JPH0269448A - Production of p-phenylenediamines - Google Patents

Abstract

PURPOSE:To obtain the title compound in one stage with high conversion rate and selectively by reacting hydroquinones and/or p-aminophenols with ammonia in the presence of a Pd catalyst and alicyclic amine and/or alicyclic ketone. CONSTITUTION:When p-aminophenols are aminated by directly reacting p- aminophenols with ammonia to produce p-phenylenediamines, the reaction is carried out in the presence of an alicyclic amine (especially preferably cyclohexylamine) and/or alicyclic ketone (especially preferably cyclohexanone) using a Pd catalyst (especially preferably metal Pd or Pd-carried support (e.g., Pd-carried carbon, alumina or zeolite). The alicyclic amine and alicyclic ketone are preferably used at amounts of 10-30mol based on hydroquinones or p- aminophenols or mixture thereof and the Pd catalyst is preferably used at an amount of 5-20wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a novel method for producing p-phenylenediamines.

<Conventional technology and problems> p-phenylenediamine is used as an antioxidant for rubber, as a dye,
It has been used in large quantities as a raw material for pigments since ancient times, and more recently it has begun to be used as a raw material for heat-resistant polyamides, and has important industrial uses.

Conventionally, p-phenylenediamine is produced by nitrating chlorobenzene, separating the obtained p-chloronitrobenzene, then ammonolyzing the obtained p-chloronitrobenzene, and then converting the obtained p-nitroaniline into It has been produced by reduction. This method of producing p-phenylenediamine requires a very complicated production process and involves multi-step synthesis.
-There was a major problem in that the yield of phenylenediamine was low. Furthermore, according to the above-described method for producing p-phenylenediamine, there is a serious problem in that unnecessary 0-nitrochlorobenzene is produced by about 50% of p-nitrochlorobenzene in the chlorobenzene nitration step. There was a point. For this reason, the manufacturing cost of p-phenylenediamine was high.

Such problems have not been solved even in the method described in US Pat. No. 3,922,304. This U.S. patent also describes a three-step process for producing p-phenylenediamine, in which 70% of aniline and carbon monoxide are
Formanilide is synthesized by reacting under high pressure of 0 atmospheres, and then the obtained formanilide is nitrated to obtain nitroformanilide using a Pd/C catalyst.
p- by reduction under H2 pressure of 00 psi.
Manufactures phenylenediamine. However, the method for producing p-phenylenediamine disclosed in this US patent has the disadvantage of being a multi-step synthesis method, as well as the following problems.

That is, in the reaction between aniline and carbon monoxide, -
Formanilide cannot be obtained in high yield unless the partial pressure of carbon oxide is increased to 700 atm, and if this method is to be implemented industrially, an ultra-pressure reactor is required and the equipment cost is extremely high. It gets wet. Furthermore, even when formanilide is nitrated, the by-product of 0-nitroformanilide is unavoidable, and 10 to 20% of 0-nitroformanilide is produced as a by-product relative to p-nitroformanilide.

In this way, even in the method for producing p-phenylenediamine described in U.S. Pat. No. 3,922,304,
p- due to multi-step synthesis, which is a problem with conventional methods.
The problems of low yield of phenylenediamine and large amount of by-product of O-phenylenediamine have not been solved.

Also, JP-A-53-119832, JP-A-54-
No. 3018 or JP-A-57-122047 discloses that aniline is diazotized and then coupled, and then p-aminoazobenzene is synthesized by a rearrangement reaction.
The obtained p-aminoazobenzene was dissolved in aniline solvent for 1
A method for producing p-phenylenediamine by catalytic reductive decomposition under pressure conditions of 0 to 100 kg/cm2 is disclosed.

Under such high pressure conditions, aniline undergoes nuclear hydrogenation, resulting in cyclohexylamine as a by-product, which induces a reaction between this compound and aniline, and a deammoniation reaction between this compound and p-phenylenediamine, resulting in N- Another disadvantage is that by-products such as phenylcyclohexylamine and N-(4-aminophenyl)cyclohexylamine are easily produced. Furthermore, p-aminoazobenzene can be obtained as a main component by diazotizing aniline and then coupling, and rearranging the resulting diazoaminobenzene. In this case, 0-aminoazobenzene is In the reductive decomposition process, about 8% of p-phenylenediamine is produced as a by-product in an amount of about 8%.
There is also the problem that 0-phenylenediamine is produced as a by-product.

