JPH0791238B2 - Method for producing tertiary amine - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a tertiary amine, and more specifically, various primary amines or secondary amines.
By reacting primary amines with formaldehyde under hydrogen pressure using a Pd catalyst prepared by a specific method,
The present invention relates to a method for producing a corresponding tertiary amine in a high yield by N-methylation. The tertiary amine produced by the present invention is a quaternary ammonium salt such as an emulsifier, a dispersant, a rust preventive, a bactericide, a leveling agent and an antistatic agent, or an intermediate of an amphoteric activator, or It is a useful substance which has various uses such as a catalyst for urethane foam.

[0002]

2. Description of the Related Art Conventionally, a long-chain aliphatic primary and secondary amine is reacted with formaldehyde and hydrogen in the presence of a hydrogenation catalyst to obtain a tertiary amine. Is well known. Specifically, there are methods described in JP-B-39-17905 and JP-A-55-9019. In the former method, a lower carboxylic acid is added as an additional catalyst to the reaction system in order to prevent the production of undesired by-products. However, according to this example, even if a primary amine or secondary amine is used as a starting material, Raney Ni is used as a catalyst, and a lower carboxylic acid such as acetic acid is added as an additional catalyst, Yield up to 83
%, And 10% or more of by-products are produced. Therefore, this method has the drawback that the suppression of by-products is incomplete despite the addition of an additional catalyst and the selectivity of the catalyst differs depending on the amine species. Further, in this method, it is unavoidable to add a foreign substance to the reaction system, so that separation and purification are required, that is, an unnecessary step is required, which is not preferable in terms of operation.

On the other hand, the latter publication discloses a technique using a general Ni-based hydrogenation catalyst, and it is said that a Ni catalyst supported on a carrier is particularly effective. However, as in the examples starting from long-chain secondary amines described in Examples 4 and 5 of this publication, this Ni-based catalyst is used before the N-methylation reaction by hydrogenation. It is necessary to contact with hydrogen beforehand to activate the catalyst at a high temperature of 180 to 230 ° C. Further, it is also necessary to perform an operation of continuously circulating hydrogen to continuously discharge water in the reaction system. Thus, this method has a drawback derived from the characteristics of the supported Ni catalyst used, that is, an additional operation of previously activating the catalyst under hydrogen and at high temperature is required, and water in the reaction system is also required. Has the drawback that it is complicated because it must be continuously discharged out of the system.

Further, in JP-A-60-112734, when methylating a long-chain aliphatic amine with hydrogen and formaldehyde, a reaction temperature of 80 to 250 ° C., a hydrogen pressure of 2 kg / cm ²
(Gauge pressure) Under the above conditions, powder or granular carbon
Co, Ni, Rh, Pd or Pt can be prepared by ion exchange method of 0.1.
〜10wt% carried hydrogenation catalyst to amine 5〜
Disclosed is a method of obtaining a tertiary amine having good yield and purity by reacting while adding 5000 ppm of added formaldehyde continuously. However, we have prepared a method of preparing the catalyst disclosed in the description of this invention, namely Advances Catalysis, 20th.
Vol. 112, p. 112 (1969), the catalyst was prepared by the ion exchange method and the reaction was carried out. Sufficient (described below as a comparative example of the invention).

[0005]

Therefore, the present inventors have solved the problems found in the conventional method, and have a high selectivity with no limitation on the starting amine species.
As a result of intensive studies to develop a method for obtaining a primary amine in a high yield, a high yield can be obtained by using a catalyst prepared by a specific method without being limited by reaction conditions and starting material species. In the present invention, a method for producing the intended tertiary amine was found, and the present invention was completed.

That is, the present inventors have conducted the analysis of the reaction mechanism of this reaction and the products of side reactions using a conventional general hydrogenation catalyst before reaching the present invention. As a result, in the conventionally known Raney Ni or supported Ni catalyst, the catalytic activity and selectivity, which are greatly involved in the hydrocracking reaction (hydrodehydration) in this reaction mechanism, are insufficient, side reactions easily occur, and amine and It was confirmed that the decomposition gas of formaldehyde is likely to be adsorbed on the catalyst and cause deterioration of the catalyst surface. Especially when a primary amine or lower amine or polyamines is used as a raw material, such a phenomenon is likely to occur, and in order to suppress such a side reaction,
It is necessary to add additives, stabilize the catalyst, and limit the reaction conditions. However, even if such measures are taken, there is some effect, but it cannot be taken for amines that are prone to side reactions. The reason for this is that when Ni-based catalysts are used, the hydrogenolysis characteristics (activity / selectivity) required for the catalysts in this reaction are inferior, so a large amount of catalyst is required and undesired side reaction products are easily generated. That is, the catalyst has a limit in the selectivity in this reaction. From the study using these known catalysts, it was concluded that a catalyst exhibiting high activity and high selectivity is indispensable for the present invention, and as a result of diligent study, a Pd catalyst prepared by a specific method is the present reaction. The amount required for hydrocracking is extremely small (10% for amine as catalyst metal).
It was found that it works, and the present invention has been completed.

