Preparation of vat dyes and pigments of the perinone series

Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...

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106493, 106498, 546 32, 548337, 548346, C09B 5712, C07D47100

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active

050749196

ABSTRACT:
The conventional condensation of naphthalene-1,4,5,8-tetracarboxylic acid with 1,2-diaminobenzene gives the resulting naphthoylenebisbenzimidazole isomers together in the cis and trans form. It is desirable to shift the isomer ratio of the mixture obtained toward the desirable trans product and to reduce the amount of cis product obtained. It is also desirable to develop a process of preparation which optimizes the yield and improves the waste water situation.
This object is achieved according to the invention by subjecting virtually stoichiometric amounts of the starting compounds to a precondensation at 60.degree. to 110.degree. C. in an aqueous medium and then completing the condensation in the aqueous medium in a second stage at 130.degree. to 180.degree. C.

REFERENCES:
patent: 3772303 (1973-11-01), Spietschka et al.
patent: 3865829 (1975-02-01), Wagner
Fiat Final Report 1313 II, p. 168.
Khoroshom, V. L. Chem. Abs. 66:1983 5K (1967).
Herzog, H. Chem. Abs. 41:101:8713j (1984).
Rusanov et al., Chim. Geterotsikl. Soedinenii 7: pp. 968-971, (1979) (translation, pp. 791-794).

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