CN108558675A - Synthesis method of 4-aminodiphenylamine - Google Patents

Abstract

The invention provides a kind of synthetic method of 4-aminodiphenylamine, it is characterized in that, comprises the following steps: 1) add aniline, nitrobenzene and molecular sieve catalyst in the reaction kettle and constantly mix and stir, at a temperature of 70-80 DEG C Reaction 3-6h under the following conditions, then add hexanaphthene and slough the water vapor that forms in the reaction under azeotropic condition, obtain the product of condensation reaction; 2) add Pd/C catalyst and pass into hydrogen in reactor, in The temperature is 70-180°C, and the pressure is 1.0-3.5MPa, and the reaction is 1-5h; 3) When the hydrogen pressure no longer drops after the reaction, filter under reduced pressure, and the obtained filtrate is subjected to vacuum distillation, and collected at 220-240°C The distillate obtains 4‑aminodiphenylamine. The synthesis method of 4-aminodiphenylamine provided by the invention has few by-products and high yield, the highest yield can reach 96%, and the catalyst has strong catalytic ability and high reutilization rate.

Description

A kind of synthetic method of 4-aminodiphenylamine

technical field

The invention belongs to the field of chemical synthesis, in particular to a preparation method of 4-aminodiphenylamine.

Background technique

4-Aminodiphenylamine is an important fine chemical intermediate, which can be used in rubber additives, dyes, textile and pharmaceutical industries, etc., and is mainly used in the production of rubber antioxidants. At present, the industrial production methods of 4-aminodiphenylamine include: diphenylamine method, aniline method, formanilide method and nitrobenzene method. The first three processes all have the disadvantages of long process flow and a large amount of difficult-to-treat waste water. However, the nitrobenzene method developed in recent years uses aniline and nitrobenzene as raw materials for condensation reaction to prepare 4-nitrodiphenylamine, 4-nitrobenzene, etc. Nitrodiphenylamine is then hydrogenated to produce 4-aminodiphenylamine. This process has a high yield and very little waste, which is not only beneficial to environmental protection, but also reduces costs. However, due to the problem of the catalyst, the production control of this technology is relatively difficult, and the product contains many impurities.

Chinese patent CN1266052A discloses a method for preparing 4-nitrodiphenylamine by the reaction of carbonanilide and nitrobenzene, and then CN1249017C discloses a method for preparing 4-nitrodiphenylamine and 4-nitrodiphenylamine by the reaction of carbonanilide and nitrobenzene. -The method of nitrosodiphenylamine, these two methods have following characteristics: the one, raw material is easy to get, and carboxanilide can be prepared by the reaction of urea and aniline; It is cheap sodium hydroxide; the third is that the product quality is good, and the side reaction at the ortho position of nitrobenzene is greatly reduced due to the steric hindrance of the amide structure; the fourth is that nitrobenzene is used instead of nitrochlorobenzene , will not produce chlorine-containing wastewater; fifth, the reaction yield is not affected by water, so there is no need to use a desiccant alone, or install distillation equipment. However, it uses polar organic solvent dimethyl sulfoxide as a solvent, which needs to be separated before hydrogenation to avoid hydrogenation catalyst poisoning.

Chinese patent 200910034650.7 discloses a method for synthesizing 4-aminodiphenylamine, mainly using urea and excess aniline as raw materials to synthesize carboanilide, and then directly adding nitrobenzene, inorganic base and phase transfer catalyst to synthesize 4-nitrodiphenylamine, 4 -Nitrosodiphenylamine, then add water to wash, recover the phase transfer catalyst and inorganic base from the water phase, recycle and apply mechanically, and directly hydrogenate the organic phase. The yield of the process method of this prior art 4-aminodiphenylamine is not high, and the hydrogenation speed is relatively slow.

Contents of the invention

The purpose of the present invention is in order to overcome above-mentioned technical difficulty, provide a kind of with nitrobenzene, aniline as raw material, adopt new catalyst and new production process flow, thereby provide the synthetic method of the high 4-aminodiphenylamine of productive rate.

