DE948056C - Process for the preparation of carbonic acid amides - Google Patents

Description

Process for the preparation of carboxamides It is from the patent 863 8oo known to amines at elevated temperature and under elevated pressure in the presence of carbonyl-forming metals or their compounds in the liquid phase carbon oxide let it take effect. The reaction products are mostly the formyl compounds or Urea of the starting amine. Even if one starts out from tertiary amines, they are N-formylamines the main product. Connections are only found in subordinate quantities have been, in their formation evidently carbon oxide between the nitrogen atom and the alkyl group of the tertiary amine had entered. So you have with carbonylation of tributylamine in addition to N-formyldibutylamine also valeric acid dibutylamide and at that of the Dimethylpalmkernfetta.mins get a product that is in the pressure saponification Acetic acid supplies.

It has now been found that the Carbonyherung tertiary amines in completely uniform reaction leads to substituted carboxamides when used as catalysts Halides of carbonyl-forming metals or the complex organic compounds derived from them Onium compounds used.

In this case, the reaction, shown using the example of trimethylamine, proceeds practically completely in accordance with the equation with formation of acetic acid dimethylamide. In addition, the corresponding imide, e.g. B.

N-methyldiacetimide.

Other tertiary materials are also suitable as starting materials for the implementation aliphatic amines, such as triethyloder tributylamine, and cycloaliphatic, araliphatic or aromatic tertiary amines, e.g. B. dimethylaniline and diethylaniline. Also tertiary Amines with heterocyclic radicals are accessible to the implementation, insofar as they are in them the nitrogen atom is not aromatically bound, as in pyridine. Suitable are for example N-alkylpyrrolidines, -piperidines, -hexamethyleneimines or -morpholines.

Among the halides used as catalysts, the cobalt or nickel halides, in particular the bromides and iodides, are particularly effective. They can also be used in the form of complex compounds with onium salts, as can be obtained by reacting the metal halides with organic ammonium, phosphonium, arsonium or stibonium salts: Suitable complex salts of this type are, for example, the di- [butylpyridinium] cobalt tetrabromide [( C, H6N) (C4H9)] 2 CoBr4, the di- [tetraethylammonium] nickel tetraiodide [(C2H5) 4N] 2 NiJ4, the di [triethylbutylphosphonium] cobalt dibromide iodide [(C, HJ3 (C4H9) P] 2 CoBdi- [Teiramethylammonium] cobalt iodide diacetate [(CH3) 4 N12 COJ2 (O CO C H3) 2.

Mixtures of such complexes can also be used. It is not necessary, to apply the complex salts prepared for themselves, but you can use the for the Add the necessary individual components to form the complexes. Because tertiary amines serve as starting materials, it is sufficient z. B., cobalt halide and alkyl halide im Molar ratio r: 2 to be added, which converts to the quaternary with the tertiary amine Combine ammonium cobalt halide, which then acts as a catalyst. The catalyst concentration is expediently between 0.2 and 2 ° / ° of the metal contained in the catalyst, «Based on the tertiary amine.

The reaction is expediently carried out at temperatures between roo and 250 ° and pressures of at least 50 atmospheres, expediently between roo and 7000 atmospheres, or above. If complex salts are used as the catalyst, the same result is usually achieved at low pressures under otherwise comparable conditions as when using the simple halides.

The carbon dioxide used can contain hydrogen; something special is sometimes advantageous when using ifobalt catalysts; but is a such addition is not absolutely necessary. . The hydrogen content should be 8o0 / 0, expediently do not exceed 50 ° / 9 '. The carbon monoxide can also contain inert gases contained, but it should be free of hydrogen sulfide if possible, and the partial pressure of the carbon monoxide will expediently be kept at least 50 atmospheres.

The reaction can be carried out continuously or batchwise will. The reaction product is expediently worked up by distillation, if necessary under increased or reduced pressure using auxiliary liquids or with the addition of steam. The catalyst used is unchanged The largest part of the shape is in the still residue; he can without further purification can be used again.