Moreover, the desired p-phenylenediamine cannot be obtained without going through a total of four steps: diazotization of aniline, coupling, rearrangement, and catalytic reduction, making the production process extremely complicated. There was a problem in that the products produced by this method had to be extremely expensive.

Also, in US Pat. No. 4,400,537-A, γ-
A method is disclosed for producing p-phenylenediamine by direct liquid phase pressure amination of hydroquinone with ammonia in a hydrocarbon solvent using alumina as a catalyst. However, in this method, p-phenyl diamine can be synthesized in good yield unless benzene as a hydrocarbon is used in a large excess of 1.2 J2 to 4 g of hydroquinone as described in the example. Therefore, if the method described in the above-mentioned U.S. patent were to be implemented industrially, a large-scale reaction apparatus would be required compared to the amount of p-phenylenediamine produced, making it difficult to implement it on an industrial scale. It's almost impossible to do.

In addition to the method described above, there is a method for directly aminating hydroquinone to produce p-phenylenediamine.
A method of reacting with 8% ammonia water, or CO1Cu% as described in JP-A-52-4289.
A method of reacting hydroquinone with 20% aqueous ammonia in the presence of an N1 halide and an ammonium halide salt has been known for a long time, but in both cases, p-
Since the amination reaction from aminophenol to p-phenylenediamine is difficult to proceed, a large amount of p-aminophenol is recovered, and p-phenylenediamine cannot be produced in good yield.

(7) Jl:'l In the conventionally known production method of p-phenylenediamine, the yield of p-phenylenediamine decreases due to the multi-step synthesis, and the by-product of 0-phenylenediamine is avoided. p-
The yield of phenylenediamine is reduced or 0.
- The purity of p-phenylenediamine decreases due to the contamination of p-phenylenediamine with phenylenediamine as an impurity, and the direct amination of hydroquinone requires a large-scale reactor due to low productivity. Since the reaction rate is low, a large amount of p-aminophenol is produced as a by-product, and there are many problems such as a low yield of p-phenylenediamine.

<Problems to be Solved by the Invention> The present invention attempts to solve the problems associated with the prior art as described above, and aims to produce p-triacetate from hydroquinones and/or p-aminophenols in a -stage weight. - It is an object of the present invention to provide a method for producing p-phenylene diamines which can produce p-phenylene diamines and can maintain conversion and selectivity at much higher levels than those of conventional techniques.

Means for Solving the Problems The present invention is characterized by reacting hydroquinones and/or p-aminophenols with ammonia in the coexistence of a Pd catalyst and an alicyclic amine and/or an alicyclic ketone. A method for producing p-phenylenediamines is provided.

Here, it is preferable to use phenols and/or anilines as a solvent during the reaction.

Hereinafter, the method for producing p-phenylenediamines according to the present invention will be specifically explained.

In the present invention, when producing p-phenylenediamines by amination by directly reacting hydroquinones and/or p-aminophenols with ammonia, the presence of alicyclic amines and/or alicyclic ketones It is characterized in that the above reaction is carried out using a Pd catalyst underneath.

Specifically, hydroquinone or an alkylhydroquinone represented by the following formula is used as the raw material hydroquinone (R in the formula is a straight or branched alkyl group having 1 to 4 carbon atoms).

This raw material is a compound in which one of the phenolic hydroxyl groups of hydroquinones is aminated,
It may also contain p-aminophenols, which are synthetic intermediates when producing p-phenylenediamines from hydroquinones. Therefore, even when a mixture of hydroquinones and p-aminophenols is used as a starting material, there is no limit to the mixing ratio.

In the present invention, the above-mentioned hydroquinones and/or
Alternatively, ammonia is used as an aminating agent for aminating p-aminophenols.

The essential conditions for producing p-phenylenediamines with high selectivity by subjecting hydroquinones or p-aminophenols or a mixture thereof to an ammoniato reaction in the liquid phase are as follows. The method is to allow an amine and/or an alicyclic ketone to coexist in the reaction system. If this condition is not met, p-phenylenediamine is not produced at all or the selectivity is significantly reduced.

In addition to hydroquinones and/or p-aminophenols, ammonia, Pd catalyst, and alicyclic amine and/or alicyclic ketone, Pd catalyst is highly dispersed to dissolve hydroquinones and promote the reaction. It is preferable to add a reaction solvent to achieve this. As a result of examining the effects of various reaction solvents, it was found that phenols and anilines are suitable as reaction solvents.

