JPH06293715A - Method for aminating and cyanating aromatic compound - Google Patents

Abstract

PURPOSE:To provide a method for directly and selectively aminating and/or cyanating an aromatic ring. CONSTITUTION:An aromatic compound is aminated and/or cyanated at 200-500 deg.C temperature in the presence of ammonia by using a catalyst supporting a group VIII element of the periodic table on a carrier. The selectivity for the amination and cyanation varies with the kind of the group VIII element. Co and Fe are suitable for the amination and Pd and Rh are suitable for the cyanation. Ni, Ru, Ir and Pt are suitable for the simultaneous progress of the amination and cyanation. A compound of an alkaline metal, an alkaline earth metal or a rare earth metal can be added to improve the performance of the catalyst. The ratio of the cyanation can be reduced by carrying out the reaction in the presence of water and hydrogen and the ratio of the cyanation can be enhanced by carrying out the reaction in the presence of air and oxygen.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a process for producing aromatic amines and nitriles.

[0002]

2. Description of the Related Art As a method for producing an aromatic amine represented by aniline, a method of reducing a nitro group, a method of substituting a phenolic hydroxyl group or a halogen with an amino group are known. Although these methods are widely practiced,
In both cases, it is necessary to convert the functional group attached to the aromatic ring, so that there is a problem that multiple steps are required until an aromatic amine is obtained.

As a method of directly aminating an aromatic ring, a method of reacting ammonia and benzene in the presence of a phosphate and water (Japanese Patent Laid-Open No. 2-115138) is known. In this method, benzene becomes phenol and phenol is aminated. Therefore, a large amount of phenol is produced as a by-product, and the selectivity of aniline is low.

Also known is a method of reacting benzene with ammonia by using a metal oxide such as nickel oxide, which is easily reduced, as a dehydrogenating agent (USP 3,91).
9, 155). This method is not a catalytic reaction, and metal oxides such as nickel oxide are reduced to hydrogen by by-product hydrogen and become inactive. In order to proceed the reaction, it is necessary to oxidize nickel metal and regenerate it into nickel oxide.

As a method of aminating an aromatic ring using a catalyst, a method of using a compound of an alkali metal and an element of Group 8 of the periodic table, such as an oxide, a halide or a sulfide, on graphite (Japanese Patent Laid-Open No. Sho 49-49). No. 52,790) is known. However, this method has a low selectivity for aromatic amines.

Further, a method of aminating benzene at 550 to 600 ° C. using reduced nickel, iron and asbestos (Berichte, 50, 541-6 (19)
17)) is known, but because the reaction temperature is too high,
It is industrially disadvantageous.

On the other hand, as a method for producing an aromatic nitrile represented by benzonitrile, a method by ammoxidation of a methyl group, a method by conversion of a carboxyl group, a substitution reaction of halogen with a cyano group, etc. are known. There is no known method for directly introducing a cyano group into an aromatic ring.

[0008]

As described above, the conventional method for introducing an amino group and / or a cyano group into an aromatic ring has many problems, and the direct and selective amination of the aromatic ring and / or cyano group is involved. It was desired to develop a method to realize this.

[0009]

In view of this situation, the present inventor has diligently studied a method for producing an aromatic amine or an aromatic nitrile, and as a result,
The present invention has been completed by discovering the novel fact that an aromatic ring is directly aminated and / or cyanated at a temperature of 500 ° C. or lower when the reaction is carried out in the presence of a catalyst in which a Group 8 element of the periodic table is supported. Came to.

That is, the present invention provides a method for aminating and / or cyanating an aromatic compound by using a catalyst in which a Group 8 element of the periodic table is supported on a carrier in the presence of ammonia.

The present invention will be described in more detail below.

In the method of the present invention, a Group 8 element of the periodic table supported on a carrier is used as a catalyst. Group 8 element of the periodic table means metallic Fe, Co, Ni, Ru, Rh, Pd, O.
s, Ir, Pt. Even with the same Group 8 element, the selectivity of amination and cyanation differs depending on the type of element.

The elements suitable for amination and cyanation are described below.

1. Elements suitable for amination: Co, Fe 2. Elements suitable for cyanation: Pd, Rh 3. Elements in which amination and cyanation proceed simultaneously: Ni,
Ru, Ir, Pt In the method of the present invention, these elements are used in the form of metal supported on a carrier. By supporting it on a carrier, the reaction proceeds at a low temperature. Examples of carriers that can be used include alumina, silica, titania, metal oxides such as zirconia, silica-alumina, silica-titania,
Examples thereof include complex oxides such as silica-calcia, zeolite, silicon carbide, porous glass and activated carbon.

