DE2117970A1 - Process for the preparation of substituted alkali amides - Google Patents

Description

P AT -Ξ N! TA NWALT

D 8 MUNICH 2, OTTOSTRASSEIa TELERAMME: MAYPATENT MUNICH TELEPHONE CO81O SQ3682

B.3592.3 AT Munich, April 14, 1971

- ~ Dr.M./Ma

CP 380/953

Commissariat ä! 'Energie Atomique in Paris, France Process for the preparation of substituted alkali amides

The invention relates to a method for producing substituted Alkali amides, d. H. of alkali derivatives of primary or secondary amides

The alkali derivatives of primary and secondary amines can be known as catalysts in isotope exchange reactions between the appropriate amines and hydrogen are used. So far, no process is known which can produce the alkali derivatives secondary amines with good yields »

The alkali solutions of primary or secondary amines of the RR ¹ KM type, in which R is in particular an aliphatic radical »R 'is an aliphatic radical or a hydrogen atom and M is an alkali metal, are difficult to obtain directly by the following reaction: RR ¹ NH + M- ^ KR'NM + 1/2 H ₃ .

Various indirect methods are known, but are general only for the primary amines or for the secondary amines only for the lithium and sodium derivatives, but not for the potassium and cesium derivatives are applicable.

109844/1965 bad original

To implement the indirect method »© in Arain with an unsubstituted alkali metal amide MHg according to the following equation: RR * NH 4 · MNH ₂ - ^ RR ¹ NM + NH ₃ (i)

is applicable in the pail of a primary amine, provided that the ammonia is removed after it has been formed, in order to shift the equilibrium to the right. Heretofore, however, it has been _believed that this method cannot be used in the case of a secondary amine.

In fact, the main difficulty in the reaction stems from the insolubility of the amides in the secondary amines. It is therefore a question of a reaction between the solid and liquid phase, which is always a slow reaction, and the amides are generally in the form of denser, more solid ones on the walls of the vessel adhesive deposits with a small surface vox ⁴ . However, it is known to manufacture by this method very vercölnnte solutions -of Kaliumdimethylamid (1O ~ ³ to 1O ~ ² Hole. / Liter).

By the invention, a method is provided werden- which an improvement dss Stoffaustauschte and Herstellimg considerable amounts of dialkylsubstituiertesa alkali amides (derivatives of secondary amines), and the production of mono- or stialkylsu bstituierten-alkali amides with higher yield and greater Geschwiadig ¹ = ness d <tr reaction enables <,

According to the invention, this object is achieved by a method Production of a ^ mono- or disubstituted Alkaliajiids dureia

of a primary or secondary AMiäs with "a @ ia Allsaliamid _e which dadurcl1. gakexmseicimet _s is ₈ that

Solution of the unsnutitiated Alkaliarßids iia liquid ammonia put this solution <a ± n primary © of the ³ sekmidtoss Assis

10S844 / 1SÜ

BATH ORIGINAL

and so the Amid in place and Stella like and then that The mixture is heated again with elimination of the gaseous ammonia formed and the solid products are permanently suspended being held.

The amine preferably corresponds to the formula R-NH-R *, in which R and R * alif ^ hatiscae radicals with 1 to 6 carbon atoms or aromatic radicals, in particular phenyl or benzyl, and R ^{f are} optionally also a simple hydrogen atom.

rar. ErClii-.lmigsgemäße method thus uses a precipitation "on site and stalls "(in situ) of the starting amide, to by a very fine distributed condition to improve the contact area with the .4min and the responsiveness of the products.

The reaction is continued until reaction (1) is completely displaced but the substituted amide is formed. The amine is advantageously used in excess, based on the stoechiometric amount.

During the entire duration of the reaction, this will happen at the same time Evaporation of the liquid ammonia of the starting solution and the reaction generated gaseous ammonia is discharged, and the solid Products, i.e. in particular the unsubstituted starting amide, are kept suspended in the amine-ammonia mixture until the substituted amide is obtained in suspension or solution in the excess amine. ■

The invention is illustrated by the following examples.

To 1.2 g Kaliianamid KNH ₂ , which in 100 cm ³ liquid ammonia

nd, be 100 ei 109844/1965

O "3

are dissolved at -50 C, 100 are given a diraethylaroin.

