JP2863646B2 - Method for producing isopropylaniline - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing isopropylanilines, and more particularly to a method for obtaining p-isopropylaniline and / or m-isopropylaniline in high yield.

[0002]

BACKGROUND OF THE INVENTION Isopropylanilines are intermediates used in organic synthesis reactions useful for the production of agricultural chemicals and the like. The following method is known as a method for producing isopropylanilines. (1) A method of nitrating cumene and reducing it. (2) A method of aminating p-isopropylphenol. (3) A method in which aniline is reacted with an alkylating agent, isopropylated using a Friedel-Crafts reaction for alkylating a benzene nucleus, and p-isopropylaniline is crystallized as a sulfate.

[0003]

However, these methods for producing isopropylaniline have the following problems. In the method (1), o-nitrocumene is by-produced at the stage of cumene nitration, and the selectivity of useful p-nitrocumene is low. Further, in this method, the m-isomer cannot be obtained in good yield. In addition, this method uses a large amount of nitric acid for nitration.
Since sulfuric acid is used, a large amount of wastewater mixed with nitric acid and sulfuric acid is discharged as a waste, and this is a pollution-type process that has many environmental health problems.

The method (2) is a step of synthesizing p-isopropylphenol by alkylating phenol.
-It is difficult to obtain the body or m- body with good selectivity,
For this reason, it is difficult to obtain p-isopropylphenol as a raw material. At present, p-isopropylphenol which is a by-product of hydroquinone production is used, but it is difficult to secure a sufficient supply amount. In the method (3), when aniline is isopropylated,
It is difficult to obtain a p-form or an m-form with good selectivity.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art and aims to provide a method for obtaining p-isopropylaniline and / or m-isopropylaniline in high yield.

That is, the present invention relates to 2,2-bis (4,4
Hydrocracking of 4'-diamino-diphenyl) propane and / or 2,2-bis (3,4'-diamino-diphenyl) propane in the presence of a hydrogenation catalyst results in p-isopropylaniline and / or m- -Providing a method for producing isopropylaniline to obtain isopropylaniline. Here, the hydrogenation catalyst is at least one metal compound selected from Ni, Mn and Cr,
A method for producing isopropylaniline, which is a catalyst supported on at least one selected from silica, alumina, titania, zirconia, magnesia and calcium oxide, is preferred.

Hereinafter, the present invention will be described in detail. 2,2-
By hydrogenating and cracking bis (4,4'-diamino-diphenyl) propane in the presence of a hydrogenation catalyst, p-isopropylaniline represented by the following reaction formula [1] is selectively obtained.

[0008]

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When 2,2-bis (3,4'-diamino-diphenyl) propane is hydrogenated and cracked in the presence of a hydrogenation catalyst, m-isopropylaniline represented by the following reaction formula [2] is selectively obtained. Can be

[0010]

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In particular, in the cracking of 2,2-bis (3,4'-diamino-diphenyl) propane represented by the above formula (2), depending on the cleavage position, both m- and p-isopropyl aniline Although a class may be formed, in the method of the present invention, almost no p-form is formed, and only an m-form is formed. In formulas [1] and [2], aniline produced together with isopropylaniline can be effectively used as a raw material for synthesizing the raw material 2,2-bis (diamino-diphenyl) propane. .

The hydrocracking represented by the above formulas [1] and [2] is performed at a temperature of 200 to 400 ° C., preferably 250 to 350 ° C. The pressure is from normal pressure to 50
Kg / cm ^2, preferably, performed in 5~30Kg / cm ^2. When the temperature and the pressure range are set at a temperature of less than 200 ° C., the single yield is low and the production is not industrialized. If the temperature is higher than 400 ° C., side reactions such as cleavage of the isopropyl group and hydrogenation of the benzene ring occur, so that the selectivity of the target isopropylaniline decreases. Hydrogen pressure is 1 kg / cm ²
Below, the yield of isopropylaniline is low, 30 kg / c
If m ² or more, isopropylaniline or the side reaction of hydrogenating the benzene ring of aniline occurs, so that the selectivity of the target isopropylaniline decreases. Hydrogen may be used alone or as a mixture with an inert gas such as argon or nitrogen. The amount of hydrogen is preferably 1 to 50 in a molar ratio to the reactants (hydrogen / raw material).