The phenol may be p-aminophenol, but since this is one of the starting materials for the method of the present invention, monohydric phenols other than p-aminophenol are used, and specifically, phenol, cresol, Lower alkylphenols such as ethylphenol or isopropylphenol are used. As the anilines, aniline and lower alkylanilines such as toluidine, xylidine, ethylaniline, propylaniline, and methylethylaniline are used. It is not preferable to use nitrobenzenes or pyridines as reaction solvents other than those mentioned above, since amination will be significantly suppressed. The reaction solvent is used in an amount of 50 to 500% by weight, particularly preferably 100 to 200% by weight, based on the hydroquinones, p-aminephenols, or a mixture thereof.

As the alicyclic amine, alicyclic monoamines such as cyclohexylamine, dicyclohexylamine, cyclohexylmethylamine, cyclohexylethylamine, and cyclohexylpropylamine, and alicyclic diamines such as cyclohexyldiamine are used, but among them, cyclohexylamine is suitable.

As the alicyclic ketone, lower alkylcyclohexanones such as cyclohexanone, methylcyclohexanone, ethylcyclohexanone, propylcyclohexanone, and dimethylcyclohexanone are used, and among them, cyclohexanone is preferred.

The amount of the alicyclic amine and alicyclic ketone added is 5 to 50 mol % based on the hydroquinones, p-aminophenols, or a mixture thereof. Particularly preferably 10 to 30 mol%.

As the Pd catalyst, exclusively metal Pd is used. metal P
Pd powder, or Pd supported on a carrier such as carbon, alumina, silica alumina, barium sulfate, or zeolite is preferably used. There is no particular limit to the amount of Pd used, but 5
Examples of %Pd/C are hydroquinones or p-
3 to 3 for aminophenols or mixtures thereof
0% by weight is used. Particularly preferably 5 to 20% by weight. In order to activate Pd more highly, it is desirable to inject hydrogen into the reaction system at a partial pressure of 1 to 5 Kg/cm2G.

Further, the Pd catalyst may be used after being subjected to hydrogen treatment in advance.

Although ammonia may be added as aqueous ammonia, it is preferably added as liquid ammonia. The preferred range of use is 2 to 20 times the mole of hydroquinones or p-aminophenols or a mixture thereof.

When directly reacting hydroquinones or p-aminophenol or a mixture thereof with ammonia, it is essential to coexist a Pd catalyst and an alicyclic amine and/or an alicyclic ketone in the reaction system.

The reaction conditions for the method of the present invention are not particularly limited, and any known method may be used, either continuous or batchwise. Preferably, in a closed container, alicyclic amines and/or alicyclic ketones, hydroquinones and/or p-aminophenols, and optionally a solvent, P
d A catalyst and liquid ammonia are charged, hydrogen is injected under pressure if necessary, and the reaction is carried out at a temperature of 150 to 250°C for 5 to 15 hours.

<Examples> The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

(Example 1) A stainless steel II 300mu autoclave was charged with 22.0 g of hydroquinone, 3.93 g of cyclohexanone, 44.6 g of phenol, and 5% Pd/C (B Engelhard) and sealed. Next, 36.5 g of liquid ammonia was charged.
After injecting 4 kg/cm2G of hydrogen, a pressure of about 4 kg/cm2G was applied. It was heated in an electric furnace and reacted at 200 t for 7 hours. The reaction pressure was 66 g/cm2G. After cooling, unreacted ammonia was collected, followed by filtering off the 5% Pd/(:) and washing with pyridine to collect the organic matter attached to the Pd/C. Product containing pyridine 192.3
I got g. As a result of analyzing the product by gas chromatography, the product composition was as follows.

Hydroquinone 6.05gp-aminophenol 2.81gp-phenylenediamine 7
．． 88g tar 5.09g aniline 17.6g phenol
27.0g When calculating the reaction results, the hydroquinone conversion rate was 73 mol%, the p-amine phenol selectivity was 18 mol%, and the p-amine phenol selectivity was 18 mol%.
The phenylenediamine selectivity was 50 mol%.

(Comparative Example 1) Hydroquinone 11.0 g was placed in the same reactor as in Example 1.
, Phenol 136, 6g, 25% ammonia water 135
．． 9 g was charged and reacted at 284°C for 2.5 hours.
The reaction pressure was 71Kg/cm2G. After cooling, unreacted ammonia was collected to obtain 11.0 g of product.
The liquid composition was as follows.

