CN118577225B - Device for continuously producing dichloroacetyl chloride and preparation method - Google Patents

Abstract

The present invention belongs to the technical field of acyl chloride compounds, and specifically relates to a device and a preparation method for continuously producing dichloroacetyl chloride. The device for continuously producing dichloroacetyl chloride comprises an oxidation reactor, a microinterface generator is arranged at the bottom of the oxidation reactor, the oxidation reactor is respectively connected to a first mixing tank and a heat exchanger, the heat exchanger is connected to a conversion kettle, the conversion kettle is connected to a light removal distillation tower, the light removal distillation tower is respectively connected to a reflux tank and a product distillation tower, the product distillation tower is respectively connected to a residual liquid storage tank and a gas-liquid separation tank, and the gas-liquid separation tank is connected to a product storage tank. The present invention can realize the continuous production of dichloroacetyl chloride, the product yield is increased to more than 98%, and the purity of the dichloroacetyl chloride product is increased to more than 99%.

Description

Device and preparation method for continuous production of dichloroacetyl chloride

Technical Field

The invention belongs to the technical field of acyl chloride compounds, and particularly relates to a device for continuously producing dichloroacetyl chloride and a preparation method thereof.

Background Art

Dichloroacetyl chloride, also known as dichloroacetyl chloride, is a colorless transparent liquid with a boiling point of 102-108°C, a relative density of 1.532, and a refractive index of 1.461. Dichloroacetyl chloride is miscible with organic solvents such as ether, and will decompose violently in contact with water and ethanol. It has a pungent and irritating odor, smokes in the air, is highly corrosive, and can cause burns after human contact. Dichloroacetyl chloride is an important organic synthesis intermediate with extremely strong acylation activity and is widely used in the field of synthetic fine chemicals.

The main methods for industrial production of dichloroacetyl chloride are dichloroacetic acid oxidation method and trichloroethylene oxidation method. Dichloroacetic acid oxidation method is divided into phosphorus trichloride method, thionyl chloride method and phosgene chlorination method according to different chlorinating agents.

The phosphorus trichloride method uses dichloroacetic acid and phosphorus trichloride as raw materials, and reacts at about 100°C under the catalysis of a mixture of calcium chloride, magnesium chloride and an appropriate amount of monovalent metal chloride to produce dichloroacetyl chloride. This method has a mild reaction and is easy to control, but it has many by-products, the product is difficult to purify, and the three wastes produced are highly polluting and difficult to treat and utilize.

The thionyl chloride method is to react dichloroacetic acid with thionyl chloride at 110°C to produce dichloroacetyl chloride. This method has a mild reaction, fewer by-products, and high product yield and purity. However, this method is costly and is rarely used.

The phosgene chlorination method is to react dichloroacetic acid and phosgene in a molar ratio of 1:1 at 120°C under the action of a catalyst such as zinc chloride to produce dichloroacetyl chloride. Phosgene can effectively inhibit the formation of by-products. This method has high product purity, high yield, and short reaction cycle, but phosgene is highly toxic and inconvenient to transport, which limits the development of this method.

At present, the commonly used method for producing dichloroacetyl chloride in industry is to use trichloroethylene and pure oxygen as raw materials, and to carry out oxidation reaction under certain pressure and temperature conditions by using azobisisobutyronitrile as catalyst, and to use a bubbling kettle reactor for oxidation reaction. This reactor has problems of uneven gas-liquid mixing and insufficient heat transfer efficiency. In order to reduce raw material consumption through deep oxidation, the reaction time will last for 30 hours, the pressure is 0.35-0.4MPa, the reaction temperature is 90-100℃, and the production efficiency is low; and the kettle reactor is prone to over-temperature and over-pressure during operation, which may lead to explosion of the kettle reactor and cause serious safety accidents.

Chinese patent CN101195563A discloses a process for preparing dichloroacetyl chloride as an insecticide, using trichloroethylene as a raw material, and comprising the following steps: 1) placing trichloroethylene in a tower reactor, and adding a composite catalyst, wherein the weight ratio of the composite catalyst to trichloroethylene is 0.1-1.0:100, and stirring evenly; then heating to 100-110°C, at which temperature, introducing dry air into the container and maintaining for 9-11 hours; 2) subjecting the product obtained in the above step to atmospheric distillation, collecting the 105-108°C fraction, and obtaining a colorless transparent liquid product, dichloroacetyl chloride. The composite catalyst used in this patent can improve the reaction efficiency to a certain extent, but the required reaction time is still 9-11 hours, and the degree of improvement in the reaction efficiency is not large.

Summary of the invention

In view of the deficiencies in the prior art, the problem to be solved by the present invention is to provide a device for continuously producing dichloroacetyl chloride, which can realize the continuous production of dichloroacetyl chloride and improve the oxygen utilization rate and reaction efficiency. The present invention also provides a preparation method using the device for continuously producing dichloroacetyl chloride.

