JPS6219422B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for selectively and in high yields producing orthoalkylated aromatic amines. More specifically, aromatic amines having at least one hydrogen atom in the ortho position and a primary or secondary alcohol are heated in the presence of a catalyst containing iron oxide and/or manganese oxide as a main component. The present invention relates to a method for producing ortho-alkylated aromatic amines by reaction. Ortho-alkylated aromatic amines are useful as intermediates in the production of pharmaceuticals, agricultural chemicals, dyes, stabilizers for resins, compounding agents for rubber, and the like. Conventionally, as a method for producing alkylated aromatic amines such as o-toluidine and 2,6-dimethylaniline, a corresponding alkylated phenol such as o-cresol and 2,6-xylenol and ammonia or amine are combined with alumina. Alternatively, a method of reacting in the presence of a dehydration catalyst such as silica alumina is known. However, the reaction rate of these phenols having an alkyl group at the ortho position with ammonia or amines is extremely slow compared to the reaction of phenols with ammonia or amines, making it difficult to select ortho-alkylated aromatic amines. The yield is also low. Moreover, since the activity of the dehydration catalyst is significantly reduced, it is difficult to say that this method is suitable as an industrial method for producing ortho-alkylated aromatic amines. Additionally, a method for reacting aromatic amines such as aniline with olefins or alcohols in the presence of a Friedel-Crafts type catalyst such as a Lewis acid is also described in ``Friedel Crafts and Related
Reactions, Vol.2, Part1”, Interscience
Published by Publishers (1964).
However, in this method, when the amino group of aromatic amines is not substituted, N-alkylated aromatic amines such as N-monoalkyl aromatic amines or N·N-dialkyl aromatic amines is produced as the main product, and only a small amount of the alkylated aromatic amines are produced as a by-product, and the alkylated aromatic amines include ortho-alkylated aromatic amines and para-alkylated aromatic amines. A mixture with group amines is produced, and the production rate of ortho-alkylated aromatic amines is low. This tendency is particularly pronounced when alcohols are used as alkylating agents. In addition, as a method to improve the drawbacks of this method, Japanese Patent Publication No. 38-4569 describes the reaction of aromatic amines such as aniline with olefins under high temperature and high pressure conditions in the presence of a Friedel-Crafts type catalyst. A method has been proposed. However, although this method slightly improves the selectivity to ortho-alkylated aromatic amines, it still
-Many alkylated aromatic amines are produced as by-products, making it difficult to selectively produce ortho-alkylated aromatic amines, which is completely satisfactory as a method for industrially producing ortho-alkylated aromatic amines. Not the method. In addition, as another method for producing ortho-alkylated aromatic amines, US Pat. A method has been proposed to
Japanese Patent Publication No. 47-24014 proposes a method of reacting an alkyl aluminum halide with an aromatic amine such as aniline, and then reacting the mixture thus produced with an olefin. Japanese Patent Publication No. 137934/1983 proposes a method of reacting aromatic amines such as aniline with lower olefins in the presence of a catalyst consisting of aromatic aminoaluminum and a halogenated hydrocarbon. Among these methods, the said U.S. Pat.
