DE305347C

DE305347C -

Info

Publication number: DE305347C
Application number: DENDAT305347D
Authority: DE

Description

KAISERLICHESIMPERIAL

PATENTAMT.PATENT OFFICE.

Die Hydrierung von aromatischen Aminen mittels Alkalimetalle konnte bisher mit befriedigender Ausbeute nur unter Anwendung von höher siedenden Alkoholen ausgeführt werden. Erforderlich war dafür aber auchThe hydrogenation of aromatic amines by means of alkali metals has so far been more satisfactory Yield can only be carried out using higher boiling alcohols. But that was also necessary

- noch ein möglichst stürmischer Verlauf der Reaktion, eine Bedingung, die für die fabrikatorische Anwendung dieses Verfahrens nicht ohne Bedenken ist.- the reaction should proceed as stormily as possible, a condition that applies to the manufacturing process Applying this procedure is not without concern.

ίο So z.B.schreibt Bamberger, Ber.2i(i888), Seite 852, über die Hydrierung von a- und β - Naphtylamin zu Tetrahydronaphtylamin: »Ändert man die Methode der Darstellung wesentlich ab, indem man z. B. den Amylalkohol durch Äthylalkohol ersetzt, oder indem man das Natrium allmählich zur Wirkung bringt, so verringert sich die Ausbaute in ersterem Falle sogar erheblich.« Ferner Ber. 21 (1888), Seite 1124 gi^{Dt er an}, »daß der Amyl-ίο For example, writes Bamberger, Ber.2i (i888), page 852, about the hydrogenation of a- and β-naphthylamine to tetrahydronaphthylamine: »If the method of representation is changed significantly by e.g. If, for example, the amyl alcohol is replaced by ethyl alcohol, or if the sodium is gradually brought into effect, the expansion in the first case is even considerably reduced. ”Further Ber. 21 (1888), page 1124 ^{, does he state} that “the amyl

alkohol dem Äthylalkohol, wenn es sich um den Zweck einer guten Ausbeute handelt, infolge der . höheren Reaktionstemperätur weit überlegen ist«; ferner »daß auch die Methode des raschen Hinzugebens der Flüssigkeit (kochende alkoholische Basenlösung) zum Natrium der anderen vorzuziehen ist«. Noch bestimmter urteilt Bamberger in Ber. 20, Seite 2916, Fußnote: »Wendet man dabei Äthylalkohol (an Stelle von Amylalkohol) an, so sinkt die Ausbeute auf ein Minimum herab, und der weitaus größte Teil des angewandten Naphtylamins geht unverändert aus dem Reaktionsprozeß hervor.«alcohol to ethyl alcohol, if it is a question of a good yield, as a result the . is far superior to higher reaction temperatures «; furthermore »that also the method the rapid addition of the liquid (boiling alcoholic base solution) to the sodium is preferable to the other «. Yet Bamberger judges more precisely in Ber. 20, page 2916, footnote: »If you use ethyl alcohol (instead of amyl alcohol), the yield drops to a minimum, and the vast majority of that used Naphthylamine leaves the reaction process unchanged emerge. "

Es wurde nun gefunden, daß man bei sehr ruhigem Verlauf der Reaktion eine gute Hydrierung von aromatischen Basen erzielen kann, wenn'man zu einem Gemisch von Alkali- oder Erdalkalimetall, einem passend gewählten indifferenten Lösungsmittel und der Base' Alkohol oder , eine alkoholische Lösung der Base bei einer für die gewünschte Hydrierungsstufe erforderlichen Temperatur allmählich zufließen läßt. Dieses läßt sich bei Anwendung von Alkoholen der verschiedensten Siedepunkte leicht erreichen, wenn man den Alkohol ungefähr in dem Tempo zufließen läßt, wie er durch die Reaktion als Alkoholat gebunden wird, oder wenn man bei schnellerer Zugabe von Alkohol den Überschuß, nötigenfalls unter Einhaltung von 5<> Überdruck, während der Reaktion abdestillieren läßt.It has now been found that if the reaction proceeds very smoothly, a good one can be obtained Hydrogenation of aromatic bases can be achieved if a mixture of alkali or alkaline earth metal, an appropriately selected inert solvent and the Base 'alcohol or, an alcoholic solution of the base at one for the desired Hydrogenation stage required temperature can gradually flow. This can easily reach when using alcohols of various boiling points, if the alcohol is allowed to flow in at approximately the same rate as it is due to the reaction Alcoholate is bound, or if, with faster addition of alcohol, the excess, If necessary, distill off during the reaction while maintaining 5 <> excess pressure leaves.

