JPH0784419B2 - Process for producing orthoalkylated aromatic amines - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an orthoalkylated aromatic amine selectively and in high yield using a catalyst having a long life. More specifically, in the presence of a catalyst containing iron oxide as a main component, which is obtained by high temperature calcination at a specific temperature,
The present invention relates to a method for producing an ortho-alkylated aromatic amine by reacting an aromatic amine having at least one hydrogen atom in the ortho position with a primary alcohol or a secondary alcohol under heating.

The ortho-alkylated aromatic amines are useful as intermediates for the production of medicines, agricultural chemicals, dyes, stabilizers for resins, compounding agents for rubber and the like.

(Prior Art) Conventionally, as a method for producing alkylated aromatic amines such as o-toluidine and 2,6-dimethylaniline, o
It is known to react the corresponding alkylated phenols such as cresol and 2,6-xylenol with ammonia or amine under heating in the presence of a dehydration catalyst such as alumina or silica-alumina. However, the reaction of these phenols having an alkyl group at the ortho position with ammonia or amine has an extremely slow reaction rate as compared with the reaction of the phenol with ammonia or amine, and the reaction for selecting ortho-alkylated aromatic amines And the yield is low. Moreover, since the activity of the dehydration catalyst is remarkably reduced, it cannot be said that the method is suitable as an industrial method for producing orthoalkylated aromatic amines.

Also, a method of reacting an aromatic amine such as aniline with olefin or alcohol in the presence of a Friedel-Crafts type catalyst such as Lewis acid is described by GAOlah, “Fr.
iedel Crafts and Related Reactions, Vol.2, Part
1 ”, published by Interscience Publishers (1964). However, in this method, N-alkylated aromatic amines such as N-monoalkyl aromatic amines or N, N-dialkyl aromatic amines are used when the amino groups of the aromatic amines are not substituted. As the main product, and the nuclear alkylated aromatic amines as a by-product only slightly, and as the nuclear alkylated aromatic amines, ortho-alkylated aromatic amines and para-alkylated aromatic amines. A mixture with aromatic amines is formed, and the production rate of ortho-alkylated aromatic amines is low. This tendency is particularly remarkable when alcohol is used as the alkylating agent.

In addition, as a method of improving the drawbacks of this method,
No. 4569 proposes a method of reacting aromatic amines such as aniline with olefin under the conditions of high temperature and high pressure in the presence of Friedel-Crafts type catalyst. However, although this method slightly improves the selectivity to orthoalkylated aromatic amines, it still produces a large amount of N-alkylated aromatic amines as a by-product, and selectively produces orthoalkylated aromatic amines. However, this method is not completely satisfactory as a method for industrially producing orthoalkylated aromatic amines.

As another method for producing ortho-alkylated aromatic amines, U.S. Pat.No. 2,814,646 discloses a method in which aromatic amines such as aniline are reacted with olefin under heating in the presence of a catalyst composed of aluminum anilide. A method of reacting an alkylaluminum halide with an aromatic amine such as aniline, and then reacting the mixture thus produced with olefin is proposed in Japanese Patent Publication No. 4724014. Has been done,
Further, JP-A-50-137934 proposes a method of reacting an aromatic amine such as aniline with a lower olefin in the presence of a catalyst composed of aromatic aminoaluminum and a halogenated hydrocarbon. Of these methods,
The method described in US Pat. No. 2,814,646 has a high selectivity for orthoalkylated aromatic amines in the product, but has a drawback of low reaction activity. Also,
The methods described in JP-B-47-24014 and JP-A-50-137934 both have high reaction activity,
Moreover, although it has an advantage that it is highly selective to ortho-alkylated aromatic amines in the product, it is disadvantageous in terms of a reaction device because the reaction is a reaction under high temperature and high pressure conditions, and it is considerably used as a catalyst. Since the amount of the aluminum compound is used, the post-treatment operation for separating and removing the aluminum compound from the mixture after completion of the reaction is complicated, and there are many problems in industrialization. Further, as a matter of course, since olefins are used as an alkylating agent in these methods, ortho-methylated aromatic amines such as methylaniline and dimethylaniline or orthomethylated aromatic amines having an alkyl group having 3 or more carbon atoms are used. Unable to produce -n-alkylated aromatic amines.

