KR20160063927A - The preparation method for the p-phenylenediamine - Google Patents

Abstract

The present invention relates to a method of preparing para-phenylenediamine, and more particularly, to a method of preparing para-phenylenediamine with excellent yield and excellent purity including: a first step of making sodium urate, potassium urate, or urate that is a mixture thereof react with mono-nitrobenzene at 40 to 120°C to prepare 4-nitrosoaniline; and a second step of performing a hydrogenation reaction of the prepared 4-nitrosoaniline to prepare para-phenylenediamine, wherein urate with excellent thermal stability is used as a reactant to prepare 4-nitrosoaniline with a high conversion rate and good yield without generating a by-product, such as carbonate, and ammonia.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing paraphenylenediamine,

The present invention relates to a process for preparing paraphenylenediamine having excellent yield and purity.

In general, p-phenylenediamine is widely used in various fields of raw materials for cosmetics and antioxidants, fuel additives and coloring agents. It is also used as a base material for producing aramid (aramid), which is a functional fiber having chemical resistance, heat resistance and high rigidity, and phenylenediisocyanate, which is a raw material of polyurethane.

The paraphenylenediamine is produced by reacting chlorobenzene with nitric acid and ammonia to prepare 4-nitroaniline and subjecting it to hydrogenation.

The process produces isomers ortho and para-nitrochlorobenzene at a ratio of 65:35 by weight in the nitration reaction of chlorobenzene. In this process, para-nitrochlorobenzene can not be separated purely, and the isomer is left in the final product, paraphenylenediamine, which makes it difficult to produce highly pure paraphenylenediamine.

In order to prevent the generation of isomers such as ortho, U.S. Patent No. 4,279,815 discloses that aniline is diazonated with nitrogen oxide and then the diazo compound is reacted with an excess of aniline to form 1,3-diphenyltriazine Is prepared, rearranged under acidic conditions, and hydrogenated to produce paraphenylenediamine.

Although the above method can produce relatively high purity paraphenylenediamine by inhibiting the formation of isomers such as ortho, it requires a complicated process and requires a multi-step reaction. Accordingly, a low yield and a high manufacturing cost are disadvantageous have.

In recent years, there has been developed a process for producing 4-nitrosoaniline, which is a reaction intermediate of para-phenylenediamine, which is highly para-selective, using a nucleophilic aromatic substitution of hydrogen (NASH) have.

In this connection, U.S. Patent No. 6,552,229 discloses a process for producing 4-nitrosoaniline as a main product and 4-nitroaniline as a by-product by reacting nitrobenzene with an amide compound in the presence of a base.

Korean Patent No. 294,125 discloses a method for producing 4-nitrosoaniline by reacting urea with nitrobenzene under a base and polar solvent conditions.

However, these processes have the disadvantage that the hydroxide ion (OH < ^- & gt ^; ) of the base reacts with the product, 4-nitrosoaniline, to produce byproducts such as 4,4'- dinitrodiphenylamine and especially the urea decomposes into carbonate and ammonia And the yield of 4-nitrosoaniline is lowered.

Therefore, there is also a problem that the yield and purity of para-phenylenediamine produced using the 4-nitrosoaniline prepared in the above-described manner are very low.

The present invention relates to a process for the production of a catalyst which prevents the decomposition of uric acid salts into carbonate and ammonia during the reaction by using an uric acid salt which is excellent in thermal stability without using a basic condition and which is a byproduct of catalytic poison which is 4,4'-dinitrodiphenylamine 4-nitrosoaniline having a high conversion and yield can be produced under a simple reaction condition. Therefore, it is an object of the present invention to provide a process for producing paraphenylenediamine having high yield and purity.

In order to achieve the above object, the present invention provides a process for producing 4-nitrosoaniline by reacting an iodate, which is sodium urate, potassium urate, or a mixture thereof, with mononitrobenzene at 40 to 120 ° C. And a second step of preparing paraphenylenediamine by hydrogenating 4-nitrosoaniline prepared in the above step.

The sodium urate may be prepared by a method selected from the group consisting of the reaction of urea with sodium hydride, the reaction of urea with sodium methoxide, and the reaction of urea with sodium hydroxide under dimethylsulfoxide.

