CH286501A - Process for the production of a vat dye. - Google Patents

Description

  

  Process for the production of a vat dye. It has been found that a valuable vat dye is obtained if 1-amino-6,7-dichloroanthraquinone is treated with an agent which releases the p-chlorobenzoyl radical.



  The new dye dissolves in concentrated sulfuric acid with a red color and dyes cotton from a red vat in pure, lightfast, yellow tones.



  The 1-amino-6,7-dichloro-anthraquinone used as the starting material in the present process can be prepared by mononitration of 2,3-diehloranthraquinone and subsequent reduction of the 1-nitro-6,7-dichloro-anthraquinone obtained.



  A reactive, functional derivative of p-chlorobenzoic acid, for example an acid halide and in particular the acid chloride, can expediently be used as the agent releasing the p-chlorobenzoyl radical.

    The reaction can advantageously be carried out in indifferent, high-boiling solvents such as mono-, di- or trichlorobenzene, nitrobenzene or naphthalene, if desired in the presence of acid-binding and / or catalytically active agents, such as tertiary bases (pyridine or dimethylaniline), at elevated temperatures temperature, for example between 1000 and the boiling point of the solvent used.



       Example: 6 parts of 1-amino-6,7-dichloroanthraquinone and 6 parts of p-chlorobenzoyl chloride are distributed in 84 parts of dry nitrobenzene and stirred at 130 to 135 for three hours. The dye which precipitates out in yellow-orange needles on cooling is filtered off with suction, washed with boiling alcohol and dried. For vatting it is advantageously first reprecipitated from a solvent.



  The 1-amino-6,7-dichloroanthraquinone can be prepared as follows: 115 parts of nitrating acid containing 50% HNO3 are added to a solution of 50 parts of 2,3-dichloroanthraehinone in 800 parts of monohydrate within one hour while stirring - dripped. After this mixture has been stirred for two hours at 50 to 55, it is filtered off with suction and washed neutral.

   The filter cake is now ground as finely as possible with a little 50% alcohol and, after adding 30 parts of sodium sulfite and 3000 parts of water, refluxed for 15 hours.

    Then it is made alkaline with sodium hydroxide solution, filtered hot, washed neutral and dried. Recrystallization from o-dichlorobenzene gives 1-nitro-6,7-dichloro-anthraquinone in almost colorless little needles which melt at around 290 (uncorrected).

   Analysis:
EMI0001.0066
  
    Ber. <SEP> found
<tb> C <SEP> 52.2, / o <SEP> 52.18 / o
<tb> H <SEP> 1.56% <SEP> 1.54%
<tb> N <SEP> 4.34% <SEP> 4.320 / a
<tb> Cl <SEP> 22.02%, <SEP> 22.11% 30 parts of the nitro compound are ground well with water and, after 1400 parts of water and 300 parts of 30% sodium sulfhydrate solution have been added, the mixture is stirred at 95 for one hour. The 1-amino-6,7-dichloroanthraquinone which has precipitated out as a red precipitate is filtered off with suction while hot, washed neutral and dried.

   It crystallizes from anisole in red needles, which melt at around 282 to 283 (uncorrupted).

 

Claims (1)

PATENT CLAIM: A process for the production of a vat dye, characterized in that 1-amino-6,7-dichloroanthraquinone is treated with an agent which releases the p-chlorobenzoyl radical. The new dye dissolves in concentrated sulfuric acid in a finite red color and dyes cotton from a red vat in pure, lightfast, yellow tones. SUBCLAIMS 1. Process according to patent claim, characterized in that a p-chlorobenzoic acid halide is used as the agent releasing the p-chlorobenzoyl radical. 2. The method according to claim, characterized in that the p-chlorobenzoyl radical releasing agent used is p chlorobenzoyle chloride. 3. The method according to claim, characterized in that the implementation is carried out in an inert, high-boiling solvent at elevated temperature.