A refining method for producing o-phenylenediamine

Abstract

The present invention relates to the technical field of chemical raw materials, and discloses a refining method for producing o-phenylenediamine, comprising the following steps: (1) chemical processing; (2) primary distillation; (3) rectification; (4) centrifugal separation; (5) drying; and (6) packaging. Industrial o-phenylenediamine is limited in use due to its low purity. Therefore, after the o-phenylenediamine is refined by the present invention, the purity of the obtained product is significantly improved, and its application is further broadened, and it can be applied to pesticide manufacturing, dye industry, additives and surfactants, photosensitive materials, etc.

Description

Technical Field

[0001] The invention relates to the technical field of chemical raw materials, in particular to a refining method for producing o-phenylenediamine. Background Art

[0002] Industrial o-phenylenediamine is an important chemical raw material. It usually appears in the form of white or light yellow crystals. The pure product is colorless monoclinic crystals, and the industrial product may appear as brown flaky crystals. The color will darken in the air or under sunlight.

[0003] It is slightly soluble in cold water, soluble in hot water, and easily soluble in organic solvents such as alcohol, ether, and chloroform. The melting point is about 103-104°C, and the boiling point is about 252-258°C.

[0004] The uses of o-phenylenediamine include:

[0005] 1. Dye synthesis: o-phenylenediamine is a key raw material for the synthesis of many important dyes, which are widely used in industries such as textiles, leather, plastics and paper, not only adding color to items, but also enhancing their appearance and value.

[0006] 2. Rubber processing: In the rubber industry, o-phenylenediamine is used as a component of accelerator and antioxidant, which can accelerate the vulcanization reaction of rubber, improve the processing performance and physical properties of rubber, and prevent the aging and decomposition of rubber during long-term use.

[0007] 3. Medical field: Since o-phenylenediamine has certain biological activity, it is also used in the medical field. For example, it can be used to synthesize antibiotics, anti-tumor drugs and anti-inflammatory drugs.

[0008] 4. Optical materials: o-phenylenediamine and its derivatives also have certain applications in the optical field. They can be used to synthesize polymer materials with special optical properties, such as liquid crystal displays, fiber optic communication materials and optical films.

[0009] 5. Chemical analysis: o-phenylenediamine can also be used as a qualitative and quantitative analytical reagent for lead and other metal ions. It can determine the content of metal ions in samples by reacting specifically with metal ions to form colored coprecipitates.

[0010] In summary, industrial o-phenylenediamine, as an important chemical raw material, has wide application value in many fields. However, in actual application, due to the low purity of industrial o-phenylenediamine, it cannot be directly applied in many fields.

[0011] Based on this, the present invention provides a refining method for producing o-phenylenediamine to solve the corresponding problem. Summary of the invention

[0012] In view of the problems in the prior art, the present invention provides a purification method for producing o-phenylenediamine.

[0013] The technical solution adopted by the present invention to solve the technical problem is: a refining method for producing o-phenylenediamine, comprising the following steps:

[0014] (1) Chemical processing: Put industrial o-phenylenediamine into a melting kettle, and use low-pressure steam to process the material under a slight vacuum. After the o-phenylenediamine is melted, it is pumped into a distillation kettle;

[0015] (2) Primary distillation: The primary distillation is carried out by a multi-stage negative pressure primary distillation method to obtain a secondary fraction, which is collected by a secondary fraction still;

[0016] Among them, the multi-stage negative pressure primary distillation method is divided into three stages of primary distillation treatment:

[0017] First level vacuum degree -30kPa, temperature 100℃;

[0018] Secondary vacuum degree -50kPa, temperature 105℃;

[0019] Level 3 vacuum degree -80kPa, temperature 115℃;

[0020] (3) Distillation: Feed the material into the tower kettle, keep the vacuum balance between the tower kettle and the rear fraction kettle, keep the feed liquid level in the tower kettle at 75-76%, and keep the heating tubes immersed under the liquid surface; the tower kettle heating tubes are heated with steam, and the rising gas phase is condensed and refluxed. The reflux liquid changes from reddish brown to orange-yellow and transparent, and tangentially flows to the large reflux pipe on the crystallization pot, and refluxes to the tower kettle to wait for material collection;

