Process for preparation of unsaturated long-chain aliphatic secondary amine

A process for selectively preparing an unsaturated long-chain aliphatic secondary amine at a high yield comprising reducing an unsaturated aliphatic nitrile having 8 to 22 carbon atoms or a nitrile mixture containing said nitrile with hydrogen in the presence of a Ni hydrogenation catalyst and a carboxylic acid amide at a reaction temperature of 160.degree. C. to 200.degree. C.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an improved process for the preparation of 
unsaturated long-chain aliphatic secondary amines by reducing unsaturated 
long-chain aliphatic nitriles with hydrogen. 
2. Description of the Related Art 
Amines having long-chain alkyl groups are generally prepared by reducing 
long-chain aliphatic nitriles, derived from natural fats and oils, with 
hydrogen. When long-chain aliphatic nitriles are reduced with hydrogen, a 
mixture of primary, secondary, and tertiary amines are obtained. Among 
these amines, unsaturated long-chain aliphatic secondary amines are 
advantageous in that the quaternary ammonium salts thereof can provide 
softness and antistaticity to various fabrics and hair, and in addition, 
can be used as a softener for providing excellent water absorbability and 
handling ease to the treated fabrics. Therefore, a process for selectively 
preparing secondary amines at a high yield is desired. 
Known processes for the preparation of unsaturated long-chain aliphatic 
secondary amines are the reduction of unsaturated long-chain aliphatic 
nitriles with hydrogen using a Cu-Cr catalyst (BP 773,432) or an Ni 
hydrogenation catalyst (USP 2,355,356, USP 2,784,232, BP 759,291, Japan 
Kokai 55-9018). The former process has a disadvantage in that a longer 
reaction time is necessary because of the low activity of the Cu-Cr 
catalyst, and the latter process gives only a poor selectivity of 
unsaturated long-chain aliphatic secondary amines because most of the 
unsaturated bonds in aliphatic chains are hydrogenated while the nitrile 
radicals are converted to amino radicals. 
SUMMARY OF THE INVENTION 
Accordingly, the objects of the present invention are to eliminate the 
above-mentioned disadvantages of the prior art and to provide a process 
for preparing an unsaturated long-chain aliphatic secondary amine at a 
good selectivity and at a high yield from an unsaturated long-chain 
aliphatic nitrile or a nitrile mixture containing said nitrile. 
Other objects and advantages of the present invention will be apparent from 
the following description. 
In accordance with the present invention, there is provided a process for 
preparing an unsaturated long-chain aliphatic secondary amine comprising 
reducing an unsaturated aliphatic nitrile having 8 to 22 carbon atoms or a 
nitrile mixture containing said nitrile with hydrogen in the presence of 
Ni hydrogenation catalysts and an carboxylic acid amides at a reaction 
temperature of 160.degree. C. to 200.degree. C. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
It is generally known in the reaction to convert unsaturated long-chain 
aliphatic nitriles to secondary amines in the presence of Ni hydrogenation 
catalysts that, when the reduction of nitrile radicals to amino radicals 
is accelerated, it is hard to obtain unsaturated long-chain aliphatic 
secondary amines in high selectivity because the hydrogenation of 
unsaturated bonds in aliphatic chains is also accelerated, and conversely, 
under the conditions needed to suppress the hydrogenation of unsaturated 
bonds in aliphatic chains, it is difficult to obtain unsaturated 
long-chain aliphatic secondary amines in high yield, since the speed of 
the amination reaction is reduced. 
As mentioned above, in the process provided by the present invention, the 
reduction of unsaturated long-chain aliphatic nitriles with hydrogen using 
Ni hydrogenation catalysts is carried out at 160.degree.-200.degree. C. in 
the presence of carboxylic acid amides. Under these conditions, the 
hydrogenation of unsaturated bonds in aliphatic chains is suppressed but 
the conversion of nitrile radicals to amino radicals is promoted, and 
consequently, unsaturated long-chain aliphatic secondary amines can be 
obtained at a good selectivity and a high yield. 
The unsaturated long-chain aliphatic nitriles used as a starting material 
in the present invention are unsaturated long-chain aliphatic or fatty 
nitriles having 8 to 22 carbon atoms or mixtures of nitriles containing 
said nitriles, e.g., nitriles prepared from oleic acid, linoleic acid, 
linolenic acid, erucic acid, tallow fatty acid, soya fatty acid, palm oil 
fatty acid, tall oil fatty acid, and rape fatty acid. 
The catalysts usable in the present invention are nickel hydrogenation 
catalysts, especially those supported on a carrier such as kieselguhr, 
alumina, silica-alumina and so on. The preferable amount of the catalyst 
added is 0.1 to 0.5 parts by weight based on 100 parts by weight of the 
starting nitrile. 
