CN104529916B - Method for separating high-purity phenazine from waste material generated in chemical product production - Google Patents

Abstract

The invention provides a method for efficiently rectifying and purifying phenazine from chemical product production waste, which adopts a light removal tower and a weight removal tower. Tower top condenser and tower kettle reboiler; it is characterized in that the phenazine-containing raw material liquid enters the middle part of the light removal tower after being heat-exchanged by the raw material preheater, and the aniline and azobenzene are removed from the top of the tower to obtain a product with a purity greater than 97%. Aniline can be recycled; the light-removing tower tower stream enters the middle part of the de-weighting tower, and the heavy component of 4-aminodiphenylamine is removed at the bottom of the tower to obtain 4-aminodiphenylamine with a purity greater than 99%, which is directly used as a product or enters the next step level refining; the top of the weight-removing tower obtains a phenazine product with a purity greater than 99.5%. The invention adopts continuous operation, and at the same time, the whole invention adopts a heat-coupled rectification separation process, which reduces the energy consumption of the system. In the present invention, since the two towers both adopt vacuum rectification and are packed towers, the separation efficiency is more efficient, and the pressure drop and the temperature of the tower still are reduced at the same time.

Description

Method for separating high-purity phenazine from chemical product production waste

technical field

The invention relates to a method for separating and purifying phenazine, in particular to a method for separating high-purity phenazine from chemical product production waste, and belongs to the field of phenazine separation and purification.

Background technique

Phenazine, also known as diazanthracene, English name: Phenazine, molecular formula C12H8N2, is colorless or light yellow needle-like crystals, almost insoluble in water, slightly soluble in ethanol, ether and benzene, soluble in inorganic acids to yellow to red solution. Phenazines have a certain special status in the field of organic chemistry. The earliest applications of phenazine and its derivatives were dyes, and then they were found to be biologically active and could be used as fungicides. In recent years, phenazines have been widely used in the fields of medicine, pesticides, chromophores, conductors and battery materials.

Phenazine is mainly prepared by the ring-closing reaction of 2-amino or nitrodiphenylamine, the condensation reaction of o-phenylenediamine and catechol, etc. The synthesis process is complicated, the yield is medium, and the cost is high. In the process of producing 4-aminodiphenylamine with nitrobenzene and aniline as raw materials, the by-product phenazine will be produced, which cannot be removed during the separation process, and forms a waste mixture with 4-aminodiphenylamine, aniline, azobenzene, etc. , direct discharge will cause environmental pollution, and incineration will cause a lot of waste. At present, some enterprises adopt the method of batch rectification to separate the mixture, and the content of phenazine after treatment is only 80%.

The invention provides a method for efficiently rectifying and purifying phenazine from chemical product production waste, and obtains a high-purity phenazine product.

Contents of the invention

The object of the present invention is to provide a method for efficiently rectifying and purifying phenazine from chemical product production waste, so as to obtain a phenazine product with a purity greater than 99.5% and a good yield.

The purpose of the present invention is accomplished through the following technical solutions:

A method for separating high-purity phenazine from chemical product production waste, using a de-light tower and a de-weight tower, the de-light tower is provided with a top condenser and a tower kettle reboiler, and the de-weight tower is provided with a top condenser And tower kettle reboiler; it is characterized in that the phenazine-containing raw material liquid enters the middle part of the light removal tower after heat exchange by the raw material preheater, and aniline and azobenzene are removed from the top of the tower to obtain aniline with a purity greater than 97%, which can be recycled Use; the stream in the de-light tower tower enters the middle part of the de-weight tower, and the heavy component of 4-aminodiphenylamine is removed at the bottom of the tower to obtain 4-aminodiphenylamine with a purity greater than 99%, which is directly used as a product or enters the next stage of refining; A phenazine product with a purity greater than 99.5% is obtained from the top of the heavy tower.

The operating pressure at the top of the light removal tower is 1-10Kpa, the operating temperature at the bottom of the tower is 214-262°C, the reflux ratio is 2-6, and the theoretical number of stages is 20-40; the operating pressure at the top of the heavy removal tower is 1-6Kpa, The operating temperature at the bottom of the tower is 217-253°C, the reflux ratio is 8-10, and the total number of theoretical stages is 30-50.

The raw material liquid containing phenazine enters the middle part of the light removal tower after exchanging heat with the heavy component flowing out from the bottom of the weight removal tower through the raw material preheater, and the temperature of the raw material liquid containing phenazine after the heat exchange is 105-125°C.