Technical scheme of the present invention is: a kind of synthetic method of 4-aminodiphenylamine, is characterized in that, comprises the steps:

1) Add aniline, nitrobenzene and molecular sieve catalyst into the reaction kettle, mix and stir continuously, react at a temperature of 70-80°C for 3-6h, then add cyclohexane to remove the reaction under azeotropic conditions to form The steam of the condensation reaction is obtained;

2) Add Pd/C catalyst and hydrogen gas into the reaction kettle, and react for 1-5h under the conditions of temperature 70-180°C and pressure 1.0-3.5MPa;

3) After the reaction until the hydrogen pressure no longer drops, filter under reduced pressure, conduct vacuum distillation on the obtained filtrate, and collect the fraction at 220-240°C to obtain 4-aminodiphenylamine.

Further, in the above preparation method, the molar ratio of the aniline and nitrobenzene fed is (4-10):1, preferably 9:1.

Furthermore, in the above preparation method, the mass fraction of the catalyst is 6-10% of the total mass of aniline and nitrobenzene, preferably 8%.

Further, in the above preparation method, the Pd/C catalyst is a 10% Pd/C catalyst.

Further, in the above preparation method, the temperature rise of the reactor in step 2) is a stepwise temperature rise, that is, it is first kept at a temperature of 70°C for 1h, then heated to 150°C at a heating rate of 5°C/min, and then heated at a temperature of 2°C. Raise the temperature to 180°C at a heating rate of /min, and keep at 180°C for 1-3 hours.

Further, in the above preparation method, the step 3) further includes: after vacuum filtration, recrystallization of the filtrate with petroleum ether, washing the crystals with water, and then performing vacuum distillation.

Further, in the above preparation method, the molecular sieve is prepared from clay ore as a raw material, calcium hydroxide as an alkali source, and tetrapropylammonium hydroxide as a template.

Further, the preparation method of the molecular sieve catalyst is as follows:

1) Iron removal by acid method: Grind, pulverize and sieve the clay ore, then place it in a hydrochloric acid solution of 3mol/L hydrochloric acid, react at 100°C for 1 hour, filter the lower layer of precipitate after the reaction, wash with water until medium and placed in a drying oven to dry;

2) Alkaline activation: Grind and mix the above-mentioned dried materials with calcium hydroxide in a mass ratio of 1:5, then dry at 100 to 300°C, and grind to a fineness of less than 50 μm;

3) crystallization: add tetrapropyl ammonium hydroxide to the product obtained in the above step 2), and add tetrapropyl ammonium hydroxide solution according to the mass ratio of product: tetrapropyl ammonium hydroxide is 1:6, 50 Stir at a temperature of ℃ for 2 hours, then place it under a constant temperature condition of 80 ℃ and react for 6-8 hours, filter and dry to obtain a molecular sieve catalyst.

Further, the crystallization of the preparation step 3) of the molecular sieve is divided into initial crystallization and late crystallization: during initial crystallization, tetrapropyl hydrogen is added according to the mass ratio of product: tetrapropyl ammonium hydroxide is 1:4 Ammonium oxide solution, after stirring for 70 minutes at a temperature of 80°C, it will be crystallized in the later stage; during the crystallization in the later stage, tetrapropylammonium hydroxide is added according to the mass ratio of product: tetrapropylammonium hydroxide solution is 1:2 After stirring the solution for 70 minutes at a temperature of 80° C., the late stage crystallization was completed.

Further, the preparation method of the molecular sieve catalyst also includes step 4): grinding the prepared molecular sieve raw material powder to a diameter of 90-150 nanometers.

Compared with prior art, the beneficial effect of the present invention is:

(1) The synthetic method of 4-aminodiphenylamine provided by the present invention adopts aniline and nitrobenzene as raw materials, and the molecular sieve of the present invention is used as a catalyst, with few by-products and high yield, and the synthetic method of 4-aminodiphenylamine is the highest The yield can reach 96%.

(2) The synthetic method of 4-aminodiphenylamine provided by the present invention has high purity of the prepared product, and the highest purity can reach 98.5%.

(3) The synthetic method of 4-aminodiphenylamine provided by the present invention has a strong catalytic ability of the catalyst and a high recycling rate of the catalyst.

