Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C221/00—Preparation of compounds containing amino groups and doubly-bound oxygen atoms bound to the same carbon skeleton
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2603/00—Systems containing at least three condensed rings
  • C07C2603/02—Ortho- or ortho- and peri-condensed systems
  • C07C2603/04—Ortho- or ortho- and peri-condensed systems containing three rings
  • C07C2603/22—Ortho- or ortho- and peri-condensed systems containing three rings containing only six-membered rings
  • C07C2603/24—Anthracenes; Hydrogenated anthracenes

Definitions

• the present invention relates to a process for the preparation of practically pure 1-amino-8-nitro-4,5-dihydroxyanthraquinone by partial reduction of 1,8-dinitro-4,5-dihydroxyanthraquinone.
• DE-OS 24 28 338 and 24 28 452 describes the partial reduction of dinitro-dihydroxyanthraquinone with hydrazine in an aqueous medium or in organic protic solvents.
• a 1-amino-8-nitro-4,5-dihydroxyanthraquinone which is suitable for the production of valuable blue dyes described in DE-OS 20 29 793, can only be obtained by the processes of the prior art if pure, from ⁇ -nitro compounds free 1,8-dinitro-4,5-dihydroxyanthraquinone is used as the starting product.
• the latter can only be obtained according to the prior art in the following way: 4,5-dichloro- or 4,5-dinitroanthraquinone is reacted with phenol to give 4,5-diphenoxyanthraquinone.
• a virtually chromatographically uniform 1-amino-8-nitro-4,5-dihydroxyanthraquinone is obtained from the crude 1,8-dinitro-4,5-dihydroxyanthraquinone obtainable by nitration of 4,5-dihydroxyanthraquinone , which is ideal for the production of dyes. It was surprising that in the process according to the invention the by-products formed in the nitration and / or the reduction products resulting therefrom selectively and practically completely from the desired 1-amino-8-nitro-4,5-dihydroxyanthraquinone be separated.
• the economic advantage of the process according to the invention lies in the fact that, instead of the pure dinitrochrysazine which can be obtained via a complex and multi-stage synthesis, the crude dinitrochrysazine obtainable by direct nitration of chrysazine can be used for partial reduction.
• the process according to the invention is generally carried out by suspending the crude dinitrochrysazine in phenol and water.
• the alkali metal phenolate is then either added as such or advantageously produced by adding alkali metal hydroxide or carbonate in the reaction mixture.
• the reducing agent is then added at temperatures between 20 and 100 ° C. with stirring and the reaction mixture is kept at the desired temperature until dinitrochrysazine is no longer present.
• the reaction mixture is filtered, the filter cake is washed phenol-free with methanol and / or with dilute sodium carbonate solution, optionally washed neutral with water and dried.
• a mixture of phenol and water serves as the reaction medium.
• the water content is between 5 and 50 percent by weight, preferably between 30 and 45 percent by weight, based on the mixture.
• the suspension of the crude dinitrochrysazine is advantageously obtained by adding the crude dinitrochrysazine in the form of the aqueous press cake to the phenol initially charged. If necessary, phenol is added so that the water content in the phenol / water mixture is below 50 percent by weight or water is distilled off as an azeotropic mixture with phenol or other entraining agents.
• the amount of reaction medium is generally between 2 and 10, preferably between 3 and 6 times, based on the crude dinitrochrysazine used.
• the amount of reaction medium depends on the one hand on the phenol content and on the other hand on the content of by-products in the crude dinitrochrysazine. With a higher phenol content, the amount of reaction medium can be lower, while higher contents of impurities require a 10 to 25% larger amount of reaction medium.
• 0.2 to about 1.5 moles of phenolate are used per mole of dinitro-dihydroxyanthraquinone, the amount depending on the water content of the reaction medium, on the reducing agent and on the amount used.
• the reducing agents used in the process according to the invention belong to the group of reductones and / or reductonates.
• Triose reductone and reductic acid result from the acidic or alkaline degradation of saccharides such as glucose, starch or molasses.
• the amount of reducing agent required for the partial reduction depends on the reducing agent itself and on the reduction conditions.
• the required amount of reducing agent is advantageously determined by tests under the reaction conditions to be used later. Samples of the reaction product are examined chromatographically and the amount of reducing agent required until all dinitrochrysazine has disappeared.
• dihydroxyacetone in particular hydroxyacetone and glucose, are suitable as reducing agents.
• Technical hydroxyacetone which still contains propylene glycol can be used here.
• the reduction is generally carried out at temperatures between room temperature (20 ° C.) and 100 ° C., preferably between 80 and 100 ° C., in particular at the boiling point of the phenol / water mixture.
• the reduction is usually completed in 0.5 to 3 hours.
• the reaction is complete when dinitrochrysazine can no longer be found in a sample; if necessary, reducing agent and - if necessary - also alkali metal hydroxide are added to the reaction mixture to form phenolate.
• a virtually pure 1-amino-8-nitro-4,5-dihydroxyanthraquinone is obtained from crude dinitrochrysazine, which is obtained by direct nitration of chrysazine.
• the process product is suitable for all purposes.
• the raw dinitrochrysazine used as the starting product was produced as follows:
• Example 5 The procedure is as given in Example 5. Instead of 5.5 parts of potassium carbonate, however, 4.25 parts of anhydrous sodium carbonate are used. This gives 10.3 parts of 1-amino-8-nitro-4,5dihydroxy-anthraquinone, which is virtually uniform chromatographically.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 1977
  • 1977-07-07 DE DE2730720A patent/DE2730720C2/de not_active Expired
• 1978
  • 1978-06-20 US US05/917,252 patent/US4154747A/en not_active Expired - Lifetime
  • 1978-06-22 EP EP78100217A patent/EP0000341B1/fr not_active Expired
  • 1978-06-22 DE DE7878100217T patent/DE2860500D1/de not_active Expired
  • 1978-07-06 JP JP8153278A patent/JPS5416462A/ja active Pending

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