[0021] (4) Centrifugal separation: After collecting the material, the collected liquid is cooled and crystallized, and then centrifuged and dehydrated. The dehydrated material is put into a barrel and sent to a drying room for drying;

[0022] (5) Drying: Before feeding, vacuum leak test is required. After the leak test is completed, start the dryer and circulate hot water for drying. Slowly increase the temperature from 50°C to 100°C and maintain it. After 1 hour, measure the water temperature of the vacuum tube. When the water temperature of the vacuum tube drops to room temperature, switch to cold water circulation and drop to room temperature for unloading and packaging.

[0023] (6) Packaging: After the finished product has passed the inspection, it will be packaged; the packaging is nitrogen-filled packaging.

[0024] As a further technical solution: the micro-vacuum state in step (1) is: the pressure is 80-90 kPa;

[0025] The supply pressure of low-pressure steam is 65-68kPa.

[0026] As a further technical solution: the micro-vacuum state in step (1) is: the pressure is 86 kPa;

[0027] The supply pressure of low-pressure steam is 67kPa.

[0028] As a further technical solution: in step (3), the vacuum degree is maintained at less than or equal to -0.092 MPa, and stirring is performed at a speed of 300-500 r / min.

[0029] As a further technical solution: the speed of centrifugal dehydration in step (4) is 1200-1400 r / min;

[0030] Among them, the centrifugal dehydration time is 40-50min.

[0031] As a further technical solution: in step (5), the heating rate of slowly heating from 50°C to 100°C is 2-3°C / min.

[0032] As a further technical solution: in step (5), the heating rate of slowly heating from 50°C to 100°C is 2°C / min.

[0033] As a further technical solution: the temperature of the cold water circulation in step (5) is 7-12°C.

[0034] Beneficial effects of the present invention:

[0035] Industrial o-phenylenediamine is limited in use due to its low purity. Therefore, the purity of the product obtained by the present invention is significantly improved after the o-phenylenediamine is refined, and its use is further broadened, and can be applied to pesticide manufacturing, dye industry, additives and surfactants, photosensitive materials, etc.

[0036] In pesticide manufacturing, by greatly improving the purity of o-phenylenediamine, it can be used as an intermediate to produce a variety of pesticide fungicides, such as carbendazim, benomyl, methyl thiophanate and thiophanate-methyl. These fungicides play an important role in disease prevention and control in agricultural production.

[0037] The invention combines multi-stage primary distillation with rectification, controls the temperature and the vacuum balance during the primary distillation and rectification process, and can greatly improve the purity and product stability of the prepared o-phenylenediamine, thereby laying a solid foundation for broadening the application scope of refined o-phenylenediamine.

[0038] By using nitrogen protection packaging during the packaging process, the occurrence of oxidation reactions can be effectively prevented, which provides a significant guarantee for maintaining high purity of o-phenylenediamine. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The present invention is a flow chart of a purification method for producing o-phenylenediamine. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0041] Example 1

[0042] A refining method for producing o-phenylenediamine comprises the following steps:

[0043] (1) Chemical processing: Put industrial o-phenylenediamine into a melting kettle, and use low-pressure steam to process the material under a slight vacuum state. After the o-phenylenediamine is melted, it is pumped into a distillation kettle; the slight vacuum state is: the pressure is 80 kPa;

[0044] The supply pressure of low-pressure steam is 65kPa.