The technical solution adopted by the present invention to solve its technical problem is:

The device for continuously producing dichloroacetyl chloride of the present invention comprises an oxidation reactor, wherein a microinterface generator is arranged at the bottom of the oxidation reactor, the oxidation reactor is respectively connected with a first mixing tank and a heat exchanger, the first mixing tank is connected with a raw material storage tank, the heat exchanger is connected with a conversion kettle, the conversion kettle is connected with a light removal distillation tower, the light removal distillation tower is respectively connected with a reflux tank and a product distillation tower, the product distillation tower is respectively connected with a residual liquid storage tank and a gas-liquid separation tank, and the gas-liquid separation tank is connected with a product storage tank; the bottom of the oxidation reactor is connected with a gas buffer tank, the top of the oxidation reactor is connected with a tail gas recovery pool, the top of the conversion kettle is connected with the tail gas recovery pool, the top of the reflux tank is connected with an incinerator, the top of the gas-liquid separation tank is connected with the incinerator, and the bottom of the reflux tank is connected with the top of the oxidation reactor.

in:

The top of the first mixing tank is provided with an initiator feeding port, and a stirrer 1 is provided in the first mixing tank, and the stirrer 1 is a flat-paddle stirrer.

The heat exchanger inlet is connected to the middle of the oxidation reactor, the heat exchanger outlet is connected to the top of the oxidation reactor, a catalyst feed port is arranged on the top of the conversion kettle, and a second agitator is arranged in the conversion kettle, and the second agitator is a flat-paddle agitator.

An oxidation condenser is arranged on the pipeline between the oxidation reactor and the tail gas recovery tank, a conversion kettle condenser is arranged on the pipeline between the conversion kettle and the tail gas recovery tank, a first condenser is arranged on the pipeline between the light removal distillation tower and the reflux tank, and a second condenser is arranged on the pipeline between the product distillation tower and the gas-liquid separation tank.

Material pumps are provided on the pipeline between the first mixing tank and the raw material storage tank, on the pipeline between the first mixing tank and the oxidation reactor, on the pipeline between the bottom of the heat exchanger and the oxidation reactor, on the pipeline between the light removal distillation tower and the product distillation tower, on the pipeline between the reflux tank and the oxidation reactor, and on the pipeline between the gas-liquid separation tank and the product storage tank.

The preparation method of the device for continuously producing dichloroacetyl chloride comprises the following steps:

(1) transporting trichloroethylene in a raw material storage tank to a first mixing tank, adding an initiator and stirring to obtain a mixed reaction liquid, transporting the mixed reaction liquid to an oxidation reactor, allowing air in a gas buffer tank to enter a microinterface generator from the bottom of the oxidation reactor, and mixing the air and the mixed reaction liquid in the microinterface generator to obtain a reaction liquid containing bubbles, and the reaction liquid containing bubbles enters the oxidation reactor for oxidation reaction to obtain an oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride;

(2) The oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is pumped out from the middle of the oxidation reactor, and after heat exchange in the heat exchanger, it enters the top of the oxidation reactor to continue the reaction; after the oxidation reaction is completed, the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is transported to the conversion kettle after passing through the heat exchanger;

(3) adding a catalyst into a conversion kettle, stirring and mixing the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride with the catalyst to carry out a catalytic reaction, thereby obtaining a crude product containing trichloroethylene and dichloroacetyl chloride;

(4) The crude product containing trichloroethylene and dichloroacetyl chloride enters a light fractionation tower for the first distillation, and the light component containing trichloroethylene is discharged from the top of the light fractionation tower and condensed to obtain condensed trichloroethylene. The condensed trichloroethylene enters a reflux tank and is then transported back to the oxidation reactor for reaction; the distillation product at the bottom of the light fractionation tower enters a product distillation tower for the second distillation and is then discharged from the top of the product distillation tower. After condensation, it enters a gas-liquid separation tank for separation to obtain a dichloroacetyl chloride product, and the dichloroacetyl chloride product is transported to a product storage tank for storage.

In the step (1), the mass ratio of the initiator to trichloroethylene is 1:500-1000, the initiator is prepared by compounding azobisisobutyronitrile and dibenzoyl peroxide, the mass ratio of azobisisobutyronitrile to dibenzoyl peroxide is 1:0.5-1, the stirring speed is 800-1000rpm; the mass ratio of air to trichloroethylene is 0.6-1:1.

In the step (1), the oxidation reaction temperature is 75-80°C, the oxidation reaction pressure is 0.2-0.3MPa, the oxidation reaction time is 1-2h, and the average diameter of the bubbles is 100-200μm.

The mass ratio of the catalyst in step (3) to the trichloroethylene in step (1) is 1:500-1000; the catalyst is prepared by compounding triethylamine and dimethylformamide, and the mass ratio of triethylamine to dimethylformamide is 1:0.5-1; the stirring speed is 800-1000rpm, the catalytic reaction temperature is 75-80°C, the catalytic reaction pressure is 0.2-0.3MPa, and the catalytic reaction time is 0.5-1.5h.

