CN115504879B - Method for continuously preparing dichloroacetyl chloride - Google Patents
Method for continuously preparing dichloroacetyl chloride Download PDFInfo
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Abstract
The invention discloses a method for continuously preparing dichloroacetyl chloride. The method specifically comprises the following steps: continuously adding a mixed solution containing trichloroethylene, azodiisobutyronitrile (AIBN) and triethylamine and gas into a loop reactor to perform oxidation reaction to obtain dichloroacetyl chloride; the volume fraction of oxygen in the gas is 18% -25%. The method can be used for introducing air for oxidation, effectively improving the utilization rate of the air, continuously feeding and discharging, simplifying the operation process, greatly improving the productivity and being convenient for industrial production.
Description
Technical Field
The invention relates to a method for continuously preparing dichloroacetyl chloride.
Background
The dichloroacetyl chloride (DCAC) is an important organic synthesis intermediate, is mainly used for synthesizing pesticides and medical intermediates, is widely used for synthesizing vinyl pesticides, can be also used for wool felt fulling finishing, bleaching, decoloring, fresh-keeping, sterilizing, disinfecting and the like, has extremely strong acylation activity, and has wide prospect in the application of synthesizing fine chemical products.
The method widely used for synthesizing the dichloroacetyl chloride at present takes trichloroethylene as a raw material, azo or peroxide initiators are used for initiating, organic amine catalysts are used for catalyzing, oxygen is introduced for oxidation and batch synthesis of DCAC, and a common reactor is a tower reactor, such as: patent publication No. CN1131140A discloses a synthesis method of DCAC: adding trichloroethylene, azodiisobutyronitrile and triethylamine into a tower reactor, heating to 150 ℃, gradually introducing pure oxygen through an insertion pipe, maintaining the pressure at 0.55MPa, evacuating oxygen and impurity phosgene which are not reacted in time after passing through a tail gas absorption system, reacting for 15h, and distilling at normal pressure to obtain DCAC product, wherein the yield is 85% and the content is about 93%.
The current industrialized production method of DCAC is basically carried out by the process method and the reaction device, and the main defects of the method for synthesizing DCAC are as follows: 1. pure oxygen is required to be introduced in the reaction, and when the air is introduced, the oxygen is insufficient due to the gas-liquid mixing difference, the reaction does not occur or the conversion rate is very low; 2. the oxygen absorption capacity is poor, the oxygen utilization rate is low, and oxygen which does not react in time is discharged along with tail gas, so that raw materials are wasted; 3. under the conditions of high reaction temperature (110-150 ℃) and high pressure (0.5-0.65 MPa), the oxygen content in the reaction device is high, and the safety risk is high; 4. the reaction speed is low, the reaction time is long (8-15 h), and the yield is low; 5. intermittent operation, namely, after the priming material is thrown in at one time, heating, introducing oxygen to a specified pressure, maintaining the reaction, and reducing the productivity.
Disclosure of Invention
The invention aims to overcome the defects of high safety risk, low reaction speed, low production efficiency and the like in the existing preparation method of the dichloroacetyl chloride, and provides the method for continuously preparing the dichloroacetyl chloride.
The invention solves the technical problems through the following technical proposal.
The invention provides a method for continuously preparing dichloroacetyl chloride, which comprises the following steps: continuously adding a mixed solution containing trichloroethylene, azodiisobutyronitrile (AIBN) and triethylamine and gas into a loop reactor to perform oxidation reaction to obtain dichloroacetyl chloride; the volume fraction of oxygen in the gas is 18% -25%.
The loop reactor is a loop reactor conventional in the art, preferably comprising a venturi nozzle, a gas-liquid mixing chamber, a reaction vessel, a circulation pump, a circulation line, a heat exchanger and a temperature control system. More preferably, the loop reactor further comprises 2 gas inlet lines, 1 liquid inlet line, a tail gas discharge line and a discharge line, wherein the tail gas discharge line and the discharge line are each independently provided with a back pressure valve and a pressure gauge. N 2, impurity gases and a small amount of unreacted O 2 are discharged to an exhaust gas absorption system through an exhaust gas discharge pipeline. The loop reactor is required to be made of materials resistant to strong acid and high pressure, such as hastelloy and the like.
