Method for producing trichloroacetyl chloride

Abstract

The invention discloses a method for producing trichloroacetyl chloride, and particularly relates to the technical field of trichloroacetyl chloride preparation, which sequentially comprises the following steps: (1) acid acylation reaction; (2) distilling and purifying; and (3) preparing trichloroacetyl chloride. The method for producing trichloroacetyl chloride provided by the invention has the beneficial effects that two-step reaction of acidification and acylation can be completed in one reaction kettle in a short time, the process is simple, and the reaction time is short; meanwhile, chloracetyl chloride does not need to be purchased, so that the production cost and the requirement on storage equipment are reduced; the acyl chloride is prevented from being carbonized to form dangerous waste, so that the cost for treating the dangerous waste is saved, the loss rate of acyl chloride gas is reduced, and the yield of a final product is improved; the discharge amount of acyl chloride gas is reduced, and the purchase cost and the use cost of condensing equipment are reduced; and the purity of the refined acyl chloride mixed solution is improved, the material is prevented from being carbonized in the distillation process, the yield of the product is improved, and the yield of the final trichloroacetyl chloride finished product can reach 99.1%.

Description

Technical Field

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

[0002] Trichloroacetyl chloride is an important organic synthesis intermediate and acylating agent, and is widely used in the synthesis of pesticides, pharmaceuticals, organic intermediates and fine chemical products. In the pesticide field, trichloroacetyl chloride is an important raw material and intermediate for synthesizing insecticide cypermethrin series products; in the pharmaceutical field, it is mainly used for synthesizing fungicides and polycyclic antibiotics; in the fine chemical field, polycyclic aromatic ethers prepared from trichloroacetyl chloride and biphenol are high-grade auxiliaries in the two major fields of polyamide (nylon) and polyester; the traditional synthesis methods of trichloroacetyl chloride are mainly divided into five types according to raw materials: trichloroacetaldehyde route, chloroacetic acid route, carbon tetrachloride route, trichloroethylene route, and tetrachloroethylene route. Among them, the trichloroacetaldehyde route is seriously polluted, with low yield and corrosive pipelines, which is not suitable for industrial production. The reaction conditions of the carbon tetrachloride route, trichloroethylene and tetrachloroethylene routes are harsh. It is more ideal at the laboratory stage and suitable for small-scale production, but it is difficult to achieve large-scale production. The chloroacetic acid route (refer to the patent with application number CN200410021491.4 and name of the method for preparing trichloroacetyl chloride from chloroacetic acid mother liquor) is the currently widely used route. This route uses chloroacetic acid mother liquor as raw material. In an aqueous system, chloroacetic acid reacts with sulfur monochloride and chlorine to obtain monochloroacetyl chloride and dichloroacetyl chloride, and then acyl chlorination is carried out to obtain trichloroacetyl chloride, and the mother liquor is recycled. However, in the current process, in the refining of the mother liquor, the impurity removal process is relatively difficult, the reaction cycle is long, and there are certain limitations.

[0003] The existing patent with application number CN201510534467.9 discloses a method for producing trichloroacetyl chloride using chlorination material, wherein glacial acetic acid, chloroacetyl chloride, chlorine gas reaction chlorinated liquid are introduced into the chlorination reaction kettle; the chlorinated liquid is injected into the primary and secondary chlorination kettle of trichloroacetyl chloride, sulfur chloride is added, chlorine reaction is passed, the reacted material is put into the crude distillation kettle for crude distillation to obtain a mixed acyl chloride semi-finished product; the mixed acyl chloride is put into the three chlorination kettles of trichloroacetyl chloride, pyridine and tetrachloropyridine are added, chlorine gas reaction is passed, the reacted material is put into the distillation kettle for rectification, sampling and analysis of the content is more than 99%, and high-purity trichloroacetyl chloride is obtained by putting it into the finished product tank. The present invention is easy to prepare, safe and reliable, low in price, solves the problem that the chloroacetic acid mother liquor production sewage cannot be treated, the product quality is relatively good, and it can be widely used in trichloroacetyl chloride production. However, the above scheme has the following problems: 1. The market price of the chloroacetyl chloride used is expensive, 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 liquid (i.e., monochloroacetic acid and dichloroacetic acid), and then react in a primary and secondary chlorination reactor to generate an acyl chloride mixed liquid. The process is complicated and the reaction time is long; 3. The reaction temperature is 130-135°C. The high reaction temperature can easily lead to carbonization of part of the acyl chloride to form hazardous waste, which increases the cost of the enterprise to treat hazardous waste, and at the same time increases the loss of acyl chloride, which reduces the yield of the final product; and the reaction temperature is 130-135°C. The high temperature leads to an increase in the amount of acyl chloride gas discharged from the top of the post-reaction kettle, 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 the company's production of trichloroacetyl chloride; 4. The acyl chloride mixed liquid semi-finished product is obtained by only crude distillation in an ordinary crude distillation kettle, and the disulfur dichloride and the acyl chloride mixture cannot be completely separated, and thus the purity of the mixed acyl chloride mixed liquid cannot be guaranteed. In addition, the material in the crude distillation kettle is continuously reduced in the later stage, and then the vaporization amount is continuously reduced, so it is necessary to increase the temperature of the heating medium, so that part of the material is carbonized, affecting 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 scheme: a method for producing trichloroacetyl chloride, which comprises the following steps in sequence: (1) Acid acylation reaction: acetic acid, chloroacetic acid and disulfur dichloride are added into 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 7-9h to obtain a crude acyl chloride mixed solution with a purity of more than 98%.