The method described in No. 2814646 has a high selectivity for ortho-alkylated aromatic amines in the product, but has the drawback of low reaction activity. In addition, the above-mentioned Japanese Patent Publication No. 47-24014 and Japanese Unexamined Patent Application Publication No. 1973
All of the methods described in JP-137934 have the advantage of high reaction activity and high selectivity to ortho-alkylated aromatic amines in the product. However, in both of these methods, the reaction is carried out under conditions of high temperature and high pressure, which is disadvantageous in terms of the reaction equipment, and since a considerable amount of aluminum compound is used as a catalyst, There are many problems in industrialization, such as the complicated post-processing operations to separate and remove aluminum compounds. Naturally, since these methods use olefin as an alkylating agent, ortho-alkylated aromatic amines such as methylaniline and dimethylaniline, or those whose alkyl group has 3 or more carbon atoms, Ortho-n-alkylated aromatic amines cannot be produced. In view of the above-mentioned circumstances of the conventional methods, the present inventors searched for a method suitable for selectively producing ortho-alkylated phenols on an industrial scale. It has been discovered that the above object can be achieved by reacting an aromatic amine having at least one hydrogen atom in the ortho position with a primary alcohol or a secondary alcohol in the presence of a catalyst contained as a component, and the present invention Reached. That is, the present invention involves heating an aromatic amine (a) having at least one hydrogen atom in the ortho position and a primary alcohol or a secondary alcohol (b) in the presence of a catalyst containing a transition metal oxide. This is a method for producing ortho-alkylated aromatic amines, which is characterized by reacting with. The aromatic amine (a) used as a raw material in the present invention is an aromatic amine having at least one hydrogen atom at the ortho position to the amino group or substituted amino group. The aromatic amine (a) may be an aromatic amine represented by a benzene ring, a naphthalene ring, an anthracene ring, or a phenanthrene ring; Any aromatic amine such as monoaromatic amines, secondary aromatic amines, or tertiary aromatic amines may be used. Further, as long as the aromatic amine (a) has at least one hydrogen atom at the ortho position with respect to the amino group or substituted amino group, the aromatic amines (a) may be One or more substituents may be bonded to a carbon atom. Specific examples of the substituent include an alkyl group, an aryl group, an alkoxyl group, an aryloxyl group, an acyl group, an acyloxyl group, a halogen atom, and a hydroxyl group. Specifically, the aromatic amines include aniline, o-toluidine, m-toluidine, 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-diisopropyloaniline, 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-diethylaniline, N
-Ethyl-2,4-diethylaniline, N-ethyl-2,5-diethylaniline, N-ethyl-
3.5-diethylaniline, N.N-diethyl-
Examples include o-ethylaniline, N·N-diethyl-m-ethylaniline, N·N-diethyl-p-ethylaniline, α-naphthylamine, and β-naphthylamine. Among these aromatic amines, it is preferable to apply the method of the present invention to aniline or o-alkylaniline. The alcohol (a) used as a raw material in the present invention is a primary alcohol or a secondary alcohol, and is usually a primary lower alcohol or a secondary lower alcohol having 1 to 6 carbon atoms. Specifically, primary alcohols include methanol, ethanol, n-propanol, n-butyl alcohol,
Examples include isobutyl alcohol, n-pentyl alcohol, isopentyl alcohol, n-hexyl alcohol, and isohexyl alcohol. Specifically, the secondary alcohols include isopropal, sec-butyl alcohol,
Examples include sec-pentyl alcohol, sec-hexyl alcohol, and cyclohexyl alcohol. Among these alcohols,
Preference is given to using alcohols having 1 to 3 carbon atoms, particularly methanol, ethanol or isopropal. The proportion of these alcohols used is usually in the range of 1 to 10 mol, preferably 3 to 6 mol, per 1 mol of the aromatic amine. The catalyst used in the present invention is a catalyst containing iron oxide and/or manganese oxide as a main component, and it is particularly preferable to use a catalyst containing iron oxide as a main component. The catalyst includes a catalyst consisting only of iron oxide and/or manganese oxide, a catalyst in which iron oxide and/or manganese oxide is supported on various carriers, and a catalyst formed by adding various binders to iron oxide and/or manganese oxide. Examples include catalysts. In the present invention, a metal oxide composition containing iron oxide and/or manganese oxide as a main component and a small amount of other metal oxides can also be used as a catalyst. Here, specific examples of other metal oxides added as minor components to the above-mentioned transition metal oxides include aluminum oxide,
Examples include oxides of non-transition metal elements such as gallium oxide, indium oxide, silicon oxide, germanium oxide, tin oxide, antimony oxide, bismuth oxide, sodium oxide, potassium oxide, magnesium oxide, calcium oxide, strontium oxide, and barium oxide. be able to. In the present invention, when a multicomponent catalyst containing iron oxide and other metal oxides such as gallium oxide, germanium oxide, tin oxide, niobium oxide, zirconium oxide, and hafnium oxide is used, ortho-alkylated aromatic It is particularly preferred because it has high selectivity to amines and can suppress the decomposition of alcohol during the reaction. The method for preparing the catalyst used in the method of the present invention includes a method of calcining an iron compound and/or a manganese compound that can become iron oxide and/or manganese oxide, a method of calcining an iron compound and/or a manganese compound that can become iron oxide and/or manganese oxide, Alternatively, a method of firing a mixture consisting of a manganese compound and a metal compound that can become another metal oxide as a minor component, or a method of firing after drying an aqueous solution of the mixture can be exemplified. In the method of the present invention, when using a catalyst in which a metal oxide containing iron oxide and/or manganese oxide as a main component is supported on a carrier, the method for preparing the catalyst is to convert the transition metal oxide to the metal oxide by calcination. A method in which a mixture consisting of a transition metal compound that can become a transition metal compound, and a metal compound that can become another metal oxide as a minor component by firing if necessary, is blended into a carrier, then molded and fired, or a mixture that is made of the metal compound. Examples include a method in which a carrier is impregnated with an aqueous solution of the mixture and then fired. In the method of the present invention, in the presence of a catalyst containing the transition metal oxide as a main component, the aromatic amine (a) having at least one hydrogen atom at the ortho position and the primary alcohol or secondary alcohol By reacting (b) under heating, ortho-alkylated aromatic amines are selectively produced.