Detailed ways

The present invention will be described in further detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Example 1

A kind of synthetic method of 4-aminodiphenylamine is characterized in that, comprises the steps:

1) Add aniline, nitrobenzene and molecular sieve catalyst into the reaction kettle, mix and stir continuously, react at a temperature of 70-80°C for 3-6h, then add cyclohexane to remove the reaction under azeotropic conditions to form The steam of the condensation reaction is obtained;

2) Add Pd/C catalyst and hydrogen gas into the reaction kettle, and react for 1-5h under the conditions of temperature 70-180°C and pressure 1.0-3.5MPa;

3) After the reaction until the hydrogen pressure no longer drops, filter under reduced pressure, conduct vacuum distillation on the obtained filtrate, and collect the fraction at 220-240°C to obtain 4-aminodiphenylamine.

The whole reaction is divided into two steps. The first step is condensation reaction: in the presence of catalyst, aniline and nitrobenzene undergo condensation reaction to produce 4-nitrosodiphenylamine. The reaction principle is as follows:

The second step is a hydrogenation reaction: using Pd/C as a catalyst, 4-nitrosodiphenylamine undergoes a hydrogenation reduction reaction.

In the preparation method, the molar ratio of aniline and nitrobenzene is (4-10):1, preferably 9:1.

The inventor has also studied the feed ratio of aniline and nitrobenzene when the molecular sieve was used as a catalyst. 1, 9: 1, 10: 1 are example, react under the same condition, the 4-aminodiphenylamine productive rate that obtains is respectively shown in following table 1:

Table 1 Effect of the feed ratio (molar ratio) of aniline and nitrobenzene on the yield of 4-aminodiphenylamine

Aniline: Nitrobenzene 4:1 5:1 6:1 7:1 8:1 9:1 10:1 4-aminodiphenylamine yield 90% 91% 92% 93% 94% 96% 96%

As can be clearly seen from the above table, when the feed ratio (mol ratio) of aniline and nitrobenzene was 9: 1, the 4-aminodiphenylamine productive rate reached 96%, and continued to increase the feed ratio of aniline and nitrobenzene, 4 -The aminodiphenylamine production rate does not continue to increase, considering the factor of economic cost, it is the optimal scheme when the feed ratio (molar ratio) of aniline and nitrobenzene is 9:1.

In the above preparation method, the mass fraction of the catalyst is 6-10% of the total mass of aniline and nitrobenzene, preferably 8%.

In the above preparation method, the Pd/C catalyst is a 10% Pd/C catalyst.

In the above preparation method, the temperature rise of the reaction kettle in step 2) is a step-by-step temperature rise, that is, it is first kept at a temperature of 70°C for 1h, then the temperature is raised to 150°C at a heating rate of 5°C/min, and then the temperature is increased at a rate of 2°C/min. Raise the temperature to 180°C, and keep the temperature at 180°C for 1-3h.

In the above preparation method, step 3) further includes: after vacuum filtration, recrystallize the filtrate with petroleum ether, wash the crystals with water, and then conduct vacuum distillation.

Example 2

A kind of synthetic method of 4-aminodiphenylamine is characterized in that, comprises the steps:

1) Add aniline, nitrobenzene and molecular sieve catalyst into the reaction kettle, mix and stir continuously, react at a temperature of 70-80°C for 3-6h, then add cyclohexane to remove the reaction under azeotropic conditions to form The steam of the condensation reaction is obtained;

2) Add Pd/C catalyst and hydrogen gas into the reaction kettle, and react for 1-5h under the conditions of temperature 70-180°C and pressure 1.0-3.5MPa;

3) After the reaction until the hydrogen pressure no longer drops, filter under reduced pressure, conduct vacuum distillation on the obtained filtrate, and collect the fraction at 220-240°C to obtain 4-aminodiphenylamine.

In the above preparation method, the molecular sieve is prepared from clay ore as a raw material, calcium hydroxide as an alkali source, and tetrapropylammonium hydroxide as a template.

