JPS6391351A - Production of n-alkylated aromatic amines - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an intermediate for producing drugs, agricultural chemicals, etc., selectively and in high yield, by reacting a specific aromatic amine with a primary or secondary alcohol in the presence of an iron oxide catalyst containing copper oxide and chromium oxide. CONSTITUTION:An aromatic amine (e.g. aniline, o-tiluidine, p-tiluidine, etc.) containing at least one H in the amino group is reacted with a primary alcohol (e.g. methanol, ethanol, n-propanol, etc.) or a secondary alcohol (e.g. isopropanol, sec-butyl alcohol, etc.) in the presence of an iron oxide catalyst containing copper oxide and chromium oxide to give an N-alkylated aromatic amine. The catalyst is obtained by a method of calcining a mixture of metallic compounds capable of becoming iron oxide, copper oxide and chromium oxide, a method of completely drying the aqueous solution of the mixture and calcining, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for selectively producing N-alkylated aromatic amines. More specifically, N-alkylated aromatic amines are produced by reacting aromatic amines having at least one hydrogen atom in the amino group with a primary alcohol or a secondary alcohol in the presence of a specific catalyst. The present invention relates to a method for selectively producing .

N-alkylated aromatic amines are used in pharmaceuticals, agricultural chemicals, explosives,
It is useful as an intermediate in the production of dyes, stabilizers for resins, compounding agents for rubber, etc.

(Prior Art) Conventionally, various methods have been known for producing N-alkylated aromatic amines.
No. 81228 proposes a method in which aniline and a lower alcohol are reacted in the presence of a phosphoric acid catalyst. However, this method produced a large amount of N,N-dialkyl by-products and was not fully satisfactory as a selective method for producing N-alkylated aniline.

Under these circumstances, the inventors of the present invention have previously
No. 6-110652 proposed a method for obtaining ortho-alkylated aromatic amines by reacting an aromatic amine such as aniline with an alcohol such as methanol in the presence of a transition metal oxide-containing catalyst.

In this method, N-alkylated amines are simultaneously produced, and as a result of subsequent research, the present inventors found that N- They discovered that alkylated amines could be selectively obtained in high yields, and based on this knowledge, they completed the invention and filed a patent application (Japanese Patent Application No. 6'0'-81'O'60).

(Objective and Structure of the Invention) Although the method disclosed in the patent application is satisfactory as a selective method for producing N-alkylated amines, the present inventors further conducted research and arrived at the present invention.

The present invention aims to provide a method for producing N-alkylated aromatic amines more selectively and in high yields.

That is, the present invention involves reacting an aromatic amine having at least one hydrogen atom in an amino group with a primary alcohol or a secondary alcohol in the presence of an iron oxide catalyst containing copper oxide and chromium oxide. This is a method for producing N-alkylated aromatic amines characterized by the following.

The aromatic amines used as raw materials in the present invention are aromatic amines having at least one hydrogen atom in the amine group. The aromatic nucleus of the aromatic amines may be any one of a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring. Further, as long as the aromatic amines have at least one hydrogen atom in the amino group, the above-mentioned benzene ring, naphthalene ring,
I can't help it. Specifically, substituents include alkyl groups, aryl groups, alkoxyl groups, aryloxyl groups, acyl groups, acyloxyl groups, halogen atoms,
Examples include hydroxyl group and nitro group. Specifically, the aromatic amines include aniline, 0-toluidine, m-) luidine, p-) luidine, 0-ethylaniline, m-ethylaniline, p-ethylaniline, 0-
Isopropylaniline, m-isopropylaniline, p
-isopropylaniline, 2,3-xylidine, 2.4
-ki, silydine, 2.5-xylidine, 3゜5-xylidine, 2.3-diethylaniline, 2.4-diethylaniline, 2.5-'; ethylaniline, 3.5-diethylaniline, 2.3 -diisopropylaniline, 2,4
-diisopropylaniline, 3,5-diisopropylaniline, N-methylaniline, N-ethylaniline, N
-isopropylaniline, N-methyl-〇-toluidine, N-methyl-2,3-xylidine, N-methyl-2,
4-xylidine, N-methyl-2,5-xylidine, N
-Methyl-3,5-xylidine, 0-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, α-naphthylamine, β-naphthylamine, and the like. Among these aromatic amines, it is preferable to apply the method of the present invention to aniline or 0-alkylaniline.