Although the starting material may be supplied alone with 2,2-bis (diamino-diphenyl) propane, it is usually supplied as a solution together with a solvent. Examples of the solvent include aliphatic alcohols, alkylbenzenes, ethers, pyridines, aliphatic amines, esters and the like. When a solvent is used, the selectivity is kept high by uniformly and stably forming the flow of the reaction system between the reactant and the product, and the contact between the reactant and hydrogen is assisted, and the hydrogenation reaction is carried out smoothly. Has the effect of causing The raw material concentration in the solution is 3 to 30 wt%. The liquid hourly space velocity of the solution containing the raw material is the weight of the reactant relative to the weight of the catalyst,
V ^{1 to} 10 h ⁻¹ , preferably 2 to 5 h ⁻¹ .

As the hydrogenation catalyst used, a hydrogenation catalyst generally used under high temperature conditions is preferable.
Metal compounds such as Cr, silica, alumina, titania,
Examples of such catalysts include zirconia, magnesia, calcium oxide and other supported catalysts. These metal compounds may be used alone or in combination. A catalyst prepared by supporting Ni and / or Mn compounds on silica-magnesia and calcining is particularly effective, and the amount of Ni supported is NiO alone.
In the case of Mn alone, the content is preferably 0.5 to 3 wt% in terms of MnO and 5 to 20 wt% in terms of MnO.

The concentration of the reaction product in the reaction system is not particularly limited, but may be isopropylaniline 1.8.
-18% by weight and aniline 1.2-12% by weight.

Although the reaction apparatus is not particularly limited, a tank type or tube type reactor equipped with a heating jacket is used, and the following examples are given. (A) Fixed-bed liquid phase continuous reaction When the reaction pressure is set to a high value, the raw material and the resulting mixture can be kept in a liquid phase, and the raw material mixture and hydrogen gas are mixed in a fixed catalyst bed heated to a predetermined temperature. Is passed as downflow to carry out hydrocracking as a continuous reaction.

(B) Fixed Bed Gas Phase Continuous Reaction When the reaction pressure is set to a low value, the raw material and the product mixture can be kept in the gas phase, the concentration of the raw material in the raw material mixture is kept low, Can be cracked. The catalyst is used as a fixed bed, and a continuous reaction can be performed by either a downward flow or an upward flow.

(C) Fluidized bed gas phase reaction The reaction conditions are the same as in (b), and the raw material and the resulting mixture are subjected to hydrocracking with hydrogen gas as a gas phase. Using a continuous or batch type reaction apparatus, the reaction is carried out in an upflow manner while the catalyst is made to flow with the raw material gas. The excess amount of hydrogen supplied to the reactor can be recycled to the reactor after gas-liquid separation of the product mixture into liquid and hydrogen as gas at the outlet of the reactor.

It is known that 2,2-bis (diamino-diphenyl) propane, which is a raw material of the method of the present invention, is produced, for example, as follows. (1) A method of condensing aniline and acetone in the presence of an acid catalyst. (2) German Patent No. 1 183 544, US Patent No. 41772
No. 11 and U.S. Pat.
A method for producing 2,2-bis (diamino-diphenyl) propane by reacting aniline with dimethyl ketone. (3) described in JP-A-61-271253.
A method in which isopropenylaniline and aniline are subjected to an addition reaction in the presence of an acid catalyst. (4) A method of reducing the nitro group of 2,2-bis (dinitrodiphenyl) propanes.

