DE886743C - Process for the production of aminomercaptals - Google Patents

Description

Process for the production of aminomercaptals It is known that by the action of methylene chloride or acetone on phthalimidoethyl mercaptan receives the corresponding mercaptal. This can then to methylene or isopropylidene-ß, ß'-aminoethyl sulfide are split. A direct manufacture of the mercaptal with formaldehyde, however, did not succeed. For the practical production of such mercaptals this method is not suitable.

It has now been found that the mercaptals can be obtained from aminomercaptans obtained in a simple manner and in good yield if the salts thereof in acidic medium with carbonyl compounds, e.g. B. formaldehyde, acetone, cyclohexanone reacts at normal or elevated temperature. The proceedings counter this the expectation to the goal even if the basic nitrogen is secondary or is primary in nature. There are no complications from side reactions, even if as the acetalization component that reacts particularly easily with amino groups Formaldehyde or a formaldehyde-supplying substance, e.g. B. paraformaldehyde or a Is used formally.

The procedure is generally applicable. For example, are named as starting materials: the aminoalkyl mercaptans of the aliphatic series, such as f-aminoethyl mercaptan and its homologues, e.g. B. y-aminobutyl mercaptan (from y-benzoylaminobutyl chloride and potassium hydrosulfide with subsequent hydrolysis), b-aminopenthyl mercaptan, α-Aminohexyl mercaptan, γ-N-methylaminopropanethiol (from the amino alcohol via the Halogen-alkyl compound with potassium hydrosulfide), pyrrolidinoethane thiol, piperidinoethane thiol, mercaptoalkyl-substituted secondary ring bases (morpholinoethane thiol). Also aminomercaptans with two or more Mercaptoalkyl groups are suitable, e.g. B. N = cyclohexyl-bis- [ß-mercapto-isopropyl] -amine.

The diamines that can be produced by this process are particularly valuable with two hydrogen-bearing, preferably primary amino groups. Such connections are new starting materials for the production of polyamides by polycondensation. Most suitable for this purpose are those easily accessible after the procedure Mercaptals which, between nitrogen and sulfur, form a chain of q. Carbon atoms or have more. But they are also products with only 2 carbon atoms good usable. The mercaptals have the advantage over the known disulfides the much higher chemical resistance. They are also more thermally stable than the simple diaminodialkyl sulfides, e.g. B. Diaminodiethylsulfid, and give condensation products usually with a higher melting point.

With polyvalent aminomercaptans, resin-like polymercaptals are formed, the predominantly linear, partly also cyclic structure with two mercapto groups and are usually still soluble as salts in much water while trivalent or polyvalent aminomercaptans crosslinked, usually insoluble reaction products deliver. The latter is e.g. B. the case, if the addition product of q. Mole Propylene sulfide on 1 mole of triethylenetetramine with formaldehyde in hydrochloric acid solution condensed. Such insoluble condensation products are e.g. B. as an animalizing agent useful for cellulose fibers; you can also use them on fibers or other porous ones Generate substrates.

For the production of the mercaptals it is usually sufficient to add the components expediently in the presence of mineral acid, especially hydrochloric acid, in aqueous, am It is best to leave the concentrated solution at room temperature or, if necessary, to leave it to stand to warm to boiling.

Of course, not only water is used as the solvent for the reaction alone in question. - Very suitable is e.g. B. also glacial acetic acid, optionally without addition another acidic catalyst.

Calcium chloride, Add zinc chloride or similar substances, if necessary also in larger quantities.

Instead of the aldehydes and ketones, their reactive Derivatives are used, e.g. B. acetals, such as. according to the Voss procedure are readily available from carbonyl compounds and sulfuric acid esters.

The aminomercaptans can also be used in the form of their primary acyl compounds, z. B. Acetylaminomercaptans or Carbäthoxyaminomercaptans find use.

Those primary and secondary aminomercaptans are particularly suitable, in which the nitrogen and sulfur atoms are linked by a chain of at least 4. Carbon atoms are separated, as in this case as a result of the low tendency the reaction proceeds particularly smoothly for the formation of ring-shaped reaction products.

You can also optionally with water or an alcohol, for. B. ethylene glycol, moistened salts of aminomercaptans in the presence of a catalyst, such as toluenesulfonic acid or camphorsulfonic acid, react with the carbonyl compound, for which you can use a ball mill, for example. The carbonyl compounds can also come into effect in vapor form. So you can get the fumes over that with slightly acidified calcium chloride or magnesium sulfate solution, moistened salt pass away in a rotatable reaction tube filled with balls or aldehyde vapors pass through a melt of the salts. Finally, you can also use the salts in Presence of a non-dissolving inert diluent with the carbonyl compound convert, keeping the mass in motion by simmering or stirring.

The not further condensed Aminomercaptals according to the invention can be used as Avischen products z. B. used in the production of linear polycondensation products. Example i Dissolve i-aminoethane thiol- (2) -hydrochloride (iMol) in 3 parts of water and treated with 1 / so mol hydrochloric acid in excess. After adding the calculated amount concentrated formaldehyde solution (1 / z mol + 5 ° (o) if you leave the liquid for so long at normal Temperature until the mercaptan reaction stops has faded. When evaporating the solution in The hydrochloric acid salt of methylene bis- [ß-aminoethyl sulfide] in good yield in color loose crystals (melting point 180 °). Example 2 One mole of i-piperidinoethanethiol- (2) (boiling point 1.5 50 up to 51 °) in the form of its hydrochloride in a little water, added the calculated amount of formaldehyde and about 1 / 5o mole of hydrochloric acid and leave to stand overnight. Then another 1 / z hour on the water bath warms and evaporates in a vacuum. It remains the methylene bis [ß-piperidino-ethyl sulfide]. Example 3 The hydrochloric acid salt of the cyclohexyl bis- [ß-mercaptoisopropyl] amine (Kpl 127 °) of the formula (Obtained from 1 mole of cyclohexylamine and 2 moles of i, 2-propylene sulfide in water), treated with formaldehyde and proceeding as in Examples i and 2. The reaction product separates out in the form of a viscous oil which is soluble in plenty of water. By further heating to 100 °, the product changes to a higher molecular weight through post-condensation. Both the relatively low molecular weight oily product formed in the cold and the resin obtained by post-condensation show an intensive binding or precipitating capacity for higher molecular weight substances with acidic groups, e.g. B. acidic dyes, substantive dyes, tannins.

Claims (1)

PATENT CLAIMS: i. Process for the production of aminomercaptals with amino or primary acylamino and mercapto groups bonded to valence-chemically saturated carbon atoms, characterized in that salts of aminomercaptans are condensed with carbonyl compounds or substances which split off. 2. The method according to claim i, characterized draws that the condensation in acidic medium is carried out. 3. The method according to claim i and 2, characterized characterized in that the starting materials are amino mercaptane with primary or secondary amino nitrogen used. q .. The method according to claim i to 3, characterized in that indicates that the starting materials are amino mercaptans with two or more mercapto groups. used. G. Method according to claim i to q, characterized in that indicates that the starting materials are bifunctional tional aminomercaptans with primary or secondary amino nitrogen used in which Nitrogen and sulfur atoms by at least 4 carbon atoms are separated.