoimide, adding to the solution of the tetrapotassium salt of perylene-3,4,9,10-tetracarboxylic acid, under nitrogen and with the exclusion of air and light, a salt of iron, nickel, calcium, magnesium, aluminum, tin, copper, lead, zinc or manganese, suspended or dissolved in water, and allowing this salt to act at a pH>10 and at temperatures from 0 DEG to 100 DEG C., then clarifying the mixture and converting the tetrapotassium salt of perylene-3,4,9,10-tetracarboxylic acid by acidification into perylene-3,4,9,10-tetracarboxylic dianhydride and isolating the latter in a customary manner.
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