[0045] (2) Primary distillation: The primary distillation is carried out by a multi-stage negative pressure primary distillation method to obtain a secondary fraction, which is collected by a secondary fraction still;

[0046] Among them, the multi-stage negative pressure primary distillation method is divided into three stages of primary distillation treatment:

[0047] First level vacuum degree -30kPa, temperature 100℃;

[0048] Secondary vacuum degree -50kPa, temperature 105℃;

[0049] Level 3 vacuum degree -80kPa, temperature 115℃;

[0050] (3) Distillation: Feed the material into the tower kettle, keep the vacuum balance between the tower kettle and the rear fraction kettle, keep the feed liquid level in the tower kettle at 75%, and keep the heating tubes immersed under the liquid surface; heat the tower kettle heating tubes with steam, and the rising gas phase is condensed and refluxed. The reflux liquid changes from reddish brown to orange-yellow and transparent, and refluxes to the large reflux pipe on the crystallization pot to wait for material collection; keep the vacuum degree at -0.094MPa, and stir at a speed of 300r / min.

[0051] (4) Centrifugal separation: After collecting the material, the collected liquid material is cooled and crystallized, and then centrifuged and dehydrated. The dehydrated material is put into a barrel and sent to a drying room for drying; the speed of the centrifugal dehydration is 1200r / min;

[0052] Among them, the centrifugal dehydration time is 40 minutes.

[0053] (5) Drying: Before feeding, vacuum leak test is required. After the leak test is completed, start the dryer and circulate hot water for drying. Slowly increase the temperature from 50°C to 100°C and maintain it. After 1 hour, measure the water temperature of the vacuum tube. When the water temperature of the vacuum tube drops to room temperature, switch to cold water circulation and reduce it to room temperature for unloading and packaging. The heating rate from 50°C to 100°C is 2°C / min.

[0054] The temperature of the cold water circulation is 7°C.

[0055] (6) Packaging: After the finished product has passed the inspection, it will be packaged; the packaging is nitrogen-filled packaging.

[0056] Example 2

[0057] A refining method for producing o-phenylenediamine comprises the following steps:

[0058] (1) Chemical processing: Put industrial o-phenylenediamine into a melting kettle, and use low-pressure steam to process the material under a slight vacuum. After the o-phenylenediamine is melted, it is pumped into a distillation kettle;

[0059] The slightly vacuum state is: the pressure is 86kPa;

[0060] The supply pressure of low-pressure steam is 67kPa.

[0061] (2) Primary distillation: The primary distillation is carried out by a multi-stage negative pressure primary distillation method to obtain a secondary fraction, which is collected by a secondary fraction still;

[0062] Among them, the multi-stage negative pressure primary distillation method is divided into three stages of primary distillation treatment:

[0063] First level vacuum degree -30kPa, temperature 100℃;

[0064] Secondary vacuum degree -50kPa, temperature 105℃;

[0065] Level 3 vacuum degree -80kPa, temperature 115℃;

[0066] (3) Distillation: Feed the material into the tower kettle, keep the vacuum balance between the tower kettle and the rear fraction kettle, keep the feed liquid level in the tower kettle at 76%, and keep the heating tubes immersed under the liquid surface; heat the tower kettle heating tubes with steam, and the rising gas phase is condensed and refluxed. The reflux liquid changes from reddish brown to orange-yellow and transparent, and refluxes to the large reflux pipe on the crystallization pot to wait for material collection; keep the vacuum degree at -0.096MPa, and stir at a speed of 300r / min.

[0067] (4) Centrifugal separation: After collecting the material, the collected liquid material is cooled and crystallized, and then centrifuged and dehydrated. The dehydrated material is put into a barrel and sent to a drying room for drying; the speed of the centrifugal dehydration is 1200r / min;

[0068] Among them, the centrifugal dehydration time is 50min.

[0069] (5) Drying: Before feeding, vacuum leak test is required. After the leak test is completed, start the dryer and circulate hot water for drying. Slowly increase the temperature from 50°C to 100°C and maintain it. After 1 hour, measure the water temperature of the vacuum tube. When the water temperature of the vacuum tube drops to room temperature, switch to cold water circulation and drop to room temperature for unloading and packaging.

[0070] The heating rate from 50°C to 100°C was 2°C / min.

[0071] The temperature of the cold water circulation is 7°C.