[0006] In addition to easily forming acetyl chloride with sulfur dichloride and chlorine, acetic acid also reacts with chlorine to form chloroacetic acid. Chloroacetic acid reacts with sulfur dichloride and chlorine to form chloroacetyl chloride, and chloroacetyl chloride reacts with chlorine to form dichloroacetyl chloride. The specific reaction equations are as follows: a. Reaction equation for the formation of acetyl chloride from acetic acid, sulfur dichloride and chlorine:

[0007] b. Reaction equation for the formation of chloroacetic acid from acetic acid and chlorine:

[0008] c. Reaction equation for the formation of chloroacetyl chloride from chloroacetic acid, sulfur dichloride and chlorine:

[0009] d. Reaction equation for the formation of dichloroacetyl chloride from chloroacetyl chloride and chlorine:

[0010] Among them, the produced acetyl chloride has a weak electrophilicity due to the influence of the electron-withdrawing group (-COCl) on its carbonyl carbon, making it difficult to directly react with Cl + directly. As a result, the reaction activity of directly chlorinating the carbonyl form (CH3COCl) of acetyl chloride is low, and thus the rate of reaction to form chloroacetyl chloride is slow. In the molecule of chloroacetic acid (ClCH2COOH), the chlorine atom (Cl) is an electron-withdrawing group, which enhances the acidity of the carboxyl group through the inductive effect. Its acidity is stronger than that of ordinary acetic acid and is more likely to dissociate into hydrogen ions (H + ). The H + dissociated from chloroacetic acid can act as a proton catalyst to accelerate the departure of the hydrogen on the α-carbon of acetyl chloride and promote the formation of the enol form. Specifically, H + can first combine with the carbonyl oxygen of acetyl chloride to enhance the polarity of the carbonyl group, making the α-hydrogen more easily abstracted. If the carbon anion intermediate formed 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 lowering the reaction activation energy, thereby accelerating the isomerization rate.

[0011] Reaction equation for the enol isomerization of acetyl chloride:

[0012] In the above enol form, the presence of the carbon-carbon double bond (C=C) and the hydroxyl group (-OH) endows it with unique reaction activity: the π electron cloud density of the double bond is relatively high, making it easy to undergo electrophilic addition with the Cl + dissociated from chlorine to form a carbocation intermediate; the hydroxyl group (-OH) in the intermediate is substituted by Cl - (or H2O is removed through proton transfer), and finally chloroacetyl chloride is formed.

[0013] The reaction formula can be simplified to:

[0014] The enol isomerization process reduces the reaction activation energy through the catalysis of chloroacetic acid, increasing the concentration of the enol form in the system. More enol intermediates participate in the chlorination reaction, which can accelerate the formation rate of chloroacetyl chloride, that is, achieving the effect of rapidly generating a mixture of monochloroacetyl chloride and dichloroacetyl chloride, and at the same time effectively improving the conversion rate of acetic acid.