In the step (4), the temperature of the first distillation is 80-90°C, and the pressure of the first distillation is normal pressure; the temperature of the second distillation is 100-110°C, and the pressure of the second distillation is normal pressure.

Trichloroethylene and an initiator are mixed in a first mixing tank by a stirrer to form a mixed reaction liquid, the mixed reaction liquid enters a micro-interface generator at the bottom of an oxidation reactor, air in a gas buffer tank enters the micro-interface generator from the bottom of the oxidation reactor, the air and the mixed reaction liquid are mixed in the micro-interface generator to obtain a reaction liquid containing micron-sized bubbles, the reaction liquid containing micron-sized bubbles enters an oxidation reactor for oxidation reaction, under the action of the initiator, trichloroethylene reacts with oxygen in the air to generate an oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride;

The oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is pumped out from the middle of the oxidation reactor, and after heat exchange in the heat exchanger, it is returned to the oxidation reactor to continue the reaction; after the oxidation reaction is completed, the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is transported to the conversion kettle after heat exchange in the heat exchanger;

A catalyst is added into the conversion kettle, and the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride undergoes a catalytic reaction in the conversion kettle, wherein the trichloroethylene oxide is rearranged to generate dichloroacetyl chloride under the action of the catalyst, and a crude product containing trichloroethylene and dichloroacetyl chloride is obtained;

The crude product containing trichloroethylene and dichloroacetyl chloride enters a light fractionation tower for the first distillation, and the light component containing trichloroethylene is discharged from the top of the light fractionation tower for condensation to obtain condensed trichloroethylene. The condensed trichloroethylene enters a reflux tank and is then transported back to the oxidation reactor for reaction, and the uncondensed tail gas enters an incinerator for incineration; the distillation product at the bottom of the light fractionation tower enters a product distillation tower for the second distillation and is then discharged from the top of the product distillation tower, and after condensation, enters a gas-liquid separation tank for separation, and obtains a dichloroacetyl chloride product after separation, and the uncondensed tail gas is transported to the incinerator for incineration, and the dichloroacetyl chloride product is transported to a product storage tank for storage.

The beneficial effects of the present invention are as follows:

The present invention can realize the continuous production of dichloroacetyl chloride, the product yield is increased to more than 98%, and the purity of the dichloroacetyl chloride product is increased to more than 99%.

The microinterface generator can mix air with the mixed reaction liquid to obtain a reaction liquid containing bubbles with an average diameter of 100-200 μm, thereby increasing the mass transfer area, improving the mass transfer efficiency, and improving the utilization rate of oxygen in the air, and can improve the oxidation reaction efficiency when performing an oxidation reaction.

Using azobisisobutyronitrile and dibenzoyl peroxide as a composite initiator can better play the role of azobisisobutyronitrile and dibenzoyl peroxide; azobisisobutyronitrile can be decomposed into isobutyronitrile free radicals, dibenzoyl peroxide can be decomposed into benzoyl free radicals, oxygen in the benzoyl free radicals and hydrogen in the isobutyronitrile free radicals can form hydrogen bonds, thereby allowing the isobutyronitrile free radicals and the benzoyl free radicals to form a free radical initiation system, greatly improving the initiation effect.

In addition, there is a significant difference in the half-life of azobisisobutyronitrile and dibenzoyl peroxide as initiators. The half-life of azobisisobutyronitrile is shorter, the initiation rate is fast but the deactivation is fast, while the half-life of dibenzoyl peroxide is longer and can complement azobisisobutyronitrile, ensuring the normal reaction of trichloroethylene and oxygen during the entire reaction cycle, improving the reaction activity and promoting the oxidation reaction.

Using air instead of pure oxygen as an oxidant reduces raw material costs and can effectively reduce the oxygen content in the exhaust gas, thereby reducing the risk of explosion during abnormal reactions and improving production safety.

When triethylamine and dimethylformamide are used as a composite catalyst, triethylamine and dimethylformamide as organic amine catalysts can cause trichloroethylene oxide to undergo a Favorskii rearrangement reaction. Triethylamine, as a strong base, can provide an alkaline environment for the Favorskii rearrangement reaction. Triethylamine is an organic amine whose nitrogen atom carries a lone pair of electrons, so it has nucleophilicity and can be used for deprotonation in the reaction to form a more stable anion intermediate, thereby promoting the rearrangement reaction. The carbonyl carbon and nitrogen atoms in dimethylformamide, the reactive sites, can change the electron distribution of triethylamine, thereby increasing the activity of the nitrogen atom in triethylamine and promoting triethylamine to form a stable anion intermediate, further promoting the rearrangement reaction; dimethylformamide can not only enhance the effect of triethylamine in promoting the rearrangement reaction, but also promote ring opening. The synergistic cooperation of dimethylformamide and triethylamine can enhance the catalytic activity and promote the rearrangement of trichloroethylene oxide to form dichloroacetyl chloride, further increasing the rate of the catalytic reaction.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of the structure of the present invention;