Therefore, in view of the above-mentioned circumstances of the conventional method, the present inventors have searched for a method suitable as a method for producing orthoalkylated aromatic amines selectively and on an industrial scale, and as a result, have found that transitions containing iron oxide A method for reacting an aromatic amine having at least one hydrogen atom at the ortho position with a primary alcohol or a secondary alcohol in the presence of a metal oxide catalyst was developed, and a patent application was previously filed. 56-110652).

(Problems to be Solved by the Invention) This prior application method is an excellent method in which the drawbacks of the conventional method are eliminated, but in view of the implementation situation after that, a catalyst having a long life and further improved durability of the catalyst Has been requested.

In response to this demand, the present invention intends to improve the durability of the catalyst used in the prior application method to prolong the catalyst life, and thus to more efficiently produce orthoalkylated aromatic amines. is there.

(Structure and Effect of the Invention) In the present invention, when an aromatic amine (a) having at least one hydrogen atom at the ortho position and a primary alcohol or a secondary alcohol (b) are heated and reacted in the presence of a catalyst, As a catalyst, 550 substances containing iron compounds as the main component
A process for producing orthoalkylated aromatic amines is characterized in that a catalyst containing iron oxide as a main component, which is obtained by firing at a temperature in the range of 850 to 850 ° C, is used.

The aromatic amines (a) used as a raw material in the present invention are aromatic amines having at least one hydrogen atom in the ortho position with respect to the amino group or the substituted amino group. The aromatic amines (a) may be aromatic amines whose aromatic nucleus is represented by any of a benzene ring, a naphthalene ring, an anthracene ring and a phenanthrene ring, and the aromatic amines (a) are It does not matter whether the aromatic amines are monoaromatic amines, secondary aromatic amines or tertiary aromatic amines. Further, the aromatic amines (a) may be any other aromatic amines (a) on the benzene ring, naphthalene ring, anthracene ring, or phenanthrene ring as long as they have at least one hydrogen atom in the ortho position with respect to the amino group or the substituted amino group. 1 for a carbon atom
It does not matter even if one or more substituents are bonded. Specifically as a substituent, an alkyl group,
Examples thereof include an aryl group, an alkoxyl group, an aryloxyl group, an acyl group, an acyloxyl group, a halogen atom and a hydroxyl group. Specific examples of aromatic amines include aniline, o-toluidine, m-toluidine, and p.
-Toluidine, o-ethylaniline, m-ethylaniline, p-ethylaniline, o-isopropylaniline,
m-isopropylaniline, p-isopropylaniline, 2,3-xylidine, 2,4-xylidine, 2,5-xylidine, 3,5-xylidine, 2,3-diethylaniline, 2,4
-Diethylaniline, 2,5-diethylaniline, 3,5-diethylaniline, 2,3-diisopropylaniline, 2,4-
Diisopropylaniline, 3,5-diisopropylaniline, N-methylaniline, N-ethylaniline, N-isopropylaniline, N, N-dimethylaniline, N, N-diethylaniline, N, N-diisopropylaniline, N-
Methyl-o-toluidine, N-methyl-2,3-xylidine, N-methyl-2,4-xylidine, N-methyl-2,5-
Xylidine, N-methyl-3,5-xylidine, N, N-dimethyl-o-toluidine, N, N-dimethyl-m-toluidine, N, N-dimethyl-p-toluidine, N, N-dimethyl-
2,3-xylidine, N, N-dimethyl-2,4-xylidine,
N, N-dimethyl-2,5-xylidine, N, N-dimethyl-3,5
-Xylidine, N-ethyl-o-ethylaniline, N-
Ethyl-m-ethylaniline, N-ethyl-p-ethylaniline, N-ethyl-2,3-dierylaniline, N-
Ethyl-2,4-diethylaniline, N-ethyl-2,5-diethylaniline, N-ethyl-3,5-diethylaniline, N, N-diethyl-o-ethylaniline, N, N-diethyl-m- Examples thereof include ethylaniline, N, N-diethyl-p-ethylaniline, α-naphthylamine and β-naphthylamine. Of these aromatic amines, it is preferable to apply the method of the present invention to aniline or o-alkylaniline.

