A method for producing trichloroacetyl chloride

Abstract

The present invention discloses a method for producing trichloroacetyl chloride, specifically relating to a technical field, which comprises the following steps in sequence: (1) acid acylation reaction; (2) distillation purification; and (3) preparation of trichloroacetyl chloride. Beneficial effects: The present invention provides a method for producing trichloroacetyl chloride, which realizes the completion of the two-step reaction of acidification and acylation in a single reactor in a short time, is simple in process, and has a short reaction time. At the same time, there is no need to purchase chloroacetyl chloride, which reduces production costs and the requirements for storage equipment. The carbonization of acyl chloride to form hazardous waste is avoided, thereby saving the cost of treating hazardous waste, reducing the loss rate of acyl chloride gas, and improving the yield of the final product. The discharge amount of acyl chloride gas is also reduced, reducing the purchase cost and use cost of condensation equipment. The purity of the refined acyl chloride mixture is improved, ensuring that the material is not carbonized during the distillation process, and improving the yield of the product. The final yield of the trichloroacetyl chloride product can reach 99.1%.

Description

Technical Field

[0001] The invention relates to the technical field of trichloroacetyl chloride preparation, and specifically to a method for producing trichloroacetyl chloride. Background Art

[0002] Trichloroacetyl chloride is an important organic synthesis intermediate and acylating agent, widely used in the synthesis of pesticides, pharmaceuticals, organic intermediates, and fine chemicals. In the pesticide field, trichloroacetyl chloride is a key raw material and intermediate in the synthesis of the cyanamide family of insecticides. In the pharmaceutical field, it is mainly used in the synthesis of fungicides and polycyclic antibiotics. In the fine chemical field, polycyclic aromatic ethers prepared from trichloroacetyl chloride and biphenol are high-end additives for polyamides (nylon) and polyesters. Traditional methods for synthesizing trichloroacetyl chloride are categorized by raw materials into five main methods: trichloroacetaldehyde, chloroacetic acid, carbon tetrachloride, trichloroethylene, and tetrachloroethylene. The trichloroacetaldehyde route is highly polluting, has low yields, and corrodes pipelines, making it unsuitable for industrial production. The carbon tetrachloride, trichloroethylene, and tetrachloroethylene routes have harsh reaction conditions and are ideal for laboratory use, suitable for small-scale production but difficult to scale up. The chloroacetic acid route (see patent application number CN200410021491.4, entitled "A Method for Preparing Trichloroacetyl Chloride from Chloroacetic Acid Mother Liquor") is currently the most widely used route. This route uses chloroacetic acid mother liquor as a raw material. In an aqueous system, chloroacetic acid is reacted with sulfur monochloride to produce monochloroacetyl chloride and dichloroacetyl chloride, which are then chlorinated to produce trichloroacetyl chloride. The mother liquor is then recycled. However, the current process has certain limitations, such as the difficulty of removing impurities during the purification of the mother liquor and the long reaction cycle.

[0003] Existing application number is the patent of CN201510534467.9, discloses a method for producing trichloroacetyl chloride using chlorination material, wherein glacial acetic acid, chloroacetyl chloride, chlorine reaction chlorinated liquid are put into chlorination reactor; chlorinated liquid is squeezed into trichloroacetyl chloride primary and secondary chlorination reactor, sulfur chloride is added, logical chlorine reaction, the reacted material is put into crude distillation kettle and crudely distilled to obtain mixed acyl chloride semi-finished product; mixed acyl chloride is put into trichloroacetyl chloride triple chlorination reactor, pyridine and tetrachloropyridine are added, chlorine reaction is passed through, the reacted material is put into rectifying kettle and rectified, sampling and analyzing content more than 99%, and is put into finished product tank to obtain high-purity trichloroacetyl chloride. The present invention is simple to prepare, safe and reliable, low in price, solves the problem that chloroacetic acid mother liquor production sewage cannot be handled, product quality is better, and can be widely used in trichloroacetyl chloride production. However, the above scheme has the following problems: 1. The chloroacetyl chloride used is expensive in the market, and it is very volatile and difficult to store, so it has strict requirements on the storage equipment; 2. It needs to react in a chlorination reactor to generate a chlorinated solution (i.e., monochloroacetic acid and dichloroacetic acid), and then react in a primary or secondary chlorination reactor to generate an acyl chloride mixture. The process is complicated and the reaction time is long; 3. The reaction temperature is 130-135°C. The high reaction temperature easily leads to the carbonization of part of the acyl chloride to form hazardous waste, which increases the cost of hazardous waste treatment for enterprises and increases the loss of acyl chloride, resulting in a lower yield of the final product; and The high temperature leads to an increase in the amount of acyl chloride gas discharged from the top of the post-reactor, and the condensation equipment for condensing it has high requirements, which increases the purchase cost and use cost of the condensation equipment, and thus increases the cost of producing trichloroacetyl chloride for the company; 4. The acyl chloride mixed liquid semi-finished product is obtained by only crude distillation in an ordinary crude distillation kettle, and it is impossible to completely separate the disulfur dichloride and the acyl chloride mixture, and thus the purity of the mixed acyl chloride mixture cannot be guaranteed. In addition, the material in the crude distillation kettle continues to decrease in the later stage, and the vaporization amount continues to decrease. It is necessary to increase the temperature of the heating medium, so that part of the material is carbonized, which affects the yield of the refined acyl chloride mixed liquid. Summary of the Invention