The carboxylic acid amides usable in the process of the present invention 
are saturated or unsaturated aliphatic carboxylic acid amides having 1 to 
22 carbon atoms or aromatic carboxylic acid amides having 7 to 22 carbon 
atoms. These carboxylic acid amides can be used alone or as a mixture of 
two or more. The saturated or unsaturated carboxylic acid amides used in 
the present invention can be, for example, acetamide, propionamide, 
butyramide, 2-ethylhexylamide, lauramide, stearamide, oleamide, erucamide, 
coco fatty acid amide, tallow fatty acid amide, or cyclohexane carboxylic 
acid amide. 
The aromatic carboxylic acid amides used can be, for example, benzamide, 
phenylacetamide, phenylpropionamide, cinnamic acid amide, 4-methyl 
benzamide, or benzanilide. 
The preferable amount of the carboxylic acid amide added is 0.03% to 3% by 
mole, based on the mole amount of the nitrile. When the aliphatic 
carboxylic acid amide is used, preferably the amount of addition is 0.3 to 
3% by mole, and when an aromatic carboxylic acid amide is used, preferably 
the amount of addition is 0.03 to 1% by mole. When the amount of the 
carboxylic acid amide added is less than the preferable amount, the 
hydrogenation of the unsaturated bonds in the aliphatic chains tends not 
to be sufficiently suppressed, and on the other hand, when the amount of 
the carboxylic acid amide added is more than the preferable amount, the 
yield of the desired secondary amines tends to be lowered in accordance 
with the decrease in the rate of reduction of the nitrile radical. 
In the practice of the present invention, it is essential to maintain the 
reaction temperature within a limited range of between 160.degree. C. and 
200.degree. C. to obtain a high yield of secondary amines having a large 
content of unsaturated bonds in aliphatic chains. When the reaction 
temperature exceeds 200.degree. C., the unsaturated bonds in aliphatic 
chains are hydrogenated faster, and consequently, the obtained secondary 
amines contain less unsaturated bonds in their aliphatic chains. When 
reaction temperature is lower than 160.degree. C., the yield of secondary 
amines decreases in accordance with the reduced rate of conversion of the 
nitrile radicals to amino radicals. 
The hydrogen pressure in the process of the present invention is not 
specifically limited as long as it is equal to or higher than atmospheric 
pressure, but from the economical point of view, the hydrogen pressure is 
preferably less than 10 kg/cm.sup. 2G. 
The process of the present invention is carried out by agitating a mixture 
of the above-mentioned nitrile, catalyst, and carboxylic acid amide 
charged into a reactor at a temperature of 160.degree.-200.degree. C. 
while allowing hydrogen to flow through the mixture. 
The process of the present invention can provide a mixture of amines having 
unsaturated long-chain aliphatic secondary amines as the main component. 
This mixture comprises 70%, preferably 75%, or more of unsaturated bonds 
in aliphatic chains in the nitriles of the starting material, and a 
selectivity to secondary amine and a conversion of nitriles to amines are 
80%, preferably 85% or more, and 97% or more, respectively.

EXAMPLES 
The present invention will now be further illustrated by, but is by no 
means limited to, the following Examples. 
EXAMPLE 1 
Into a 1 liter autoclave were charged 500 g of oleonitrile, 1 g of 
Ni-kieselguhr catalyst, and 1.2 g of acetamide (1.07% by mole based on the 
mole amount of nitrile). Hydrogen was passed through the mixture while 
stirring. The hydrogen pressure was maintained at 3 kg/cm .sup. 2G, and 
the contents of the autoclave were heated. The temperature was raised to 
180.degree. C., and the flow of hydrogen was continued through the mixture 
while stirring at 180.degree. C. for 2 hrs; the hydrogen pressure was 
maintained at 3 kg/cm.sup. 2G. 
After the reaction, the mixture was cooled to 100.degree. C. and the 
catalyst removed by filtration. The amine mixture thus obtained contained 
5.2% of primary amine, 89.1% of secondary amine and 5.1% of tertiary 
amine. The iodine value of this amine mixture is 86.6% of Theoretical 
Iodine Value (iodine value of amine mixture when nitriles of starting 
material are converted to secondary amines at a 100% selectivity and 100% 
yield, and in addition, all of the unsaturated bonds in fatty chains 
remain after the reaction. This also applies to the following Examples and 
Comparative Examples). The results are thus obtained are shown in Table 1. 
EXAMPLES 2-6 and COMATIVE Example 1 
The reactions were carried out in the manner described in Example 1 except 
that the kind and the amount of the carboxylic acid amides added was 
changed. 