Preferably, in the mixed solution, the mass ratio of the trichloroethylene to the azodiisobutyronitrile is 1: (0.0002-0.002) (e.g., 1:0.0002, 1:0.001, or 1:0.002); more preferably, the mass ratio of the trichloroethylene to the azodiisobutyronitrile is 1: (0.0008-0.002); further, the mass ratio of the trichloroethylene to the azobisisobutyronitrile is 1: (0.001-0.002).
Preferably, in the mixed solution, the mass ratio of the trichloroethylene to the triethylamine is 1: (0.00001-0.00012) (e.g., 1:0.00001, 1:0.00005, or 1:0.00012); more preferably, the mass ratio of the trichloroethylene to the triethylamine is 1: (0.00004-0.00012); further, the mass ratio of trichloroethylene to triethylamine is 1: (0.00004-0.0006).
Preferably, the feed rate of the mixed solution is conventional for such reactions in the art, preferably, the feed rate of the mixed solution is 200-1600g/h (e.g., 250g/h, 480g/h, or 1500 g/h), more preferably, the feed rate of the mixed solution is 200-500g/h; further, the feeding speed of the mixed solution is 400-500g/h.
Preferably, the product from the oxidation reaction is discharged from the outlet of the circulation line into the receiving bottle at a rate that is conventional in such reactions in the art, preferably at a rate of 200-1600g/h (e.g., 250g/h, 480g/h or 1500 g/h), more preferably at a rate of 200-500g/h; further, the discharge speed of the product obtained by the oxidation reaction is 400-500g/h.
Preferably, the discharging speed of the product obtained by the oxidation reaction is the same as the feeding speed of the mixed solution.
Preferably, the gas is air.
Preferably, the molar ratio of gas to trichloroethylene is (0.5-1), based on the oxygen content: 1, e.g., 0.6:1.
Preferably, the raw materials for the oxidation reaction comprise trichloroethylene, azobisisobutyronitrile, triethylamine and air.
The temperature of the oxidation reaction is conventional in the art for such reactions, preferably the temperature of the oxidation reaction is 40-110 ℃ (e.g., 40 ℃, 70 ℃ or 110 ℃), more preferably the temperature of the oxidation reaction is 60-80 ℃, and further the temperature of the oxidation reaction is 70-75 ℃. In the temperature range, the reaction conversion rate and the yield are high.
The pressure of the oxidation reaction is conventional in the art for such reactions, preferably the pressure of the oxidation reaction is from 0.3 to 0.7MPa (e.g., 0.30MPa, 0.50MPa, or 0.65 MPa); more preferably, the pressure of the oxidation reaction is 0.4-0.7MPa; further, the pressure of the oxidation reaction is 0.5-0.7MPa. In the pressure range, the reaction conversion rate and the yield are high, and the safety is high.
The residence time of the oxidation reaction is set according to the reaction scale, and is generally mainly determined by the reaction temperature, pressure and feeding and discharging speed, and the progress of the reaction can be monitored by adopting a conventional detection method (such as HPLC, TLC or NMR) in the field, preferably, the residence time of the oxidation reaction is 1-6h (such as 1h, 3h or 6 h); more preferably, the residence time of the oxidation reaction is from 2 to 6 hours; further, the residence time of the oxidation reaction is 3-3.5 hours.
Preferably, dichloroacetyl chloride is added to the loop reactor as a primer solution prior to continuous addition of the mixed solution. In the priming solution, dichloroacetyl chloride is commercially available, and can also be prepared by the following method: adding trichloroethylene, azodiisobutyronitrile and triethylamine, and introducing air to perform oxidation reaction to obtain the priming solution. Wherein the amounts of trichloroethylene, azobisisobutyronitrile, triethylamine and air used and the conditions of the oxidation reaction are as described in any of the preceding claims.
The dosage of the priming solution is not particularly limited, and is generally set to be higher than the stirring volume of the loop reactor or the matched circulating pump can work normally.
More preferably, the primer solution is heated to a temperature required for the oxidation reaction before the mixed solution is continuously added.
The method for continuously preparing the dichloroacetyl chloride can further comprise the following post-treatment steps: and (3) distilling the oxidation reaction product at normal pressure, and collecting the fraction at 105-108 ℃. Wherein the fraction below 105 ℃ can be recycled.