The potassium urate may be prepared by reaction of urea with potassium hydride or by reaction of urea with potassium hydroxide under dimethylsulfoxide.

The uric acid salt may be used in an amount of 1.5 mole or more per mole of mononitrobenzene.

The uric acid salt may be used in the range of 1.5 to 7 mol per mol of mononitrobenzene.

The one-step reaction can be carried out under anaerobic conditions or under oxygen conditions.

The 1-step reaction may have a yield of 4-nitrosoaniline of 60% or more and a conversion of mononitrobenzene of 90% or more.

The two-step reaction can be carried out in the presence of a palladium (Pd / C) or platinum (Pt / C) hydrogenation catalyst.

The method of preparing paraphenylenediamine according to the present invention uses a uric acid salt having excellent thermal stability as a reactant in the production of an intermediate, and has resistance to reaction conditions such as carbonate and ammonia, so that unintended decomposition can be suppressed, There is an advantage in that the yield and purity of the paraphenylenediamine phosphorus are excellent.

In addition, the process for preparing paraphenylenediamine according to the present invention has an advantage in that it can prevent the formation of by-products of 4,4'-dinitrodiphenylamine acting as a catalyst poison since conventional base conditions are not used in the production of intermediates .

In addition, the process for preparing paraphenylenediamine according to the present invention has an advantage that 4-nitrosoaniline having a high conversion and yield can be obtained by carrying out a reaction under a simple reaction condition.

In addition, the process for preparing paraphenylenediamine according to the present invention has an advantage that 4-nitrosoaniline having a very high para selectivity can be used to produce paraphenylenediamine, which does not require a product separation and purification process have.

The present invention relates to a process for preparing paraphenylenediamine having excellent yield and purity.

Hereinafter, the present invention will be described in detail.

The process for preparing paraphenylenediamine according to the present invention comprises reacting an iodate salt, which is sodium urate, potassium urate or a mixture thereof, with mononitrobenzene at 40 to 120 ° C to prepare 4-nitrosoaniline And a step of hydrogenating 4-nitrosoaniline prepared in the above step to produce paraphenylenediamine.

The preparation of the paraphenylenediamine is carried out in the same manner as in Reaction Scheme 1, and each step will be described in detail.

[Reaction Scheme 1]

(Wherein M < ^{+ >} is sodium or potassium)

In step 1, the uric acid salt of formula (1), which is sodium urate, potassium urate or a mixture thereof, and the mononitrobenzene of formula (2) are subjected to NASH reaction at 40 to 120 ° C to prepare 4-nitrosoaniline of formula (3).

The starting material, uric acid salt, is a nucleophile and has excellent thermal stability up to a temperature of 120 ° C. Therefore, the decomposition of the urate salt does not occur during the reaction with the mononitrobenzene, thereby suppressing the formation of by-products such as carbonates and ammonia.

In the present invention, the urate can be sodium urate, potassium urate or a mixture thereof.

Said uric acid sodium can be prepared by methods commonly used in the art, such as the reaction of urea with sodium hydride, the reaction of urea with sodium methoxide, and the reaction of urea with sodium hydroxide under dimethylsulfoxide Can be prepared by the selected method. Preferably, it is prepared by the reaction of urea and sodium hydroxide in the presence of dimethylsulfoxide as solvent. When produced by the above method, the yield and purity of sodium uricosylate produced are high, and the manufacturing cost is low, so that an economical effect can be obtained.

The potassium uric acid can be prepared by a commonly used method in the art, for example, by reacting urea with potassium hydride, by reaction of urea with potassium methoxide, and by reaction of urea with potassium hydroxide under dimethylsulfoxide Can be prepared by the selected method. Preferably, it is prepared by the reaction of urea and potassium hydroxide in the presence of dimethylsulfoxide as a solvent. The potassium urate produced when produced by the above-described method has a high yield and purity and a low manufacturing cost, thereby providing economical advantages.

At this time, an element which reacts with sodium hydroxide or potassium hydroxide under dimethylsulfoxide may be added in excess.

Specifically, the above element may be added in an amount of 1.1 to 10 mol, preferably 2 to 4 mol, per mol of sodium hydroxide or potassium hydroxide.

