JPH03181447A - Production of n,n-disubstituted anilines - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful as a synthetic raw material for azo dye, etc., under mild condition in a short time by reacting an N- substituted aniline compound with an organic halide in he presence of a phosphoric acid salt as an acid acceptor and an inorganic iodide compound as a catalyst. CONSTITUTION:The objective compound of formula III can be produced by reacting an N-substituted aniline compound of formula I (R is H, Cl, No2, 1-6C alkyl, alkyloxy, alkenyl, etc.; R<1> is 1-6C alkyl or alkenyl) with an organic halide compound of formula II (R<2> is organic substituent; X is Cl or Br) (e.g. methyl chloride or methoxyethyl bromide) at 60-160 deg.C (preferably 90-110 deg.C) under a pressure of <=5kg/cm<2>G (preferably 2-4kg/cm<2>G) in the presence of a phosphoric acid salt as an acid acceptor and an inorganic iodide compound as a catalyst. The iodide compound is e.g. NaI and its amount is preferably 0.03-0.2mol per 1mol of the compound of formula I.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing N,N-disubstituted aniline, and particularly relates to a method for producing N,N-disubstituted aniline represented by the formula - .

The N,N-disubstituted aniline compound of formula (nl) or (rV) above is an intermediate of N,N-disubstituted p-phenylenediamine, which is useful as a raw material for the synthesis of color developing agents and many azo dyes. .

[Prior art] Synthesis of N,N-disubstituted aniline, which has been known as an intermediate in the production of N,N-disubstituted p-phenylenediamine, which is useful as a raw material for various industrial chemicals such as the main ingredient of color developers. As a method, a method of reacting an N-substituted aniline with an alkyl bromide for a long time (Japanese Patent Application Laid-open No. 47-1
1534 and JP-A-50-131526), a method of reacting p-toluenesulfonic acid ester of monoalkyl ether with N-substituted aniline (see JP-A-51-95849), and N A method is known in which N-substituted aniline is reacted with an alkyl chloride in the presence of anhydrous phosphate (see Japanese Patent Publication No. 60-13023).

Furthermore, a method of reacting an aromatic amine with an organic halide in the presence of a strong alkali such as sodium hydroxide or potassium hydroxide is well known.

[Problem to be Solved by the Invention 1] However, the method of reacting N-substituted aniline with alkyl bromide has problems in that the alkyl bromide used as a raw material is extremely expensive and the reaction takes a long time. There is. Also, 1 liter of monoalkyl ether
The method of reacting -)-luenesulfonic acid ester with N-substituted aniline has the problem of elimination. Furthermore, the method of reacting an alkyl chloride with an N-substituted aniline in the presence of anhydrous phosphate requires high temperature and high pressure, and the reaction system is non-aqueous because the raw material alkyl chloride is hydrolyzed at high temperature. Both of these methods pose problems in terms of equipment and industrial production.

On the other hand, in the presence of a strong alkali such as sodium hydroxide,
When reacting an aromatic amine and an organic halide 5
If high temperatures are used to speed up the reaction rate, problems such as equipment corrosion may occur, and if the organic halide has a hydroxyl group in its molecule, such as ethylene chlorohydrin, the organic halide itself may polymerize. Undesirable reactions such as

Although it is necessary to use organic iodides to achieve high reaction efficiency by performing the reaction at low temperatures, organic iodides are extremely expensive and are problematic for industrial use for economic reasons.

An object of the present invention is to provide highly purified N and N- under mild conditions.

[Means for Solving the Problems 1] As a result of intensive research in view of the above-mentioned problems, the present invention has been developed by using a phosphate as a deoxidizing agent and an inorganic iodide compound as a catalyst. We have discovered a new production method that allows the reaction to proceed in a short time under mild reaction conditions under low pressure.

That is, 1 the present invention is - a mathematical formula (where R in the formula is H, C1, NO□ or carbon v
It is an alkyl group, alkyloxy group or alkenyl group having from 1 to 6 carbon atoms, and R' is an alkyl group or alkenyl group having 1 to 6 carbon atoms. ) and the general formula % formula % () (wherein R2 in formula 1 is an organic substituent, X is Ct or Br
It is. ) is reacted in the presence of an aqueous phosphate solution and an iodide compound (wherein R, R' and R2 are the same as above). , a method for producing N-disubstituted anilines.