[0015] (2) Distillation and purification: Continuously feed the crude acyl chloride mixture in step (1) into a primary distillation kettle for atmospheric distillation, where the distillation temperature is 70 - 90°C. The liquid phase continuously discharged from the bottom of the primary distillation kettle enters a secondary distillation kettle for micro-negative pressure distillation, where the distillation temperature is 90 - 100°C and the distillation pressure is -0.03 to -0.05 MPa. The gas phase drawn from the top of the secondary distillation kettle is condensed by a purification condenser to obtain a refined acyl chloride mixture with a purity of over 99%. (3) Preparation of trichloroacetyl chloride: Add the refined acyl chloride mixture in step (2) and pyridine into a secondary chlorination kettle according to a mass ratio of 1:0.02 - 0.04. Then, introduce chlorine gas into the secondary chlorination kettle at a flow rate of 60 - 150 mL / min until the reaction ends. Then, discharge the reacted material into a rectification kettle for rectification to obtain a trichloroacetyl chloride product with a purity of over 99%.

[0016] Furthermore, step (1) also includes the following steps: The gas phase drawn from the top of the primary chlorination kettle is successively condensed by a primary condenser and a secondary condenser. The primary condenser condenses the raw materials and sends them back into the primary chlorination kettle to continue participating in the reaction. The secondary condenser condenses acetyl chloride and sends it back into the primary chlorination kettle to continue participating in the reaction.

[0017] Furthermore, the condensation temperature of the primary condenser is 20 - 30°C, and the condensation temperature of the secondary condenser is -15 to -30°C.

[0018] 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%.

[0019] Furthermore, the feed rate of the primary distillation kettle in step (2) is 2 - 3 t / h; the feed rate of the secondary distillation kettle is 1.7 - 2 t / h.

[0020] Furthermore, the condensation temperature of the purification condenser in step (2) is -15 to -30°C.

[0021] Further, the reaction temperature in the secondary chlorination kettle in step (3) is controlled at 90°C - 115°C, and the reaction time is controlled for 30h - 40h.

[0022] Further, the rectification temperature of the rectification kettle in step (3) is 115 - 117°C, and the rectification time is 20h.

[0023] Advantages of the present invention: 1. The present invention provides a method for producing trichloroacetyl chloride. Through an acylation reaction, that is, adding acetic acid, chloroacetic acid, and disulfur dichloride into the primary chlorination kettle and then introducing chlorine gas, the acidification and acylation steps are completed in a short time in one reaction kettle. The process is simple and the reaction time is short. At the same time, there is no need to purchase chloroacetyl chloride, reducing the production cost and the requirements for storage equipment.

[0024] 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, avoiding the formation of hazardous waste due to the carbonization of acyl chloride, thereby saving the cost of treating hazardous waste. At the same time, the loss rate of acyl chloride gas is reduced, the yield of the final product is increased, the discharge amount of acyl chloride gas is reduced, and the purchase cost and use cost of condensation equipment are reduced.

[0025] 3. The present invention provides a method for producing trichloroacetyl chloride. The crude acyl chloride mixture is first separated from the disulfur dichloride and acyl chloride mixture through atmospheric distillation in a primary distillation kettle, and then the acyl chloride mixture undergoes micro-vacuum distillation in a secondary distillation kettle to fully separate the impurity gases therein, improving the purity of the refined acyl chloride mixture. At the same time, the distillation temperature of the secondary distillation kettle is only 90 - 100°C, lower than 110°C, ensuring that the materials are not carbonized during the distillation process, increasing the yield of the product. Finally, the yield of the trichloroacetyl chloride finished product can reach 99.1%. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 It is the process system diagram of the present invention. Detailed Embodiments

[0028] The following will further elaborate on the present invention through embodiments.

[0029] Example 1: A method for producing trichloroacetyl chloride, which successively includes the following steps: (1) Acid acylation reaction: Acetic acid, chloroacetic acid and sulfur dichloride are added to the primary chlorination kettle according to a mass ratio of 9:1:3. Then, chlorine gas is introduced into the primary chlorination kettle at a flow rate of 80 mL / min. The reaction temperature in the primary chlorination kettle is controlled at 60 °C, and the reaction time is controlled for 7 h to obtain a crude acyl chloride mixture with a purity of 98.3%. The gas phase taken out from the top of the primary chlorination kettle is condensed successively through a primary condenser and a secondary condenser. The primary condenser condenses the raw materials and sends them back into the primary chlorination kettle to continue participating in the reaction. The secondary condenser condenses acetyl chloride and sends it back into the primary chlorination kettle to continue participating in the reaction. The condensation temperature of the primary condenser is 20 °C, and the condensation temperature of the secondary condenser is -15 °C. Among them, the purity of acetic acid is 99.8%, the purity of chloroacetic acid is 89%, and the purity of sulfur dichloride is 99.8%.