[0004] The object of the present invention is to provide a method for producing trichloroacetyl chloride, which has a simple reaction process, improves the yield of the final product and reduces the production cost.

[0005] The purpose of the present invention is implemented by the following technical solution: a method for producing trichloroacetyl chloride, which comprises the following steps in sequence:

[0006] (1) Acid acylation reaction: acetic acid, chloroacetic acid and disulfur dichloride are added to a primary chlorination kettle in a mass ratio of 9-11:1:3-5, and chlorine gas is then introduced into the primary chlorination kettle at a flow rate of 80-150 mL / min. The reaction temperature in the primary chlorination kettle is controlled at 60°C-90°C, and the reaction time is controlled at 7-9 h to obtain a crude acyl chloride mixture with a purity of more than 98%.

[0007] In addition to easily generating acetyl chloride with disulfur dichloride and chlorine, acetic acid also reacts with chlorine to generate chloroacetic acid. Chloroacetic acid reacts with disulfur dichloride and chlorine to generate chloroacetyl chloride. Chloroacetyl chloride reacts with chlorine to generate dichloroacetyl chloride. The specific reaction equations are as follows:

[0008] a. The reaction equation for acetyl chloride generated by acetic acid, disulfur dichloride and chlorine:

[0009]

[0010] b. The reaction equation for acetic acid and chlorine to generate chloroacetic acid:

[0011]

[0012] c. The reaction equation for generating chloroacetyl chloride from chloroacetic acid, disulfur dichloride and chlorine:

[0013]

[0014] d. The reaction equation for the generation of dichloroacetyl chloride from chloroacetyl chloride and chlorine is:

[0015]

[0016] The acetyl chloride produced is affected by the electron-withdrawing group (-COCl) on its carbonyl carbon and has a weak electrophilicity, making it difficult to react with Cl + Direct reaction results in low reactivity of the carbonyl group (CH3COCl) of acetyl chloride for direct chlorination, and the reaction rate of generating chloroacetyl chloride is slow; because the chlorine atom (Cl) in the chloroacetic acid (ClCH2COOH) molecule is an electron-withdrawing group, the acidity of the carboxyl group is enhanced through the inductive effect. Its acidity is stronger than that of ordinary acetic acid, and it is easier to dissociate hydrogen ions (H + ), H + It can act as a proton catalyst to accelerate the departure of hydrogen from the α-carbon of acetyl chloride and promote the formation of the enol form. Specifically, H + It can first combine with the carbonyl oxygen of acetyl chloride to enhance the polarity of the carbonyl group, making it easier for α-hydrogen to be captured. If the formed carbon anion intermediate is adjacent to an electron-withdrawing group (such as Cl), the negative charge can be dispersed through the inductive effect, reducing the energy of the intermediate and the activation energy of the reaction, thereby accelerating the isomerization rate.

