CH329255A - Process for the preparation of aryl-triamino-sulfamic acids and their salts - Google Patents

Description

  

  Process for the preparation of aryl-triamino-sulfamic acids and their salts In patent M, 318447 there has been described a process for the preparation of aryl-triamino-sulfamic acids and their salts starting from starting materials aromatics having one or two nitro groups which are reduced, after sulfonation, to amino groups.



  The present patent relates to another process for the preparation of such aryl-triamino-sulfamic acids and their salts.



  These compounds are used for the preparation of so-called oxidation dyes and correspond to the following general formula
EMI0001.0010
    wherein R represents an aromatic residue which may bear other substituents than those mentioned herein <I> and A </I> represents a cation, such as a hydrogen ion or the ion of a monoval metal.



  The preparation of sulfates derived from monoamines or diamines has already been described, but those derived from triamines are not known.



  The process according to the present invention is characterized in that an aromatic compound substituted by at least three groups is treated with a sulfonating agent, one of which is an amino group, the other a nitro group and the third an acylamido group. , and in that, after sulfonation, the nitro group is transformed into an amino group by reduction and the acylamido group into an amino group by hydrolysis.

   The conversion of nitro and acylamido groups to amino groups can take place in any order.



  Sulphonation on the amino group can be carried out using a sulphonating agent such as, for example, sulfuric chlorohydrin, sulfur trioxide, oleum, sulphuric acid, sulphamic acid, combinations sulfur trioxide with a tertiary amine, an amide or an ether.

   As examples of tertiary mines capable of entering into the preceding combinations, mention may be made of pyridine, trimethylamine, triethylamine, ethylmorpholine and dimethylcyclohexylamine; as examples of amides, there may be mentioned dimethyl-formamide, and as an example of ethers, dioxane. The reaction can be carried out with or without solvents.

   The solvents which can be used can be, for example, organic solvents such as the nitro and chlorinated derivatives of hydrocarbons, amides, ethers, tertiary amines and even water in the case where the sulphination is carried out by combinations. sulfur trioxide with certain tertiary amines. Mixtures of solvents can also be used.

      The reduction of the nitro group can be carried out in an alkaline, neutral, or very weakly acidic medium. Any known reduction method can be used which makes it possible to operate under these conditions. Among the reducing agents which can be used for this operation, there may be mentioned, for example, alkali metal sulphides and polysulphides, hydrosulphites, salts of sulphurous acid, zinc and iron.



  The hydrolysis of the acylamido group can also be carried out in an alkaline, neutral or very slightly acidic medium; it is preferably carried out with caustic alkalis. The free acids of aromatic triamines sulfonated on a single amino group are, in general, less soluble in water than their sodium salts. These are white products or more or less colored brown, most often very soluble in water.

      The various salts of the new sulfonated derivatives obtained by the process according to the invention can be used for the preparation of oxidation dyes and they are particularly advantageous when this preparation is carried out on the fiber or on any other object. Their use has been described in the main patent.

      <I> Example:, </I> 45 parts of sulfuric chlorohydrin are slowly introduced into 150 parts of anhydrous pyridine so that the temperature does not exceed 35 C; 60 parts of acetylamino-4-nitro-2-ami.nobenzene are then added at room temperature. The mixture obtained naked, well stirred, is slowly heated to 501 ° C .; stirring is continued for 2 hours, then poured into a solution containing 70 parts of sodium carbonate and 200 parts of water; the reaction should remain alkaline on Brilliant Yellow paper.

   After stripping the pyridine with steam, the derivative sulfonated on the amino group crystallizes on cooling. It is filtered off and washed to neutrality with saturated sodium chloride solution. It is then gradually introduced into 300 parts of vigorously stirred water and kept at the boil, in which have previously introduced 80 parts of fine iron turnings and 2 parts of glacial acetic acid. After the reduction is complete, 3 parts of sodium carbonate are added, filtered hot and the alkaline filtrate is concentrated until crystallization begins. Allowed to cool and the product obtained is filtered off.

   This is then boiled for 30 minutes with 10 times its weight of a 5% caustic soda solution. After cooling to 10 ° C., most of the excess alkali is neutralized with concentrated hydrochloric acid, so as to maintain a slightly alkaline reaction; it is concentrated in the absence of air until an abundant precipitate is obtained by cooling. Sodium 1,2,4-triaminobenzene-NI-sulfonate precipitates. After drying in vacuum, it forms a brown powder. It can be recrystallized in a 50 <B>% </B> water - alcohol mixture. It then forms a beige powder.

           Acetylamino-4-nitro-2-aminobenzene is prepared by following the indications of Bülow and Mann (Berichte 30, page 981).

 

Claims (1)

CLAIM Process for the preparation of compounds of general formula EMI0002.0040 in which R is an aromatic residue and A is a cation, characterized in that an aromatic compound substituted by at least three groups is treated with a sulfonating agent, one of which is an amino group, the other a nitro group, the third an acylamido group, and in that the nitro group is converted, after suffonation, into an amino group by reduction and the acylamido group into an amino group by hydrolysis.