DE264927C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

■ - ■ j

In the patent specification 65236, cl. 22, it has been shown that the action product from bisulfites to hydrochloric acid p-nitrosodimethylaniline when heated to a higher temperature 5 or with concentrated hydrochloric acid with cleavage of the alkylamino group into two isomers p-Aminophenoldisulfonicäuren passes over. Furthermore, in the patent specification 14014, class 22, stated that when boiling an alcoholic solution of free p-nitrosodimethylaniline with neutral sulphurous ammonium with neutralization with carbonate of ammonium in addition to a lot of neutral Ammonium sulphate the ammonium salt of a sulphonic acid, which is produced when heated with Mineral acids split in aqueous solution into sulfuric acid and p-aminodimethylaniline will. It has now been found that the elimination of the alkylamino group can be avoided and arrive at previously unknown sulfonic acids of the p-aminomono- or dialkylanilines can, if one uses the free nitroso bases of the general formula:

(R = phenyl radical or homologues, R ₁ = hydrogen or alkyl or aralkyl, R ₂ - alkyl or aralkyl) brings neutral alkali sulfites to action at normal or elevated temperatures and heats the resulting solutions with mineral acid. If you wear z. B. p-nitrosodimethylaniline in a solution of neutral sodium sulfite, the base gradually goes into solution. In contrast to the solution of p-nitrosodimethylaniline in bisulphite, no unchanged nitroso base can be precipitated from this solution by alkalis, although apparently no reduction has taken place; for in the solution, by means of hydrochloric acid and chlorobarium, not significantly more sulfuric acid can be detected in the cold than was already contained in the sulfite used. Only when boiling does the splitting off of a large amount of sulfuric acid become noticeable through the separation of a strong barium sulphate precipitate. Quantitative determinations have shown that the amount of sulfuric acid split off is almost 1 mole per mole of the nitroso base used.

The solution heated with acids contains only traces of ρ aminodimethylaniline salt, on the other hand a new sulfonic acid of p-aminodimethylaniline. The process therefore probably proceeds in such a way that from the nitroso base and sulfite first a sulfamine sulfonic acid:

/ * (CH ₃ J ₂

Q H ₃ SS O ₃ H

WH-SO ₃ H

arises, which when heated with acids loses the sulfo group in the N H residue.

In the patent specification 77536, class 22, is the representation of a p-aminodiphenylamine sulfonic acid by the action of neutral sulfite on p-nitrosodiphenylamine- described. But it was not to be foreseen that either

one from iV-alkyl derivatives of p-nitrosoaniline alkylated p-phenylenediaminesulfonic acid is obtained because the alkylamine radicals are much more labile are bound as the arylamine residues.

Example i.

10 parts of hydrochloric acid p-nitrosodimethylaniline are dissolved in 100 parts of water and, with vigorous stirring, by adding a solution converted from 28 parts of sodium carbonate into the base. For this one gives with ordinary Temperature with continued stirring a concentrated solution of 30 parts of neutral Sodium sulfate, the nitroso compound

ig gradually goes into solution. When complete solution has occurred, one gives about Add 90 parts of concentrated hydrochloric acid and boil. The resulting new acid is so light soluble that they cannot be obtained in a pure state by evaporation of the reaction liquid can be. For separation, but for further processing (e.g. for azo dyes) is not absolutely necessary, you can treat it with aromatic aldehydes, z. B. salicylaldehyde, converted into the benzylidene compound by adding the solution neutralizes or makes weakly alkaline and the aldehyde, z. B. 6 parts of salicylaldehyde added. The benzylidene compound separates out in crystalline form and can easily be separated from the lye. The benzylidene compound can be cleaved and the Exaggerate the aldehyde with steam. When the residual solution is evaporated one then a mixture of the new acid with some common salt, from which the sulfonic acid with Alcohol can be extracted. In a pure state it is thoroughly constant and not hygroscopic. The analysis resulted in the following figures:

0.1563 g of substance gave 0.2531 g of CO ₂ , 0.0777 g of ^H 2 O.

Calculated for ^ r ₁

CHNSO- Found:

C = 44.44 percent, C = 44.16 percent,
H = 5.55 - H = 5.55 -.

The aminodimethylaniline sulfonic acid thus obtained is of that in the above-mentioned patent 14014, cl. 22, described differently in that they lead to the formation of methylene blue is poorly qualified. It probably contains the sulfo group in the o-position to Amino group.

In a similar way, an aminodiethylaniline sulfonic acid is obtained from nitrosodiethylaniline, which is easily obtained in a nicely crystallized form from the solutions by evaporation can be.

The aminoethylbenzylanilinesulfonic acid obtained in an analogous manner is characterized by the poor solubility of its sodium salt. To represent them, it is useful for a slightly elevated temperature to work.

Example 2.

135 parts of monoethyl-o-toluidine are dissolved in 400 parts of hydrochloric acid of 20 ° Be \, and a concentrated aqueous solution of 73 parts of sodium nitrite is added at ^{0 ° with thorough stirring.} The nitrosamine formed is extracted with ether or benzene. For rearrangement into the p-nitroso compound, the nitrosamine is mixed with about 500 parts of absolute alcohol, according to the information provided by O. Fischer and Hepp (cf. reports of the German Chemical Society 19 [1886], p. 2994) Hydrochloric acid had become saturated. The hydrochloric acid p-nitrosoethyl-o-toluidine separates out in yellow crystals. For the reduction, the hydrochloric acid salt is converted into the free base with sodium carbonate and this is boiled for several hours with an aqueous solution of 504 parts of neutral sodium sulfite. After the solution has cooled, the residue is filtered off, hydrochloric acid is added to the filtrate until it reacts in the Congo acid and the mixture is boiled. Because of its high solubility, the aminosulfonic acid can only be isolated from this solution via the benzylidene compound (with salicylaldehyde).

The products are intended to be used in the manufacture of dyes.

Claims (1)

Patent claim: Process for the preparation of N- alkyl-p-phenylenediamine sulfonic acids, consisting in that neutral alkali metal sulfites are added to the free p-nitroso compounds of tertiary or secondary aromatic amines of the benzene series of the general formula: / NO ^R \ / ^R i \ / fi. (R = phenyl radical or homologues, A ₁ = hydrogen or alkyl or aralkyl, R ₂ = alkyl or aralkyl) can act., And., The solutions thus obtained are heated with mineral acids.