The method of supporting the Group 8 element of the periodic table on the carrier is not particularly limited, but examples thereof include an impregnation method, a coprecipitation method, a deposition method, a kneading method, an ion exchange method and a CVD method.

After the Group 8 element of the periodic table is supported on the carrier, if the Group 8 element is not in the metallic state, it must be reduced to the metallic state. As a reduction method, it is common to use a reducing agent such as hydrogen, hydrazine, ammonia, or alcohol.

In the method of the present invention, in order to improve the performance of the catalyst, a compound of an alkali metal, an alkaline earth metal or a rare earth metal may be added to the Group 8 element of the periodic table. Further, it does not matter if nitrogen or carbon atom is contained in Group 8 metal of the periodic table.

The raw materials used in the process of the present invention are aromatic compounds and ammonia. The cyano group consists of nitrogen and carbon atoms, but the nitrogen source is ammonia.
Although the carbon source cannot be determined, it is considered to be an organic substance such as an aromatic compound.

As the aromatic compound, not only a hydrocarbon compound such as benzene, toluene, xylene, naphthalene and anthracene but also a compound containing a hetero atom such as oxygen and nitrogen can be used.

As the nitrogen source, amines can be used instead of ammonia. At that time, carbon contained in the amines can be used as a carbon source.

Besides the aromatic compounds and ammonia, it is also possible to use aliphatic organic compounds as carbon sources. Further, an inorganic substance such as carbon monoxide can be used as the carbon source.

In the method of the present invention, nitrogen, oxygen, air and the like may be flowed simultaneously with ammonia. Note that oxygen,
Air or the like may be supplied in a gas state or may be supplied in a state of being dissolved in an aromatic compound as a raw material.

In the method of the present invention, the presence of water and hydrogen suppresses cyanation. Therefore, the ratio of cyanation can be lowered by reacting in the presence of water and hydrogen. Further, since cyanation is promoted in the presence of oxygen and air, it is possible to increase the cyanation ratio by reacting in the presence of oxygen and air.

In the method of the present invention, the reaction temperature is 200.
The temperature is in the range of ℃ to 500 ℃. When the reaction temperature is lower than the above range, the reaction rate is slow, and when the reaction temperature is higher than the above range, side reactions often occur and the selectivity decreases. In particular, when the reaction is carried out at a temperature higher than 500 ° C., the aromatic compound is decomposed to cause industrially low value reactions such as methylation rather than amination and cyanation, and aggregation of metal components and deposition of carbonaceous matter. Therefore, the catalytic activity also decreases, which is not preferable.

In the method of the present invention, the reaction may or may not be carried out under pressure.

[0026]

INDUSTRIAL APPLICABILITY The present invention provides a method for directly aminating and / or cyanating an aromatic ring, and is extremely significant.

[0027]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto.

Examples 1 to 8 A heat-resistant glass tubular reactor was charged with 10 g of the catalyst shown in Table 1 and heated to 400 ° C. while flowing nitrogen and hydrogen at a rate of 100 ml / min. After maintaining at 400 ° C. for 1 hour, nitrogen and hydrogen were stopped, and ammonia was flown at a rate of 110 ml / min. After 2 hours, benzene was fed at a rate of 1.2 g / min. The reaction liquid was trapped between 1 hour and 2 hours after the start of benzene supply, and this was analyzed by gas chromatography. The results are shown in Table 1. As a notation of the catalyst, for example, 1% Fe silica means 1% F
It means a silica carrying e, and the same notation will be used hereinafter.

[0029]

[Table 1]

Examples 9 and 10 and Comparative Examples 1 and 2 18 g of 1% Fe silica was filled in a tubular reactor made of heat-resistant glass and heated to 450 ° C. while flowing nitrogen and hydrogen at a rate of 100 ml / min. After maintaining at 450 ° C. for 1 hour, nitrogen and hydrogen were stopped, and ammonia was flown at a rate of 110 ml / min. After 2 hours, the temperature was changed to that shown in Table 2 and benzene was fed at a rate of 1.2 g / min. The reaction liquid was trapped between 1 hour and 2 hours after the start of benzene supply, and this was analyzed by gas chromatography. The results are shown in Table 2.

Comparative Example 1 was reacted in the same manner as in Example 9 except that the reaction temperature was 550 ° C. The results are shown in Table 2.
However, the selectivity of aniline was significantly reduced, and undesired methylation mainly occurred. Comparative Example 2 is an example in which after the reaction of Comparative Example 1 was carried out, the temperature was lowered to 400 ° C. to carry out the reaction. The results are shown in Table 2, but the catalyst activity decreased after the reaction at a high temperature of 550 ° C.