In a preferred embodiment, the continuous process for preparing dichloroacetyl chloride comprises the steps of: adding dichloroacetyl chloride into a loop reactor as a priming solution, heating the priming solution to 60-80 ℃, continuously adding a mixed solution containing trichloroethylene, azodiisobutyronitrile and triethylamine and gas, and carrying out an oxidation reaction, wherein the temperature of the oxidation reaction is 60-80 ℃, the pressure of the oxidation reaction is 0.4-0.7MPa, and the residence time is 2-6h.
In a preferred embodiment, the continuous process for preparing dichloroacetyl chloride comprises the steps of: adding dichloroacetyl chloride into a loop reactor as a priming solution, heating the priming solution to 70-75 ℃, continuously adding a mixed solution containing trichloroethylene, azodiisobutyronitrile and triethylamine and gas, and carrying out an oxidation reaction, wherein the temperature of the oxidation reaction is 70-75 ℃, the pressure of the oxidation reaction is 0.50-0.55MPa, and the residence time is 3.0-3.5h.
The above preferred conditions can be arbitrarily combined on the basis of not deviating from the common knowledge in the art, and thus, each preferred embodiment of the present invention can be obtained.
The reagents and materials used in the present invention are commercially available.
The invention has the positive progress effects that: according to the invention, the loop reactor is used as an oxidation device for continuously producing the dichloroacetyl chloride for the first time, so that the reaction can be carried out under a milder reaction condition, the defect that air cannot be used for the reaction is overcome, the safety risk of the reaction is reduced, and the production capacity is effectively improved.
Detailed Description
The invention is further illustrated by means of the following examples, which are not intended to limit the scope of the invention. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications.
In the following examples, loop reactors were used: the design volume, pressure and temperature of the LP-1 type loop reactor manufactured by Shanghai engineering industrial equipment Co., ltd are respectively as follows: 2L, 4MPa, 200 ℃.
Preparation example 1
Before continuous synthesis, the preparation part in the loop reactor kettle is primed with a primer to ensure that the reaction liquid can be circularly mixed, and the specific preparation method comprises the following steps:
Uniformly mixing 800g of trichloroethylene, 0.8g of AIBN and 40mg of triethylamine, putting the mixture into a 2L reaction kettle of a loop reactor, starting a circulating pump, starting a heat exchanger jacket heating medium, and heating the reaction liquid to 70 ℃; and (3) starting to introduce compressed air (to be dried) at a constant speed for oxidation reaction, discharging N 2, a small amount of unreacted O 2 and impurity gas by controlling a back pressure valve on a tail exhaust pipe line in the reaction process, controlling the pressure of a system to be 0.5-0.55MPa, stopping ventilation after 3 hours, slowly exhausting air, and cooling to obtain about 850g of DCAC reaction liquid as priming material for standby.
Example 1
Priming material was prepared by the method of preparation example 1, and 850g of the prepared priming material was added to the tank of the loop reactor by a advection pump. Starting a circulating pump, starting a heat exchanger jacket heating medium, heating a primer in a kettle to 40 ℃, introducing compressed air to fill the pressure in a reactor to 0.5MPa, pumping a mixed solution of trichloroethylene/AIBN/triethylamine into the kettle at 480g/h (wherein the mass of the trichloroethylene, the AIBN and the triethylamine is 1:0.001:0.00005), simultaneously introducing compressed air into the reactor at the speed of 0.6 times of the mole ratio of the trichloroethylene per minute, controlling the pressure in the system to be 0.5-0.55MPa by controlling the opening of a back pressure valve on a tail discharge pipe, controlling the temperature to be 40 ℃, continuously pumping for 1.5h (the retention time is 3h in total), controlling the opening of a discharge valve, gradually discharging the mixed solution into a reaction solution receiving bottle from an outlet of a circulating pipe at 480g/h, discharging N 2, impurity gas and a small amount of unreacted O 2 to a tail gas absorbing system through a tail discharge pipe, continuously feeding the mixed solution into the tail gas absorbing system for 6h, and stopping feeding the mixed solution. The reaction liquid is distilled at a constant pressure, and the fraction below 105 ℃ can be recycled; collecting fraction at 105-108 deg.C to obtain DCAC product with purity of 98.5%. The reaction conversion (referred to as conversion of trifluoroethylene) was 45.4%, and the yield was 44.8%.