The results are shown in Table 1. 
TABLE 1 
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Com. 
Example No. or Comparative 
Example Ex. 
Example No. 1 2 3 4 5 6 1 
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Carboxylic 
Kind acetamide 
lauramide 
oleamide 
benzamide 
4-methyl 
benzanilide 
none 
benzamide 
acid amide 
Amount (g) 
1.2 5 5 1 1 1.5 
of addition 
mole %/nitrile 
(1.07) 
(1.32) 
(0.94) 
(0.43) 
(0.39) 
(0.40) 
Composition 
Prim. Am. (%) 
5.2 5.0 6.1 5.1 5.4 5.8 5.2 
of amine 
Sec. Am. (%) 
89.1 88.0 88.1 87.5 87.2 87.8 89.1 
mixture 
tert. Am. (%) 
5.1 5.3 4.8 5.4 5.6 5.8 4.9 
##STR1## 86.6 81.2 80.7 
94.3 91.2 92.7 69.1 
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EXAMPLES 7-8 AND COMATIVE EXAMPLES 2-3 
Into a 1 liter autoclave were charged 500 g of oleonitrile, 1 g of 
Ni-kieselguhr catalyst, and 1 g of benzamide (0.43% by mole based on the 
mole amount of the nitrile). The reactions were carried out in a manner as 
described in Example 1 except that the reaction temperature was changed to 
each of those shown in Table 2. After the reaction, the amine mixture was 
obtained by removing the catalyst in the manner described in Example 1. 
The results are shown in Table 2. 
TABLE 2 
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Example No. or Comparative 
Example Com. Ex. 
Example No. 7 8 2 3 
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Reac. Temp. (.degree.C.) 
190 170 210 150 
Composition 
Prim. Am. (%) 
4.6 6.6 3.7 9.4 
of amine Sec. Am. (%) 
89.2 86.1 91.2 81.4 
mixture Tert. Am. (%) 
4.7 5.3 4.4 5.2 
##STR2## 87.4 96.1 71.6 97.6 
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EXAMPLE 9 
Into a 1 liter autoclave were charged 500 g of tallow nitrile (IV =50.9), 1 
g of Ni-kieselguhr catalyst, and 0.5 g of benzamide (0.22% by mole based 
on the mole amount of the nitrile). The reaction was carried out and the 
catalyst removed in the manner described in Example 1. The amine mixture 
thus obtained contained 4.7% of primary amines, 86.4% of secondary amines, 
and 8.2% of tertiary amines. The iodine value of this amine mixture is 
87.0% of Theoretical Iodine Value. 
EXAMPLE 10 
Into a 1 liter autoclave were charged 500 g of soya nitrile (IV =112.7), 1 
g of Ni-kieselguhr, and 1.5 g of acetamide (1.32% by mole based on the 
mole amount of nitrile). The reaction was carried out and the catalyst 
removed in the manner described in Example 1. The amine mixture thus 
obtained contained 5.4% of primary amines, 89.2% of secondary amines and 
4.8% of tertiary amines. The iodine value of this amine mixture is 83.9% 
of Theoretical Iodine Value. 
EXAMPLES 11-14 
The reactions were carried out in the manner described in Example 1 except 
that the amount of acetamide added was changed to each of those shown in 
Table 3. 
The results are shown in Table 3. 
TABLE 3 
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Example 
Example No. 11 12 13 14 
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Amount of 
g 3 0.5 4.5 0.2 
acetamide 
(mole %/ (2.67) (0.45) 
(4.01) 
(0.18) 
nitrile) 
Composition 
Prim. Am. (%) 
5.5 5.9 3.7 5.3 
of amine Sec. Am. (%) 
86.2 89.1 83.4 89.4 
mixture Tert. Am. (%) 
5.8 4.5 2.6 4.9 
##STR3## 89.2 78.2 92.4 72.1 
______________________________________ 
EXAMPLES 15-18 
The reactions were carried out in the manner described in Example 4 except 
that the amount of benzamide added was changed to each of those shown in 
Table 4. 
The results are shown in Table 4. 
TABLE 4 
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Example 
Example No. 15 16 17 18 
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Amount of 
g 2 0.1 3 0.05 
acetamide 
(mole %/ (0.87) (0.043) 
(1.30) 
(0.022) 
nitrile) 
Composition 
Prim. Am. (%) 
5.4 5.6 5.3 5.8 
of amine Sec. Am. (%) 
86.3 88.9 82.0 89.2 
mixture Tert. Am. (%) 
5.8 4.3 6.7 4.2 
##STR4## 96.7 76.0 98.2 71.4 
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