JPS63208555A - Production of bis(4-aminocyclohexyl)methane - Google Patents

Abstract

PURPOSE:To obtain the titled compound which is liquid at room temperature in high selectivity and yield, by subjecting bis(4-aminophenyl)methane to nuclear hydrogenation with H2 gas in the presence of a noble metal catalyst using a specific solvent and further in a controlled specific degree of conversion. CONSTITUTION:Bis(4-aminophenyl)methane is subjected to nuclear hydrogenation in the presence of a noble metal catalyst such as Ru-alumina, etc., using a glycol diether expressed by the formula (R<1> and R<2> are CH3, C2H5 or C3H7; n is 1-3) as a solvent under a H2 atmosphere having 100-200 deg.C and >=20kg/cm<2> and further the degree of conversion is controlled to <=99.8% to provide the aimed compound which is liquid at room temperature and useful as a dye intermediate and raw material of surfactant, corrosion inhibitor, polyamide, etc. As the above-mentioned compound expressed by the formula, diglyme, ethylene glycol dimethyl ether, triethylene glycol dimethyl ether, etc., is used. The compound is readily separated from water and the solvent can repeatedly be reused.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing bis(4-aminocyclohexyl)methane, and more specifically, the present invention relates to a method for producing bis(4-aminophenyl)methane using a glycol diether solvent in the presence of a noble metal catalyst. The present invention is characterized by hydrogenation and further relates to a method for obtaining liquid bis(4-aminocyclohexyl)methane at room temperature in high yield.

[Industrial Application Fields] Bis(4-aminocyclohexyl)methane is useful as a dye intermediate, a surfactant, a corrosion inhibitor, a bactericide, and a raw material for polyamide or polyurethane. The same item is 3
There are isomers of species, including cis-cis form and rc-c form.
(hereinafter referred to as "rT-T body"), cis-trans body (hereinafter referred to as "rC-T body"), and trans-trans body (hereinafter referred to as "rT-T body") are mixed at a constant ratio. It is known that when producing polyamide by polycondensing bis(4-aminocyclohexyl)methane and dicarboxylic acid, transparency, moldability, etc. are improved by increasing the content of C-0 isomer. It is being Furthermore, when using isocyanate obtained by reacting bis(4-aminocyclohexyl)methane with phosgene as a raw material for polyurethane, it is often desirable to have a high content of C-.0 isomer or C-T isomer. . This is because liquid products that are easy to handle are preferred due to the skin damage properties of isocyanates.

[Conventional techniques and problems to be solved by the present invention] The conventional method for synthesizing bis(4-aminocyclohexyl)methane by nuclear hydrogenation of bis(4-aminophenyl)methane is either without solvent or using ethanol as a solvent. , isopropanol, dioxane, tetrahydrofuran, n-hexane, cyclohexane, etc. have been disclosed, but there are the following problems.

In the case of no solvent, the melting point of the raw material bis(4-aminophenyl)methane is as high as 100°C, and there are problems such as the heat resistance of the f1 charging pump and heating of the raw material transfer pipe.
Furthermore, oligomers as by-products tend to adhere to the catalyst, resulting in a decrease in the activity of the catalyst, so nuclear hydrogenation reactions in a solvent system are often used.

On the other hand, when using a solvent, alcohols, ethers, and other solvents that are usually preferably used tend to contain water due to their nature, and the presence of water in the reaction system increases the amount of by-products produced. It is known that the yield decreases and the purification process becomes complicated, and there has been a need for a solvent that can extremely easily remove water.

In addition, the aforementioned solvents have low boiling points, resulting in losses during solvent recovery, safety issues due to high vapor pressure, and furthermore, product quality deterioration due to repeated use of the solvents. .

An example using dioxane is a ruthenium catalyst with 1
Example of testing at 20℃ and 50kg/cm
1-68539), but the reaction time is as long as 5 hours or more, resulting in poor productivity. It has been conventionally recognized that ruthenium catalysts have low activity at around 100°C and that hydrogenation must be carried out at 200°C or higher in order to obtain a practical reaction rate (Japanese Patent Publication No. 55-15464).

In an example using tetrahydrofuran, a cobalt-manganese catalyst was used at a temperature of 210°C to 215°C and a hydrogen pressure of 250k.
g/cm” with a yield of 94% (Ger, 0ff
en2039818), also using a ruthenium catalyst,
40% tetrahydrofuran solution, 200℃,
An example of reaction under the condition of 200kg/cm” (Ger
, 0ffen2125790). Solvents such as dioxane and tetrahydrofuran have problems in terms of long reaction times, the need to increase hydrogen pressure, low allowable environmental exposure concentrations, toxicity, and safety issues. High solvent strength is desired.

