DE386930C - Process for the preparation of tanning agents - Google Patents

Description

Process for the representation of tanning agents. In the literature are so far only esters and ethers of glycolic acid have been described, while condensation products nothing is known. The important observation has now been made that with very good yields. the glycolic acid in the presence of sulfuric acid with aromatic Hydrocarbons or similar compounds' condense. The .received Products show excellent tannery properties. Everyone known so far Artificial tanning agents lacked one of the most important properties of the natural ones Tannins: »The filling effect«. Surprisingly, one now achieves with tanning with the tanning agents produced according to the present process, this filling too Effect.

Example r.

26 parts by weight in a closed apparatus, naphthalene warmed to r0o ° - leaves inan a warm mixture of 40 parts by weight of concentrated sulfuric acid and 8 parts by weight of glycolic acid drip and hold this temperature for about ao minutes. Immediately begins Reaction. If there is a clear SO, smell, it is over. The cooled reaction product is easily soluble in water, it is neutralized and has a very strong leaning effect excellent, tanning. In contrast to leather, the leathers obtained with it have were tanned with the previously known synthetic tanning agents, pronounced lohgar, -ii character. The tanning process can be carried out in a surprisingly short time. It should also be noted that: in the procedure just mentioned of: the glycolic acid, Sulfuric acid, naphthalene mixture, the sulfuric acid and. replace the naphthalene can by naphthalenesulfonic acid while carrying out the condensation in vacuo.

Of course, the naphthalene can also be replaced by - similarly constituted hydrocarbons, such as deer, carbazole, etc.

The product of naphthalene and glycolic acid, when dissolved in water, shows the following precipitation and color reactions: Lead nitrate. . . . . . . brown precipitate, Ferric chloride (III-valued). . . . olive-yellow precipitation, Ferroammon sulfate (IIwertig). . . . no precipitation, Calcium formate. . . orange-brown precipitate, Aluminite formate. . brown-black rubber like precipitation, Bromine water. . . . . brown-black coloring, Aniline sulfate. . . . . orange-yellow precipitate, Chromium sulfate. . . . olive coloring. Salting out: Sodium sulfate. . . . brown precipitate, Table salt. . . . . . . light brown precipitate, Potassium sulfate. . . . . brown precipitate, : @inmonsulfat. . . . yellow precipitation, IS 3n7 cleared Sulfuric acid. _ black resinous low blow, Hydrochloric acid gas. . . . . black flaky low blow. Garancine stripe coloring: Zircon. . . . . . . . weak brown, Gadolinum. . . . . . very pale brown. Aluminum. . . . . . very pale brown. Chrome. . . . . . . . very strong brown. Cadmium. . . . . . very strong olive, Antimony. . . . . . . weak brown, Bismuth. . . . . . . . - strong olive roast, Lead . . . . . . . . . . quite strong olive, Tin. . . . . . . . . weak brown, Thorium. . . . . . . pale brown. Iron. . . . . . . . . strong brown. The product can be used not only as a tanning agent, but also as a stain for textile fibers. The hides and skins tanned with the product have great lightfastness of the color.

The condensation product is a black-violet mass. It is in Water soluble. It dissolves in alcohol with a brown color. It is partly soluble in ant ester (violet color), chloroform, it is insoluble in Ben-7_o1, toluene, Yylene, ether, etc.

To achieve a product in the specified color, tannability, For filling, etc. it is important to keep the temperature at around 160 ° C. If, on the other hand, the reaction temperature is kept below 160 ° C., the result is blue-green Reaction products that are glue-precipitating, but not the cheap Berber Have properties of the product obtained at a higher temperature.

The naphthalene can be aromatic, but not aliphatic Hydrocarbons are replaced.

Example e.

4.o parts by weight of xylene are heated to 130 ° and, while stirring, a mixture of 20 parts by weight of oleuil, 25 percent, and 16 parts by weight of glycolic acid are added over the course of one hour. It turns red with elimination of water and gradual unification of the two layers. The product is easily soluble in water and can be used for tanning after the acid has dulled. Example 3.

2o parts by weight of toluene are, as described under Example: 2, at 130 ° with a mixture of 8 parts by weight of glycolic acid and 2o parts by weight Oleum also displaced within a mouth. The reaction is similar to that below Example e. Described. This reaction product, too, dissolved in water. let yourself use for tanning.

Example d ..

16 parts by weight of benzene heated to boiling temperature are added with a mixture of 20 parts by weight of oleum, 25 percent by weight of 8 parts by weight Glycolic acid within an hour and increases the temperature up to 100 ° C. It brown color occurs with elimination of water and formation of a brown homogeneous Liquid. the, in water rrel @@ a. for tanning (after dulling the acid) suitable.

. It should also be noted that in the above examples, glycolic acid can be successfully replaced by the appropriate amount of glycolide.

Example. 1; Parts by weight of carbazole are mixed with 8 parts by weight of glycolic acid or 6 parts by weight of glycolide mixed, slowly with 35 parts by weight more concentrated Sulfuric acid is added and the mixture is stirred on the water bath for 10 to 12 hours heated in vacuum. First there is a purple color, then a green color and to the Finally brown color and intense blistering. Once a sample water solubility shows, the reaction has ended. The reaction product is taken up in water and reset the excess acid to the bare minimum, and can this solution applied directly to the tanning of hides and skins in a known manner will.

Claims (1)

Claim: Process for the preparation of tannins, characterized in that glycolic acid is allowed to act in the presence of sulfuric acid on aromatic hydrocarbons in the heat with or without application of the vacuum.