The light removal tower and the weight removal tower are packed towers.

The present invention reduces the boiling point of the high-boiling compound in the phenazine-containing raw material liquid by performing vacuum rectification on the system, the separation efficiency is more efficient, and the temperature of the tower still is reduced; in addition, in the rectification separation process of the present invention, containing The phenazine raw material liquid exchanges heat with the phenazine product flowing out from the top of the weight removal tower through the raw material preheater. Compared with the traditional distillation separation process, the total energy consumption of the process is reduced by about 20%.

The advantages of the present invention are:

(1) The present invention adopts continuous operation, and the whole invention adopts heat-coupled rectification separation process at the same time, which reduces the energy consumption of the system.

(2) In the present invention, because both towers adopt vacuum rectification and both are packed towers, the separation efficiency is more efficient, and the pressure drop and the temperature of the tower still are reduced simultaneously.

(3) the phenazine product purity >=99.5% that the process of the present invention produces, aniline total content＜0.01%, azobenzene＜0.25%, 4-aminodiphenylamine＜0.2%, it can be seen that the present invention can effectively improve the phenazine product purity, Guarantee the performance index of the product.

Description of drawings

Accompanying drawing 1: Process flow diagram of the present invention.

detailed description

The present invention will be further described in detail below in conjunction with the embodiments and accompanying drawings, but the present invention is not limited thereto.

Adopt the connection mode of accompanying drawing 1, light removal tower 3 is provided with tower top condenser 4 and tower still reboiler 7, and weight removal tower 9 is provided with tower top condenser 10 and tower still reboiler 13. The phenazine-containing raw material liquid 1 enters the middle part of the light removal tower 3 after the pipeline passes through the raw material preheater 2 to remove aniline and azobenzene 6, and its tower stream 8 enters the middle part of the weight removal tower 9 to remove 4 -Aminodiphenylamine is a heavy component and a small amount of phenazine 14 is lost, and a phenazine product 12 with a purity greater than 99.5% is obtained at the top of the tower.

A system for efficient distillation and purification of phenazine from chemical product production waste (aniline 47-55%, azobenzene 0.6-1.5%, phenazine 6-10%, 4-aminodiphenylamine 35-42%), light removal tower There is a top condenser and a bottom reboiler, and the weight removal tower is equipped with a top condenser and a bottom reboiler. The phenazine-containing raw material liquid enters the middle part of the light removal tower after heat exchange by the raw material preheater, and aniline and azobenzene are removed at the top of the tower to obtain aniline with a purity greater than 97%, which can be recycled. The stream in the bottom of the light removal tower enters the middle part of the heavy removal tower, and the heavy component of 4-aminodiphenylamine is removed at the bottom of the tower and a small amount of phenazine is lost to obtain 4-aminodiphenylamine with a purity greater than 99%, which can be directly used as a product or enter the next First grade refined. A phenazine product with a purity greater than 99.5% is obtained from the top of the weight-removing tower.

The light removal tower and the weight removal tower described in the present invention are preferably packed towers.

The operating pressure at the top of the light removal tower is 1-10Kpa, the operating temperature at the bottom of the tower is 214-262°C, the reflux ratio is 2-6, and the theoretical number of stages is 20-40; the operating pressure at the top of the heavy removal tower is 1-6Kpa, The operating temperature at the bottom of the tower is 217-253°C, the reflux ratio is 8-10, and the total number of theoretical stages is 30-50.

The raw material liquid containing phenazine of the present invention enters the middle part of the light removal tower after exchanging heat with the heavy component flowing out from the bottom of the weight removal tower through the raw material preheater, and the temperature of the raw material liquid containing phenazine after the heat exchange is 105-125°C .

Example 1:

Purification of raw materials containing phenazine at a rate of 6000 kg per hour, the feed composition is as follows: 55% aniline, 6% phenazine, 1.5% azobenzene, and 37.5% 4-aminodiphenylamine.