Example 2
Primer was prepared by the method of preparation example 1, and 850g of the prepared primer was added to the tank of the loop reactor. Starting a circulating pump, starting a heat exchanger jacket heating medium, heating a primer liquid in a kettle to 70 ℃, introducing compressed air to fill the pressure in a reactor to 0.5MPa, pumping a mixed solution of trichloroethylene/AIBN/triethylamine into the kettle at 480g/h (wherein the mass ratio of the trichloroethylene to the AIBN to the triethylamine is 1:0.001:0.00005), simultaneously introducing compressed air into the reactor at the speed of 0.6 times of the mole ratio of the trichloroethylene per minute, controlling the pressure in the system to be 0.5-0.55MPa by controlling the opening of a back pressure valve on a tail discharge pipe, controlling the temperature to be 70 ℃, continuously pumping for 1.5h (the retention time is 3 h), controlling the opening of a discharge valve, gradually discharging N 2, impurity gas and a small amount of unreacted O 2 from an outlet of a circulating pipe to a tail gas absorption system at 480g/h, continuously feeding and discharging for 6h, and stopping feeding. The reaction liquid is distilled at a constant pressure, and the fraction below 105 ℃ can be recycled; the fraction at 105-108 ℃ is extracted, and the DCAC product with the purity of 99.2% can be obtained. The reaction conversion was 97.2% and the yield was 91.0%.
Example 3
Priming material was prepared by the method of preparation example 1, and 850g of the prepared priming material was added to the tank of the loop reactor by a advection pump. Starting a circulating pump, starting a heat exchanger jacket heating medium, heating a primer liquid in a kettle to 110 ℃, introducing compressed air to fill the pressure in a reactor to 0.5MPa, pumping a mixed solution of trichloroethylene/AIBN/triethylamine into the kettle at 480g/h (wherein the mass ratio of the trichloroethylene to the AIBN to the triethylamine is 1:0.001:0.00005), simultaneously introducing compressed air into the reactor at the speed of 0.6 times of the mole ratio of the trichloroethylene per minute, controlling the pressure in the system to 0.5-0.55MPa by controlling the opening of a back pressure valve on a tail discharge pipe, controlling the temperature to 110 ℃, continuously pumping for 1.5h (the retention time is 3h in total), controlling the opening of a discharge valve, gradually discharging N 2, impurity gas and a small amount of unreacted O 2 from an outlet of a circulating pipe to a tail gas absorption system at 480g/h, continuously feeding and discharging for 6h, and stopping feeding. The reaction liquid is distilled at a constant pressure to produce a fraction at 105-108 ℃, and the fraction below 105 ℃ can be recycled; the DCAC product with the purity of 98.2 percent can be obtained. The reaction conversion was 99.7% and the yield was 74.2%.
Example 4
Priming material was prepared by the method of preparation example 1, and 850g of the prepared priming material was added to the tank of the loop reactor by a advection pump. Starting a circulating pump, starting a heat exchanger jacket heating medium, heating a primer liquid in a kettle to 70 ℃, introducing compressed air to fill the pressure in a reactor to 0.3MPa, pumping a mixed solution of trichloroethylene/AIBN/triethylamine into the kettle at 480g/h (wherein the mass ratio of the trichloroethylene to the AIBN to the triethylamine is 1:0.001:0.00005), simultaneously introducing compressed air into the reactor at the speed of 0.6 times of the mole ratio of the trichloroethylene per minute, controlling the pressure in the system to be 0.3-0.35MPa by controlling the opening of a back pressure valve on a tail discharge pipe, controlling the temperature to be 70 ℃ and continuously pumping the mixture for 1.5h (the retention time is 3h in total), controlling the opening of a discharge valve, gradually discharging the mixture into a reaction liquid receiving bottle from an outlet of the circulating pipe at 480g/h, discharging N 2, impurity gas and a small amount of unreacted O 2 to a tail gas absorbing system through the tail discharge pipe, and stopping feeding the mixture after continuously feeding the mixture for 6 h. The reaction liquid is distilled at a constant pressure to produce a fraction at 105-108 ℃, and the fraction below 105 ℃ can be recycled; the DCAC product with the purity of 98.6 percent can be obtained. The reaction conversion was 78.4% and the yield was 72.2%.