Alcohol (b) used as a raw material in the present invention
Is a primary alcohol or secondary alcohol, usually a primary lower alcohol or secondary lower alcohol having 1 to 6 carbon atoms. Specifically as the primary alcohol,
Examples thereof include methanol, ethanol, n-propanol, n-butycohol, isobutycohol, n-pentyl alcohol, isopentyl alcohol, n-hexyl alcohol, and isohexyl alcohol. Specific examples of the secondary alcohol include isopropanol, sec-butyl alcohol, sec-pentyl alcohol, sec-hexyl alcohol, cyclohexyl alcohol and the like. Among these alcohols, it is preferable to use an alcohol having 1 to 3 carbon atoms, and it is particularly preferable to use methanol, ethanol or isopropanol. The proportion of these alcohols used is usually 1 to 10 mol, preferably 3 to 6 mol, per 1 mol of the aromatic amines.

The catalyst used in the present invention is a catalyst containing iron oxide as a main component, which is obtained by firing a substance containing an iron compound as a main component at a temperature in the range of 550 to 850 ° C. Examples of the substance containing an iron compound as a main component include various salts, for example, substances including inorganic acid salts such as hydrochlorides, sulfates and nitrates, organic acid salts such as acetates and oxides. .

The catalyst used in the present invention is obtained by firing such a substance containing an iron compound as a main component at a high temperature in the range of 550 to 850 ° C. If the calcination temperature is less than 550 ° C, the life of the obtained catalyst is not sufficient, and if it exceeds 850 ° C, the activity of the obtained catalyst for producing orthoalkylated aromatic amines is decreased, which is not preferable. .

By such high temperature calcination, the substance containing the iron compound as the main component is changed to an oxide, and the catalyst containing iron oxide as the main component used in the present invention is obtained. In the present invention, a substance containing an iron compound as a main component and a substance containing a compound of another transition metal as a main component are calcined, and an iron oxide as a main component is added to such other transition metal in the resulting catalyst. The oxide may be included. And as such other transition metals, for example, titanium, vanadium, chromium, manganese, cobalt, nickel, zinc,
Examples thereof include yttrium, zirconium, niobium, molybdenum, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum and mercury. As such a transition metal compound, similar to the iron compound,
Mention may be made of various salts, for example salts of inorganic acids such as hydrochlorides, sulphates, nitrates, organic acid salts and oxides such as acetates.

By firing a substance containing such a compound of another transition metal as a main component together with a substance containing an iron compound as a main component as described above, iron oxide as a main component, and such other transition A catalyst containing a metal oxide can be obtained.

Furthermore, in the method of the present invention, a metal oxide composition containing iron oxide (and other oxides of other transition metals) as a main component and a non-transition metal oxide as a minor component as a catalyst is used as a catalyst. It can also be used.

Examples of such non-transition metal oxides include aluminum oxide, gallium oxide, indium oxide, silicon oxide, germanium oxide, tin oxide, antimony oxide, bismuth oxide, sodium oxide, potassium oxide, magnesium oxide, calcium oxide, Examples thereof include strontium oxide and barium oxide.

In the present invention, among these non-transition metal oxides, when metal oxides such as gallium oxide, germanium oxide, and tin oxide are used, the selectivity to orthoalkylated aromatic amines is high and the reaction is high. It is particularly preferable because the decomposition of alcohol at the time can be suppressed.

In the method of the present invention, the catalyst may be used as it is, or may be used as a product supported on various carriers or added with various binders.

As a method for preparing the catalyst used in the method of the present invention, a substance containing the iron compound as a main component is added to 550 to 850.
℃, preferably at a temperature in the range of 650 ~ 750 ℃, 0.5 ~ 20,
Preferably, a method of performing heat treatment for 2 to 10 hours (hr) in an atmosphere of air such as air or nitrogen gas, usually air.

According to the method of the present invention, the aromatic amines (a) having at least one hydrogen atom at the ortho position and the above-mentioned compound are prepared in the presence of the thus-prepared catalyst containing iron oxide as a main component. By reacting the primary alcohol or the secondary alcohol (b) with heating, orthoalkylated aromatic amines are selectively produced. This reaction can be carried out by a liquid phase reaction or a gas phase reaction, but is preferably carried out by a gas phase reaction.