That is, the present invention is directed to primary amines or secondary amines.
In the method of producing a corresponding tertiary amine by reacting a primary amine with formaldehyde under hydrogen pressure, preferably under hydrogen pressure of 3 to 50 kg / cm ² (gauge pressure), powder or granular carbon is used as a catalyst in the following ( A method for producing a tertiary amine, characterized by using a Pd catalyst supporting 0.1 to 10% by weight of Pd by the method of a) or (b). (a) A predetermined amount of activated carbon is added to a palladium chloride or palladium nitrate aqueous solution containing hydrochloric acid to remove water and hydrochloric acid under reduced pressure, and then dried and calcined in air. (b) A predetermined amount of activated carbon is added to a palladium chloride or palladium nitrate aqueous solution containing hydrochloric acid, water and hydrochloric acid are removed under reduced pressure, and then reduction treatment is performed in a hydrogen atmosphere.

As described above, the method of the present invention is the first to use a Pd catalyst prepared by a specific method using a primary amine, a secondary amine, or a polyamine as a starting material, which is difficult with a conventionally known catalyst. It is possible to obtain various corresponding tertiary amines with high yield and high purity.

According to the method of the present invention, the desired tertiary amine can be quantitatively obtained from the raw material. In the conventional method, the corresponding tertiary amine can be obtained in a high yield of 95% or more even when a primary amine, a diamine or a polyamine which easily produces a side reaction product is used as a raw material. Moreover, since the catalyst has excellent performance, it is not necessary to add a co-catalyst or an additive for increasing the selectivity or yield, and no special operation is required for increasing the catalytic activity, and the use of the catalyst The amount is very small and the reaction can be completed in a short time.

The Pd catalyst used in the reaction of the present invention is as described above.
The activity is extremely higher than that of Pd catalysts prepared by methods other than (a) and (b), and the activity per unit weight of metal is several tens of times higher than that of Raney Ni or supported Ni. Therefore, it is sufficient that the amount of the catalyst metal added is several tens to several hundreds of ppm with respect to the starting material amine. The Pd catalyst used in the present invention is more expensive than other metals, but as described above, addition of an extremely small amount can sufficiently achieve the purpose, and the durability of the catalyst is excellent. Even after repeated use, the activity of the catalyst is hardly reduced.

The Pd catalyst used in the present invention is prepared by loading Pd metal on powdery or granular carbon by the method (a) or (b) above in an amount of 0.1 to 10% by weight. Generally, the solid catalyst preparation method can be divided into an impregnation method, a deposition method, a kneading method, an ion exchange method, a coprecipitation method, a melting method, and the like depending on the operation method of the process (see “Progress of Chemical Industry, Vol. 15 "Catalyst design" published by Maki Shoten; see page 35). As a result of intensive studies on the difference in activity / selectivity of these Pd catalysts by these preparation methods and the selection of the carrier species, the present inventors have found that Pd can be added to powdery or granular carbon by the method (a) or (b) above. The inventors have found that only the catalyst prepared by supporting the catalyst meets the object of the present invention and can carry out a reaction with high yield and high selectivity, and completed the present invention.

The method for preparing the Pd catalyst used in the present invention is either the above method (a) or (b). Specifically, a specific amount of palladium chloride or palladium nitrate and a small amount of concentrated hydrochloric acid are used. Alternatively, dilute hydrochloric acid is dissolved in water, activated carbon is added thereto so that the Pd loading rate becomes 0.1 to 10% by weight, and after sufficiently stirring, heat treatment under reduced pressure of 1 to 200 torr and further 50 to It is dried at 150 ° C to obtain a precursor of an activated carbon-supported Pd catalyst, and then in air for 1 to 5 hours at 200 to 400 ° C.
1 ~ 5 under hydrogen atmosphere
Activated carbon supported by reduction treatment at 80-300 ℃ for a long time
Obtain the Pd catalyst. The method for preparing the Pd catalyst of the present invention will be described in detail in the examples below.

