DE1083258B - Process for the preparation of sodium or potassium salts of benzene-1,4-disulfonic acid or naphthalene-2,6-disulfonic acid - Google Patents

Description

Process for the production of sodium or potassium salts of the benzene 1,4-disulfonic benzene-1,4-disulfonic acid or naphthalene-2,6-disulfonic acid The invention relates to a process for the production of sodium or potassium salts benzene-1,4-disulfonic acid or naphthalene-2,6-disulfonic acid.

From Liebigs Annalen der Chemie, 378, p. 359, it is known that when heating m- or p-benzene disulphonic acid with sulfuric acid and mercury an equilibrium of the two isomers is established at 250 "C.

In these isomerization reactions of with strong sulfuric acid catalyzed aromatic disulfonic acid forms an equilibrium with only 33.90 / 0 Parasic acid.

In contrast, in the thermal conversion according to the invention of Sodium salts of any aromatic catalyzed by heavy metal compounds Sulphonic acids over 50% obtained.

Likewise, according to the in J. Am. Chem. Soc., 49, p. 844 (1927), described procedure naphthalene-2,7-disulfonic acid in the presence of sulfuric acid converted to naphthalene-2,6-disulfonic acid at 42% at 1600C. According to Houben-Weyl, Methods of the org. Chemistry, 4th edition, Volume 9, p. 526, penultimate paragraph, benefits rearrangement by iron. It is pointed out here that this is the case with the known Reactions occurring water of reaction splits off a sulfo group and a new sulfonation enabled elsewhere. In contrast, the rearrangement of the sulfonic acids takes place in the present invention in the form of the alkali salts under anhydrous conditions.

It has now been found that sodium or potassium salts of benzene-t , 4-disulfonic acid or naphthalene-2,6-disulfonic acid can thereby produce that - the sodium or potassium salts of the corresponding 1,3- or 2,7-disulfonic acids to at least 375 "C or in the presence of a heavy metal catalyst to at least 2500 C are heated.

Implementation can either be at atmospheric or superatmospheric Press. The reaction takes place preferably in an inert atmosphere, such as carbon dioxide or nitrogen, instead, although it is not essential is that the air is completely excluded. But when there is air, so it is desirable that only a small amount of air is admitted to the reaction vessel.

The isomerization takes place in the absence of a catalyst a temperature of 3750 C or above. It is preferred, however, the procedure to be carried out in the presence of a heavy metal catalyst, since lower in this case Working temperatures can be used, d. H. Temperatures down to 2500 C. Heavy metal catalysts that contain mercury or chromium are considered Particularly suitable catalysts. In any case, it is desirable to follow the procedure not to be carried out at temperatures above about 600 ° C., otherwise decomposition is easy the reaction substances occur.

The potassium and sodium salts of benzene-1,3- or naphthalene-2,7-disulfonic acids have proven to be particularly suitable starting materials, and from these are the sodium salts are preferred, since in this case the initial yield of the desired Disulfonic acids is slightly higher than when using the corresponding potassium salts and since the cost thereof is less.

It is often expedient to free the products by clearing them Isolate disulfonic acids in a crude form.

In the following examples, in which all parts and percentages based on weight, the invention is explained in more detail.

Example 1 282 parts of the anhydrous disodium salt of benzene-1,3-disulfonic acid were mixed with 43 parts of mercury dioxide and the mixture was allowed to stir for 6 hours heated to 425 "C in a carbon dioxide atmosphere under a pressure of 4 at.

The product was extracted with water and the extracts filtered were passed through a column of an activated cation exchange resin to obtain the to make free sulfonic acid free. This was in raw Shape with obtained in a yield of 230 parts. From a corresponding part of this product was bis (S-benzylthiuronium) -benzene-p-disulfonate (melting point 2470 C) in a Amount produced, from which it can be seen that the benzene 1,4-disulfonic acid with a Yield was obtained which corresponds to 52 ° lo of theory. The product was next characterized in that it could be converted to benzene p-disulfonyl chloride, which on reaction with ammonia, benzene-p-disulfonamide (melting point 291 "C) resulted.

Example 2 If 315 parts of the anhydrous potassium salt of benzene-l , 3-disulfonic acid are processed according to the procedure of the example 50 parts, d. H.