Example 5
Priming material was prepared by the method of preparation example 1, and 850g of the prepared priming material was added to the tank of the loop reactor by a advection pump. Starting a circulating pump, starting a heat exchanger jacket heating medium, heating a primer liquid in a kettle to 70 ℃, introducing compressed air to fill the pressure in a reactor to 0.65MPa, pumping a mixed solution of trichloroethylene/AIBN/triethylamine into the kettle at 480g/h (wherein the mass ratio of the trichloroethylene to the AIBN to the triethylamine is 1:0.001:0.00005), simultaneously introducing compressed air into the reactor at the speed of 0.6 times of the mole ratio of the trichloroethylene per minute, controlling the pressure in the system to be 0.65-0.7MPa by controlling the opening of a back pressure valve on a tail discharge pipe, controlling the temperature to be 70 ℃ and continuously pumping for 1.5h (the retention time is 3 h), controlling the opening of a discharge valve, gradually discharging N 2, impurity gas and a small amount of unreacted O 2 from an outlet of a circulating pipe to a tail gas absorption system at 480g/h, continuously feeding and discharging for 6h, and stopping feeding. The reaction liquid is distilled at a constant pressure to produce a fraction at 105-108 ℃, and the fraction below 105 ℃ can be recycled; the DCAC product with the purity of 98.6 percent can be obtained. The reaction conversion was 98.4% and the yield was 91.5%.
Example 6
Priming material was prepared by the method of preparation example 1, and 850g of the prepared priming material was added to the tank of the loop reactor by a advection pump. Starting a circulating pump, starting a heat exchanger jacket heating medium, heating a primer liquid in a kettle to 70 ℃, introducing compressed air to fill the pressure in a reactor to 0.5MPa, pumping a mixed solution of trichloroethylene/AIBN/triethylamine into the kettle at a speed of 1500g/h (residence time of 1 h), wherein the mass ratio of the trichloroethylene to the AIBN to the triethylamine is 1:0.001:0.00005, simultaneously introducing the compressed air into the reactor at a speed of 0.6 times of the mole ratio of the trichloroethylene per minute, controlling the pressure in the system to be 0.5-0.55MPa by controlling the opening of a back pressure valve on a tail discharge pipe, controlling the opening of a discharge valve after continuously pumping the pressure in the system to be 70 ℃ for 0.5h, gradually discharging the mixed solution into a reaction liquid receiving bottle at a speed of 1500g/h, discharging N 2, impurity gas and a small amount of unreacted O 2 to a tail gas absorbing system through the tail discharge pipe, and continuously feeding and discharging the mixed solution for 3h, and stopping feeding the mixed solution. The reaction liquid is distilled at a constant pressure to produce a fraction at 105-108 ℃, and the fraction below 105 ℃ can be recycled; the DCAC product with the purity of 99.0 percent can be obtained. The reaction conversion was 36.3% and the yield was 32.7%.
Example 7
Priming material was prepared by the method of preparation example 1, and 850g of the prepared priming material was added to the tank of the loop reactor by a advection pump. Starting a circulating pump, starting a heat exchanger jacket heating medium, heating a primer liquid in a kettle to 70 ℃, introducing compressed air to fill the pressure in a reactor to 0.5MPa, pumping a mixed solution of trichloroethylene/AIBN/triethylamine into the kettle at the speed of 250g/h (residence time of 6 h) (wherein the mass ratio of the trichloroethylene to the AIBN to the triethylamine is 1:0.001:0.00005), simultaneously introducing the compressed air into the reactor at the speed of 0.6 times of the mole ratio of the trichloroethylene per minute, controlling the pressure in the system to be 0.5-0.55MPa by controlling the opening of a back pressure valve on a tail discharge pipe, controlling the opening of a discharge valve after continuously pumping for 3h, gradually discharging the mixed solution from the outlet of the circulating pipe to a reaction liquid receiving bottle at the speed of 250g/h, discharging N 2, impurity gas and a small amount of unreacted O 2 to a tail gas absorbing system through the tail discharge pipe, continuously feeding the mixed solution into the reaction liquid receiving bottle for 12h, and stopping feeding the mixed solution. The reaction liquid is distilled at a constant pressure to produce a fraction at 105-108 ℃, and the fraction below 105 ℃ can be recycled; the DCAC product with the purity of 98.2 percent can be obtained. The reaction conversion was 99.5% and the yield was 88.1%.