Next, the outline of the reaction of the method of the present invention will be described. Various primary amines or secondary amines, which will be described later, are added to the reaction vessel.
After charging at least one of the primary amines and the Pd catalyst of the present invention, hydrogen is introduced into the reaction vessel while stirring the content. Hydrogen pressure is preferably 3 to 50 kg / cm ² (gauge pressure), more preferably 3 to 20 kg / cm ² (gauge pressure).
After reaching a predetermined reaction temperature, preferably 80 to 180 ° C., formaldehyde is added to the reaction system. The addition is
Although it is possible to carry out all at once or continuously, a method of carrying out continuously is preferred.

The formaldehyde used in the present invention may be formalin or a methanol solution of formaldehyde. The formaldehyde concentration is preferably 30 to 60%, preferably 35 to 37% formalin water. The amount of formaldehyde used is 1.0 to 1.2 equivalent times per active hydrogen group of the amino group of the starting amine. The reaction time is arbitrarily determined depending on the amount of catalyst added, the supply rate of formaldehyde and the number of active hydrogen groups of amine, but it is usually 2 to 10 hours. The amount of the catalyst added is preferably within the range of 10 to 500 ppm as the Pd metal of the catalyst metal with respect to the amine. More than this amount may be added, but normally the target is sufficiently achieved within this range. Further, since the catalyst has good durability, it can be used repeatedly and the amount used per one time is further reduced.

The reactor during the reaction may be a system which is closed by hydrogen pressure, and when the produced water, formalin water and the like coexist with the amine, the catalytic activity is not affected and excess formaldehyde is present. Alternatively, a system may be used in which a small amount of gas is continuously discharged under hydrogen pressure in order to discharge the excess amount thereof or to discharge a low-grade gas derived from the raw material. After the reaction is completed in this way, an extremely high-purity and high-quality tertiary amine can be obtained by distilling the reaction product as it is, or distilling the catalyst after filtering or just filtering the catalyst as it is. .

For example, a general formula R ¹ R ² NH (in the formula, R ¹ and R ² may be the same or different, and is a saturated or unsaturated hydrocarbon group having a straight or branched chain having 8 to 22 carbon atoms. In a reaction of a long-chain aliphatic secondary amine represented by the formula (5) with formaldehyde, the Pd catalyst of the present invention (loading amount: 5%) is 0.05% by weight with respect to the amine (25 ppm as Pd metal based on the amine). Addition, reaction temperature 140 ℃, hydrogen pressure 15kg / cm ² (gauge pressure)
Then, a tertiary amine having a purity of 99% or more was obtained as a product under the condition of adding an equimolar amount of formalin to the amine for 4 hours and aging for 0.5 hour. Originally, the di-long-chain aliphatic alkyl tertiary amine obtained by this reaction is industrially difficult to purify by distillation due to its high boiling point, and therefore it is necessary to use only by removing the catalyst used after the reaction by filtration. Therefore, it is necessary to maintain high purity at the end of the reaction, but the method according to the present invention can sufficiently meet these requirements.

On the other hand, the general formula RNH ₂ (wherein R is a carbon number 8
22 represents a saturated or unsaturated hydrocarbon group having a straight chain or a branched chain of 22), and a long-chain aliphatic primary amine represented by
The side reaction is likely to occur in the hydrogenation catalyst, and carboxylic acid or the like is added to suppress it. However, this method does not have the effect of improving the selectivity of the catalyst.
As disclosed in the example of -17905, the yield of the intended mono-long-chain alkyldimethyl tertiary amine is about 88% at the maximum. It contains about 10% by-products and requires distillation purification in order to obtain the desired tertiary amine in high purity, which naturally lowers the yield obtained.

On the other hand, when the catalyst of the present invention is used,
In the reaction of a long-chain aliphatic primary amine represented by the general formula RNH ₂ (wherein R has the above meaning) with formaldehyde and hydrogen, for example, a Pd catalyst (support amount: 5%) of the present invention is used as an amine. 0.1% by weight (50% for amine as Pd metal)
ppm), the reaction temperature was 120 ° C., the hydrogen pressure was 15 kg / cm ² (gauge pressure), and formalin was added in an amount of 2 times the amount of amine over 4 hours and aged for 0.5 hours. Dimethyl tertiary amine was obtained with a purity of 98% or more.

As described above, according to the method of the present invention, it is possible to obtain a tertiary amine with high selectivity even in a reaction from a primary amine in which a side reaction is likely to occur. When the catalyst of the present invention is used, it is possible to obtain a high-quality tertiary amine without distillation simply by removing the used catalyst by filtration after the reaction.