90 / o of theory, bis (S-benzylthiuronium) -benzene-p-disulfonate isolated.

Example 3 A mixture of 664 parts of disodium naphthalene-2,7-disulfonate and 43.2 parts of mercury was added under a carbon dioxide atmosphere for 6 hours heated to 425etc. After cooling, the product was extracted with water, and a corresponding amount of the same was mixed with an aqueous solution of S-benzylthiuronium chloride treated, whereby Ris- (S-benzylthiuronium) -naphthalene-2,6-disulfonat with a Yield was obtained corresponding to the presence in the product of at least 150 / o Disodium naphthalene-2,6-disulfonate.

The melting point of 271 to 274 "C as well as the infrared absorption spectrum of the salt were identical to those of a corresponding sample of bis- (S-benzylthiuronium) -naphthalene-2,6-disulfonate.

Example 4 When disodium naphthalene-2,7-disulfonate is used in the example 3 was treated using 22 parts of cadmium metal dust instead of mercury dioxide, bis (S-benzylthiuronium) naphthalene-2,6-disulfonate was obtained obtained in a yield equivalent to the presence of 1001o of the 2,6-disulfonate is equivalent in the reaction product.

Example 5 If, according to Example 3, disodium naphthalene-2,7-disulfonate heated alone, the yield of bis (5-benzylthiuronium) naphthalene is 2,6-disulfonate is equivalent to the presence of 70% of the 2,6-disulfonate in the Reaction product. The same yield was obtained when using 41.4 parts of lead powder the disodium salt were added and the mixture in that described in Example 3 Way was treated.

If comparatively 820 parts disodium benzene-g! , 3-disulfonate 24 Heating at 275 "C for hours in a carbon dioxide atmosphere found none Implementation of the material instead.

Example 6 If 800 parts of disodium benzene -1,3-disulfonate 12 hours long in a carbon dioxide atmosphere 425D C were heated, a reaction occurred and 720 parts of a product were obtained which is composed of 70 to 750 / o disodium benzene p-disulfonate, about 5010 disodium benzene-m-disulfonate, about 200/0 trisodium benzene-1,3,5-trisulfonate consisted of about 1 to 30Io of sodium sulfate.

Example 7 820 parts of disodium benzene-1,3-disulfonate became intimate mixed with 57 parts of potassium chrome alum, and the mixture was then left for 24 hours heated to 275 "C for a long time in a carbon dioxide atmosphere. 640 parts of a Product obtained, which to about 85%, from disodium benzene p-disulfonate and about 150% trisodium benzene trisulfonate existed, as determined by infrared analysis became.

Example 8 820 parts of disodium benzene-1 3-disulfonate were added with 43 Parts of mercuric oxide mixed; and the mixture was then made in that described in Example 7 Treated wisely.

There were 760 parts of one. Product received; that from disodium benzene-1 , 4-disulfonate - consisted of ,. which is about 5010 m-disulfonate and about 1001 trisulfonate as determined by infrared analysis.

Example 9 500 parts of disodium benzene, disulfonate and 60 parts of mercuric sulfate were mixed intimately, and the mixture was left in a nitrogen atmosphere for 6 hours heated to 425 "C. The product was described in the previous examples Wise worked up, and 450 parts of disodium benzene-1,4-disulfonate were obtained, which contained a small amount of trisodium benzene-1,3,5-trisulfonate.

PTENTAN APPROACH: 1. Process for the production of sodium or potassium salts of benzene-1,4-disulfonic acid or naphthalene-2,6-disulfonic acid, characterized in that that the sodium or potassium salts of the corresponding 1,3- or 2,7-disulfonic acids to at least 375 "C or in the presence of a heavy metal catalyst to at least 2500 C are heated.

Claims (1)

2. The method according to claim 1, characterized in that the implementation is carried out under superatmospheric pressures. 3. The method according to claim 1, characterized in that the used Heavy metal catalyst contains mercury or chromium. 4. The method according to claim 1, characterized in that the implementation in the absence of air and in the presence of an inert gas, - such as Carbon dioxide or nitrogen. Considered publications: Liebig's Annalen der Chemie, 378, p. 359; J. Am. Chem. Soc., 49, 8,844 (1927); Houben-Weyl, Methods of the org. Chemie, 4th Edition, Vol. 9, p. 526.