Dieses Verfahren hat gegenüber den von Bamberger und anderen Autoren beschriebenen Verfahren noch den großen Vorzug, daß bei der Fabrikation der teure und gesundheitsschädliche Amylalkohol z. B. durch den harmlosen und billigen Äthylalkohol vollkommen ersetzt werden kann. Außerdem zeichnet sich das Verfahren durch eine große Betriebssicherheit und Regulierbarkeit aus, weil z. B. einerseits die leicht entzündbaren AlkalimetalleThis procedure has opposite to that described by Bamberger and other authors Process still has the great advantage that in the manufacture of the expensive and harmful to health Amyl alcohol e.g. B. can be completely replaced by the harmless and cheap ethyl alcohol. Also draws the process is characterized by a high level of operational reliability and controllability, because z. B. on the one hand the highly flammable alkali metals

Claims

permanently here of an inert ^solvent: the response may remain b'edeckt medium, and on the other hand, by interrupting the inflow of alcohol at any time can be brought to a standstill.

; ^; / Example i.

; To a mixture of 175 parts by weight metallic sodium and 800 parts by weight of solvent naphtha are gradually left one ; ■ ·, solution of 200 parts by weight of a-naphthylamine / -: in 200 parts by weight of absolute fuel

'/ run by making sure that the Temperature does not drop below 130 °. The alcoholic solution is allowed to flow in ideally through the filler tube that extends below the surface of the solvent naphtha. On that 150 to 170 parts by weight of fuel are still needed slowly added at a reaction temperature of 130 °, whereby the hydrogenation to End is performed. To dilute the reaction mass, another 400 bis are then added Add 500 parts of alcohol in a thin stream, in such a way that the temperature is within ι slowly drops from 130 ° to 108 to 107 ° for up to 2 hours. To work up adds if water is added to the reaction mass, the sodium hydroxide solution is separated from that dissolved in the solvent naphtha Hydrobase and separates the latter by fractional distillation. Yield 90 percent the theory.

The tetrahydro- a- naphthylamine obtained shows the properties described by Bamberger. You can also start from other bases, such as ethyl-a-naphthylamine, aminocarbazole, etc.

When using a lower boiling solvent, e.g. B. toluene is obtained from α-naphthylamine dihydro-α-naphthylamine. Is used in the hydrogenation instead of ethyl alcohol Methyl alcohol or other alcohols also give a smooth hydrogenation.

Example 2.

In a mixture of 88 parts by weight of metallic sodium, 400 parts by weight of solvent naphtha and 100 parts by weight of a-naphthylamine, which is heated to the boil, is left Add 140 parts by weight of methyl alcohol (anhydrous) slowly by taking care of it contributes to the fact that the temperature does not drop significantly below 130 to 140 °. One then sets . for the purpose of diluting the reaction mass, still.

Add 200 parts by weight of methyl alcohol slowly with constant boiling. Then the Mass mixed with water and worked up as indicated in Example ι. The yield in tetrahydro-a-naphthylamine is go Pro ^ cent of the theory.

60 Example 3.

To a mixture of 88 parts by weight of sodium, 400 parts by weight of solvent naphtha and 100 parts by weight of quinaldine which is heated to the boil, 180 parts by weight are left Run in ethyl alcohol slowly so that the temperature is maintained at 130 ° during the reduction. . ,

Finally, about 250 parts by weight of ethyl alcohol are added for dilution gradually added with brisk boiling. The reaction mass is when the reduction is complete decomposed with water, the sodium hydroxide solution from the tetrahydroquinaldine dissolved in the solvent naphtha separated and the latter isolated by fractional distillation. There are those with ferric chloride and with potassium ferricyanide characteristic blood-red color; the picrate melts at 153 to 154 °. The yield is 85 to 90 percent of theory.

The same product is also obtained when replacing solvent naphtha according to the example above Toluene obtained at a correspondingly lower temperature.

The hydrogenation can also be carried out at temperatures which are below the melting point of the alkali or alkaline earth metals, if one takes care that the metals in question are in well-crushed stand to apply. So z. B. the a-naphthylamine can be dissolved in toluene with sodium and ethyl or methyl alcohol at temperatures of up to 95 ° (melting point of metallic sodium 96 °) can be easily converted into dihydro-a-naphthylamine. Other alkali or alkaline earth metals can also be used.

Godfather τ-An saying :.

Process for the preparation of hydrogenated compounds, characterized in that ■ one in the presence of inert solvents alkali metals or alkaline earth metals and allows alcohols to act on aromatic isocyclic or heterocyclic bases.