[0032]

[Table 2]

Examples 11 and 12 10 g of 1% Co alumina was added to a tubular reactor made of heat-resistant glass.
It was filled and heated to 450 ° C. with flowing nitrogen and hydrogen at a rate of 100 ml / min. After maintaining at 450 ° C. for 2 hours, nitrogen and hydrogen were stopped, and ammonia was caused to flow at a rate of 110 ml / min. After 2 hours, the temperature was set as shown in Table 3 and benzene was fed at a rate of 1.2 g / min. The reaction liquid was trapped between 1 hour and 2 hours after the start of benzene supply, and this was analyzed by gas chromatography. The results are shown in Table 3.

[0034]

[Table 3]

Examples 13 to 16 In a tubular reactor made of heat-resistant glass, 15 g of 1% Pd carbon was used.
It was filled and heated to the temperature shown in Table 4 while flowing nitrogen at 90 ml / min. After the catalyst layer reached a predetermined temperature, nitrogen was stopped and ammonia was flowed at a rate of 80 ml / min. After 30 minutes, benzene was fed at 12.3 g / hour. The reaction liquid was trapped between 1 hour and 2 hours after the start of benzene supply, and this was analyzed by gas chromatography. The results are shown in Table 4.

[0036]

[Table 4]

Example 17 1% 0.5% Pd carbon was added to a tubular reactor made of heat-resistant glass.
5 g was filled. The reactor was heated while flowing nitrogen at 90 ml / min. When the temperature of the catalyst layer reached 450 ° C, the nitrogen was stopped, ammonia was flown at 40 ml / min, and water was 9 ml.
/ Hour. After the temperature of the catalyst layer was stabilized, benzene was supplied at a rate of 17.7 g / hour. The benzene conversion rate in the first hour of the reaction was 0.20%, and the benzonitrile selectivity was 40.5%. When the water supply was stopped and ammonia was flowed at 80 ml / min, the benzene conversion rate was 2.
It was 30% and the benzonitrile selectivity was 95.0%. When hydrogen was added at a rate of 40 ml / min, the benzene conversion rate was 0.46% and the benzonitrile selectivity was 64.0%.

Example 18 1% of 0.5% Pd alumina was added to a tubular reactor made of heat-resistant glass.
5 g was filled. Air at 15 ml / min and ammonia 9
The reactor was heated while flowing at 0 ml / min. When the temperature of the catalyst layer reached 200 ° C., the reaction temperature was adjusted to 400 ° C. while supplying benzene at 14 g / hour. The benzene conversion rate from the 1st hour to the 2nd hour of the reaction was 1.88%, and the benzonitrile selectivity was 92.4%.

Example 19 A tubular reactor made of heat-resistant glass was charged with 10 g of 1% Co silica, and heated to 450 ° C. while flowing nitrogen and hydrogen at a rate of 100 ml / min. After maintaining at 450 ° C. for 1 hour, nitrogen and hydrogen were stopped, and ammonia was flown at a rate of 110 ml / min. After 2 hours, the temperature was raised to 400 ° C., and toluene was supplied at a rate of 1.2 g / min. After starting benzene supply 1
The reaction solution was trapped between the second hour and the second hour, and this was analyzed by gas chromatography. As a result, the toluene conversion was 2.34%, and the selectivities were o-toluidine: 0.48%, m-toluidine: 0.96%, o-tolunitrile: 0.80%, m-tolunitrile: 2. Fifty
%, P-tolunitrile: 1.29%, benzene: 30.
34%, aniline: 7.92%, benzonitrile: 4
It was 9.01%.

Example 20 1% of 0.5% Pd carbon was added to a tubular reactor made of heat-resistant glass.
0 g was filled. The reactor was heated while flowing ammonia at a rate of 90 ml / min. When the temperature of the catalyst layer reached 400 ° C., toluene was supplied at 11.0 g / hour. Reaction 1
When the reaction solution from the second hour to the second hour was analyzed, the benzonitrile selectivity was 47.0% and the tolunitrile selectivity was 2
It was 4.8% (total value of isomers).

[0041]

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Claims (4)

[Claims] 1. A method of aminating and / or cyanating an aromatic compound using a catalyst in which a Group 8 element of the periodic table is supported on a carrier in the presence of ammonia. 2. The method according to claim 1, wherein the amination catalyst is cobalt or iron supported on a carrier. 3. The method according to claim 1, wherein the cyanation catalyst is palladium or rhodium supported on a carrier. 4. The method according to claim 1, wherein the amination and cyanation catalyst is nickel, ruthenium, iridium or platinum supported on a carrier.