AT70369B - Process for the preparation of water-soluble condensation products, which dissolve poorly soluble components of natural tannins with ease. - Google Patents

Description

  

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   It has been found that condensation products of outstanding technical importance are obtained if naphthalene sulfonic acids or their homologues are used in the presence or absence of agents having a condensing action, such as. B. sulfuric acid, hydrochloric acid, glacial acetic acid, etc., with formaldehyde or formaldehyde developing substances treated under such conditions, in particular at such temperature, as long and in such proportions that essentially only water-soluble compounds are obtained. In the case of the use of sulfuric acid, for example, an excessively large excess of it and too long exposure to it, especially in heat, should be avoided.

   Such products can also be obtained if the water-insoluble action products of formaldehyde or formaldehyde-developing agents on naphthalene or its homologues, such as those used, for. B. by the action of more than one molecule of formaldehyde to 1 molecule of naphthalene in the presence of acids or otherwise obtainable, converted into water-soluble compounds by treatment with sulfating agents.



   The substances obtainable in this way have, among other things, the valuable property that they easily dissolve the poorly soluble components of natural tanning agents.



   Example 1.



   10 parts of naphthalene are heated to 130 to 1400 with 12 # 5 parts of 98% strength sulfuric acid until the sulfonation has ended. You then cool down to about 80 to 90, adds to that
Sulfuric acid-containing reaction mixture, with vigorous stirring, add 4 parts of 30 weight percent formaldehyde in portions at a temperature of 60 to 1000 and hold at this temperature. After a while the mass becomes thicker and thicker, so that towards the end of the reaction it is very difficult to stir. It is therefore advisable to add enough water towards the end of the operation that the reaction mixture still remains mobile, and stir until the folmaldehyde residue has disappeared.

   The product thus obtained is at
It cools down and then turns into a resinous, slightly colored, easily soluble in cold water
Mass. Instead of sulfuric acid, others can also condense during the condensation
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   A similar procedure is used for the condensation of pure naphthalene sulfonic acid with formaldehyde in the absence of condensation agents.



   Example 9.
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 dissolved and freed from excess sulfuric acid in the usual way with barite or lime. So you get a solution of the Su! phosic acid; the alkali salts, like the free sulfonic acid, are easily soluble in water. Example 3.



  Example 3.



   250 parts of methylnaphthalene are mixed with 250 parts of concentrated sulfuric acid at 130
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 Wise. The sulfonic acid obtainable in this way is amorphous or tough and syrupy; their alkali salts, like the free acid, are easily soluble in water.

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Claims (1)

PATENT. CLAIM : EMI1.5 Agents treated in the presence or absence of condensing agents under such conditions, in particular at such a temperature, for as long and in such a quantitative ratio that essentially only water-soluble compounds are obtained, or that they are obtained by condensation EMI1.6 ** WARNING ** End of CLMS field may overlap beginning of DESC **.