In the figure: 1. Raw material storage tank; 2. Initiator feeding port; 3. First mixing tank; 4. Agitator 1; 5. Oxidation condenser; 6. Oxidation reactor; 7. Micro-interface generator; 8. Gas buffer tank; 9. Heat exchanger; 10. Converter condenser; 11. Catalyst feeding port; 12. Converter; 13. Agitator 2; 14. Tail gas recovery pool; 15. Light removal distillation tower; 16. First condenser; 17. Reflux tank; 18. Product distillation tower; 19. Residual liquid storage tank; 20. Second condenser; 21. Gas-liquid separation tank; 22. Incinerator; 23. Product storage tank.

DETAILED DESCRIPTION

The present invention is further described below with reference to the embodiments.

Example 1

As shown in Figure 1, the device for continuously producing dichloroacetyl chloride includes an oxidation reactor 6, a micro-interface generator 7 is arranged at the bottom of the oxidation reactor 6, the oxidation reactor 6 is respectively connected to the first mixing tank 3 and the heat exchanger 9, the first mixing tank 3 is connected to the raw material storage tank 1, the heat exchanger 9 is connected to the conversion kettle 12, the conversion kettle 12 is connected to the light removal distillation tower 15, the light removal distillation tower 15 is respectively connected to the reflux tank 17 and the product distillation tower 18, the product distillation tower 18 is respectively connected to the residual liquid storage tank 19 and the gas-liquid separation tank 21, and the gas-liquid separation tank 21 is connected to the product storage tank 23; the bottom of the oxidation reactor 6 is connected to the gas buffer tank 8, the top of the oxidation reactor 6 is connected to the tail gas recovery tank 14, the top of the conversion kettle 12 is connected to the tail gas recovery tank 14, the top of the reflux tank 17 is connected to the incinerator 22, the top of the gas-liquid separation tank 21 is connected to the incinerator 22, and the bottom of the reflux tank 17 is connected to the top of the oxidation reactor 6.

An initiator feeding port 2 is arranged at the top of the first mixing tank 3, and a stirrer 4 is arranged inside the first mixing tank 3, and the stirrer 4 is a flat-paddle stirrer.

The inlet of the heat exchanger 9 is connected to the middle of the oxidation reactor 6, and the outlet of the heat exchanger 9 is connected to the top of the oxidation reactor 6. A catalyst feeding port 11 is provided on the top of the conversion kettle 12, and a stirrer 13 is provided in the conversion kettle 12. The stirrer 13 is a flat-paddle stirrer.

An oxidation condenser 5 is provided on the pipeline between the oxidation reactor 6 and the tail gas recovery tank 14, a conversion kettle condenser 10 is provided on the pipeline between the conversion kettle 12 and the tail gas recovery tank 14, a first condenser 16 is provided on the pipeline between the light removal distillation tower 15 and the reflux tank 17, and a second condenser 20 is provided on the pipeline between the product distillation tower 18 and the gas-liquid separation tank 21.

Material pumps are provided on the pipeline between the first mixing tank 3 and the raw material storage tank 1, on the pipeline between the first mixing tank 3 and the oxidation reactor 6, on the pipeline between the bottom of the heat exchanger 9 and the oxidation reactor 6, on the pipeline between the light removal distillation tower 15 and the product distillation tower 18, on the pipeline between the reflux tank 17 and the oxidation reactor 6, and on the pipeline between the gas-liquid separation tank 21 and the product storage tank 23.

The preparation method of the device for continuously producing dichloroacetyl chloride comprises the following steps:

(1) Compounding azobisisobutyronitrile and dibenzoyl peroxide in a mass ratio of 1:0.8 to obtain an initiator; conveying the initiator and trichloroethylene in a raw material storage tank 1 to a first mixing tank 3 and mixing them by a stirrer 4 to obtain a mixed reaction liquid, wherein the mass ratio of the initiator to trichloroethylene is 1:1000, and the rotation speed of the stirrer 4 is 800 rpm; conveying the mixed reaction liquid to an oxidation reactor 6 and then entering a micro-interface generator 7; adding air in a gas buffer tank 8 from the bottom of the oxidation reactor 6 to the micro-interface generator 7, wherein the mass ratio of air to trichloroethylene is 1:1; mixing the air and the mixed reaction liquid in the micro-interface generator 7 to obtain a reaction liquid containing bubbles with an average diameter of 100 μm; the reaction liquid containing bubbles with an average diameter of 100 μm enters the oxidation reactor 6 and reacts for 1 hour at a temperature of 80°C and a pressure of 0.3 MPa to obtain an oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride;