[0020]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

(Preparation of hydrogenation catalyst) 3.7 g of nickel nitrate hexahydrate and 25 g of manganese acetate tetrahydrate were dissolved in 60 g of distilled water to form a homogeneous solution. Silica magnesia in the _{(SiO 2 / MgO: 5/95 (} wt ratio), Nikki Chemical Co. E53J1,3mm × 3mm tablets) 5
0 g was charged and left overnight. The mixture left overnight was transferred to a rotary evaporator, and the aqueous solution was concentrated and dried. The obtained catalyst precursor was transferred to a magnetic dish and subjected to heat treatment in an electric furnace. 315 under air atmosphere
By heating at 480 ° C. for 1 hour and 480 ° C. for 2 hours, an oxide catalyst discolored to black green was obtained.

(Example 1) Inner diameter 25 mm, length 500 m
m in a tubular reactor, 28 ml of the resulting catalyst (25.8
g) was charged. 85-95 m of hydrogen from the top of the reactor
at a temperature of 300 to 345 ° C. and a pressure of 20 while flowing at 1 / min.
The catalyst was pretreated for 1 hour under the condition of Kg / cm ² G. 2,
2-bis (4,4'-diaminodiphenyl) propane 1
A solution in which 0.0 g was dissolved in 154.0 g of isopropanol (specific gravity 0.782 g / ml) was continuously supplied as a raw material mixture from the top of the reactor at a rate of 84 ml / hr. At the same time, hydrogen was co-flowed with the raw material mixture at a flow rate of 4 to 5 l / hr. Reaction temperature 285 ° C, pressure 20Kg / c
while maintaining m ² G, it was 2,2-bis hydrocracking of (4,4'-diaminodiphenyl) propane.
The reaction mixture discharged from the lower part of the reactor was separated into gas and liquid, and a liquid reaction liquid was collected. One hour after the start of the reaction, 34.5 g of the liquid reaction solution collected was separated by gas chromatography. As a result, 2,2-bis (4,4'-
Conversion of diaminodiphenyl) propane is 99% (mol%, the same applies hereinafter), and the yield of isopropylaniline is 7
The reaction result was 2.7%. The breakdown of each isomer in the isopropylaniline product was 0.8% for o-isopropylaniline, 6.6% for m-isopropylaniline, and 92.6% for p-isopropylaniline. As a product other than isopropylaniline, diisopropylaniline 20.1% 2,2-bis (3,4'-diaminodiphenyl) propane 3.6% was obtained. The yield of aniline, which is a coproduct of hydrocracking of 2,2-bis (4,4'-diaminodiphenyl) propane, is 102.1.
%Met.

Examples 2 to 4 The same procedure as in Example 1 was carried out except that the starting material was changed to 2,2-bis (3,4'-diaminodiphenyl) propane. Reaction temperature of 215 ° C to 3
The results obtained are summarized in Table 1 when the temperature was changed to 40 ° C.

[0024]

[0025]

According to the method of the present invention, by using a specific starting material, it can be hydrocracked to obtain p-isopropylaniline or m-isopropylaniline in high yield, which is industrially effective. A highly pure p-form or m-form to be used is obtained.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 211/45 B01J 23/889 C07C 209/68 C07B 61/00 300 CA (STN) WPI / L (QUESTEL)

Claims (2)

(57) [Claims] (1) 2,2-bis (4,4′-diamino-diphenyl) propane and / or 2,2-bis (3,
4'-diamino-diphenyl) propane is hydrogenated and cracked in the presence of a hydrogenation catalyst to obtain p-isopropylaniline and / or m-isopropylaniline. 2. The method according to claim 1, wherein the hydrogenation catalyst comprises Ni, Mn and Cr.
At least one metal compound selected from the group consisting of silica,
The method for producing isopropylanilines according to claim 1, wherein the catalyst is a catalyst supported on at least one selected from alumina, titania, zirconia, magnesia, and calcium oxide.