109844 /

BATH ORIGINAL

It is allowed to evaporate gradually under atmospheric pressure with constant stirring. Most of the ammonia is quickly evaporated. Then hall? the temperature is close to 6 ° C (boiling point des Dimethylamine), the distillate being collected in a receiver at 0 ° C if a slow distillation is carried out, which allows the ammonia generated in the exchange reaction to be gradually removed into the reaction vessel given fresh amine from time to time so that the precipitate does not occur gets dry. After slow distillation of 400 cm amine finds one that the reaction (1) with a yield of conversion of 90% has expired.

If this yield is considered sufficient, the unsubstituted amide which has reacted at night can be filtered off at this stage, while the dimethylamide is soluble in the dimethylamine. With the same amounts used, the same reaction time and the same consumption of Araia, the usual process, in which the amine is added to the dry amide at the beginning, only gives a yield of a few parts per thousand.

Example 2

If the conditions are the same as in Example 1, the reaction is complete after 700 cm ** of dimethylamine has been distilled off. Since the Ealiumdiisetfeylaiiiiä is soluble in the dimethylamine, the end of the leaktioa ctecla complete disappearance of the precipitate is indicated. This requires a few days, while such a result according to the above-mentioned usual procedure pst & ktiseh at all; not even na.eh m @ hw <BTen weeks, can be obtained «

BATH ORIGINAL

. - - 5 - Example 3

In this example, instead of the simple evaporation, as in Examples 1 and 2, its mixture of ammonia and amine and the replacement of the sympathetic amine by periodic additions, the ammonia is separated off by fractional distillation, which offers the advantage that nxw. low Arainmengen be coevaporated and therefore is required cain Aminsusata. For 30 g of cesium cccaid, which is dissolved in 100 cm of liquid ammonia at -50 ° C

are dissolved, 700 ml of liquid dimethyl arain are added, and the ammonia is distilled off by fractional distillation over a packed column at atmospheric pressure. The distillate is analyzed by gas chromatography. When ammonia no longer escapes at the top of the column * the reaction is over and you have a clear solution of cesiumdimethylamide in dimethylamine in your hand. Analysis of the solute shows that it does not contain cesium asnide flour ¹ .

Example 4

imiii "ι 'nil him ■ ■■ ii» ^ i

7m 100 g of potassium amide dissolved in 500 cm ^{3 of} liquid ammonia at -40 ° C., 600 cm of dimethylamine are added, and the ammonia is separated off as in Example 3. In this case the final concentration of the dimethyl amide is above the saturation value, and the potassium dimethyl amide is obtained in suspension in the dimethyl amine.

600 cm of diethylamine are added to 13 g of sodium amide dissolved in 500 cm of ammonia at -40 ° C. The ammonia is distilled off under atmospheric pressure as in Example 3, and after the ammonia has been completely separated off, a clear solution of sodium diethylamide in diethy 2 amine is obtained.

1098U / 1965

BATH ORIGINAL

Example 6

In order to show that the inventive method itself brings about a considerable improvement in the case of the primary amines, in the following an example of its application in the production of Kaliumaionomethylamid is added to 14 g · potassium ,, the dissolved in 200 aar ammonia at -40 C 500 cm of monomethylamine are given. The method described in aen _: above examples provides

by slow distillation at -6 ° C in 8 to 10 hours pure solution of potassium methylamide in methylamine, while according to the known method the same result even with a higher one Temperature was only reached after more than 100 hours. Also will there is a risk of decomposition when working at low temperatures of the alkylamide. «r avoided ·

0 98 ^44/1 9 6-5 ßAD original

! .5-ί, ΐί

Claims (1)

Claims 1. λ process for the preparation of a mono- or disubstituted alkali ids by reacting a primary or secondary amine with an unsubstituted alkali amide, characterized in that a solution of the unsubstituted alkali amide is prepared in liquid ammonia, a primary or secondary amine is added to this solution and so one Precipitation of the amide on the spot is effected and the mixture is heated again with separation of the gaseous ammonia produced and the solid products are kept permanently suspended 2.) Process according to claim 1, characterized in that the amine used corresponds to the formula R-JiR-R *, in which R and R ^{1 are} aliphatic radicals with 1 to 6 carbon atoms or aromatic radicals, in particular phenyl or 6enzyl _/ and R * can also be a hydrogen atom 100844 / 196S BATH ORIGINAL