(2) The oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is pumped out from the middle of the oxidation reactor 6, and after heat exchange in the heat exchanger 9, it enters the oxidation reactor 6 from the top to continue the reaction; after the oxidation reaction is completed, the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is transported to the conversion kettle 12 after passing through the heat exchanger 9, and the tail gas generated during the oxidation reaction is condensed in the oxidation condenser 5, and the condensate is returned to the oxidation reactor 6, and the remaining gas is transported to the tail gas recovery tank 14;

(3) triethylamine and dimethylformamide are compounded in a mass ratio of 1:0.8 to obtain a catalyst, the catalyst is added to the conversion kettle 12, the catalyst and the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride are stirred and mixed by the stirrer 13, wherein the mass ratio of the catalyst to the trichloroethylene in step (1) is 1:1000, the speed of the stirrer 13 is 800 rpm, and the catalytic reaction is carried out at a temperature of 80° C. and a pressure of 0.3 MPa for 0.5 h to obtain a crude product containing trichloroethylene and dichloroacetyl chloride, the tail gas generated during the catalytic reaction is condensed by the conversion kettle condenser 10, the condensate is returned to the conversion kettle 12, and the remaining gas is transported to the tail gas recovery pool 14;

(4) The crude product containing trichloroethylene and dichloroacetyl chloride enters the light fractionation tower 15 and undergoes the first atmospheric distillation at a temperature of 80°C. The light component containing trichloroethylene is discharged from the top of the light fractionation tower 15 and condensed by the first condenser 16 before entering the reflux tank 17. The condensed trichloroethylene is transported back to the oxidation reactor 6 for reaction, and the tail gas is transported to the incinerator 22 for incineration. The distillation product at the bottom of the light fractionation tower 15 enters the product distillation tower 18 and undergoes the second atmospheric distillation at a temperature of 100°C. It is then discharged from the top of the product distillation tower 18, condensed by the second condenser 20, and enters the gas-liquid separation tank 21 for separation to obtain the dichloroacetyl chloride product and the tail gas. The dichloroacetyl chloride product is transported to the product storage tank 23 for storage, and the tail gas is transported to the incinerator 22 for incineration. The heavy component in the product distillation tower 18 is transported from the bottom to the residual liquid storage tank 19.

Example 2

The device for continuously producing dichloroacetyl chloride used in this example is the same as that in Example 1.

The preparation method of the device for continuously producing dichloroacetyl chloride comprises the following steps:

(1) Compounding azobisisobutyronitrile and dibenzoyl peroxide in a mass ratio of 1:1 to obtain an initiator; conveying the initiator and trichloroethylene in a raw material storage tank 1 to a first mixing tank 3 and mixing them by a stirrer 4 to obtain a mixed reaction liquid, wherein the mass ratio of the initiator to trichloroethylene is 1:500, and the rotation speed of the stirrer 4 is 1000 rpm; conveying the mixed reaction liquid to an oxidation reactor 6 and then entering a micro-interface generator 7; adding air in a gas buffer tank 8 from the bottom of the oxidation reactor 6 to the micro-interface generator 7, wherein the mass ratio of air to trichloroethylene is 0.6:1; mixing the air and the mixed reaction liquid in the micro-interface generator 7 to obtain a reaction liquid containing bubbles with an average diameter of 150 μm; the reaction liquid containing bubbles with an average diameter of 150 μm enters the oxidation reactor 6 and reacts for 2 hours at a temperature of 75°C and a pressure of 0.2 MPa to obtain an oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride;

(2) The oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is pumped out from the middle of the oxidation reactor 6, and after heat exchange in the heat exchanger 9, it enters the oxidation reactor 6 from the top to continue the reaction; after the oxidation reaction is completed, the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is transported to the conversion kettle 12 after passing through the heat exchanger 9, and the tail gas generated during the oxidation reaction is condensed in the oxidation condenser 5, and the condensate is returned to the oxidation reactor 6, and the remaining gas is transported to the tail gas recovery tank 14;

(3) triethylamine and dimethylformamide are compounded in a mass ratio of 1:1 to obtain a catalyst, the catalyst is added to a conversion kettle 12, the catalyst and the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride are stirred and mixed by a stirrer 13, wherein the mass ratio of the catalyst to the trichloroethylene in step (1) is 1:500, the speed of the stirrer 13 is 1000 rpm, and the catalytic reaction is carried out at a temperature of 75° C. and a pressure of 0.2 MPa for 1 hour to obtain a crude product containing trichloroethylene and dichloroacetyl chloride, the tail gas generated during the catalytic reaction is condensed by the conversion kettle condenser 10, the condensate is returned to the conversion kettle 12, and the remaining gas is transported to the tail gas recovery pool 14;