Operating conditions of each tower in the process flow

light tower Weight removal tower tower type packed tower packed tower Tower diameter (mm) 2600 1200 packing type Stainless steel wire mesh structured packing Stainless steel wire mesh structured packing Theoretical progression 20 30 Operating pressure at the top of the tower (absolute pressure)/Kpa 1 1 Bottom operating temperature/°C 214 217 Reflux ratio 2 8

Note: The temperature of the raw material entering the tower after heat exchange is 105°C

The main indicators of the phenazine product produced under the above-mentioned process conditions are as follows:

main indicators Product purity 99.54% Aniline content 0.01% Azobenzene 0.25% 4-Aminodiphenylamine 0.20% Product recovery rate 95.3%

Example 2:

Purification of raw materials containing phenazine at a rate of 6000 kg per hour, the feed composition is as follows: 50% aniline, 8% phenazine, 1% azobenzene, and 41% 4-aminodiphenylamine.

Operating conditions of each tower in the process flow

light tower Weight removal tower tower type packed tower packed tower Tower diameter (mm) 2600 1200 packing type Stainless steel plate corrugated structured packing Stainless steel plate corrugated structured packing Theoretical progression 30 40 Operating pressure at the top of the tower (absolute pressure)/Kpa 3 3 Bottom operating temperature/°C 232 236 Reflux ratio 4 9

Note: After the heat exchange of raw materials, the temperature of entering the tower is 115°C

The main indicators of the phenazine product produced under the above-mentioned process conditions are as follows:

main indicators Product purity 99.87% Aniline content 3ppm Azobenzene 0.032% 4-Aminodiphenylamine 0.098% Product recovery rate 98.8%

Example 3:

Process 6000 kg per hour for the purification of raw materials containing phenazine. The feed composition is as follows: 47.4% of aniline, 10% of phenazine, 0.6% of azobenzene, and 42% of 4-aminodiphenylamine.

Operating conditions of each tower in the process flow

light tower Weight removal tower tower type packed tower packed tower Tower diameter(mm) 2600 1200 packing type Stainless steel wire mesh structured packing Stainless steel wire mesh structured packing Theoretical progression 40 50 Operating pressure at the top of the tower (absolute pressure)/Kpa 10 6 Bottom operating temperature/°C 262 253 Reflux ratio 6 10

Note: After the heat exchange of raw materials, the temperature of entering the tower is 125°C

The main indicators of the phenazine product produced under the above-mentioned process conditions are as follows:

main indicators Product purity 99.52% Aniline content 0.002% Azobenzene 0.473% 4-Aminodiphenylamine 0.002% Product recovery rate 99.5%

It can be seen from the above table that the present invention is feasible, and the whole separation process not only has simple process operation, low energy consumption, but also high separation efficiency.

A kind of method that the present invention proposes from the high-efficiency rectification and purification of phenazine from chemical product production waste has been described by preferred implementation examples, and those skilled in the art can clearly understand the content, spirit and scope of the present invention. The rectification and purification method described above is modified or appropriately modified and combined to realize the technology of the present invention. In particular, it should be pointed out that all similar substitutions and modifications will be obvious to those skilled in the art, and they are all considered to be included in the spirit, scope and content of the present invention.

Claims (3)

1. A method for separating high-purity phenazine from chemical product production waste, adopting a light removal tower and a weight removal tower, the light removal tower is provided with a tower top condenser and a tower still reboiler, and the weight removal tower is provided with a tower top Condenser and tower reboiler; it is characterized in that the phenazine-containing raw material liquid enters the middle part of the light removal tower after heat exchange by the raw material preheater, and aniline and azobenzene are removed from the top of the tower to obtain aniline with a purity greater than 97%. It can be recycled; the stream in the bottom of the light removal tower enters the middle of the heavy removal tower, and the heavy component of 4-aminodiphenylamine is removed from the bottom of the tower to obtain 4-aminodiphenylamine with a purity greater than 99%, which is directly used as a product or enters the next stage of refining The phenazine product with a purity greater than 99.5% is obtained at the top of the heavy removal tower; the operating pressure at the top of the light removal tower is 1～10Kpa, the operating temperature at the bottom of the tower is 214～262°C, the reflux ratio is 2～6, and the theoretical series is 20-40; the operating pressure at the top of the de-weighting tower is 1-6Kpa, the operating temperature at the bottom of the tower is 217-253°C, the reflux ratio is 8-10, and the total number of theoretical stages is 30-50. 2. method as claimed in claim 1, it is characterized in that containing phenazine raw material liquid enters the middle part of light removal tower after heat exchange with the heavy component flowing out from the bottom of weight removal tower through raw material preheater, after heat exchange, contains phenazine The temperature of the raw material liquid entering the tower is 105-125°C. 3. The method according to claim 1, characterized in that said light removal tower and weight removal tower are packed towers.