The alcohol used as a raw material in the present invention is a primary alcohol or a secondary alcohol, and usually has 1 carbon number.
to 6 primary lower alcohols or secondary lower alcohols. Specifically, primary alcohols include methanol, ethanol, n-propanol, n-butyl alcohol, isobutyl alcohol, n-pentyl alcohol,
Examples include impentyl alcohol, n-hexyl alcohol, and isohexyl alcohol. Specifically, the secondary alcohol includes Impropatool, 5
Examples include ec-butyl alcohol, 5ec-pentyl alcohol, 5ec-hexyl alcohol, and cyclohexyl alcohol. Among these alcohols, it is preferable to use alcohols having 1 to 3 carbon atoms, and it is particularly preferable to use methanol ethanol or impropatol. The proportion of these alcohols used is usually 1 to 20 parts by mole, preferably 3 to 1 part by mole, per 1 part by mole of the aromatic amine.
The range is 0 mole part.

The catalyst used in the present invention is an iron oxide catalyst containing copper oxide and chromium oxide. The catalyst may be formed by supporting a metal oxide on a carrier, or by adding various binders to the metal oxide and forming the catalyst.

The catalyst used in the present invention is an iron oxide catalyst containing copper oxide and chromium oxide, and the atomic ratio of iron in this catalyst is usually 5% to the total amount of iron, copper, and chromium.
It is 0% or more, preferably 80% or more. In addition, the atomic ratio of copper to iron is usually 0.5 to 20%, preferably 1 to 20%.
10%, and the atomic ratio of chromium to iron is usually 0.5
-20%, preferably 1-5%.

Examples of methods for preparing the catalyst used in the non-invention include a method in which a mixture of metal compounds that can become iron oxide, copper oxide, and chromium oxide is calcined, or a method in which an aqueous solution of the mixture is dried and then calcined. be able to.

The catalyst can be supported on a carrier by mixing a mixture of metal compounds that can be converted into a metal oxide by baking into a carrier, then molding and baking, or by impregnating the carrier with an aqueous solution of a mixture of metal compounds. Examples include a method in which the material is fired later.

Examples of the above metal compounds include hydrochloride, sulfate,
Examples include substances containing inorganic acid salts such as nitrates, organic acid salts such as acetates, and metal oxides.

The catalyst used in the present invention usually has a molecular weight of 400 to 800
It is obtained by firing at a temperature of 50°C, preferably in the range of 550 to 800°C.

In addition to the catalyst preparation method described above, for example, a mixture of an iron compound and a copper compound is fired at a temperature of 400 to 850°C to form iron oxide-copper oxide, and then a chromium compound is kneaded therein.
Alternatively, there is also a method of impregnating an aqueous solution of a chromium compound and then calcining it again at a temperature of 400 to 850°C to prepare a catalyst consisting of iron oxide, copper oxide, and chromium oxide.

In the present invention, the reaction is usually carried out at 180-400°C, preferably 220-300°C. When carrying out the reaction, the liquid hourly space velocity (LH3V) of the feedstock usually ranges from 0.05 to 5 hr', preferably from 0.1 to 1, Qhr-'. Although the reaction can be carried out under reduced pressure or increased pressure, it is preferably carried out under a pressure in the range of normal pressure to 30 kg/c/(gauge). In the present invention, the reaction between aromatic amines and alcohols can also be carried out in the presence of water, in which case the proportion of water is 1 mole part of aromatic amines.
~10 molar parts.

This reaction can be carried out by either a liquid phase reaction or a gas phase reaction, but is preferably carried out by a gas phase reaction.

When the reaction is completed, the unreacted alcohol is separated from the mixture, and the unreacted raw material aromatic amines are recovered, and then the target N-alkylated aromatic amine is extracted by a conventional method such as distillation, crystallization, or extraction. get the kind. The recovered unreacted alcohol and raw aromatic amines are recycled and reused in the reaction.