In the method of the present invention, when the reaction is carried out by a gas phase method, the reaction temperature is usually 200 to 500 ° C., preferably
It is in the range of 250 to 450 ° C. Liquid space velocity of the feedstock when the reaction is carried out (LHSV) to not usually 0.05 10 hr ^-1, preferably in the range from 0.2 to 4.0hr ^-1. The reaction can be carried out either under reduced pressure or under increased pressure, but preferably atmospheric pressure or 30
It is carried out under pressure in the range of kg / cm ² -G. After the reaction, the unreacted alcohol is separated from the mixture, and the unreacted starting aromatic amines are recovered, and then treated by a conventional method such as distillation, crystallization, or extraction to obtain an orthoalkylated aromatic amine. Kind is obtained. The recovered unreacted alcohol and aromatic amines having ortho hydrogen are recycled to the reaction.

(Examples and Comparative Examples) Example 1 After dissolving 202.0 g of ferric nitrate nonahydrate in 2 of distilled water, 25% aqueous ammonia was gradually added to adjust the pH of the solution to 7. The formed precipitate was washed with water and filtered. To this, 1.62 g of germanium dioxide was added, and the mixture was kneaded for 1 hour using an automatic mortar. This was dried at 90 ° C for 24 hours and then calcined at 650 ° C for 2 hours to prepare a Fe ₂ O ₃ · GeO ₂ -containing catalyst.

10 ml of the catalyst crushed to 6 to 10 mesh was filled in a Pyrex reaction tube having an inner diameter of 20 mm and then heated to 360 ° C. After reaching the predetermined temperature, a reaction mixture was fed at a rate of 3 ml / hr with a mixture of aniline: methanol: H ₂ O in a molar ratio of 1: 5: 2. The results are shown in Table 1.

Example 2 202 g of ferric nitrate nonahydrate, chromium nitrate nonahydrate 4.28
An aqueous solution 0.5 in which 2.52 g of germanium oxide was dissolved was added to an aqueous solution 2 in which g was dissolved, and then 25% aqueous ammonia was gradually added to adjust the pH of the solution to 9. The formed precipitate was washed with water, filtered, dried at 90 ° C for one day and then calcined at 700 ° C for 3 hours to prepare a Fe ₂ O ₃ · GeO ₂ · Cr ₂ O ₃ catalyst. Using this catalyst, a reaction was carried out under the conditions of Example 1, and the results shown in Table 1 were obtained.

Example 3 The catalyst was prepared and the reaction was carried out under the same conditions as in Example 2 except that the calcination temperature was changed to 750 ° C. The results are shown in Table 1.

Example 4 The reaction was performed under the same conditions as in Example 2, except that methanol was changed to ethanol. The results are shown in Table 1.

Example 5 In Example 2, after firing at 600 ° C. for 3 hours, 700 ° C.
A catalyst was prepared and reacted under the same conditions except that the temperature was raised to 3, and the treatment was continued for 3 hours. The results are shown in Table 1.

Example 6 A catalyst was prepared under the same conditions as in Example 2, except that 2.52 g of germanium oxide was replaced with 15 g of 20% silica sol,
The reaction was carried out. The results are shown in Table 1.

Comparative Examples 1 and 2 In Example 2, the firing temperature was 500 ° C. (Comparative Example 1) or 8
The reaction was performed under the same conditions except that the temperature was changed to 80 ° C (Comparative Example 2). The results are shown in Table 1.

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Claims (5)

[Claims] 1. A catalyst for heating an aromatic amine (a) having at least one hydrogen atom at the ortho position and a primary alcohol or a secondary alcohol (b) in the presence of a catalyst, using iron as a catalyst. 55 substances containing compounds as main components
A method for producing ortho-alkylated aromatic amines, which comprises using a catalyst containing iron oxide as a main component obtained by firing at a temperature in the range of 0 to 850 ° C. 2. The method according to claim 1, wherein the aromatic amine (a) having at least one hydrogen atom in the ortho position is aniline or o-alkylaniline. 3. The method according to claim (1) or (2), wherein the alcohol is methanol, ethanol or isopropanol. 4. A method according to claim 1, wherein the reaction is carried out in a gas phase.
The method according to any one of items 1 to 3. 5. The method according to any one of claims (1) to (4), wherein the reaction is carried out at a temperature in the range of 250 to 450 ° C.