[0017] Acetyl chloride enol isomerization reaction equation:

[0018]

[0019] In the above enol formula, the presence of carbon-carbon double bond (C=C) and hydroxyl group (-OH) makes it have unique reactivity: the double bond π electron cloud density is high, and Cl is easily dissociated with chlorine. +Electrophilic addition occurs to generate a carbon cation intermediate; the hydroxyl group (-OH) in the intermediate is replaced by Cl - Substitution (or removal of H2O by proton transfer) ultimately forms chloroacetyl chloride.

[0020] The reaction can be simplified as:

[0021]

[0022] The enol isomerization process uses chloroacetic acid as a catalyst to reduce the activation energy of the reaction, increasing the concentration of the enol form in the system. More enol intermediates participate in the chlorination reaction, accelerating the formation of chloroacetyl chloride, effectively generating a mixture of monochloroacetyl chloride and dichloroacetyl chloride, while also effectively increasing the conversion rate of acetic acid.

[0023] (2) Purification by distillation: the crude acyl chloride mixture in step (1) is continuously fed into a first-stage distillation kettle for atmospheric distillation, wherein the distillation temperature is 70-90°C, the liquid phase continuously discharged from the bottom of the first-stage distillation kettle is fed into a second-stage distillation kettle for slight negative pressure distillation, wherein the distillation temperature is 90-100°C and the distillation pressure is -0.03~-0.05MPa, the gas phase extracted from the top of the second-stage distillation kettle is condensed in a purification condenser to obtain a refined acyl chloride mixture with a purity of more than 99%;

[0024] (3) Preparation of trichloroacetyl chloride: The acetyl chloride mixture in step (2) and pyridine are added to a secondary chlorination kettle at a mass ratio of 1:0.02-0.04, and chlorine is then introduced into the secondary chlorination kettle at a flow rate of 60-150 mL / min until the reaction is completed. The reacted material is then placed in a distillation kettle for rectification to obtain a finished trichloroacetyl chloride product with a purity of more than 99%.

[0025] Furthermore, step (1) further includes the following steps: the gas phase extracted from the top of the primary chlorination kettle is sequentially condensed through a primary condenser and a secondary condenser, the primary condenser condenses the raw material and sends it to the primary chlorination kettle to continue to participate in the reaction, and the secondary condenser condenses the acetyl chloride and sends it to the primary chlorination kettle to continue to participate in the reaction.

[0026] Furthermore, the condensation temperature of the primary condenser is 20-30°C, and the condensation temperature of the secondary condenser is -15~-30°C.

[0027] Furthermore, the purity of the acetic acid in step (1) is 99.8-99.9%, the purity of the chloroacetic acid is 89-91%, and the purity of the disulfur dichloride is 99.8-99.9%.

[0028] Furthermore, in step (2), the feed rate of the first-stage distillation kettle is 2-3 t / h; the feed rate of the second-stage distillation kettle is 1.7-2 t / h.

[0029] Furthermore, the condensation temperature of the purification condenser in step (2) is -15~-30°C.

[0030] Furthermore, the reaction temperature in the secondary chlorination reactor in step (3) is controlled at 90°C-115°C, and the reaction time is controlled at 30h-40h.

[0031] Furthermore, the distillation temperature of the distillation kettle in step (3) is 115-117° C., and the distillation time is 20 h.

[0032] Advantages of the present invention:

[0033] 1. The present invention provides a method for producing trichloroacetyl chloride, wherein an acylation reaction is carried out, i.e., acetic acid, chloroacetic acid and disulfur dichloride are added to a primary chlorination kettle, and then chlorine gas is introduced, so that the acidification and acylation reactions are completed in a single reactor in a short time. The process is simple and the reaction time is short. At the same time, there is no need to purchase chloroacetyl chloride, thereby reducing production costs and the requirements for storage equipment.

[0034] 2. The present invention provides a method for producing trichloroacetyl chloride. The acid acylation reaction temperature of the present invention is only 60°C-90°C, which avoids the carbonization of the acyl chloride to form hazardous waste, thereby saving the cost of treating hazardous waste, while reducing the loss rate of the acyl chloride gas and improving the yield of the final product; and reducing the discharge amount of the acyl chloride gas, thereby reducing the purchase cost and use cost of the condensation equipment.