Hydroquinone 3.54gp-aminephenol 6.76gp-phenylenediamine t
When the race reaction results were calculated, the hydroquinone conversion rate was 68 mol%, the p-aminophenol selectivity was 91 mol%, and the p-phenylenediamine selectivity was approximately 0 mol%.

(Comparative Example 2) Hydroquinone 5. OOg, cobalt chloride (hexahydrate') 1. O
Og, ammonium chloride 1, OOg, and 20.1 g of 25% ammonia water were charged, and the mixture was reacted at 274°C for 8.0 hours.

The reaction pressure was 30 g/cm2G. After cooling, the reaction product was analyzed by gas chromatography, and the conversion rate of hydroquinone was 99 mol%, p-aminophenol selectivity was as low as 3.2 mol%, and p-phenylenediamine was not detected. Ta.

(Comparative Example 3) In a reactor similar to Example 1, 22.0 g of hydroquinone was added.
, 4.1 g of cyclohexylamine.

Prepared 44.5g of phenol and 5.8g of Raney Ni.
It was sealed. 43.8 g of liquid ammonia was injected into this and reacted at 180'C for 10.9 hours. After cooling,
After recovering unreacted ammonia and subsequently filtering off Raney Ni, the reaction solution (170.6 g) was analyzed by gas chromatography, and the hydroquinone conversion rate was 20 mol%, and the p-aminophenol selectivity was 12 mol%. p-phenylenediamine was not detected.

(Example 2) In a reactor similar to Example 1, 220 g of hydroquinone,
4.03 g of cyclohexylamine, 5% Pd/C (Japan Engelhardt 3,00 g, and 44.7 g of phenol were charged and sealed. Next, 37.4 g of liquid ammonia was injected and reacted at 180°C for 13.6 hours. After cooling, unreacted ammonia was collected, Pd/C was filtered, and 17
0.9g was obtained. The results of the analysis using the gas chromad method,
The hydroquinone conversion rate was 50 mol%, the p-aminophenol selectivity was 20 mol%, and the p-phenylenediamine selectivity was 39 mol%.

(Example 3) In a reactor similar to Example 1, 10.0 g of hydroquinone was added.
．． 1.81 g of cyclohexanone, 5% Pd,/c (Japan Engelhard g, 20.0 g of 2.6-xylidine were charged and sealed. Next, 18.3 g of liquid ammonia was injected, and 20.0 g of 2.6-xylidine was charged.
The reaction was carried out at .degree. C. for 6.8 hours, and after cooling, unreacted ammonia was collected and Pd/C was filtered to obtain 114.2 g. As a result of analysis by gas chromatography, the conversion rate of hydroquinone was 72 mol%, the p-aminophenol selectivity was 15 mol%, and the p-phenylenediamine selectivity was 43 mol%.

(Example 4) In a reactor similar to Example 1, 22.0 g of hydroquinone was added.
, 3.93 g of cyclohexanone, 5% Pd/C (Japan Engelhard G, 44.0 g of aniline), and the flask was sealed.

Next, liquid ammonia 40. ag was injected and reacted at 200° C. for 6.8 hours. After cooling, unreacted ammonia was collected and Pd/C was filtered to obtain 169.6 g. As a result of analysis using the gas chromatography method, the hydroquinone conversion rate was 8.
0 mol%, p-aminophenol selectivity is 15 mol%,
The p-phenylenediamine selectivity was 34 mol%.

<Effects of the Invention> According to the method of the present invention, p-phenylenediamines can be produced from hydroquinones and/or p-aminephenols in a high yield in one step. Also, 0
- Since phenylene diamines are not produced as a by-product during the amination process, highly pure p-phenylene diamines can be produced.

In addition, according to the method of the present invention, since only a Pd catalyst is used as a catalyst, the product obtained by filtering the catalyst can be purified by distillation as it is, and high purity p-phenylenediamines can be easily produced. can do.

Furthermore, the process according to the invention clearly reduces the amount of undesirable by-products that are difficult to remove.

Claims (2)

[Claims] (1) Production of p-phenylenediamines, which is characterized by reacting hydroquinones and/or p-aminophenols with ammonia in the coexistence of a Pd catalyst and an alicyclic amine and/or an alicyclic ketone. Method. (2) The method for producing p-phenylenediamines according to claim 1, wherein phenols and/or anilines are used as a solvent during the reaction.