Process for the production of 3-cyanopropionamide

3-Cyanopropionamide is produced by adding hydrocyanic acid on acrylamide in the presence of an aprotic organic solvent and an alkali metal cyanide at a temperature between 20.degree. and 150.degree. C. 3-cyanopropionamide is an important intermediate product for the production of pyrrolidone or 4-aminobutyramide.

BACKGROUND OF THE INVENTION 
3-cyanopropionamide is an important intermediate product for the production 
of pyrrolidone or of 4-aminobutyramide and 4-aminobutyramide derivatives 
interesting as pharmaceuticals. 
Known processes for the production of 3-cyanopropionamide start from 
succinodinitrile, which is partially saponified (see British Pat. No. 
782,258 or German patent 1132913). Succinodinitrile itself is 
comparatively difficult to produce, and its partial hydrolysis over and 
above produces also unsatisfactory yields of 3-cyanopropionamide. 
SUMMARY OF THE INVENTION 
The invention is directed to a process for the production of 
3-cyanopropionamide which is characterized by adding hydrocyanic acid on 
acrylamide in the presence of an aprotic organic solvent and an alkali 
metal cyanide at a temperature between 20.degree. and 150.degree. C. 
Hydrocyanic acid (hydrogen cyanide) and acrylamide are readily available 
materials. The addition of hydrocyanic acid on the acrylamide proceeds 
surprisingly very smoothly and leads in high selectivity and very good 
yields to the 3-cyanopropionamide. Polymerization of the acrylamide takes 
place at all events to a very minor extent. 
The hydrocyanic acid is suitably employed in a stoiochiometric amount to 
the acrylamide, however, it can also be used in a slight excess. 
The reaction takes place in the presence of an aprotic organic solvent. 
Especially preferred organic solvents are dimethyl formamide and dimethyl 
sulfoxide. Further suited organic solvents for example are diethyl 
formamide, dimethyl acetamide, N-methyl pyrrolidone, tetrahydrofuran, 
tetramethylene sulfone (sulfolan) and tetramethyl urea, as well as 
homologues of the named compounds with up to a total of 8 carbon atoms in 
the molecule, e.g. N,N-dimethyl-N',N'-diethyl urea, dipropyl acetamide. 
The amount of solvent is not critical, however, it should suitably be so 
measured that at the selected reaction temperature the acrylamide employed 
as well as the 3-cyanopropionamide formed are present in dissolved form. 
The process of the invention furthermore requires the presence of an alkali 
metal cyanide as catalyst. Preferably sodium or potassium cyanide is used. 
The amount of catalyst also is not critical. For obtaining short reaction 
times, however, it is advantageous to employ the catalyst in an amount of 
0.1 to 50, preferably from 5 to 20, weight percent, based on the amount of 
hydrocyanic acid employed. 
The reaction takes place at a temperature between 20.degree. and 
150.degree. C., preferably between 70.degree. and 120.degree. C. The 
pressure has no ascertainable influence on the speed of reaction and the 
composition of the reaction mixture after ending the reaction. 
The process of the invention can be carried out in such manner that a 
suspension of the catalyst is present in a part of the solvent and a 
solution of the acrylamide and the hydrocyanic acid in the residual part 
of the solvent is fed in. However, just as well there can also be present 
a solution of the acrylamide in which the catalyst is suspended and the 
hydrocyanic acid led in. To recover the 3-cyanopropionamide formed, after 
complete reaction, the solution is concentrated and treated with a 
precipitating agent, for example toluene, whereupon 3-cyanopropionamide 
crystallizes out. 
Unless otherwise indicated all parts and percentages are by weight. 
The process can comprise, consist essentially of or consist of the stated 
steps with the indicated materials.

The invention will be explained in connection with the following examples: 
EXAMPLE 1 
There were slowly dropped into a suspension of 2 grams of potassium cyanide 
in 75 ml of dimethyl formamide at a temperature of 90.degree. to 
110.degree. C. a solution of 71.08 grams (1 mole) of acrylamide and 27 
grams (1 mole) of hydrocyanic acid in an additional 75 ml of dimethyl 
formamide. After a further reaction time of about 5 minutes, there were 
distilled 100 ml of dimethyl formamide in a water jet vacuum. The still 
warm distillation residue was stirred with 150 ml of toluene. Thereby the 
3-cyanopropionamide formed crystallized out. After filtering off and 
drying at 60.degree. to 70.degree. C. this was determined to be 89.1 grams 
(91% of theory). Melting point: 90.degree. to 93.degree. C., after 
recrystallization from ethyl acetate: 93.degree. to 95.degree. C. 
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C.sub.4 H.sub.6 N.sub.2 Molecular Weight (98.11) 
C H N 
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48.97% 
6.16% 28.56% 
48.97% 
6.06% 28.32% 
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EXAMPLE 2 
Example 1 was repeated with the sole difference that in place of potassium 
cyanide there were used 2 grams of sodium cyanide. Yield: 89% of theory. 
Melting Point: 90.degree. to 93.degree. C. (recrystallized from 
isopropanol). 
EXAMPLE 3 
Example 1 was repeated with the sole difference that in place of dimethyl 
formamide there was used the same volume amount of dimethyl sulfoxide. 
Yield: 88% of theory. Melting Point: 89.degree. to 92.degree. C. 
(recrystallized from n-butanol). 
EXAMPLE 4 
Example 1 was repeated with the difference that in place of potassium 
cyanide there was used 2 grams of sodium cyanide and in place of the 
dimethyl formamide there was used the same volume amount of dimethyl 
sulfoxide. Yield: 89% of theory. Melting Point: 89.degree. to 92.degree. 
C. 
EXAMPLE 5 
There were suspended 2 grams of potassium cyanide in a solution of 71.08 
grams (1 mole) of acrylamide in 100 ml of dimethyl formamide. Then there 
were led in at 40.degree. to 50.degree. C. 27 grams (1 mole) of 
hydrocyanic acid. After the ending of the introduction of hydrocyanic acid 
the reaction mixture was held for one hour at a temperature between 
70.degree. and 100.degree. C. The dimethyl formamide was distilled off to 
reduce the volume in half and the residue stirred with 150 ml of toluene. 
There were obtained 91.1 grams of 3-cyanopropionamide (93% of theory) 
having a Melting Point of 93.degree. to 95.degree. C. 
EXAMPLE 6 
Example 5 was repeated with the sole difference that in place of potassium 
cyanide there were used 2 grams of sodium cyanide. Yield: 89% of theory. 
Melting Point: 90.degree. to 93.degree. C. 
The entire disclosure of German priority application No. P 2947475.7-42 is 
hereby incorporated by reference.