In addition, as an example of using an alcohol solvent, bis(4
-aminophenyl)methane in a solution of 30% isopropanol, using a ruthenium catalyst at 195 to 200°C and hydrogen pressure of 184 to 199 kg/cm"% for 19 hours (Ger, Off en 2520848),
Using butanol as a solvent with a ruthenium catalyst, 180 ~
Method for obtaining bis(4-aminocyclohexyl)methane in a short time within 30 minutes at 300°C and 35kg/cm'' (U
SP3347917) etc. are disclosed. In the case of alcohol-based solvents, it is known that they react with the raw material bis(4-aminophenyl)methane or the product bis(4-aminocyclohexyl)methane to produce N-alkyl compounds. Since a solution was desired and the reaction conditions required a long time, high temperature, and high pressure, a method to further improve the reaction rate was desired.

In order to prevent the formation of N-alkyl bodies, nitrates or sulfates of alkali metals or alkaline earth metals are added to the ruthenium catalyst as a modifier for the purpose of suppressing the formation of oligomers produced as by-products in the deammonization condensation reaction. A method for nuclear hydrogenation using 2-propanol as a solvent (US Pat. No. 4,448,925) is disclosed. However, this method produces a large amount of by-product oligomers, and the effect of preventing the formation of N-alkylated products, which are the reaction products with 2-propatol used as a solvent, is insufficient, and the by-products cannot be completely suppressed. However, since it requires a purification process such as distillation, a decrease in yield becomes a problem. Furthermore, addition of basic salts results in a decrease in the activity of the catalyst.

On the other hand, the equilibrium composition of bis(4-aminocyclohexyl)methane obtained by conventional hydrogenation reactions is usually about 7% C-C form, about 38% C-T form, and about 55% T-T form. , exhibits a freezing point of about 40°C and is solid at room temperature. Therefore, in order to obtain a liquid product, it is necessary to adjust the mixing ratio of isomers within a certain range, and specifically, it is essential to increase the C-C body temperature or the concentration of C-T body. .

Solvent fractionation is widely known as one of the methods for achieving this purpose. That is, bis(4-aminocyclohexyl)methane having an equilibrium composition is formed into an adduct with a lower acid using a lower acid such as octyl acid as a solvent, and T-T
This is a method of selectively crystallizing the C-T body and separating bis(4-aminocyclohexyl)methane with a high concentration of the C-T body remaining in the mother liquor. However, the fractionation method is complicated, and although liquid bis(4-aminocyclohexyl)methane is separated, it is necessary to consider the purpose and method of using the remaining high-melting-point bis(4-aminocyclohexyl)methane. There is.

In addition to the solvent fractionation method, studies have also been made to obtain a liquid product at room temperature by nuclear hydrogenating bis(4-aminophenyl)methane using a rhodium-based, palladium-based, or iridium-based catalyst. An example of obtaining a liquid product by reacting for 6 hours with a rhodium-platinum catalyst at 50°C or lower using ethanol as a solvent (Japanese Patent Publication No. 47-45435) or using an iridium-based catalyst at room temperature to 200°C. There is an example of obtaining a liquid product with a yield of 88% using dioxane as a solvent at a reaction temperature of up to °C (Japanese Patent Publication No. 55-15464). Compared to ruthenium-based catalysts, which are said to be expensive, they are even more expensive, and in order to obtain a liquid product at room temperature using conventional solvents, nuclear hydrogenation must be carried out at a low temperature of 100°C or less. Although they are active at low temperatures, they inevitably have a slow reaction rate, resulting in poor productivity.

On the other hand, using dioxane as a solvent using a ruthenium catalyst, nuclear hydrogenation was carried out in the same way, and the reaction rate was suppressed to 90-95%. ) How to get methane (
USP2606928) is also being considered. However, the method of controlling the reaction rate to 90-95% using a ruthenium-based catalyst, which is said to be relatively inexpensive among precious metal catalysts, is to stop the reaction before reaching the equilibrium composition of isomers. , is a method for suppressing the production of T-T bodies.

This can suppress the generation of T-T bodies, but
Separation and purification of unreacted substances is required, which is a considerable disadvantage in terms of yield and productivity. In conventional technology,
Catalyst prices are relatively low, such as ruthenium, and 100%
Until now, there has been no example of obtaining liquid bis(4-aminocyclohexyl)methane in high yield at room temperature at a reaction temperature of 95% or higher and at a reaction temperature of 95% or higher.

[Means for Solving the Problems] The present inventors have conducted intensive studies to solve the above problems, and have found that these problems can be solved by using a specific solvent, that is, a glycol diether solvent. We have discovered that all of these problems can be solved, and have arrived at the present invention.

When the solvent of the present invention is used, in a hydrogen atmosphere of 50 kg/cm" or more, even at a reaction rate of 95% or more,
It has been found that bis(4-aminocyclohexyl)methane, which is liquid at room temperature, can be obtained over a wide temperature range from 100<0>C to 200<0>C.