You can also work in the presence of inert solvents, in particular if you want to improve the solubility of the catalyst in the reaction mixture. as Solvents can be, for. B. hydrocarbons, carboxamides, N-alkyl lactams use.

The parts mentioned in the examples below are parts by weight. Example x A mixture of 25o parts of dimethylaniline and 2o parts of di- [triphenylmethylphosphonium] cobalt dibromide iodide is allowed to act in a high-pressure autoclave at rgo ° a mixture of 95 percent by volume of carbon oxide and 5 percent by volume of hydrogen under a pressure of 700 at for 4 hours. When the completely crystalline reaction product is distilled, in addition to traces of diacetanilide, 295 parts of N-methylacetanilide (F: - roo °) are obtained in practically quantitative yield and roo% conversion. The catalyst used is found unchanged as a distillation residue; it can be used again without further treatment. EXAMPLE 2 A mixture of 250 parts of dimethylaniline, 8 parts of cobalt iodide and 8 parts of ethyl iodide is allowed to act in a high pressure autoclave at 2oo °, a mixture of 95 percent by volume of carbon oxide and 5 percent by volume of hydrogen under a pressure of 700 at for 6 hours. The distillation gives 285 parts of N-methylacetanide in a practically quantitative yield. The distillation residue remains di- [dimethylethylanulinium cobalt tetraiodide, which can be used again as a catalyst. EXAMPLE 3 A mixture of 250 parts of dimethylaniline and 20 parts of nickel iodide is allowed to act in a high-pressure autoclave at 200 ° carbon oxide under a pressure of 700 at ro hours. In addition to some unreacted dimethylaniline, 240 parts are obtained in the distillation. - N-Methylacetanüid, corresponding to a conversion of 790/0 with a practically quantitative yield. EXAMPLE 4 In a high pressure autoclave, a mixture of 25o parts diethylaniline and 20 parts di- [triphenylnethylphosphonium] cobalt dibromide iodide is allowed to act for 3 hours at a pressure of 70o at 95 % by volume carbon oxide and 5% by volume hydrogen. The distillation gives 245 parts of N-ethylpropionanilide (boiling point 14 = 146 to i48 °), corresponding to a 83% yield.

EXAMPLE 5 In a high pressure autoclave, a mixture of 15 volume percent hydrogen and 85 volume percent carbon oxide is allowed to act on a mixture of 100 parts of dimethylaniline and 6 parts of di- [triphenylmethylphosphonium] cobalt dibromide iodide under a pressure of zoo at 1g0 ° for 30 hours. When the liquid reaction product is worked up by vacuum distillation, 72 parts of N-methylacetanilide are obtained in addition to unchanged dimethylaniline, corresponding to a conversion of 58%. The yield is almost quantitative. The catalyst used remains as the distillation residue. EXAMPLE 6 In a high pressure autoclave, a mixture of zoo parts of trimethylamine, zoo parts of N-methylpyrrolidone as solvent, 25 parts of di- [tetramethylammonium] cobalt dibromide and 7 parts of cobalt bromide at 70o at and 20o ° is allowed to give a mixture of 95 percent by volume of carbon monoxide and Soak in 5 percent by volume hydrogen for 7 hours. The distillation gives, in addition to unchanged N-methylpyrrolidone and some N-methyldiacetimide, 265 parts of N-dimethylacetamide (bp 1 $ = 64 to 66 °), corresponding to a good yield with quantitative conversion of the trimethylamine. The distillation residue consists of the unchanged catalyst mixture.

Claims (2)

PATENT CLAIMS: i. Process for the preparation of carboxamides by the action of carbon oxide, possibly in the presence of hydrogen, on tertiary amines at elevated temperature and pressure in the presence of compounds Carbonyl-forming metals, characterized in that the catalysts used are halides of the carbonyl-forming metals, in particular cobalt or nickel halides, are used. 2. Process for the preparation of carboxamides according to Claim i, characterized in that that complex compounds of nickel or cobalt halides are used as catalysts used with organic onium salts. Publications considered: German Patent application B 7011 IV b / 12 o (Patent No. 863 800).