The preparation of the sodium urate and the potassium urate is carried out in the presence of a solvent. The solvent is not limited to those generally used in the art. For example, the solvent may be methanol, dimethylsulfoxide, dimethylformamide, N-methylpyrrolidone, pyridine, dioxane, tetrahydrofuran and the like.

Also, in the production of sodium uric acid and potassium uric acid, the reaction temperature is preferably raised to 40 to 120 ° C, preferably to 70 ° C.

The thus produced urate, which is sodium urate, potassium urate or a mixture thereof, reacts with mononitrobenzene in the solution in the presence of NASH to produce 4-nitrosoaniline having a very high para selectivity.

Specifically, a mixture of urate and mononitrobenzene is dissolved in the presence of a solvent, and after a lapse of a certain time, the product, 4-nitrosobenzene, is partially present as a saturated solution and the other part is dispersed in the solid phase.

The uric acid salt may be used in an amount of 1.5 mole or more, preferably 1.5 to 7 moles, more preferably 2.5 to 7 moles per mole of mononitrobenzene.

When the amount of the urate salt is less than 1.5 mol, the conversion of mononitrobenzene is lowered, so that unreacted mononitrobenzene and a final product, 4-nitrosoaniline, generate a diazo compound as a by- There is a problem that the yield of aniline rapidly decreases to 50% or less.

The solvent may be any solvent commonly used in the art without limitation. For example, dimethylsulfoxide, which can improve the reactivity of NASH, may be used alone, or an organic solvent capable of being miscible with dimethylsulfoxide may be used . The organic solvent may be at least one selected from the group consisting of methanol, ethanol, butanol, and isopropyl alcohol, although the organic solvent is not particularly limited and is generally used in the art.

In this case, the mixing ratio of the solvent and the urate salt may be 1: 2 to 1:10 wt%, and preferably 1: 2.5 to 1: 6 wt%.

In the present invention, the reaction temperature is preferably 40 to 120 ° C, and more preferably 60 to 100 ° C. When the reaction temperature is lower than 40 ° C, the reactivity of NASH is lowered and the yield of 4-nitrosoaniline may be decreased. When the reaction temperature is higher than 120 ° C, pyrolysis of the uric acid occurs and the formation of by- There is a problem that the yield and purity of aniline are reduced.

Further, the reaction is preferably carried out under anaerobic or oxygen conditions such as nitrogen, more preferably under nitrogen conditions in order to inhibit the formation of by-products and increase the yield of 4-nitrosoaniline.

At this time, an element dissolved in dimethyl sulfoxide may be further added to increase the yield and purity of 4-nitrosoaniline.

The addition of the above elements further increases the solubility of the uric acid salt to dimethylsulfoxide, increases the reaction efficiency by inhibiting the decomposition of the uric acid salt into urea and enhances the yield of 4,4'-dinitrodiphenyleneamine Thereby suppressing the generation.

The amount of the urea to be added is not particularly limited and may be appropriately changed depending on the recovery rate of 4-nitrosoaniline. However, if an element is added in excess of the required amount, the unreacted elements must be recovered separately, thereby resulting in a problem that the cost is increased.

The dimethylsulfoxide used as the reaction solvent is preferably 1 to 50 mol, preferably 1.5 to 10 mol, per 1 mol of the urea.

In order to increase the selectivity of the product, 4-nitrosoaniline, the reaction can be carried out by gradually injecting the uric acid salt and the mononitrobenzene for a predetermined time while maintaining the temperature at 40 to 120 ° C, preferably 60 to 100 ° C .

The production rate of 4-nitrosoaniline produced in the above step 1 is 60% or more, and the conversion rate of mononitrobenzene is maintained at 90% or more. Since this method does not use a strong base such as sodium hydroxide in the prior art, 4-nitrosoaniline with excellent yield can be produced by suppressing the formation of by-products such as 4,4-dinitrodiphenylamine.

In the second step, the 4-nitrosoaniline of Formula 3 prepared above is hydrogenated to produce the final product, paraphenylenediamine of Formula 4. [

It is preferable that the 4-nitrosoaniline is diluted by adding an alcohol such as ethanol or isopropanol before the hydrogenation reaction, and the alcohol is preferably 50 to 500 parts by weight based on 100 parts by weight of the solvent. There is a problem in that the hydrogenation reaction does not proceed unless diluted with alcohol before the hydrogenation reaction.