Example 8
Priming material was prepared by the method of preparation example 1, and 850g of the prepared priming material was added to the tank of the loop reactor by a advection pump. Starting a circulating pump, starting a heat exchanger jacket heating medium, heating a primer liquid in a kettle to 70 ℃, introducing compressed air to fill the pressure in a reactor to 0.5MPa, pumping a mixed solution of trichloroethylene/AIBN/triethylamine into the kettle at the speed of 480g/h (residence time of 3 h), wherein the ratio of trichloroethylene to AIBN to triethylamine is 1:0.0002:0.00005, simultaneously introducing compressed air into the reactor at the speed of 0.6 times of the mole ratio of trichloroethylene per minute, controlling the pressure in the system to be 0.5-0.55MPa by controlling the opening of a back pressure valve on a tail discharge pipe, controlling the opening of a discharge valve after continuously pumping for 3h, gradually discharging N 2, impurity gas and a small amount of unreacted O 2 from an outlet of the circulating pipe to a reaction liquid receiving bottle at the speed of 480g/h, continuously feeding and discharging the mixture to a tail gas absorbing system for 6h, and stopping feeding. The reaction liquid is distilled at a constant pressure to produce a fraction at 105-108 ℃, and the fraction below 105 ℃ can be recycled; the DCAC product with the purity of 97.9 percent can be obtained. The reaction conversion was 83.5%, and the yield was 76.0%.
Example 9
Priming material was prepared by the method of preparation example 1, and 850g of the prepared priming material was added to the tank of the loop reactor by a advection pump. Starting a circulating pump, starting a heat exchanger jacket heating medium, heating a primer liquid in a kettle to 70 ℃, introducing compressed air to fill the pressure in a reactor to 0.5MPa, pumping a mixed solution of trichloroethylene/AIBN/triethylamine into the kettle at the speed of 480g/h (residence time of 3 h), simultaneously introducing compressed air into the reactor at the speed of 0.6 times of the mole ratio of trichloroethylene per minute, controlling the pressure in the system to be 0.5-0.55MPa by controlling the opening of a back pressure valve on a tail discharge pipe, controlling the opening of a discharge valve after continuously pumping for 3h, gradually discharging N 2, impurity gas and a small amount of unreacted O 2 from an outlet of the circulating pipe to a reaction liquid receiving bottle at the speed of 480g/h, continuously feeding the mixture into a discharge system for 6h again through the tail discharge pipe, and stopping feeding. The reaction liquid is distilled at a constant pressure to produce a fraction at 105-108 ℃, and the fraction below 105 ℃ can be recycled; the DCAC product with the purity of 99.1 percent can be obtained. The reaction conversion was 98.1% and the yield was 90.3%.
Example 10
Priming material was prepared by the method of preparation example 1, and 850g of the prepared priming material was added to the tank of the loop reactor by a advection pump. Starting a circulating pump, starting a heat exchanger jacket heating medium, heating a primer liquid in a kettle to 70 ℃, introducing compressed air to fill the pressure in a reactor to 0.5MPa, pumping a mixed solution of trichloroethylene/AIBN/triethylamine into the kettle at the speed of 480g/h (residence time of 3 h), simultaneously introducing compressed air into the reactor at the speed of 0.6 times of the mole ratio of trichloroethylene per minute, controlling the pressure in the system to be 0.5-0.55MPa by controlling the opening of a back pressure valve on a tail discharge pipe, controlling the opening of a discharge valve after continuously pumping for 3h, gradually discharging N 2, impurity gas and a small amount of unreacted O 2 from an outlet of the circulating pipe to a reaction liquid receiving bottle at the speed of 480g/h, continuously feeding the mixture into a discharge system for 6h again through the tail discharge pipe, and stopping feeding. The reaction liquid is distilled at a constant pressure to produce a fraction at 105-108 ℃, and the fraction below 105 ℃ can be recycled; the DCAC product with the purity of 96.4 percent can be obtained. The reaction conversion was 97.8% and the yield was 49.5%.