In the method of the present invention, when R1 of the N-substituted aniline of the formula (I) as a raw material is hydrogen, that is, when starting from an aromatic amine of the formula -, the N,N-disubstituted aniline obtained is: An N,N-disubstituted aniline of the general formula is obtained.

[Detailed description of the invention]

(1) Raw material N-aniline and Group amine Examples of the N-substituted aniline of formula (I) or the aromatic amine of formula (■°) used in the present invention include aniline, chloroaniline, nitroaniline, N-
Aniline derivatives such as hydroxyethylaniline, N-hydroxypropylaniline, N-methoxyethylaniline, toluidine, N-hydroxyethyltoluidine,
Toluidine derivatives such as N-hydroxypropyltoluidine and N-methoxyethyltoluidine, anisidine, N
Examples include anisidine derivatives such as -hydroxyethylanisidine, N-hydroxypropylanisidine, and N-methoxyethylanisidine.

The organic halides of formula (TI) used in the present invention include methyl chloride, ethyl chloride, n chloride,
- Organic chlorides such as propyl, ethylene chlorohydrin, methoxyethyl chloride, methyl bromide, ethyl bromide, n-propyl bromide.

Examples include organic bromides such as ethylene bromohydrin and methoxyethyl bromide.

The amount of organic halide to be used is 1.0 to 2.0 times, preferably 1.1 to 1.3 times, by mole per unsubstituted hydrogen of the amino group in raw material (1).

That is, for aromatic amines with a large number of N-substituents, twice the amount used for N-substituted aniline is required.

If the amount used is less than 1.0 per hydrogen, unreacted N-
Substituted aniline remains and the yield of N,N-disubstituted aniline decreases, and even if it exceeds 2.0, no improvement in the yield of N,N-disubstituted aniline can be expected, and instead a large amount of unreacted organic halide remains. It remains industrially disadvantageous.

(2) Reaction such N-substituted aniline of formula (I) or formula, (I'
N,N- represented by formula (III) or formula (TV) by reacting l aromatic amine with organic chloride of formula (II) in the presence of an aqueous phosphate solution and an iodized compound.
A di-substituted aniline is obtained.

The aqueous phosphate solution used in the present invention functions as a deoxidizing agent. As such a phosphate aqueous solution,
Inorganic phosphate aqueous solutions are particularly effective.

This inorganic phosphate aqueous solution is obtained by reacting phosphoric acid with an alkaline compound.

As the alkaline compound, hydroxides of alkali and alkaline earth metals are effective, for example.

Examples of NaOH1 include OH, CafOH)+, and the like. There are three forms of phosphorus salt: secondary salt, secondary salt, and tertiary salt, but the salt is made by adjusting the amount of the alkaline compound and phosphoric acid to form the secondary salt or tertiary salt. is preferable.

The alkaline compound forming the inorganic phosphate is consumed by the hydrogen halide produced as one reaction progresses. Therefore, the amount of alkaline compound used corresponds to the consumption amount of organic halide required to produce N,N-disubstituted aniline, and is 1.0 to 6.0 per hydrogen of the amino group of the raw aniline derivative. Two times the molar amount, preferably 1.8 to 4.5 times the molar amount, is used. If the amount used per amino group hydrogen is less than 1.0 times the mole, the deoxidizing agent will be consumed before the substitution of amino group hydrogen is completed, and unreacted N-substituted aniline will remain, reducing the yield. becomes worse. Furthermore, if the amount exceeds 6.0 times the mole, no improvement in yield can be expected.

During the reaction, the alkaline compound to be used may be charged in advance into the reaction system in its entirety, neutralized with phosphoric acid to form a second salt or a third salt, and then used. It is also possible to reduce the amount of phosphoric acid used.

That is, as one reaction progresses, chlorides of alkali and alkaline earth metals are generated and alkaline compounds are consumed. .3 times the mole is charged into the reaction system, and neutralized with an alkaline compound to form a second salt or a tertiary salt. As the reaction progresses with the introduction of the organic chloride, the alkaline compound is consumed accordingly, so it is also possible to adopt a method in which only the consumed amount of alkaline compound is replenished at the same time as the introduction of the organic chloride. .