[0072] (6) Packaging: After the finished product has passed the inspection, it will be packaged; the packaging is nitrogen-filled packaging.

[0073] Example 3

[0074] A refining method for producing o-phenylenediamine comprises the following steps:

[0075] (1) Chemical processing: Put industrial o-phenylenediamine into a melting kettle, and use low-pressure steam to process the material under a slight vacuum state. After the o-phenylenediamine is melted, it is pumped into a distillation kettle; the slight vacuum state is: the pressure is 85 kPa;

[0076] The supply pressure of low-pressure steam is 66kPa.

[0077] (2) Primary distillation: The primary distillation is carried out by a multi-stage negative pressure primary distillation method to obtain a secondary fraction, which is collected by a secondary fraction still;

[0078] Among them, the multi-stage negative pressure primary distillation method is divided into three stages of primary distillation treatment:

[0079] First level vacuum degree -30kPa, temperature 100℃;

[0080] Secondary vacuum degree -50kPa, temperature 105℃;

[0081] Level 3 vacuum degree -80kPa, temperature 115℃;

[0082] (3) Distillation: Feed the material into the tower kettle, keep the vacuum balance between the tower kettle and the rear fraction kettle, keep the feed liquid level in the tower kettle at 76%, and keep the heating tubes immersed under the liquid surface; heat the heating tubes in the tower kettle with steam, and the rising gas phase is condensed and refluxed. The reflux liquid changes from reddish brown to orange-yellow and transparent, and refluxes to the large reflux pipe on the crystallization pot to wait for material collection; keep the vacuum degree at -0.096MPa, and stir at a speed of 350r / min.

[0083] (4) Centrifugal separation: After collecting the material, the collected liquid material is cooled and crystallized, and then centrifuged and dehydrated. The dehydrated material is put into a barrel and sent to a drying room for drying; the speed of the centrifugal dehydration is 1200r / min;

[0084] Among them, the centrifugal dehydration time is 40 minutes.

[0085] (5) Drying: Before feeding, vacuum leak test is required. After the leak test is completed, start the dryer and circulate hot water for drying. Slowly increase the temperature from 50°C to 100°C and maintain it. After 1 hour, measure the water temperature of the vacuum tube. When the water temperature of the vacuum tube drops to room temperature, switch to cold water circulation and reduce it to room temperature for unloading and packaging. The heating rate from 50°C to 100°C is 2.5°C / min.

[0086] The temperature of the cold water circulation is 8°C.

[0087] (6) Packaging: After the finished product has passed the inspection, it will be packaged; the packaging is nitrogen-filled packaging.

[0088] Example 4

[0089] A refining method for producing o-phenylenediamine comprises the following steps:

[0090] (1) Chemical processing: Put industrial o-phenylenediamine into a melting kettle, and use low-pressure steam to process the material under a slight vacuum state. After the o-phenylenediamine is melted, it is pumped into a distillation kettle; the slight vacuum state is: the pressure is 88 kPa;

[0091] The supply pressure of low-pressure steam is 68kPa.

[0092] (2) Primary distillation: The primary distillation is carried out by a multi-stage negative pressure primary distillation method to obtain a secondary fraction, which is collected by a secondary fraction still;

[0093] Among them, the multi-stage negative pressure primary distillation method is divided into three stages of primary distillation treatment:

[0094] First level vacuum degree -30kPa, temperature 100℃;

[0095] Secondary vacuum degree -50kPa, temperature 105℃;

[0096] Level 3 vacuum degree -80kPa, temperature 115℃;

[0097] (3) Distillation: Feed the material into the tower kettle, keep the vacuum balance between the tower kettle and the rear fraction kettle, keep the feed liquid level in the tower kettle at 75%, and keep the heating tubes immersed under the liquid surface; heat the tower kettle heating tubes with steam, and the rising gas phase is condensed and refluxed. The reflux liquid changes from reddish brown to orange-yellow and transparent, and refluxes to the large reflux pipe on the crystallization pot to wait for material collection; keep the vacuum degree at -0.092MPa, and stir at a speed of 300r / min.