Example 11
Priming material was prepared by the method of preparation example 1, and 850g of the prepared priming material was added to the tank of the loop reactor by a advection pump. Starting a circulating pump, starting a heat exchanger jacket heating medium, heating a primer liquid in a kettle to 70 ℃, introducing compressed air to fill the pressure in a reactor to 0.5MPa, pumping a mixed solution of trichloroethylene/AIBN/triethylamine into the kettle at the speed of 480g/h (residence time of 3 h) (wherein the ratio of trichloroethylene to AIBN to triethylamine is 1:0.001:0.00012), simultaneously introducing compressed air into the reactor at the speed of 0.6 times of the mole ratio of trichloroethylene per minute, controlling the pressure in the system to be 0.5-0.55MPa by controlling the opening of a back pressure valve on a tail discharge pipe, controlling the opening of a discharge valve after continuously pumping for 3h, gradually discharging N 2, impurity gas and a small amount of unreacted O 2 from an outlet of the circulating pipe to a reaction liquid receiving bottle at the speed of 480g/h, continuously feeding the mixture into a discharge system for 6h, and stopping feeding the mixture. The reaction liquid is distilled at a constant pressure to produce a fraction at 105-108 ℃, and the fraction below 105 ℃ can be recycled; the DCAC product with the purity of 97.5 percent can be obtained. The reaction conversion was 98.5% and the yield was 82.3%.
Claims (10)
1. A method for continuously preparing dichloroacetyl chloride, which is characterized by comprising the following steps: continuously adding a mixed solution containing trichloroethylene, azodiisobutyronitrile and triethylamine and gas into a loop reactor, and performing oxidation reaction to obtain dichloroacetyl chloride; the volume fraction of oxygen in the gas is 18% -25%;
the temperature of the oxidation reaction is 60-80 ℃;
in the mixed solution, the mass ratio of the trichloroethylene to the azodiisobutyronitrile is 1: (0.001-0.002);
in the mixed solution, the mass ratio of trichloroethylene to triethylamine is 1: (0.00004-0.00005);
The pressure of the oxidation reaction is 0.5-0.7MPa;
the feeding speed of the mixed solution is 400-500g/h;
the discharging speed of the product obtained by the oxidation reaction is 400-500g/h;
The gas is air.
2. The method for continuously preparing dichloroacetyl chloride according to claim 1, wherein the method for continuously preparing dichloroacetyl chloride satisfies one or more of the following conditions:
(1) The loop reactor comprises a Venturi nozzle, a gas-liquid mixing chamber, a reaction kettle, a circulating pump, a circulating pipeline, a heat exchanger and a temperature control system;
(2) The molar ratio of the gas to trichloroethylene is (0.5-1) based on the oxygen content: 1, a step of;
(3) The residence time of the oxidation reaction is 1-6h.
3. The continuous process for preparing dichloroacetyl chloride according to claim 1, wherein the residence time of the oxidation reaction is 2-6h.
4. The method for continuously preparing dichloroacetyl chloride according to claim 1, wherein the method for continuously preparing dichloroacetyl chloride satisfies one or more of the following conditions:
(1) The discharging speed of the product obtained by the oxidation reaction is the same as the feeding speed of the mixed solution;
(2) The raw materials of the oxidation reaction consist of trichloroethylene, azodiisobutyronitrile, triethylamine and air;
(3) The temperature of the oxidation reaction is 70-75 ℃;
(4) The residence time of the oxidation reaction is 3-3.5h.
5. The method for continuously preparing dichloroacetyl chloride according to claim 1, wherein the method for continuously preparing dichloroacetyl chloride satisfies one or more of the following conditions:
(1) The loop reactor further comprises 2 air inlet pipelines, 1 liquid inlet pipeline, a tail gas discharge pipeline and a discharge pipeline, wherein the tail gas discharge pipeline and the discharge pipeline are respectively and independently provided with a back pressure valve and a pressure gauge;
(2) In the mixed solution, the mass ratio of the trichloroethylene to the azodiisobutyronitrile is 1:0.001 or 1:0.002;
(3) In the mixed solution, the mass ratio of trichloroethylene to triethylamine is 1:0.00005;
(4) The feeding speed of the mixed solution is 480g/h;
(5) The discharging speed of the product obtained by the oxidation reaction is 480g/h;
(6) The molar ratio of the gas to the trichloroethylene is 0.6:1 based on the oxygen content;
(7) The temperature of the oxidation reaction is 70 ℃;
(8) The pressure of the oxidation reaction is 0.50MPa or 0.65MPa;
(9) The residence time of the oxidation reaction is 1h, 3h or 6h.