The concentration of the phosphate aqueous solution is 10-80%, preferably 30%.
~60%. If the concentration is less than 10%, the amount of water relative to the N-substituted aniline increases, resulting in a decrease in the yield of N,N-disubstituted aniline obtained in one reaction, which is industrially disadvantageous. Furthermore, if the concentration is 80% or more, a large amount of by-product salt will precipitate, resulting in a disadvantage that the slurry concentration will become high.

The iodized compound used in the present invention acts as a catalyst. Specific examples of such iodine compounds include inorganic salts of iodine such as Nal and KI, and h.

The amount of this iodide compound to be used is 0.00% as the theoretical amount of iodine based on the aniline compound as the raw material. O1 to 0.5 times the mole, preferably 0.03 to 0.2 times the mole. If the amount used is less than the above range, the reaction time will become longer. Although it is possible to use the amount exceeding the above range, since the iodide compound is expensive, the catalyst cost becomes too high, which is industrially disadvantageous.

The average reaction temperature is 60 to 160°C, preferably 90 to 110°C.
It is. If the temperature is below 60°C, the reaction time will be longer and 16
At high temperatures exceeding 0℃, side reactions such as hydrolysis occur, which is undesirable.The reaction pressure is 5kg/ctx2G under UJ.
The reaction is preferably carried out at a pressure of 2 to 4 kg/cm''G, and usually within the range of pressure increase due to heating within the reaction vessel, but there is not much of an improvement effect.

Although a solvent may be used in carrying out the method of the present invention, it is preferable to carry out the reaction without a solvent except for the aqueous phosphoric acid solution unless there is a problem with the solubility of the raw materials.

(3) Reaction product N, N- of the above general formula (nr) obtained by the method of the present invention
Examples of di-substituted anilines include N-ethyl-N-(β-
hydroxyethyl)-aniline, N-ethyl-N-(β
-hydroxypropyl)-aniline, N-ethyl-N-
(β-hydroxyethyl)-toluidine, N-propyl-Niβ-hydroxyethyl)-toluidine, N-butyl-N-1β-hydroxyethyl)-toluidine, N-
Ethyl-N-(β-methoxyethyl)-toluidine, N
-ethyl-N-(β-methoxyethyl)-toluidine,
N, N-di(β-ethoxyethyl)-toluidine, N-
Examples include 1β-methoxyethyl 1-N-(β-hydroxyethyl)-toluidine, N-ethyl-N-(β-hydroxyethyl)-anidine, and the like.

Further, examples of N,N-disubstituted aniline of general formula (rV) include N,N-dimethylaniline, N,N-dimethyltoluidine, N,N-dimethylanisidine, N,N-diethylaniline, N , N-diethyltoluidine, N, N
-diethylanisidine, N,N-dipropylaniline.

N,N-dipropyltoluidine, N,N-dipropylanisidine, N,N-dibutylaniline, N,N-dibutyltoluidine, N,N-dibutylanisidine, N,
N-di(β-methoxyethyl)-aniline, N,N
-di(β-methoxyethyl)-toluidine, N,N-
Examples include di(β-methoxyethyl)-anisidine.

[Example J Example 1 N-ethyl-N-1β-hydroxyethyl)1-toluidine H-ethyl-tm-toluidine 67.5 g (0,50
0(-l, 30% trisodium phosphate aqueous solution 287
gT 0.525 mol) and potassium iodide 2.5 g (0
, 015 mol) was charged into an electric M1 stirring type 500 ml autoclave, and after purging the inside of the container with nitrogen gas, 10
44.3 g of ethylene chlorohydrin fo at 0 ± 5°C,
550 mol) was gradually introduced over a period of 1 hour.

After the introduction, aging was carried out at the same temperature for 9 hours, and by-product salts were then removed by washing with water to obtain 86.8 g of N-ethyl-N-(β-hydroxyethyl)1-toluidine. Yield is 97
%Met.

The purity of the reaction product measured by gas chromatography was 99%.