That is, the present inventors focused on the fact that the reaction rate, selectivity, etc. in a nuclear hydrogenation reaction are greatly influenced by the type of solvent, and as a result of examining various solvents, the results shown in formula (I) were obtained. We have found that by using a glycol dialkyl ether, the reaction rate and selectivity can be improved, its boiling point is above the water level, it can be easily separated from water, and the solvent can be repeatedly reused.

R'O[C! H40] nR1(I) (R', R'' = methyl, ethyl, propyl groups, which may be different from each other, and n represents an integer of 1 to 3.) The glycol ether represented by the formula (I) is Specifically, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, diethylene glycol dimethyl ether (hereinafter referred to as "diglyme"), diethylene glycol diethyl ether, diethylene glycol dipropyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether. , triethylene glycol dipropyl ether, etc.

Furthermore, in the process of investigating glycol diether-based solvents, the present inventors discovered that when the reaction rate of nuclear hydrogenation exceeds 99.8%, the number of T-T isomers increases rapidly. As a result of a detailed study, it was found that by suppressing the reaction rate to 99.8% or less, the formation of the T-T form could be suppressed and liquid bis(4-aminocyclohexyl)methane could be obtained at room temperature. The amount of the T-T form varies depending on the hydrogen pressure, reaction temperature, and concentration of the raw material bis(4-aminophenyl)methane. As shown in Figure 2, it has been found that generally, the higher the hydrogen pressure and the lower the reaction temperature, the lower the production rate of the T-T form.

Although the reason for this is not clear, it is presumed as follows. That is, even at 200°C, in the absence of a catalyst, bis(4-aminocyclohexyl)methane is not isomerized even under hydrogen, and even under the conditions of the present invention, the reaction rate is 99%.
．． When the concentration exceeds 8%, isomerization progresses and the T-T isomer increases, but below that, the formation of the T-T isomer is suppressed to 24% or less. It inhibits the adsorption of aminocyclohexyl)methane onto the catalyst surface and promotes the adsorption of bis(4-aminophenyl)methane onto the catalyst surface, thereby increasing the reaction rate and inhibiting the formation of T-T bodies. It is estimated to be.

Therefore, by carefully controlling the reaction rate using ultraviolet absorption spectroscopy, etc., it is possible to obtain a liquid at room temperature with a reaction rate of 9.
Bis(4-aminocyclohexyl)methane of 9% or more can be obtained by simply distilling the solvent without requiring any special purification steps.

Moreover, when the reaction rate is increased to 99.8% or more, the isomerization reaction occurs rapidly and the number of T-T forms increases, and bis(4-aminocyclohexyl)methane is obtained as a solid at room temperature. Therefore, if it is desired to obtain solid bis(4-aminocyclohexyl)methane at room temperature, the solid product can be easily obtained by increasing the reaction rate to 99.8% or more.

The present invention can be accomplished by using glycol ethers, but among the glycol diethers mentioned above, diglyme is relatively preferred from the viewpoint of boiling point.

In particular, diglyme is not only suitable as a liquefaction solvent, but is also stable under a range of reaction conditions and has advantageous physical characteristics.

That is, it has a large boiling point difference with the target substance, and is easy to separate and purify by distillation or the like.

Furthermore, advantageously, in the glycol diether used in the present invention, even if the catalyst is modified with alkali, no decrease in catalyst activity is observed. It is also a scale that uses a drug.

The nuclear hydrogenation catalyst used in the present invention can be any noble metal catalyst. However, in view of catalyst activity and catalyst price, the noble metal catalyst is preferably ruthenium, palladium, rhenium, etc., and ruthenium is particularly preferred, but the noble metal catalyst is not limited to these.

The amount of catalyst supported is 0.1 to s weight % on a carrier such as alumina or carbon, and the shape thereof may be powder or granule.

Furthermore, if necessary, modifiers such as alkali metals and alkaline earth metals may be used (the amount used is 1 to 501i% relative to noble metals such as ruthenium). At the time of preparation, it can be used by being fixed on the surface of a carrier together with the catalyst metal, but it can also be used by being directly added to the reaction example together with, for example, a ruthenium-alumina catalyst.

In the present invention, the nuclear hydrogenation temperature to obtain liquid bis(4-aminocyclohexyl)methane at room temperature is 10
0°C to 200°C, and if the reaction temperature is lower than this,
The nuclear hydrogenation reaction is slow, and if the temperature is higher than this, it will be difficult to obtain a liquid product at room temperature even if a glycol diether solvent is used. However, when the purpose is to obtain bis(4-aminocyclohexyl)methane, which is solid at room temperature, it is possible to further increase the temperature and shorten the reaction time.

The reaction method can be either a batch reaction or a continuous reaction method, and is appropriately selected depending on the production amount and the like.