6. The continuous process for producing dichloroacetyl chloride according to claim 1, wherein dichloroacetyl chloride is added as a bottoming solution to the loop reactor prior to continuously adding the mixed solution.
7. The method for continuously preparing dichloroacetyl chloride according to claim 6, wherein in the primer solution, the dichloroacetyl chloride is prepared by the following method: adding trichloroethylene, azodiisobutyronitrile and triethylamine, and introducing air to perform oxidation reaction to obtain priming solution; wherein the amounts of trichloroethylene, azobisisobutyronitrile, triethylamine and air used and the conditions of the oxidation reaction are as defined in any one of claims 1 to 5;
and/or heating the primer solution to a temperature required for the oxidation reaction prior to continuously adding the mixed solution.
8. The continuous process for preparing dichloroacetyl chloride according to claim 1, further comprising the following post-treatment steps: distilling the oxidation reaction product under normal pressure, and collecting fraction at 105-108 deg.C; wherein the fraction below 105 ℃ is recycled.
9. The method for continuously preparing dichloroacetyl chloride according to claim 1, wherein the method for continuously preparing dichloroacetyl chloride comprises the following steps: adding dichloroacetyl chloride into a loop reactor as a priming solution, heating the priming solution to 60-80 ℃, continuously adding a mixed solution containing trichloroethylene, azodiisobutyronitrile and triethylamine and gas, and carrying out an oxidation reaction, wherein the temperature of the oxidation reaction is 60-80 ℃, the pressure of the oxidation reaction is 0.5-0.7MPa, and the residence time is 2-6h.
10. The method for continuously preparing dichloroacetyl chloride according to claim 1, wherein the method for continuously preparing dichloroacetyl chloride comprises the following steps: adding dichloroacetyl chloride into a loop reactor as a priming solution, heating the priming solution to 70-75 ℃, continuously adding a mixed solution containing trichloroethylene, azodiisobutyronitrile and triethylamine and gas, and carrying out an oxidation reaction, wherein the temperature of the oxidation reaction is 70-75 ℃, the pressure of the oxidation reaction is 0.50-0.55MPa, and the residence time is 3.0-3.5h.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1196509A (en) * | 1967-09-20 | 1970-06-24 | Shell Int Research | A process for Oxidizing Trichloroethylene to Dichloroacetyl Chloride |
| CN112457176A (en) * | 2020-11-25 | 2021-03-09 | 山东华夏神舟新材料有限公司 | Method for continuously producing hexafluoroacetone |
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| BE681232A (en) * | 1965-05-21 | 1966-11-18 | ||
| CN1131140A (en) * | 1995-03-09 | 1996-09-18 | 济南市天桥天营科工贸开发中心 | Method for preparation of dichloracetyl chloride |
| EP1900719A1 (en) * | 2006-09-01 | 2008-03-19 | BUSS ChemTech AG | Manufacture of substantially pure monochloroacetic acid |
| CN100575328C (en) * | 2006-12-08 | 2009-12-30 | 江苏长青农化股份有限公司 | Process for preparing dichloroacetyl chloride |
| CN101445445A (en) * | 2008-12-26 | 2009-06-03 | 山东胜达化工有限公司 | Production method of dichloroacetyl chloride with high conversion |
| WO2014108351A1 (en) * | 2013-01-11 | 2014-07-17 | Basf Se | Device and method for the continuous reaction of liquids with gases |
| CN111606790B (en) * | 2020-06-02 | 2023-06-09 | 武汉有机实业有限公司 | System and method for continuously producing high-quality high-selectivity benzaldehyde and benzoic acid by using jet loop reactor |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1196509A (en) * | 1967-09-20 | 1970-06-24 | Shell Int Research | A process for Oxidizing Trichloroethylene to Dichloroacetyl Chloride |
| CN112457176A (en) * | 2020-11-25 | 2021-03-09 | 山东华夏神舟新材料有限公司 | Method for continuously producing hexafluoroacetone |
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