[0030] (2) Distillation and purification: The crude acyl chloride mixture in step (1) is continuously fed into the primary distillation kettle for atmospheric distillation. The distillation temperature is 70 °C. The liquid phase continuously discharged from the bottom of the primary distillation kettle enters the secondary distillation kettle for vacuum distillation. The distillation temperature is 90 °C, and the distillation pressure is -0.03 MPa. The gas phase taken out from the top of the secondary distillation kettle is condensed by a purification condenser to obtain a refined acyl chloride mixture with a purity of 99.3% and a yield of 98.7%. Among them, the feeding rate of the primary distillation kettle is 2 t / h; the feeding rate of the secondary distillation kettle is 1.7 t / h; the condensation temperature of the purification condenser is -15 °C. (3) Preparation of trichloroacetyl chloride: The refined acyl chloride mixture in step (2) and pyridine are added to the secondary chlorination kettle according to a mass ratio of 1:0.02. Then, chlorine gas is introduced into the secondary chlorination kettle at a flow rate of 60 mL / min until the reaction ends. Then, the reacted material is put into a rectification kettle for rectification to obtain trichloroacetyl chloride products with a purity of 99.5% and a yield of 98.4%. Among them, the reaction temperature in the secondary chlorination kettle is controlled at 90 °C, and the reaction time is controlled for 30 h; the rectification temperature of the rectification kettle is 115 °C, and the rectification time is 20 h.

[0031] Example 2: A method for producing trichloroacetyl chloride, which successively includes the following steps: (1) Acid acylation reaction: Acetic acid, chloroacetic acid and sulfur dichloride were added to the primary chlorination kettle according to a mass ratio of 11:1:5. Then, chlorine gas 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 for 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 successively through a primary condenser and a secondary condenser. The primary condenser condensed the raw materials and sent them back to the primary chlorination kettle to continue participating in the reaction. The secondary condenser condensed acetyl chloride and sent it back to the primary chlorination kettle to continue participating in 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 sulfur dichloride was 99.9%.

[0032] (2) Distillation and purification: The crude acyl chloride mixture in step (1) was continuously fed into the primary distillation kettle for atmospheric distillation. The distillation temperature was 90 °C. The liquid phase continuously discharged from the bottom of the primary distillation kettle entered the secondary distillation kettle for micro-vacuum distillation. The distillation temperature was 100 °C, and the distillation pressure was -0.05 MPa. The gas phase extracted from the top of the secondary distillation kettle was condensed by a purification condenser to obtain a refined acyl chloride mixture with a purity of 99.5% and a yield of 98.9%. Among them, the feed rate of the primary distillation kettle was 3 t / h; the feed rate of the secondary distillation kettle was 2 t / h; the condensation temperature of the purification condenser was -30 °C. (3) Preparation of trichloroacetyl chloride: The refined acyl chloride mixture in step (2) and pyridine were added to the secondary chlorination kettle according to a mass ratio of 1:0.04. Then, chlorine gas was introduced into the secondary chlorination kettle at a flow rate of 150 mL / min until the reaction ended. Then, the reaction product was put into the rectification kettle for rectification to obtain trichloroacetyl chloride product with a purity of 99.8% and a yield of 98.6%. Among them, the reaction temperature in the secondary chlorination kettle was controlled at 115 °C, and the reaction time was controlled for 40 h; the rectification temperature of the rectification kettle was 117 °C, and the rectification time was 20 h.

[0033] Example 3: A method for producing trichloroacetyl chloride, which successively includes the following steps: (1) Acid acylation reaction: Acetic acid, chloroacetic acid, and sulfur dichloride were added to the primary chlorination kettle in a mass ratio of 10:1:4. Then, chlorine gas 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 at 75°C, and the reaction time was controlled for 8 h to obtain a crude acyl chloride mixture with a purity of 99%. The gas phase drawn from the top of the primary chlorination kettle was successively condensed by a primary condenser and a secondary condenser. The primary condenser condensed the raw materials and sent them back to the primary chlorination kettle to continue participating in the reaction. The secondary condenser condensed acetyl chloride and sent it back to the primary chlorination kettle to continue participating in 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 sulfur dichloride was 99.8%.