(4) The crude product containing trichloroethylene and dichloroacetyl chloride enters the light fractionation tower 15 and undergoes the first atmospheric distillation at a temperature of 85°C. The light component containing trichloroethylene is discharged from the top of the light fractionation tower 15 and condensed by the first condenser 16 before entering the reflux tank 17. The condensed trichloroethylene is transported back to the oxidation reactor 6 for reaction, and the tail gas is transported to the incinerator 22 for incineration. The distillation product at the bottom of the light fractionation tower 15 enters the product distillation tower 18 and undergoes the second atmospheric distillation at a temperature of 105°C. It is then discharged from the top of the product distillation tower 18, condensed by the second condenser 20, and enters the gas-liquid separation tank 21 for separation to obtain the dichloroacetyl chloride product and the tail gas. The dichloroacetyl chloride product is transported to the product storage tank 23 for storage, and the tail gas is transported to the incinerator 22 for incineration. The heavy component in the product distillation tower 18 is transported from the bottom to the residual liquid storage tank 19.

Example 3

The device for continuously producing dichloroacetyl chloride used in this example is the same as that in Example 1.

The preparation method of the device for continuously producing dichloroacetyl chloride comprises the following steps:

(1) Compounding azobisisobutyronitrile and dibenzoyl peroxide in a mass ratio of 1:0.5 to obtain an initiator; conveying the initiator and trichloroethylene in the raw material storage tank 1 to the first mixing tank 3 and mixing them by a stirrer 4 to obtain a mixed reaction liquid, wherein the mass ratio of the initiator to trichloroethylene is 1:800, and the rotation speed of the stirrer 4 is 900 rpm; conveying the mixed reaction liquid to an oxidation reactor 6 and then entering a micro-interface generator 7; adding air in a gas buffer tank 8 from the bottom of the oxidation reactor 6 to the micro-interface generator 7, wherein the mass ratio of air to trichloroethylene is 0.8:1; mixing the air and the mixed reaction liquid in the micro-interface generator 7 to obtain a reaction liquid containing bubbles with an average diameter of 200 μm; the reaction liquid containing bubbles with an average diameter of 200 μm enters the oxidation reactor 6 and reacts for 2 hours at a temperature of 75°C and a pressure of 0.25 MPa to obtain an oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride;

(2) The oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is pumped out from the middle of the oxidation reactor 6, and after heat exchange in the heat exchanger 9, it enters the oxidation reactor 6 from the top to continue the reaction; after the oxidation reaction is completed, the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is transported to the conversion kettle 12 after passing through the heat exchanger 9, and the tail gas generated during the oxidation reaction is condensed in the oxidation condenser 5, and the condensate is returned to the oxidation reactor 6, and the remaining gas is transported to the tail gas recovery tank 14;

(3) triethylamine and dimethylformamide are compounded in a mass ratio of 1:0.5 to obtain a catalyst, the catalyst is added to the conversion kettle 12, the catalyst and the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride are stirred and mixed by the stirrer 13, wherein the mass ratio of the catalyst to the trichloroethylene in step (1) is 1:800, the speed of the stirrer 13 is 900 rpm, and the catalytic reaction is carried out at a temperature of 75° C. and a pressure of 0.25 MPa for 1.5 hours to obtain a crude product containing trichloroethylene and dichloroacetyl chloride, the tail gas generated during the catalytic reaction is condensed by the conversion kettle condenser 10, the condensate is returned to the conversion kettle 12, and the remaining gas is transported to the tail gas recovery pool 14;

(4) The crude product containing trichloroethylene and dichloroacetyl chloride enters the light fractionation tower 15 and undergoes the first atmospheric distillation at a temperature of 90°C. The light component containing trichloroethylene is discharged from the top of the light fractionation tower 15 and condensed by the first condenser 16 before entering the reflux tank 17. The condensed trichloroethylene is transported back to the oxidation reactor 6 for reaction, and the tail gas is transported to the incinerator 22 for incineration. The distillation product at the bottom of the light fractionation tower 15 enters the product distillation tower 18 and undergoes the second atmospheric distillation at a temperature of 110°C. It is then discharged from the top of the product distillation tower 18, condensed by the second condenser 20, and enters the gas-liquid separation tank 21 for separation to obtain the dichloroacetyl chloride product and the tail gas. The dichloroacetyl chloride product is transported to the product storage tank 23 for storage, and the tail gas is transported to the incinerator 22 for incineration. The heavy component in the product distillation tower 18 is transported from the bottom to the residual liquid storage tank 19.

Comparative Example 1

The device for continuously producing dichloroacetyl chloride does not have a microinterface generator, and the remaining steps and structure are the same as those in Example 1.

Comparative Example 2

The apparatus for continuously producing dichloroacetyl chloride is the same as that in Example 1.

In step (1), azobisisobutyronitrile is used alone as an initiator, and the remaining steps are the same as those in Example 1.

Comparative Example 3

The apparatus for continuously producing dichloroacetyl chloride is the same as that in Example 1.

In step (1), dibenzoyl peroxide is used alone as an initiator, and the remaining steps are the same as those in Example 1.