[0035] 3. The present invention provides a method for producing trichloroacetyl chloride, wherein a crude acyl chloride mixture is first subjected to atmospheric distillation in a primary still to separate disulfur dichloride from the acyl chloride mixture, and then the acyl chloride mixture is subjected to slight negative pressure distillation in a secondary still to fully separate the impurity gases therein, thereby improving the purity of the refined acyl chloride mixture. At the same time, the distillation temperature of the secondary still is only 90-100°C, lower than 110°C, which ensures that the material is not carbonized during the distillation process, thereby improving the yield of the product. The final yield of the trichloroacetyl chloride product can reach 99.1%. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 It is a process system diagram of the present invention. DETAILED DESCRIPTION

[0038] The present invention will be further described in detail below by way of examples.

[0039] Example 1: A method for producing trichloroacetyl chloride, comprising the following steps in sequence:

[0040] (1) Acid acylation reaction: acetic acid, chloroacetic acid and disulfur dichloride were added to a primary chlorination kettle in a mass ratio of 9:1:3, and then chlorine was introduced into the primary chlorination kettle at a flow rate of 80 mL / min. The reaction temperature in the primary chlorination kettle was controlled at 60°C, and the reaction time was controlled at 7 h to obtain a crude acyl chloride mixture with a purity of 98.3%. The gas phase extracted from the top of the primary chlorination kettle was condensed in a primary condenser and a secondary condenser in turn. The primary condenser condensed the raw materials and sent them to the primary chlorination kettle to continue the reaction. The secondary condenser condensed acetyl chloride and sent it to the primary chlorination kettle to continue the reaction. The condensation temperature of the primary condenser was 20°C, and the condensation temperature of the secondary condenser was -15°C. Among them, the purity of acetic acid was 99.8%, the purity of chloroacetic acid was 89%, and the purity of disulfur dichloride was 99.8%.

[0041] (2) Purification by distillation: The crude acyl chloride mixture in step (1) is continuously fed into a first-stage distillation kettle for atmospheric distillation, wherein the distillation temperature is 70°C, and the liquid phase continuously discharged from the bottom of the first-stage distillation kettle is fed into a second-stage distillation kettle for slight negative pressure distillation, wherein the distillation temperature is 90°C and the distillation pressure is -0.03 MPa. The gas phase extracted from the top of the second-stage distillation kettle is condensed in a purification condenser to obtain a refined acyl chloride mixture with a purity of 99.3% and a yield of 98.7%. The feed rate of the first-stage distillation kettle is 2 t / h; the feed rate of the second-stage distillation kettle is 1.7 t / h; and the condensation temperature of the purification condenser is -15°C.

[0042] (3) Preparation of trichloroacetyl chloride: The acetyl chloride mixture in step (2) and pyridine were added to a secondary chlorination kettle at a mass ratio of 1:0.02, and chlorine gas was then introduced into the secondary chlorination kettle at a flow rate of 60 mL / min until the reaction was completed. The reacted material was then placed in a distillation kettle for distillation to obtain a trichloroacetyl chloride product with a purity of 99.5% and a yield of 98.4%. The reaction temperature in the secondary chlorination kettle was controlled at 90°C, and the reaction time was controlled at 30 h. The distillation temperature of the distillation kettle was 115°C, and the distillation time was 20 h.

[0043] Example 2: A method for producing trichloroacetyl chloride, comprising the following steps in sequence:

[0044] (1) Acid acylation reaction: acetic acid, chloroacetic acid and disulfur dichloride were added to a primary chlorination kettle in a mass ratio of 11:1:5, and then chlorine was introduced into the primary chlorination kettle at a flow rate of 150 mL / min. The reaction temperature in the primary chlorination kettle was controlled at 90 °C, and the reaction time was controlled at 9 h to obtain a crude acyl chloride mixture with a purity of 98.7%. The gas phase extracted from the top of the primary chlorination kettle was condensed in a primary condenser and a secondary condenser in turn. The primary condenser condensed the raw materials and sent them to the primary chlorination kettle to continue the reaction. The secondary condenser condensed acetyl chloride and sent it to the primary chlorination kettle to continue the reaction. The condensation temperature of the primary condenser was 30 °C, and the condensation temperature of the secondary condenser was -30 °C. Among them, the purity of acetic acid was 99.9%, the purity of chloroacetic acid was 91%, and the purity of disulfur dichloride was 99.9%.