The preparation method of molecular sieve catalyst is as follows:

In the above preparation method 1) iron removal by acid method: grind, pulverize and sieve the clay ore, then place it in a hydrochloric acid solution of 3mol/L hydrochloric acid, react at 100°C for 1 hour, and filter to obtain the lower layer of precipitate after the reaction is completed , washed with water until neutral and dried in a drying oven;

2) Alkaline activation: Grind and mix the above-mentioned dried materials with calcium hydroxide in a mass ratio of 1:5, then dry at 100 to 300°C, and grind to a fineness of less than 50 μm;

3) crystallization: add tetrapropyl ammonium hydroxide to the product obtained in the above step 2), and add tetrapropyl ammonium hydroxide solution according to the mass ratio of product: tetrapropyl ammonium hydroxide is 1:6, 50 Stir at a temperature of ℃ for 2 hours, then place it under a constant temperature condition of 80 ℃ and react for 6-8 hours, filter and dry to obtain a molecular sieve catalyst.

In order to further improve the crystallization effect, the crystallization of the preparation step 3) of the molecular sieve can be divided into initial crystallization and later crystallization: during initial crystallization, according to product: tetrapropyl ammonium hydroxide is a mass ratio of 1:4 Add tetrapropyl ammonium hydroxide solution, after stirring for 70 minutes at a temperature of 80° C., carry out late stage crystallization; during late stage crystallization, add tetrapropyl ammonium hydroxide solution according to the mass ratio of 1:2. Propyl ammonium hydroxide solution, after stirring for 70 minutes at a temperature of 80° C., the late stage crystallization is completed.

In order to further improve the performance of the molecular sieve and facilitate the preparation of molecular sieve balls, in step 4), the prepared molecular sieve raw material powder can also be ground to a diameter of 90-150 nanometers, preferably 100 nanometers.

In the above preparation method, the mass fraction of the catalyst is 6-10% of the total mass of aniline and nitrobenzene, preferably 8%.

The inventor has also studied the influence of molecular sieve on the productive rate of 4-aminodiphenylamine as the consumption of catalyst, and the spherical 4A type molecular sieve prepared as raw material with clay ore is an example as the catalyst of reaction, and the consumption of catalyst is aniline, nitro 6-10% of the total mass of benzene, the specific values are respectively 6%, 7%, 8%, 9%, and 10%. Taking the method of raising the temperature in stages to a maximum temperature of 180° C. as an example, and keeping the temperature at 180° C. for 2 hours, the obtained yields are shown in Table 2 below.

Table 2 The influence of the amount of catalyst on the yield of 4-aminodiphenylamine

The amount of catalyst 6% 7% 8% 9% 10% 4-aminodiphenylamine yield 95% 94% 96% 96.5% 96.5%

As can be clearly seen from the above table, when the consumption of the catalyst is 8% of the total mass of aniline and nitrobenzene, a higher productive rate can be obtained, and when the consumption of the catalyst is increased to 9%, the productive rate is slightly improved, considering Considering the factor of economic cost, it is the optimal scheme when the amount of catalyst is 8% of the total mass of aniline and nitrobenzene. Moreover, the inventors also found in practice that when molecular sieves are used as catalysts, the catalysts can be reused, further reducing production costs.

The synthetic method of 4-aminodiphenylamine provided by the present invention adopts aniline and nitrobenzene as raw materials, uses the molecular sieve of the present invention as a catalyst, has few by-products and high yield, and the highest yield of the synthetic method of 4-aminodiphenylamine can reach The maximum purity can reach 96%, and the highest purity can reach 98.5%. Moreover, the synthesis method of 4-aminodiphenylamine provided by the present invention has strong catalytic ability of the catalyst and high recycling rate of the catalyst.

The foregoing description shows and describes preferred embodiments of the present invention, and as previously stated, it is to be understood that the present invention is not limited to the form disclosed herein and should not be construed as excluding other embodiments but may be used in various other embodiments. Combinations, modifications and circumstances, and can be modified within the scope of the inventive concept described herein, by the above teachings or by skill or knowledge in the relevant field. However, changes and changes made by those skilled in the art do not depart from the spirit and scope of the present invention, and should all be within the protection scope of the appended claims of the present invention.