When these reactions are carried out using a conventionally known Ni-based catalyst, side reactions are likely to occur from the long-chain aliphatic primary amine as described above, and the yield of the target tertiary amine is increased. Will fall. Furthermore, lower primary amines, or primary
When a starting material is a polyamine such as a diamine or a triamine having a primary amino group or a secondary amino group or a mixture thereof, the side reaction further increases and the yield of the tertiary amine decreases. On the other hand, even when such amines that are prone to side reactions are used as the starting material, the use of the Pd catalyst prepared by the method of the present invention leads to a higher yield than the conventional catalyst. Tertiary amines can be produced.

The starting amines that can be used in the present invention include the following. A long-chain aliphatic primary represented by the general formula RNH ₂ (wherein R has the above meaning)
Secondary amines such as 2-ethylhexylamine, octylamine, decylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine, eicosylamine, oleylamine, etc. Mixtures and the like; long-chain aliphatic secondary amines represented by the general formula R ¹ R ² NH (wherein R ¹ and R ² have the above-mentioned meanings), for example, dioctylamine, didecylamine, didodecylamine, di Octadecylamine, dioleylamine, stearyl-oleylamine, dieicosylamine, etc., or a mixture thereof; general formula R ¹ O (CH ₂ ) ₃ NH
Primary amine represented by ₂ (in the formula, R ¹ has the above meaning), for example, 3- (2-ethylhexyloxy) propylamine, 3-octyloxypropylamine, 3-decyloxypropylamine, 3-dodecyloxypropylamine, 3-octadecyloxypropylamine, etc .; general formula
A secondary amine represented by (R ¹ O (CH ₂ ) ₃ ) ₂ —NH (wherein R ¹ has the above-mentioned meaning), for example, di (3- (2-ethylhexyloxy) propyl) amine. , Di (3-octyloxypropyl) amine, di (3-decyloxypropyl) amine, di (3-dodecyloxypropyl) amine, di (3-
Octadecyloxypropyl) amine, etc .; general formula H ₂ N−
(R ³ ) —NH ₂ (wherein R ³ represents a linear or branched alkylene group having 2 to 12 carbon atoms) and has a primary amino group, for example, ethylenediamine, 1,3 -Butanediamine, pentamethylenediamine, hexamethylenediamine, octamethylenediamine, etc .; general formula H ₂ NR ⁴
(NHR ⁵ ) _n NH ₂ (In the formula, R ⁴ and R ⁵ may be the same or different, and are a linear or branched alkylene group having 2 to 12 carbon atoms, n
Represents a number from 1 to 10) and has a primary and secondary amino group, such as polyamines such as diethylenetriamine, triethylenetetramine, and tetraethylenepentamine; general formula (CH ₃ ) ₂ N [CH ₂ ) ₃ NH] _m -H (wherein _m represents a number from 1 to 5), such as N, N
-Dimethylpropylenediamine, N, N-dimethyldipropylenetriamine, etc .; aromatic primary or secondary amines having an aromatic group, such as aniline, benzylamine,
Xylylenediamine and the like; alicyclic primary or secondary amines having an alicycle having 4 to 6 carbon atoms, such as cyclobutylamine, cyclopentylamine, cyclohexylamine and the like; cyclic primary or secondary having a heterocycle Amine,
For example, morpholine, piperidine, piperazine, piperazineethaneamine, pyrrolidine, etc .; primary or secondary amines which are amino alcohols having a monovalent or divalent hydroxyl group, such as monoethanolamine, isopropanolamine, diethanolamine, diisopropanolamine. And so on.

[0022]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples,% is based on weight unless otherwise specified.
The catalysts used in Examples and Comparative Examples were prepared by the following method.

Catalyst A : Palladium chloride (0.42 g) and concentrated hydrochloric acid (1 ml) were added to water (15 ml) to prepare an aqueous palladium chloride solution. Next, activated carbon (4.6 g) was added to this aqueous solution, stirred sufficiently, and heated under reduced pressure to remove water and hydrochloric acid, and further dried at 100 ° C. in air overnight.
Then, it was calcined in air at 400 ° C. for 2 hours to obtain a 5% activated carbon-supported Pd catalyst (catalyst A).