[0045] (2) Purification by distillation: The crude acyl chloride mixture in step (1) is continuously fed into a first-stage distillation kettle for atmospheric distillation, wherein the distillation temperature is 90°C, and the liquid phase continuously discharged from the bottom of the first-stage distillation kettle is fed into a second-stage distillation kettle for slight negative pressure distillation, wherein the distillation temperature is 100°C and the distillation pressure is -0.05 MPa. The gas phase extracted from the top of the second-stage distillation kettle is condensed in a purification condenser to obtain a refined acyl chloride mixture with a purity of 99.5% and a yield of 98.9%. The feed rate of the first-stage distillation kettle is 3 t / h; the feed rate of the second-stage distillation kettle is 2 t / h; and the condensation temperature of the purification condenser is -30°C.

[0046] (3) Preparation of trichloroacetyl chloride: The acetyl chloride mixture in step (2) and pyridine were added to a secondary chlorination kettle at a mass ratio of 1:0.04, and chlorine gas was then introduced into the secondary chlorination kettle at a flow rate of 150 mL / min until the reaction was completed. The reacted material was then placed in a distillation kettle for distillation to obtain a trichloroacetyl chloride product with a purity of 99.8% and a yield of 98.6%. The reaction temperature in the secondary chlorination kettle was controlled at 115°C, and the reaction time was controlled at 40 h. The distillation temperature of the distillation kettle was 117°C, and the distillation time was 20 h.

[0047] Example 3: A method for producing trichloroacetyl chloride, comprising the following steps in sequence:

[0048] (1) Acid acylation reaction: acetic acid, chloroacetic acid and disulfur dichloride were added to a primary chlorination kettle in a mass ratio of 10:1:4, and then chlorine was introduced into the primary chlorination kettle at a flow rate of 115 mL / min. The reaction temperature in the primary chlorination kettle was controlled to 75 ° C, and the reaction time was controlled to 8 h to obtain a crude acyl chloride mixture with a purity of 99%; the gas phase extracted from the top of the primary chlorination kettle was condensed in a primary condenser and a secondary condenser in turn. The primary condenser condensed the raw materials and sent them to the primary chlorination kettle to continue the reaction. The secondary condenser condensed acetyl chloride and sent it to the primary chlorination kettle to continue the reaction. The condensation temperature of the primary condenser was 25 ° C, and the condensation temperature of the secondary condenser was -23 ° C. Among them, the purity of acetic acid was 99.9%, the purity of chloroacetic acid was 90%, and the purity of disulfur dichloride was 99.8%.

[0049] (2) Purification by distillation: The crude acyl chloride mixture in step (1) is continuously fed into a first-stage distillation kettle for atmospheric distillation, wherein the distillation temperature is 80°C, and the liquid phase continuously discharged from the bottom of the first-stage distillation kettle is fed into a second-stage distillation kettle for slight negative pressure distillation, wherein the distillation temperature is 95°C and the distillation pressure is -0.04 MPa. The gas phase extracted from the top of the second-stage distillation kettle is condensed in a purification condenser to obtain a refined acyl chloride mixture with a purity of 99.6% and a yield of 99.6%. The feed rate of the first-stage distillation kettle is 2.5 t / h; the feed rate of the second-stage distillation kettle is 1.8 t / h; and the condensation temperature of the purification condenser is -21°C.

[0050] (3) Preparation of trichloroacetyl chloride: The acetyl chloride mixture in step (2) and pyridine were added to a secondary chlorination kettle at a mass ratio of 1:0.03, and chlorine gas was then introduced into the secondary chlorination kettle at a flow rate of 110 mL / min until the reaction was completed. The reacted material was then placed in a distillation kettle for distillation to obtain a trichloroacetyl chloride product with a purity of 99.8% and a yield of 99.1%. The reaction temperature in the secondary chlorination kettle was controlled at 105°C, and the reaction time was controlled at 35 h. The distillation temperature of the distillation kettle was 116°C, and the distillation time was 20 h.

[0051] Comparative Example 1: The overall process was the same as Example 3, except that the reaction temperature in the primary chlorination reactor in step (1) was controlled at 120°C and the reaction time was controlled at 32 hours. A crude acyl chloride mixture with a purity of 83.4% was obtained. The purity of the refined acyl chloride mixture obtained was 90.1%, and the yield was 84.7%. The purity of the final trichloroacetyl chloride product obtained was 92.1%, and the yield was 82.6%.