This reaction can be carried out by a liquid phase reaction or a gas phase reaction, but it 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 in the range of 250 to 450℃. When carrying out the reaction, the liquid hourly space velocity (LHSV) of the feedstock is usually between 0.1 and 10 hr ^-1 , preferably 0.4.
to 4.0hr ^-1 . The reaction can usually be carried out under reduced pressure or increased pressure, but preferably 1 to 30
It is carried out under pressures in the range Kl/cm ² -G. Separate unreacted alcohol from the mixture after the reaction is complete,
Next, unreacted raw material aromatic amines are recovered and treated by conventional methods such as distillation, crystallization, and extraction to obtain ortho-alkylated aromatic amines. The recovered unreacted alcohol and aromatic amines having hydrogen at the ortho position are recycled and reused in the reaction. Next, the method of the present invention will be specifically explained using examples. Example 1 After dissolving 202.0 g of ferric nitrate nonahydrate in distilled water from Step 2, 25% ammonia water was gradually added to adjust the pH of the liquid to 7. The generated precipitate was washed with water. Add 0.55g of germanium dioxide to this,
The mixture was kneaded for 1 hour using an automatic mortar. This was dried at 90°C for a day and night, and then calcined at 450°C for 3 hours to prepare a catalyst consisting of iron oxide and germanium oxide. 20ml of catalyst crushed into 6-10 meshes with inner diameter of 20mm
After filling a Pyrex reaction tube, the mixture was heated to 370°C. After reaching a predetermined temperature, a mixture of aniline and methanol in a molar ratio of 1:5 was supplied at a rate of 14 ml/hr to carry out a reaction. The results are shown in Table 1. Example 2 The reaction was carried out under the same conditions as in Example 1 except that the raw materials were changed to a mixture of aniline:methanol:H ₂ O in a molar ratio of 1:5:2. The results are shown in Table 1. Example 3 The reaction was carried out under the same conditions as in Example 1 except that the catalyst was changed to Mno-SiO ₂ and the reaction temperature was changed to 430°C. The results are shown in Table 1. Example 4 The reaction was carried out under the same conditions as in Example 1 except that methanol as a raw material was changed to ethanol. The results are shown in Table 1. Comparative Example 1 The reaction was carried out under the same conditions as in Example 1 except that the catalyst was changed to commercially available silica-alumina (SiO ₂ :Al ₂ O ₃ =85:15 weight ratio). The results are shown in Table 1. 【table】

Claims (1)

[Claims] 1. Aromatic amines (a) having at least one hydrogen atom in the ortho position and a primary alcohol or a secondary alcohol in the presence of a catalyst containing iron oxide and/or manganese oxide as a main component. A method for producing ortho-alkylated aromatic amines, which comprises reacting alcohol (b) under heating. 2. The method according to claim 1, wherein the catalyst is a catalyst containing iron oxide as a main component. 3. The method according to any one of claims 1 to 2, wherein the aromatic amine (a) having at least one hydrogen atom at the ortho position is aniline or o-alkylaniline. 4. The method according to any one of claims 1 to 3, wherein the alcohol is methanol, ethanol, or isopropanol. 5. The method according to any one of claims 1 to 4, wherein the reaction is carried out by a gas phase method. 6. A method according to any one of claims 1 to 5, wherein the reaction is carried out at a temperature in the range of 250 to 450°C.