Examples 2 to 14 The reaction was carried out under the same conditions as in Example 1 except that each amine shown in Table 1 was used. The results are shown in Table 1.

Comparative Example 1 In Example 1, Kl was not added, and the other conditions were as in Example 1.
When the reaction was carried out under the same conditions as above, N-ethyl-toluidine and ethylene chlorohydrin did not react at all.

Comparative Example 2 In place of the 30% trisodium phosphate aqueous solution in Example 1, a 30% potassium carbonate aqueous solution was used.

The reaction was carried out in the same manner as in Example 1.

The reaction stopped when 65% of N-ethyroot (β-hydroxyethyl) 1-toluidine was produced. At this time, 35% of the ethylene chlorohydrin charged
was hydrolyzed.

Example 15 N,N-dipropylanilineAniline 93.0g (1,00mol), 30%'
)”, trisodium i acid aqueous solution 574.0 g (1,0
5 mol) and potassium iodide 5.0 g 10.03 mol)
Electromagnetic stirring type! After charging the autoclave and replacing the inside of the container with nitrogen gas, propychloride JL was heated at 100+5℃.
, 164.8 g (2.10 mol) were introduced over a period of 2 hours. After the introduction was completed, aging was carried out at the same temperature for 18 hours.

After the aging, by-product salts were removed by washing with water to obtain 171.7 g of N,N-dipropylaniline. The yield was 97%.

The purity of the obtained N,N dipropylaniline was measured by gas chromatography and found to be 98%.

Examples 16-27 The compounds shown in Table 2 were synthesized in the same manner as in Example 15.

Comparative Example 3 Anili: /93.0g (1,0nmol) and 50%
After putting NaOH aqueous solution (2.10 mol) into a magnetic stirring type 11 autoclave and purging the inside of the container with nitrogen gas,
258.1 g of propyl bromide (2,10
mol) was introduced. The introduction was completed in 2 hours, and then aging was carried out at the same temperature for 18 hours.

After the reaction, by-product salts were removed by washing with water to obtain 155.0 g of N,N-dipropylaniline. The yield was 88%.

The purity of N,N-dipropylaniline measured by gas chromatography was 80%.

Furthermore, metal corrosion was observed inside the container of the autoclave (material: SO231G+).

Comparative Example 4 In Comparative Example 3, the reaction temperature was lowered to 60±5° C., and the other conditions were the same as in Comparative Example 3.

No metal corrosion was observed in the autoclave, but the reaction itself did not progress at all.

[Effects of the Invention] Compared to conventional methods for synthesizing N,N-disubstituted anilines, the method for producing N,N-disubstituted anilines of the present invention can be carried out under mild reaction conditions at relatively low temperatures and low pressures. Since the reaction can proceed in a short time and there is no problem of equipment corrosion, industrial production can be carried out using simple equipment.

Claims (4)

[Claims] (1) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (I) (However, R in the formula is H, Cl, NO_2, or an alkyl group having 1 to 6 carbon atoms, an alkyloxy group, or an alkenyl group, R^1 is an alkyl group or alkenyl group having 1 to 6 carbon atoms.) N-substituted anilines represented by the general formula R^2-X (II) group, X is Cl or B
It is r. ) A general formula characterized by reacting an organic halide represented by the following in the presence of an aqueous phosphate solution and an iodide compound ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III) (However, R, R^ 1 and R^2 are the same as above.) A method for producing N,N-disubstituted anilines represented by (2) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (I') (However, R in the formula is H, Cl, NO_2, or an alkyl group having 1 to 6 carbon atoms, an alkyloxy group, or an alkenyl group. ) aromatic amines represented by the general formula R^2-X(II) (wherein R^2 is an organic substituent, and X is Cl or B
It is r. ) A general formula characterized by reacting an organic halide represented by the following in the presence of an aqueous phosphate solution and an iodide compound ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (IV) (However, R and R ^2 is the same as above.) A method for producing N,N-disubstituted anilines. (3) The method according to claim 1 or 2, wherein the phosphate aqueous solution is obtained by reacting phosphoric acid with an alkali metal or alkaline earth metal hydroxide. (4) The method according to any one of claims 1 to 3, wherein the iodized compound is iodine or an inorganic iodide.