The two-step reaction may also be carried out in the presence of a palladium (Pd / C) or platinum (Pt / C) hydrogenation catalyst.

At this time, the hydrogenation catalyst is preferably 0.2 to 0.7 parts by weight based on 100 parts by weight of 4-nitrosoaniline. When the hydrogenation catalyst is less than 0.2 part by weight, hydrogenation reaction does not occur well and purity can be lowered. When the hydrogenation catalyst is more than 0.7 part by weight, further improvement in purity can not be obtained and a manufacturing cost may be increased.

It is also preferable that the temperature of the hydrogenation reaction is 50 to 150 ° C and the hydrogen pressure is 1 to 5 MPa.

According to the present invention, it is possible to produce 4-nitrosoaniline having excellent yield without the formation of by-products such as carbonate and ammonia by using an uric acid salt having excellent thermal stability as a reactant. In addition, since a strong base such as sodium hydroxide is not used, 4-nitrosoaniline having excellent yield and conversion can be produced by suppressing the formation of by-products such as 4,4-dinitrodiphenylamine.

Thus, 4-nitrosoaniline can be prepared by the hydrogenation reaction to produce paraphenylenediamine having excellent yield and purity.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

[Equipment to be used and measurement conditions]

In the following examples, for quantitative analysis of the product, it was measured by high performance liquid chromatography (Shimadzu LC 10, HPLC). Distilled water and acetonitrile were used as the solvent and distilled water was used at a developing rate of 1.0 ml / min, oven temperature of 40 ° C, wavelength UV, 260, 280, 320, 370 and 410 nm.

The solvent gradient elution conditions are shown in Table 1 below.

Time (minutes) %Distilled water % Acetonitrile 0 60 40 12 60 40 18 50 50 25 0 100 35 0 100

Manufacturing example  One

First, a five-necked flask equipped with a stirrer, a thermometer, a dosing funnel, a gas injection capillary and a column was prepared, and a thermometer, a condenser and a glass valve were connected to the column head.

400 ml of xylene was injected into the prepared five-necked flask, and then the temperature was raised to 120 ° C with stirring at 500 rpm, and the gas was flowed at a rate of 180 ml / min through a gas injection capillary. Then, a mixed solution prepared by dissolving urea (66.6 g; 1.12 mol) and sodium methoxide (60 g; 1.12 mol) in methanol was injected. After a period of time, methanol-xylene vapor was formed and condensed, yielding 125.8 g of wet solid beads. The wet solid bead was composed of 68% uric acid and 32% xylene. After removing the xylene by distillation under reduced pressure, 85.7 g (yield: 93%) of sodium urate was obtained.

Manufacturing example  2

(33 g; 0.55 mol) and methoxide potassium (38 g; 0.56 mol) were dissolved in methanol to prepare a mixed solution. 32.39 g (yield: 60%) of potassium urate as a target compound was dissolved in methanol, ≪ / RTI >

Example  1-1

A 150 ml four-necked flask equipped with a stirrer, condenser, thermometer, dosing funnel and gas inlet capillary tube was prepared.

(15 g; 0.25 mol) was dissolved in DMSO (75 g, 0.96 mol) and injected into a four-necked flask. To the DMSO-urea solution was added sodium uric acid (20 g, 0.244 mol) prepared in Preparation Example 1 .

A mixture of mononitrobenzene (10.5 g; 0.085 mol) and DMSO (11.5 g; 0.15 mol) was then injected into a four-necked flask on the dosing funnel.

The mixture was poured into the flask for 120 minutes and the reaction temperature was maintained at 90 < 0 > C. After the completion of the injection, the reaction was further carried out at 90 DEG C for 120 minutes.

At this time, nitrogen gas was bubbled through the gas injection capillary tube during the entire reaction time.

The product of the reaction was separated into a solid (16.8 g) and a liquid (112.5 g), and their components were quantitatively analyzed and shown in Table 2 below.

division Solid content (% by weight) Liquid fraction (% by weight) Yield (mol%) Sodium urate 4.37 5.40 - ammonia 0 0 - Sodium carbonate 0 0 - Mononitrobenzene 0 0 - 4-nitroaniline 0.21 0.35 3.56 4-nitrosoaniline 3.49 7.76 89.50 4.4'-dinitrodiphenylamine 0 0 -

Example  1-2

Except that mononitrobenzene (10.5 g; 0.085 mol) and DMSO (0.15 g) were used in place of the mixture of mononitrobenzene (10.5 g; 0.085 mol) and DMSO 15 g; 0.19 mol) were mixed.