Comparative Example 4

The apparatus for continuously producing dichloroacetyl chloride is the same as that in Example 1.

In step (3), triethylamine is used alone as a catalyst, and the remaining steps are the same as those in Example 1.

Comparative Example 5

The apparatus for continuously producing dichloroacetyl chloride is the same as that in Example 1.

In step (3), dimethylformamide is used alone as a catalyst, and the remaining steps are the same as those in Example 1.

The test results of Examples 1-3 and Comparative Examples 1-5 are as follows:

Example 1: The yield of dichloroacetyl chloride product is 98.1%, and the purity of dichloroacetyl chloride product is 99.2%;

Example 2: The yield of dichloroacetyl chloride product is 98.2%, and the purity of dichloroacetyl chloride product is 99.0%;

Example 3: The yield of dichloroacetyl chloride product is 98.4%, and the purity of dichloroacetyl chloride product is 99.1%;

Comparative Example 1: The yield of dichloroacetyl chloride product is 23.2%, and the purity of dichloroacetyl chloride product is 89.4%;

Comparative Example 2: The yield of dichloroacetyl chloride product is 88.2%, and the purity of dichloroacetyl chloride product is 92.2%;

Comparative Example 3: The yield of dichloroacetyl chloride product is 78.3%, and the purity of dichloroacetyl chloride product is 93.4%;

Comparative Example 4: The yield of dichloroacetyl chloride product is 88.4%, and the purity of dichloroacetyl chloride product is 93.2%;

Comparative Example 5: The yield of the dichloroacetyl chloride product was 87.1%, and the purity of the dichloroacetyl chloride product was 94.7%.

It can be seen from the data of Example 1 and Comparative Example 1 that when Comparative Example 1 is prepared without using a microinterface generator, oxygen in the air cannot fully contact with trichloroethylene to react, and the yield and purity of the dichloroacetyl chloride product are low.

It can be seen from the data of Example 1 and Comparative Example 2 that the yield and purity of the dichloroacetyl chloride product produced by the composite initiator of the present invention are higher; in Comparative Example 2, only a single initiator azobisisobutyronitrile is used, and the reaction activity is lower, resulting in a lower yield and purity of the dichloroacetyl chloride product.

It can be seen from the data of Example 1 and Comparative Example 3 that the yield and purity of the dichloroacetyl chloride product produced by the composite initiator of the present invention are higher; in Comparative Example 3, only a single initiator, dibenzoyl peroxide, is used, and the reaction activity is lower, resulting in a lower yield and purity of the dichloroacetyl chloride product.

It can be seen from the data of Example 1 and Comparative Example 4 that the yield and purity of the dichloroacetyl chloride product produced by the composite catalyst of the present invention are high; Comparative Example 4 only uses a single catalyst triethylamine, which has a low catalytic activity, resulting in a low yield and purity of the dichloroacetyl chloride product.

It can be seen from the data of Example 1 and Comparative Example 5 that the yield and purity of the dichloroacetyl chloride product produced by the composite catalyst of the present invention are high; Comparative Example 5 only uses a single catalyst dimethylformamide, which has a low catalytic activity, resulting in a low yield and purity of the dichloroacetyl chloride product.

Claims (9)