The present invention will be described in detail below with reference to Examples, but the present invention is not limited thereto.

[Example] Example 1 A mixture of 50 g of bis(4-aminophenyl)methane, 50 g of diglyme, 15 g of 5% by weight ruthenium supported on alumina, and 7.5 g of sodium carbonate was charged into an autoclave with an internal volume of 500 m1, and the reaction temperature was increased. at 200℃, hydrogen pressure 190-200 kg/cm”
The nuclear hydrogenation reaction was carried out for 1 hour while maintaining the temperature. After the reaction, the catalyst was removed and the solvent was recovered by distillation to obtain bis(4-aminocyclohexyl)methane. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1.

Example 2゜Example 1 except that ethylene glycol dimethyl ether was used as the solvent. I did the same thing.

The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1. Shown below.

Example 3 Example 1 except that diethylene glycol diethyl ether was used as the solvent. I did the same thing.

The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1. Shown below.

Example 4゜' A mixture of 50 g of bis(4-aminophenyl)methane, 50 g of diglyme, 15 g of 5 wt% ruthenium catalyst supported on alumina, and 7.5 g of sodium carbonate was added to an inner volume of 5 g.
Pour into a 00ml autoclave and set the reaction temperature to 130°C.
The nuclear hydrogenation reaction was carried out for 3 and a half hours while maintaining the hydrogen pressure at 190 to 200 kg/cm. After the reaction, the catalyst was removed and the solvent was distilled and recovered to produce bis(4-aminocyclohexyl).
I got methane. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1. Shown below.

Example 5 Example 4 except that triethylene glycol dimethyl ether was used as the reaction solvent. I did the same thing. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1.
．． Shown below.

Example 6° Example 4. except that a 5% by weight ruthenium catalyst supported on carbon was used as the catalyst. I did the same. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1. Shown below.

Example 7° Example 4 except that a 5 wt% palladium catalyst supported on alumina was used as the catalyst. I did the same. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1. Shown below.

Example 8. Example 4 except that 1 g of sodium carbonate was used as the alkali. I did the same. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1.

Example 9° Example 4 except that the catalyst was 2 g of 5 wt % ruthenium catalyst supported on alumina and the reaction temperature was 150°C. I did the same thing. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1.

Example 10° Example 4 except that ethylene glycol dipropyl ether was used as the solvent. I did the same thing. The resulting reaction rate,
The purity, isomer ratio, and properties at room temperature of the product are shown in Table 1. Not shown.

Example 1 It was the same as Example 4 except that hydrogen was injected at 30 kg/cm" and the reaction was carried out at the reaction temperature and hydrogen pressure of 50 to 55 kg/cm". I did the same thing. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1.

Example 12゜ Internal volume: 700 m1 (inner diameter: 2.1 cm, column length: 200 m
Cm) was filled with a 0.5% ffi amount of ruthenium-supported alumina molded catalyst (3% by weight of sodium carbonate was immobilized on the catalyst as a modifier). 200
A packed tower of 120 to 130 kg/cm" of hydrogen flows through it.
of bis(4-aminophenyl)methane kept at 30 °C.
% weight diglyme solution was fed at a feeding rate of 200 ml/h to carry out a continuous reaction. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1. Shown below.

Comparative Example 1° Example 1 except that tetrahydrofuran was used as the solvent. I did the same thing. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1.

Comparative Example 2 The same procedure as in Example 1 was carried out except that dioxane was used as the solvent. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1. Shown below.

Comparative Example 3 Example 4 except that tetrahydrofuran was used as the solvent. I did the same thing. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1.

Comparative Example 4 The same procedure as in Example 4 was carried out except that dioxane was used as the solvent. The resulting reaction rate, product purity, isomer ratio, and properties at room temperature are shown in Table 1. Shown below.

Claims (2)

[Claims] (1) Bis(4-aminophenyl) in the presence of a noble metal catalyst
In the reaction of nuclear hydrogenating methane with hydrogen gas to produce bis(4-aminocyclohexyl)methane, (I
) A method characterized in that a glycol diether shown in the formula is used as a solvent. R^1O[C_2H_4O]nR^2(I)(R^1
, R^2 may be methyl, ethyl, or propyl groups and may be different from each other, and n represents an integer of 1 to 3) (2) Bis(4-aminophenyl) in the presence of a noble metal catalyst
In the reaction of nuclear hydrogenating methane with hydrogen gas to produce bis(4-aminocyclohexyl)methane, (I
) In the method for producing bis(4-aminocyclohexyl)methane using the glycol diether shown in the formula as a solvent, by suppressing the reaction rate to 99.8% or less, bis(4-aminocyclohexyl) which is liquid at room temperature ) How to get methane. R^1O[C_2H_4O]nR^2(I)(R^1
, R^2 may be methyl, ethyl, or propyl groups and may be different from each other, and n represents an integer of 1 to 3)