The product of the reaction was separated into a solid (18.4 g) and a liquid (113 g), and their components were quantitatively analyzed and shown in Table 3 below.

division Solid content (% by weight) Liquid fraction (% by weight) Yield (mol%) Sodium urate 4.78 5.43 - ammonia 0 0 - Sodium carbonate 0 0 - Mononitrobenzene 0 0 - 4-nitroaniline 0.20 0.34 3.49 4-nitrosoaniline 3.39 7.53 87.70 4.4'-dinitrodiphenylamine 0 0 -

Example  1-3

(20 g, 0.244 mol) prepared in Preparation Example 1 was injected into DMSO (75 g; 0.96 mol) without further addition of urea, and the reaction was carried out Respectively.

The product of the reaction was separated into a solid (14.9 g) and a liquid (99.8 g), and their components were quantitatively analyzed and shown in Table 4 below.

division Solid content (% by weight) Liquid fraction (% by weight) Yield (mol%) Sodium urate 3.88 4.79 - ammonia 0 0 - Sodium carbonate 0 0 - Mononitrobenzene 0 0 - 4-nitroaniline 0.18 0.30 2.68 4-nitrosoaniline 3.34 7.42 67.30 4.4'-dinitrodiphenylamine 0 0 -

Example  1-4

(25g, 0.42mol) was dissolved in DMSO (75g; 0.96mol) instead of dissolving urea (15g; 0.25mol) in DMSO (75g; 0.96mol) The reaction was carried out.

The product of the reaction was separated into a solid (26.4 g) and a liquid (112.7 g), and their components were quantitatively analyzed and shown in Table 5 below.

division Solid content (% by weight) Liquid fraction (% by weight) Yield (mol%) Sodium urate 13.20 5.41 - ammonia 0 0 - Sodium carbonate 0 0 - Mononitrobenzene 0 0 - 4-nitroaniline 0.20 0.33 3.53 4-nitrosoaniline 3.24 7.20 88.70 4.4'-dinitrodiphenylamine 0 0 -

Example  1-5

The reaction was carried out in the same manner as in Example 1-1 except that the urea sodium (10 g, 0.12 mol) prepared in Preparation Example 1 was injected into DMSO (75 g; 0.96 mol) Respectively.

The product of the reaction was separated into a solid (15.7 g) and a liquid (89.1 g), and their components were quantitatively analyzed and shown in Table 6 below.

division Solid content (% by weight) Liquid fraction (% by weight) Yield (mol%) Sodium urate 4.09 4.28 - ammonia 0 0 - Sodium carbonate 0 0 - Mononitrobenzene 0 0 - 4-nitroaniline 0.19 0.32 2.65 4-nitrosoaniline 3.24 7.20 66.50 4.4'-dinitrodiphenylamine 0 0 -

Example  1-6

The reaction was carried out in the same manner as in Example 1-1 except that potassium urate (23.9 g, 0.244 mol) prepared in Preparation Example 2 was used instead of sodium urate (10 g, 0.12 mol) prepared in Preparation Example 1 Respectively.

The product of the reaction was separated into a solid (19.4 g) and a liquid (109.7 g), and their components were quantitatively analyzed and shown in Table 7 below.

division Solid content (% by weight) Liquid fraction (% by weight) Yield (mol%) Potassium urate 5.04 5.27 - ammonia 0 0 - Sodium carbonate 0 0 - Mononitrobenzene 0 0 - 4-nitroaniline 0.17 0.29 2.89 4-nitrosoaniline 2.87 6.38 72.50 4.4'-dinitrodiphenylamine 0 0 -

Comparative Example  1-1

A 150 ml four-necked flask equipped with a stirrer, condenser, thermometer, dosing funnel and gas inlet capillary tube was prepared.

(15 g; 0.25 mol) was dissolved in DMSO (75 g; 0.96 mol), and this was injected into a four-necked flask. Sodium hydroxide (8.8 g;

A mixture of mono nitrobenzene (9 g; 0.073 mol) and DMSO (11.5 g; 0.15 mol) was then introduced into a four-necked flask.