1. A preparation method using a device for continuously producing dichloroacetyl chloride, characterized in that the device for continuously producing dichloroacetyl chloride comprises an oxidation reactor (6), a microinterface generator (7) is arranged at the bottom of the oxidation reactor (6), the oxidation reactor (6) is respectively connected to a first mixing tank (3) and a heat exchanger (9), the first mixing tank (3) is connected to a raw material storage tank (1), the heat exchanger (9) is connected to a conversion kettle (12), the conversion kettle (12) is connected to a light removal distillation tower (15), and the light removal distillation tower (15) is respectively connected to a reflux tank (17) and a product distillation tower (18), the product distillation tower (18) is respectively connected to a residual liquid storage tank (19) and a gas-liquid separation tank (21), and the gas-liquid separation tank (21) is connected to a product storage tank (23); the bottom of the oxidation reactor (6) is connected to a gas buffer tank (8), the top of the oxidation reactor (6) is connected to a tail gas recovery tank (14), the top of the conversion kettle (12) is connected to the tail gas recovery tank (14), the top of the reflux tank (17) is connected to an incinerator (22), the top of the gas-liquid separation tank (21) is connected to the incinerator (22), and the bottom of the reflux tank (17) is connected to the top of the oxidation reactor (6); The preparation method of the device for continuously producing dichloroacetyl chloride comprises the following steps: (1) trichloroethylene in a raw material storage tank (1) is transported to a first mixing tank (3), and an initiator is added and stirred to obtain a mixed reaction liquid, the mixed reaction liquid is transported to an oxidation reactor (6), air in a gas buffer tank (8) enters a micro-interface generator (7) from the bottom of the oxidation reactor (6), the air and the mixed reaction liquid are mixed in the micro-interface generator (7) to obtain a reaction liquid containing bubbles, the reaction liquid containing bubbles enters the oxidation reactor (6) to undergo an oxidation reaction, and an oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is obtained; (2) The oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is pumped out from the middle of the oxidation reactor (6), and after heat exchange in the heat exchanger (9), it enters the top of the oxidation reactor (6) to continue the reaction; after the oxidation reaction is completed, the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride is transported to the conversion kettle (12) after passing through the heat exchanger (9); (3) adding a catalyst into a conversion kettle (12), stirring and mixing the oxidation reaction liquid containing trichloroethylene oxide and dichloroacetyl chloride with the catalyst to carry out a catalytic reaction, and obtaining a crude product containing trichloroethylene and dichloroacetyl chloride; (4) The crude product containing trichloroethylene and dichloroacetyl chloride enters a light fractionation tower (15) for a first distillation, and the light component containing trichloroethylene is discharged from the top of the light fractionation tower (15) and condensed to obtain condensed trichloroethylene. The condensed trichloroethylene enters a reflux tank (17) and is then transported back to the oxidation reactor (6) for reaction. The distillation product at the bottom of the light fractionation tower (15) enters a product distillation tower (18) for a second distillation and is then discharged from the top of the product distillation tower (18). After condensation, it enters a gas-liquid separation tank (21) for separation to obtain a dichloroacetyl chloride product. The dichloroacetyl chloride product is transported to a product storage tank (23) for storage. 2. The method for preparing dichloroacetyl chloride using a continuous production device according to claim 1, characterized in that an initiator feeding port (2) is provided at the top of the first mixing tank (3), and a stirrer (4) is provided in the first mixing tank (3), and the stirrer (4) is a flat-paddle stirrer. 3. The method for preparing dichloroacetyl chloride by using a continuous production device according to claim 1, characterized in that the inlet of the heat exchanger (9) is connected to the middle of the oxidation reactor (6), the outlet of the heat exchanger (9) is connected to the top of the oxidation reactor (6), a catalyst feeding port (11) is provided at the top of the conversion kettle (12), and a second agitator (13) is provided in the conversion kettle (12), and the second agitator (13) is a flat-paddle agitator. 4. The method for preparing dichloroacetyl chloride using a continuous production device according to claim 1, characterized in that an oxidation condenser (5) is provided on the pipeline between the oxidation reactor (6) and the tail gas recovery tank (14), a conversion tank condenser (10) is provided on the pipeline between the conversion tank (12) and the tail gas recovery tank (14), a first condenser (16) is provided on the pipeline between the light removal distillation tower (15) and the reflux tank (17), and a second condenser (20) is provided on the pipeline between the product distillation tower (18) and the gas-liquid separation tank (21). 5. The method for preparing dichloroacetyl chloride using a continuous production device according to claim 1, characterized in that material pumps are provided on the pipeline between the first mixing tank (3) and the raw material storage tank (1), on the pipeline between the first mixing tank (3) and the oxidation reactor (6), on the pipeline between the bottom of the heat exchanger (9) and the oxidation reactor (6), on the pipeline between the light removal distillation tower (15) and the product distillation tower (18), on the pipeline between the reflux tank (17) and the oxidation reactor (6), and on the pipeline between the gas-liquid separation tank (21) and the product storage tank (23). 6. The method for preparing dichloroacetyl chloride by continuous production of the device according to claim 1, characterized in that in step (1), the mass ratio of the initiator to trichloroethylene is 1:500-1000, the initiator is prepared by compounding azobisisobutyronitrile and dibenzoyl peroxide, the mass ratio of azobisisobutyronitrile to dibenzoyl peroxide is 1:0.5-1, the stirring speed is 800-1000rpm; the mass ratio of air to trichloroethylene is 0.6-1:1. 7. The method for preparing dichloroacetyl chloride using a continuous production device according to claim 1, characterized in that in step (1), the oxidation reaction temperature is 75-80°C, the oxidation reaction pressure is 0.2-0.3MPa, the oxidation reaction time is 1-2h, and the average diameter of the bubbles is 100-200μm. 8. The method for preparing dichloroacetyl chloride using a continuous production device according to claim 1, characterized in that the mass ratio of the catalyst in step (3) to the trichloroethylene in step (1) is 1:500-1000; the catalyst is prepared by compounding triethylamine and dimethylformamide, and the mass ratio of triethylamine to dimethylformamide is 1:0.5-1; the stirring speed is 800-1000 rpm, the catalytic reaction temperature is 75-80° C., the catalytic reaction pressure is 0.2-0.3 MPa, and the catalytic reaction time is 0.5-1.5 h. 9. The method for preparing dichloroacetyl chloride using a continuous production device according to claim 1, characterized in that the temperature of the first distillation in step (4) is 80-90° C. and the pressure of the first distillation is normal pressure; the temperature of the second distillation is 100-110° C. and the pressure of the second distillation is normal pressure.