Catalyst B : Palladium chloride (0.42 g) and concentrated hydrochloric acid (1 ml) were added to water (15 ml) to prepare an aqueous palladium chloride solution. Next, activated carbon (4.6 g) was added to this aqueous solution, stirred sufficiently, and heated under reduced pressure to remove water and hydrochloric acid, and further dried at 100 ° C. in air overnight.
After that, reduction treatment is performed in a hydrogen atmosphere at 200 ° C. for 2 hours, and then 5
% Active carbon-supported Pd catalyst (Catalyst B) was obtained.

Comparative catalysts A and B : Palladium chloride (0.42
g) and concentrated hydrochloric acid (1 ml) were added to water (15 ml) to prepare an aqueous palladium chloride solution. Then, silica or silica / alumina (4.6 g) was added to this aqueous solution, stirred sufficiently, and heated under reduced pressure to remove water and hydrochloric acid,
It was further dried in air at 100 ° C overnight. Then, it was calcined in air at 400 ° C. for 2 hours to obtain a 5% silica-supported Pd catalyst (comparative catalyst A) or a 5% silica / alumina-supported Pd catalyst (comparative catalyst B).

Comparative catalyst C : Palladium chloride (0.42 g) and concentrated hydrochloric acid (0.6 ml) were added to water (20 ml) to prepare a palladium chloride aqueous solution. Then, activated carbon (4.6 g) was added to this aqueous solution.
Was added and stirred well. Then, 10% NaH aqueous solution (4.2 g) was gradually added at 60 ° C. Then, sodium hydrogen carbonate (0.09 g) was further added, and the mixture was stirred for 12 hours. After filtration / washing with water, it was dried in air at 100 ° C. overnight to obtain a 5% activated carbon-supported Pd catalyst (comparative catalyst C; deposition method).

Comparative catalyst D : Activated carbon treated with nitric acid (1.9
g) was suspended in water (5 ml), and 0.02 mol / liter tetraamminepalladium chloride (47 ml) was added dropwise over 1 hour.
After leaving it at room temperature for 2 days, it was filtered, washed with water, dried (150 ° C., overnight), and further hydrogenated at 300 ° C. for 4 hours to obtain a 5% activated carbon-supported Pd catalyst (comparative catalyst D; ion exchange method). .

Example 1 300 g of dodecylamine (purity 99%) and 0.3 g of catalyst A were charged in an autoclave of 1 liter and hydrogen pressure was 15 kg /
Hydrogen was filled up to cm ² (gauge pressure), and the temperature was set to 120 ° C. Then, while maintaining this hydrogen pressure, hydrogen was introduced at a rate of 5 liters / hr, and at the same time, a 37% aqueous formaldehyde solution (2.2 times mole to amine) was injected for 4 hours.
After aging for 0.5 hour, the catalyst was removed by filtration to obtain N, N-dimethyldodecylamine. The composition of the finished product is shown in Table 1.

Example 2, Comparative Examples 1 to 4 N, N-dimethyldodecylamine was obtained in the same manner as in Example 1 except that catalyst B and comparative catalysts A to D were used instead of catalyst A. The composition of the finished product is shown in Table 1.

[0030]

[Table 1]

From the results shown in Table 1, as compared with the conventional catalyst,
It can be seen that the target tertiary amine can be obtained in high yield when the catalyst of the present invention is used.

Examples 3 to 6 As starting materials, dioctadecylamine (Example 3),
Hexamethylenediamine (Example 4), di (3-octyloxypropyl) amine (Example 5), and diethanolamine (Example 6) were used, and also catalyst A as catalyst.
Was used to synthesize the corresponding tertiary amine. The reaction conditions are the same as in Example 1. Table 2 shows the composition of the obtained reaction-completed product.

[0033]

[Table 2]

From the results shown in Table 2, it can be seen that the catalyst of the present invention is useful for various amines.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C07C 217/08 7457-4H // C07B 61/00 300

Claims (1)

[Claims] 1. In a method for producing a corresponding tertiary amine by reacting a primary amine or a secondary amine with formaldehyde under hydrogen pressure, a powder or granular carbon is used as a catalyst in the following (a) or ( A method for producing a tertiary amine, which comprises using a Pd catalyst supporting 0.1 to 10% by weight of Pd by the method of b). (a) A predetermined amount of activated carbon is added to a palladium chloride or palladium nitrate aqueous solution containing hydrochloric acid to remove water and hydrochloric acid under reduced pressure, and then dried and calcined in air. (b) A predetermined amount of activated carbon is added to a palladium chloride or palladium nitrate aqueous solution containing hydrochloric acid, water and hydrochloric acid are removed under reduced pressure, and then reduction treatment is performed in a hydrogen atmosphere.