Claims (10)

1. a kind of synthetic method of 4-ADPA, it is characterised in that：Include the following steps：

1) aniline, nitrobenzene and molecular sieve catalyst are added in reaction kettle and are constantly mixed, in the case where temperature is 70-80 DEG C Reaction 3-6h is carried out, hexamethylene is then added and sloughs the vapor formed in reaction under conditions of azeotropic, obtains condensation reaction Product；

2) Pd/C catalyst is added into reaction kettle and is passed through hydrogen, is 70-180 DEG C in temperature, pressure is 1.0-3.5MPa's Under the conditions of react 1-5h；

3) it when reaction no longer declines to Hydrogen Vapor Pressure, is filtered under diminished pressure, gained filtrate is evaporated under reduced pressure, collect 220-240 DEG C fraction to get 4-ADPA.

2. the synthetic method of 4-ADPA according to claim 1, it is characterised in that：The molecular sieve is with carclazyte The molecular sieve that mine is raw material, is prepared using calcium hydroxide as alkali source, by template of tetrapropylammonium hydroxide.

3. the synthetic method of 4-ADPA according to claim 1, it is characterised in that：The aniline, nitrobenzene are thrown The molar ratio of material is (4-10): 1.

4. the synthetic method of 4-ADPA according to claim 1, it is characterised in that：The quality of the catalyst point It counts as the 6-10% of aniline, nitrobenzene gross mass.

5. the synthetic method of 4-ADPA according to claim 1, it is characterised in that：The molecular sieve catalyst system Preparation Method is as follows：

1) acid system removes iron：Carclazyte mine is ground, crush, is sieved, is subsequently placed in the hydrochloric acid solution of the hydrochloric acid of 3mol/L, It is reacted 1 hour at 100 DEG C, filters to obtain lower sediment after reaction, be washed to neutrality and be placed in drying oven and dry；

2) alkaline process activates：Material after above-mentioned drying is ground with calcium hydroxide according to 1: 5 mass ratio and is uniformly mixed, Then it is dried at 100 to 300 DEG C, it is levigate to 50 μm or less；

3) crystallization：By above-mentioned steps 2) obtained by product tetrapropylammonium hydroxide is added, and according to product：Tetrapropyl hydroxide Tetrapropylammonium hydroxide solution is added in the mass ratio that ammonium is 1: 6, stirs 2h at a temperature of 50 DEG C, is subsequently placed in the perseverance at 80 DEG C 6-8h is reacted under the conditions of temperature, filtering, drying obtain molecular sieve catalyst.

6. the synthetic method of 4-ADPA according to claim 5, it is characterised in that：The preparation of the molecular sieve walks Rapid crystallization 3) is divided into Initial Crystallization and later stage crystallization：In the early stage when crystallization, according to product：Tetrapropylammonium hydroxide is 1: 4 Tetrapropylammonium hydroxide solution is added in mass ratio, and later stage crystallization is carried out after being stirred 70 minutes at a temperature of 80 DEG C；Rear When phase crystallization, according to product：Tetrapropylammonium hydroxide solution is added in the mass ratio that tetrapropylammonium hydroxide solution is 1: 2, Later stage crystallization is completed after being stirred 70 minutes at a temperature of 80 DEG C.

7. the synthetic method of 4-ADPA according to claim 5, it is characterised in that：The molecular sieve catalyst Preparation method further includes step step 4)：Obtained molecular screen primary feed powder is ground to diameter at 90-150 nanometers.

8. the synthetic method of 4-ADPA according to claim 1, it is characterised in that：The Pd/C catalyst is 10%Pd/C catalyst.

9. the synthetic method of 4-ADPA according to claim 1, it is characterised in that：Reaction kettle in the step 2) Heating be step-up temperature, i.e., first at a temperature of 70 DEG C keep the temperature 1h, be then warming up to 150 DEG C with the heating rate of 5 DEG C/min, 180 DEG C are warming up to the heating rate of 2 DEG C/min again, 1-3h is kept the temperature at a temperature of 180 DEG C.

10. the synthetic method of 4-ADPA according to claim 1, it is characterised in that：It is also wrapped in the step 3) It includes, after being filtered under diminished pressure, filtrate is recrystallized with petroleum ether, is evaporated under reduced pressure again after crystal is washed.