[0098] (4) Centrifugal separation: After collecting the material, the collected liquid material is cooled and crystallized, and then centrifuged and dehydrated. The dehydrated material is put into a barrel and sent to a drying room for drying; the speed of the centrifugal dehydration is 1200r / min;

[0099] Among them, the centrifugal dehydration time is 50min.

[0100] (5) Drying: Before feeding, vacuum leak test is required. After the leak test is completed, start the dryer and circulate hot water for drying. Slowly increase the temperature from 50°C to 100°C and maintain it. After 1 hour, measure the water temperature of the vacuum tube. When the water temperature of the vacuum tube drops to room temperature, switch to cold water circulation and reduce it to room temperature for unloading and packaging. The heating rate from 50°C to 100°C is 2.6°C / min.

[0101] The temperature of the cold water circulation is 10°C.

[0102] (6) Packaging: After the finished product has passed the inspection, it will be packaged; the packaging is nitrogen-filled packaging.

[0103] Example 5

[0104] A refining method for producing o-phenylenediamine comprises the following steps:

[0105] (1) Chemical processing: Put industrial o-phenylenediamine into a melting kettle, and use low-pressure steam to process the material under a slight vacuum state. After the o-phenylenediamine is melted, it is pumped into a distillation kettle; the slight vacuum state is: the pressure is 90 kPa;

[0106] The supply pressure of low-pressure steam is 68kPa.

[0107] (2) Primary distillation: The primary distillation is carried out by a multi-stage negative pressure primary distillation method to obtain a secondary fraction, which is collected by a secondary fraction still;

[0108] Among them, the multi-stage negative pressure primary distillation method is divided into three stages of primary distillation treatment:

[0109] First level vacuum degree -30kPa, temperature 100℃;

[0110] Secondary vacuum degree -50kPa, temperature 105℃;

[0111] Level 3 vacuum degree -80kPa, temperature 115℃;

[0112] (3) Distillation: Feed the material into the tower kettle, keep the vacuum balance between the tower kettle and the rear fraction kettle, keep the feed liquid level in the tower kettle at 76%, and keep the heating tubes immersed under the liquid surface; heat the tower kettle heating tubes with steam, and the rising gas phase is condensed and refluxed. The reflux liquid changes from reddish brown to orange-yellow and transparent, and refluxes to the large reflux pipe on the crystallization pot to wait for material collection; keep the vacuum degree at -0.092MPa, and stir at a speed of 500r / min.

[0113] (4) Centrifugal separation: After collecting the material, the collected liquid material is cooled and crystallized, and then centrifuged and dehydrated. The dehydrated material is put into a barrel and sent to a drying room for drying; the speed of the centrifugal dehydration is 1400r / min;

[0114] Among them, the centrifugal dehydration time is 50min.

[0115] (5) Drying: Before feeding, vacuum leak test is required. After the leak test is completed, start the dryer and circulate hot water for drying. Slowly increase the temperature from 50°C to 100°C and maintain it. After 1 hour, measure the water temperature of the vacuum tube. When the water temperature of the vacuum tube drops to room temperature, switch to cold water circulation and reduce it to room temperature for unloading and packaging. The heating rate from 50°C to 100°C is 3°C / min.

[0116] The temperature of the cold water circulation is 12°C.

[0117] (6) Packaging: After the finished product has passed the inspection, it will be packaged; the packaging is nitrogen-filled packaging.

[0118] Comparative Example 1:

[0119] The difference from Example 1 is that no preliminary distillation treatment is performed.

[0120] Comparative Example 2:

[0121] The difference from Example 1 is that the vacuum degree in step (3) is -0.1 MPa.

[0122] test

[0123] Industrial o-phenylenediamine purity 90%;

[0124] The purity of the o-phenylenediamine obtained by refining in the embodiment and the comparative example was tested:

[0125] Table 1

[0126]

[0127]

[0128] It can be seen from Table 1 that the o-phenylenediamine refined by the method of the present invention has a higher purity.