The mixture was poured into the flask for 120 minutes and the reaction temperature was maintained at 90 < 0 > C. After the completion of the injection, the reaction was further carried out at 90 DEG C for 120 minutes.

At this time, nitrogen gas was bubbled through the gas injection capillary tube during the entire reaction time.

The product of the reaction was separated into a solid (15.2 g) and a liquid (103.8 g), and their components were quantitatively analyzed and shown in Table 8 below.

division Solid content (% by weight) Liquid fraction (% by weight) Yield (mol%) Sodium hydroxide 3.95 4.98 - ammonia 0 0 - Sodium carbonate 0 0 - Mononitrobenzene 0 1.02 - 4-nitroaniline 0.13 0.22 4-nitrosoaniline 2.20 4.89 2.34 4.4'-dinitrodiphenylamine 0.12 0.24 58.90

Comparative Example  1-2

The reaction was carried out in the same manner as in Comparative Example 1-1 except that potassium hydroxide (20.2 g; 0.36 mol) was dispersed instead of dispersing sodium hydroxide in the DMSO-urea solution.

The product of the reaction was separated into a solid (16.5 g) and a liquid (110.3 g), and their components were quantitatively analyzed and shown in Table 9 below.

division Solid content (% by weight) Liquid fraction (% by weight) Yield (mol%) Potassium hydroxide 4.29 5.29 - ammonia 0 0 - Sodium carbonate 0 0 - Mononitrobenzene 0 0.98 - 4-nitroaniline 0.12 0.20 2.35 4-nitrosoaniline 2.07 4.60 59.12 4.4'-dinitrodiphenylamine 0.19 0.21 -

Comparative Example  1-3

The reaction was carried out in the same manner as in Example 1-1 except that the reaction temperature was changed to 30 ° C.

The product of the reaction was separated into solid (43.9 g) and liquid (81.5 g), and their components were quantitatively analyzed and shown in Table 10 below.

division Solid content (% by weight) Liquid fraction (% by weight) Yield (mol%) Sodium urate 38.21 3.91 - ammonia 0 0 - Sodium carbonate 0 0 - Mononitrobenzene 0 0.75 - 4-nitroaniline 0.09 0.15 1.40 4-nitrosoaniline 1.53 3.41 35.20 4.4'-dinitrodiphenylamine 0 0.01 -

Comparative Example  1-4

The reaction was carried out in the same manner as in Example 1-1 except that the reaction temperature was changed to 130 ° C.

The product of the reaction was separated into a solid (69.1 g) and a liquid (58.9 g), and their components were quantitatively analyzed and shown in Table 11 below.

division Solid content (% by weight) Liquid fraction (% by weight) Yield (mol%) Sodium urate 17.98 2.83 - ammonia 24.30 0 - Sodium carbonate 50.80 0 - Mononitrobenzene 0 1.12 - 4-nitroaniline 0.10 0.17 1.37 4-nitrosoaniline 1.67 3.72 34.30 4.4'-dinitrodiphenylamine 0.13 0.02 -

Example  2-1

The 4-nitrosoaniline prepared in Example 1-1 was injected into an autoclave and diluted with 300 ml of ethanol. Then, 4.5 g of Pd / C catalyst (3.8% Pd) was injected, and the hydrogenation reaction was carried out at a hydrogen pressure of 2 MPa at a temperature of 80 ° C. Thereafter, the ethanol and water were evaporated, and 8.55 g (99.5 mol% in yield) of paraphenylenediamine (purity 99.9%) was obtained.