[0034] (2) Distillation and purification: The crude acyl chloride mixture in step (1) was continuously fed into the primary distillation kettle for atmospheric distillation. The distillation temperature was 80°C. The liquid phase continuously discharged from the bottom of the primary distillation kettle entered the secondary distillation kettle for vacuum distillation. The distillation temperature was 95°C, and the distillation pressure was -0.04 MPa. The gas phase drawn from the top of the secondary distillation kettle was condensed by a purification condenser to obtain a refined acyl chloride mixture with a purity of 99.6% and a yield of 99.6%. Among them, the feed rate of the primary distillation kettle was 2.5 t / h; the feed rate of the secondary distillation kettle was 1.8 t / h; the condensation temperature of the purification condenser was -21°C. (3) Preparation of trichloroacetyl chloride: The refined acyl chloride mixture in step (2) and pyridine were added to the secondary chlorination kettle in a mass ratio of 1:0.03. Then, chlorine gas was introduced into the secondary chlorination kettle at a flow rate of 110 mL / min until the reaction ended. Then, the reaction mixture was discharged into a rectification kettle for rectification to obtain trichloroacetyl chloride product with a purity of 99.8% and a yield of 99.1%. Among them, the reaction temperature in the secondary chlorination kettle was controlled at 105°C, and the reaction time was controlled for 35 h; the rectification temperature of the rectification kettle was 116°C, and the rectification time was 20 h.

[0035] Comparative Example 1: The overall method was the same as that of Example 3, except that the reaction temperature in the primary chlorination kettle in step (1) was controlled at 120°C, and the reaction time was controlled for 32 h to obtain a crude acyl chloride mixture with a purity of 83.4%. The purity of the obtained refined acyl chloride mixture was 90.1%, and the yield was 84.7%. The purity of the finally obtained trichloroacetyl chloride product was 92.1%, and the yield was 82.6%.

[0036] Comparative Example 2: The overall method is the same as that of Example 3, except that in step (2), only the crude acyl chloride mixture is fed into the first-stage distillation still for atmospheric distillation, where the distillation temperature is 110°C. The gas phase collected from the top of the first-stage distillation still is condensed by a purification condenser to obtain a refined acyl chloride mixture with a purity of 93.6% and a yield of 87.3%. The purity of the final trichloroacetyl chloride product obtained is 94.7%, and the yield is 85.2%.

[0037] As can be seen from the above, the trichloroacetyl chloride produced in Example 3 of the present invention has a higher purity and yield than those produced in Comparative Example 1 and Comparative Example 2, thereby achieving an improvement in the quality of trichloroacetyl chloride.

[0038] The above are the preferred embodiments of the present invention. For those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for producing trichloroacetyl chloride, characterized in that, It successively includes the following steps: (1) Acid acylation reaction: Acetic acid, chloroacetic acid and sulfur dichloride are added to a primary chlorination kettle according to a mass ratio of 9-11:1:3-5. 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 h to obtain a crude acyl chloride mixture with a purity of over 98%; (2) Distillation and purification: The crude acyl chloride mixture in step (1) is continuously fed into a primary distillation kettle for atmospheric distillation, where the distillation temperature is 70-90°C. The liquid phase continuously discharged from the bottom of the primary distillation kettle enters a secondary distillation kettle for micro-vacuum distillation, where the distillation temperature is 90-100°C and the distillation pressure is -0.03~-0.05 MPa. The gas phase taken out from the top of the secondary distillation kettle is condensed by a purification condenser to obtain a refined acyl chloride mixture with a purity of over 99%; (3) Preparation of trichloroacetyl chloride: The refined acyl chloride mixture in step (2) and pyridine are added to a secondary chlorination kettle according to a mass ratio of 1:0.02-0.

04. Then, chlorine gas is introduced into the secondary chlorination kettle at a flow rate of 60-150 mL / min until the reaction ends. Then, the reacted material is put into a rectification kettle for rectification to obtain a trichloroacetyl chloride product with a purity of over 99%.

2. The method for producing trichloroacetyl chloride according to claim 1, characterized in that, The following steps are also included in step (1): The gas phase taken out from the top of the primary chlorination kettle is successively condensed by a primary condenser and a secondary condenser. The primary condenser condenses the raw materials and sends them back into the primary chlorination kettle to continue participating in the reaction. The secondary condenser condenses acetyl chloride and sends it back into the primary chlorination kettle to continue participating in the reaction.

3. The method for producing trichloroacetyl chloride according to claim 2, wherein 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 sulfur dichloride is 99.8-99.9%.

5. A method for producing trichloroacetyl chloride according to claim 1, wherein the feed rate of the primary distillation kettle in step (2) is 2-3 t / h; the feed rate of the secondary 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°C.

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

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

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