[0052] Comparative Example 2: The overall process was the same as that of Example 3, except that in step (2), only the crude acyl chloride mixture was fed into a primary still for atmospheric distillation at a distillation temperature of 110°C. The vapor phase extracted from the top of the primary still was condensed in a purification condenser to obtain a refined acyl chloride mixture with a purity of 93.6% and a yield of 87.3%. The final trichloroacetyl chloride product had a purity of 94.7% and a yield of 85.2%.

[0053] As can be seen from the above, the trichloroacetyl chloride produced in Example 3 of the present invention has higher purity and yield than the trichloroacetyl chloride produced in Comparative Examples 1 and 2, thereby achieving an improvement in the quality of trichloroacetyl chloride.

[0054] The above is a preferred embodiment of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. A method for producing trichloroacetyl chloride, characterized in that, It includes the following steps in sequence: (1) Acid acylation reaction: acetic acid, chloroacetic acid and disulfur dichloride are added to a primary chlorination kettle in a mass ratio of 9-11:1:3-5, and then chlorine gas is introduced into the primary chlorination kettle at a flow rate of 80-150 mL / min. The reaction temperature in the primary chlorination kettle is controlled at 60°C-90°C, and the reaction time is controlled at 7-9 hours to obtain a crude acyl chloride mixture with a purity of more than 98%; (2) Purification by distillation: the crude acyl chloride mixture in step (1) is continuously fed into a first-stage distillation kettle for atmospheric distillation, wherein the distillation temperature is 70-90°C, the liquid phase continuously discharged from the bottom of the first-stage distillation kettle is fed into a second-stage distillation kettle for slight negative pressure distillation, wherein the distillation temperature is 90-100°C and the distillation pressure is -0.03~-0.05MPa, the gas phase extracted from the top of the second-stage distillation kettle is condensed in a purification condenser to obtain a refined acyl chloride mixture with a purity of more than 99%; (3) Preparation of trichloroacetyl chloride: The acetyl chloride mixture in step (2) and pyridine are added to a secondary chlorination kettle at a mass ratio of 1:0.02-0.04, and chlorine is then introduced into the secondary chlorination kettle at a flow rate of 60-150 mL / min until the reaction is completed. The reacted material is then placed in a distillation kettle for rectification to obtain a finished trichloroacetyl chloride product with a purity of more than 99%.

2. A method for producing trichloroacetyl chloride according to claim 1, characterized in that, Step (1) also includes the following steps: the gas phase extracted from the top of the primary chlorination kettle is condensed in sequence through a primary condenser and a secondary condenser, the primary condenser condenses the raw material and sends it to the primary chlorination kettle to continue to participate in the reaction, and the secondary condenser condenses the acetyl chloride and sends it to the primary chlorination kettle to continue to participate in the reaction.

3. A method for producing trichloroacetyl chloride according to claim 2, characterized in that, The condensation temperature of the primary condenser is 20-30°C, and the condensation temperature of the secondary condenser is -15~-30°C.

4. A method for producing trichloroacetyl chloride according to claim 1, characterized in that, The purity of the acetic acid in step (1) is 99.8-99.9%, the purity of the chloroacetic acid is 89-91%, and the purity of the disulfur dichloride is 99.8-99.9%.

5. A method for producing trichloroacetyl chloride according to claim 1, characterized in that, The feed rate of the first-stage distillation kettle in step (2) is 2-3 t / h; the feed rate of the second-stage distillation kettle is 1.7-2 t / h.

6. A method for producing trichloroacetyl chloride according to claim 1, characterized in that, The condensation temperature of the purification condenser in step (2) is -15~-30℃.

7. A method for producing trichloroacetyl chloride according to claim 1, characterized in that, The reaction temperature in the secondary chlorination reactor in step (3) is controlled at 90°C-115°C, and the reaction time is controlled at 30h-40h.

8. A method for producing trichloroacetyl chloride according to claim 1, characterized in that, The distillation temperature of the distillation kettle in step (3) is 115-117°C, and the distillation time is 20h.

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