Specifically, the N-alkylated aromatic amines obtained by the method of the present invention include, for example, N-methylaniline,
N-ethylaniline, N-isopropylaniline, N,
N-dimethylaniline, N, N-diethylaniline, N
-Methyl-N-ethylaniline, N,N-diisopropylaniline, N-methyl-o-)luidine, N-methyl-p-toluidine, N-methyl-m-)luidine, N-
Methyl-xylidine, N-ethyl-xylidine, N, N
-dimethyl-toluidine, N,N-dimethyl-xylidine, N-ethyl-〇-ethylaniline, N,N-diethyl-〇-ethylaniline, N,N-diethyl-p-ethylaniline, N-methyl-naphthylamine be. Among these, N-methylaniline, N-methyl-
It is suitable to apply the method of the present invention to the production of 0-toluidine, N-methyl-xylidine, N-ethylaniline, and N,N-dimethylaniline.

(Examples and Comparative Examples) The catalysts, raw materials, some of the reaction conditions, and the results in each Example and each Comparative Example are collectively shown in Table 1 (Parts 1 to 3) below.

Example 1 Ferric nitrate nonahydrate 202g, copper nitrate trihydrate 6.01g
g, 25% by weight ammonia water was gradually added to aqueous solution 21 in which 6.61 g of chromium nitrate nonahydrate was dissolved, and the p of the liquid was
H was set to 7. After washing the generated precipitate with water and filtering, 90
It was dried at ℃ for a day and night, then fired at 750℃ for 3 hours, and the atomic ratio of iron, copper, and chromium was 92.5/4.5/3.
．． A Fe2O* .CuO.Cr2O+ catalyst having a concentration of 0 was prepared.

10 mji of catalyst crushed into 6 to 20 pieces! The inner diameter 2
After filling a 0 mm Pyrex reaction tube, 280
heated to ℃. Next, at the same temperature, a mixed solution having a molar ratio of aniline:methanol:water of 1:5:2 was supplied at a rate of 4 mf/hr to carry out a reaction.

Example 2 202 g of ferric nitrate nonahydrate and chromium nitrate nonahydrate 6.
25% by weight aqueous ammonia was gradually added to the aqueous solution 2β in which 61 g was dissolved, and the pH of the liquid was adjusted to 7. After washing the generated precipitate with water and filtering it, 6.01 g of copper nitrate trihydrate was added to the precipitate.
g was added and kneaded in an automatic mortar for 1 hour. This is 90℃
It was dried at 750°C for 3 hours, and then
An e2O, -CuO.Cr20a catalyst was prepared.

A reaction was carried out in the same manner as in Example 1 using this catalyst.

Examples 3 to 4 In Example 1, the reaction temperature was changed from 280°C to 240°C (
Example 3) or 320°C (Example 4)
A catalyst was prepared and a reaction was carried out under the same conditions as in Example 1.

Examples 5 to 7 In Example 1, the raw material aniline was replaced with para-toluidine (
Example 5) A catalyst was prepared and a reaction was carried out under the same conditions as in Example 1, except that m-isopropylaniline (Example 6) or m-interobenylaniline (Example 7) was used.

Examples 8 to 9 In Example 1, methanol as a raw material was prepared into ethanol,
The reaction was carried out.

Examples 10 to 11 In Example 1, the atomic ratio of iron, copper, and chromium was 95 and 5.
/ 1.5 / 3°0 (Example 10) or Example 1 except that the quantitative ratio was changed to Example 12 reaction time of 5 hours to 300 hours.
The reaction was carried out in the same manner.

Example 13 20 g of the powdered catalyst prepared in Example 1 and 250 g of a raw material having a molar ratio of aniline:methanol-125 were added to 500 g of the powdered catalyst prepared in Example 1.
The mixture was placed in a mj2 autoclave and reacted in a liquid phase at 250°C for 5 hours.

Comparative Examples 1 to 3 Fear 3 catalyst (Comparative Example 1), atomic ratio of iron and copper is 95,
Fe2O3/CuO catalyst (comparative example 2) with a ratio of 5/4.5, Fe2O3 with an atomic ratio of iron and chromium of 97/3
-'Cr2O.

Example 1 except that each catalyst (Comparative Example 3) was used.
The reaction was carried out in the same manner.

Table 1 (Part 3) Procedural amendment July 11, 1986

Claims (1)

[Claims] (1) An aromatic amine having at least one hydrogen atom in the amino group and a primary alcohol or a secondary alcohol are reacted in the presence of an iron oxide catalyst containing copper oxide and chromium oxide. A method for producing N-alkylated aromatic amines.