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US 4,784,805 AGranted
Process for the preparation of anthraquinoid intermediates and vat dyes
AssigneeCiba-Geiby Corporation
InventorRudolf Blattner
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AssigneeCiba-Geiby Corporation
InventorRudolf Blattner
Estimating the term…
A novel process for the preparation of anthraquinoid intermediates and vat dyes by alkali fusion of suitable precursors in the presence of alcohol. The process comprises starting from benzanthrone, pyrazolanthrone or anthraquinone derivatives and carrying out the reaction in a machine with kneading action and in the presence of an alkali metal hydroxide and an aliphatic alcohol with a boiling point below 120.degree. C., at elevated temperature, to effect dimerization or cyclization, the weight ratio of alkali metal hydroxide to benzanthrone, pyrazolanthrone or anthraquinone derivative being <1:1. The process makes it possible to prepare in good quality anthraquinoid intermediate which can be further processed to dyes, as well as vat dyes which are suitable for dyeing or printing cellulosic material.
A process for the preparation of anthraquinoid intermediates and vat dyes obtained from unsubstituted or substituted benzanthrone, pyrazolanthrone or anthraquinone derivatives, in the presence of an alkali metal hydroxide and an aliphatic alcohol with a boiling point below 120.degree. C., at elevated temperature, to effect dimerisiation or cyclisation, which process comprises carrying out the reaction with a weight ratio of alkali metal hydroxide to benzanthrone, pyrazolanthrone or anthraquinone derivative of less than 1:1 in a machine with kneading action but without grinding action.
Dependencies are inferred from the claim text.