Example  2-2 to 2-7

The reaction was carried out in the same manner as in Example 2-1, but using 4-nitrosoaniline and a hydrogenation catalyst as shown in the following Table 12, p-phenylenediamine was obtained. The yield and purity of the obtained paraphenylenediamine were quantitatively analyzed and shown in Table 12 below.

division 4-nitroso
aniline Hydrogenation
catalyst Paraphenylenediamine
Content (g) The yield of paraphenylenediamine (mol%) Purity (%) of paraphenylenediamine Example 2-1 Example 1-1 Pd / C 8.55 99.5 99.9 Example 2-2 Examples 1-2 Pd / C 8.32 98.9 99.1 Example 2-3 Example 1-3 Pd / C 7.12 98.2 98.9 Examples 2-4 Examples 1-4 Pd / C 8.22 99.4 99.9 Example 2-5 Examples 1-5 Pd / C 6.26 98.1 98.7 Example
2-6 Examples 1-6 Pd / C 6.87 98.6 99.0 Examples 2-7 Example 1-1 Pt / C 8.55 99.5 99.9

Comparative Example  2-1 to 2-5

The reaction was carried out in the same manner as in Example 2-1, but hydrogenation was carried out using 4-nitrosoaniline and a hydrogenation catalyst as shown in the following Table 13 to obtain paraphenylenediamine. The yield and purity of the obtained paraphenylenediamine were quantitatively analyzed and shown in Table 13 below.

division 4-nitroso
aniline Hydrogenation
catalyst Paraphenylenediamine
Content (g) The yield of paraphenylenediamine (mol%) Purity (%) of paraphenylenediamine Comparative Example 2-1 Comparative Example 1-1 Pd / C 3.48 69.8 77.2 Comparative Example 2-2 Comparative Example 1-2 Pd / C 3.45 70.2 76.5 Comparative Example 2-3 Comparative Example 1-3 Pd / C 3.49 75.5 78.4 Comparative Example 2-4 Comparative Example 1-4 Pd / C 2.40 74.3 77.9 Comparative Example 2-5 Comparative Example 1-1 Pt / C 2.30 69.8 77.2

As shown in the above examples, the yields of 4-nitrosoaniline and mononitrobenzene prepared in Examples 1-1 to 1-6 of the present invention were 90% or higher, It was very high. Thus, the paraphenylenediamine yields of Examples 2-1 to 2-7 thus prepared were 90% or higher and the purity was 95% or higher, and the yield and purity of paraphenylene It was confirmed that diamine could be obtained.

On the other hand, the yields of 4-nitrosoaniline and mononitrobenzene prepared in Comparative Examples 1-1 to 1-4 were 60% or less and 80% or less, respectively. Thus, it was confirmed that the yields of paraphenylenediamine in Comparative Examples 2-1 to 2-5 prepared therefrom were 76% or less and the purity was 80% or less.

In Comparative Examples 1-1 and 1-2, it was confirmed that the yield and conversion of 4-nitrosoaniline were decreased due to a large amount of by-products generated due to the side reaction of urea and sodium hydroxide during the production of the intermediate. In Comparative Example 1-3, the reaction was carried out at a temperature lowering the reactivity of NASH, and the yield of 4-nitrosoaniline was remarkably decreased. In Comparative Example 1-4, pyrolysis of the urate salt occurred, and byproducts such as ammonia and carbonate The yield of 4-nitrosoaniline was also remarkably reduced.

Claims (8)

A step of producing 4-nitrosoaniline by reacting an iodate, which is sodium urate, potassium urate, or a mixture thereof, with mononitrobenzene at 40 to 120 ° C, and
And 2) a step of hydrogenating 4-nitrosoaniline produced in the above step to prepare paraphenylenediamine.
The method of claim 1, wherein the sodium urate is prepared by a method selected from the group consisting of the reaction of urea and sodium hydride, the reaction of urea with sodium methoxide, and the reaction of urea and sodium hydroxide under dimethylsulfoxide. Diamine.
The process according to claim 1, wherein the potassium urate is prepared by reaction of urea with potassium hydride or by reaction of urea with potassium hydroxide under dimethylsulfoxide.
[4] The method according to claim 1, wherein the uric acid salt is used in an amount of 1.5 mol or more per 1 mol of mononitrobenzene.
[5] The method according to claim 4, wherein the uric acid salt is used in a range of 1.5 to 7 mol per mol of mononitrobenzene.
The process according to claim 1, wherein the first step reaction is carried out under anaerobic conditions or oxygen conditions.
[2] The process according to claim 1, wherein the 1-step reaction has a yield of 4-nitrosoaniline of 60% or more and a conversion of mononitrobenzene of 90% or more.
The process according to any one of claims 1 to 7, wherein the two-step reaction is carried out in the presence of a palladium (Pd / C) or platinum (Pt / C) hydrogenation catalyst.