[0129] Based on Example 1, the effects of different initial distillations on the purity of refined o-phenylenediamine are compared:

[0130] Group 1: Primary distillation is only carried out in one stage;

[0131] Group 2: Primary distillation only undergoes secondary primary distillation treatment;

[0132] Group 3: Primary distillation only undergoes three-stage primary distillation treatment;

[0133] Group 4: Primary distillation only carries out primary distillation treatment and secondary primary distillation treatment;

[0134] Table 2

[0135] purity% Group 1 98.6 Group 2 98.8 Group 3 99.0 Group 4 99.4

[0136] It can be seen from Table 2 that the purity of o-phenylenediamine can be greatly improved through multi-stage primary distillation treatment.

[0137] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A purification method for producing o-phenylenediamine, characterized in that: The following steps are involved: (1) Chemical processing: Put industrial o-phenylenediamine into a melting kettle, and use low-pressure steam to process the material under a slight vacuum. After the o-phenylenediamine is melted, it is pumped into a distillation kettle; (2) Primary distillation: The primary distillation is carried out by a multi-stage negative pressure primary distillation method to obtain a secondary fraction, which is collected by a secondary fraction still; Among them, the multi-stage negative pressure primary distillation method is divided into three stages of primary distillation treatment: First level vacuum degree -30kPa, temperature 100℃; Secondary vacuum degree -50kPa, temperature 105℃; Level 3 vacuum degree -80kPa, temperature 115℃; (3) Distillation: Feed the material into the tower kettle, keep the vacuum balance between the tower kettle and the rear fraction kettle, keep the feed liquid level in the tower kettle at 75-76%, and keep the heating tubes immersed under the liquid surface; the tower kettle heating tubes are heated with steam, and the rising gas phase is condensed and refluxed. The reflux liquid changes from reddish brown to orange-yellow and transparent, and tangentially flows to the large reflux pipe on the crystallization pot, and refluxes to the tower kettle to wait for material collection; (4) Centrifugal separation: After collecting the material, the collected liquid is cooled and crystallized, and then centrifuged and dehydrated. The dehydrated material is put into a barrel and sent to a drying room for drying; (5) Drying: Before feeding, vacuum leak test is required. After the leak test is completed, start the dryer and circulate hot water for drying. Slowly increase the temperature from 50°C to 100°C and maintain it. After 1 hour, measure the water temperature of the vacuum tube. When the water temperature of the vacuum tube drops to room temperature, switch to cold water circulation and drop to room temperature for unloading and packaging. (6) Packaging: After the finished product has passed the inspection, it will be packaged; the packaging is nitrogen-filled packaging.

2. A method for refining o-phenylenediamine according to claim 1, characterized in that: The micro-vacuum state in step (1) is: the pressure is 80-90 kPa; The supply pressure of low-pressure steam is 65-68kPa.

3. A refining method for producing o-phenylenediamine according to claim 1, characterized in that: The micro-vacuum state in step (1) is: the pressure is 86 kPa; The supply pressure of low-pressure steam is 67kPa.

4. A refining method for producing o-phenylenediamine according to claim 1, characterized in that: In step (3), the vacuum degree is maintained at less than or equal to -0.092 MPa, and stirring is performed at a speed of 300-500 r / min.

5. A refining method for producing o-phenylenediamine according to claim 1, characterized in that: The rotation speed of the centrifugal dehydration in step (4) is 1200-1400 r / min; Among them, the centrifugal dehydration time is 40-50min.

6. A refining method for producing o-phenylenediamine according to claim 1, characterized in that: In step (5), the heating rate of slowly heating from 50°C to 100°C is 2-3°C / min.

7. A refining method for producing o-phenylenediamine according to claim 1, characterized in that: In step (5), the heating rate of slowly increasing the temperature from 50°C to 100°C is 2°C / min.

8. A refining method for producing o-phenylenediamine according to claim 1, characterized in that: The temperature of the cold water circulation in step (5) is 7-12°C.

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