Preparation method of 3 '-(trifluoromethyl) acetophenone (TFMAP)

Abstract

A system (100) and method (300) for preparing 3 '-(trifluoromethyl) acetophenone (TFMAP) is disclosed, wherein the disclosed TFMAP provides an appearance ranging from a colorless liquid to an orange liquid, a purity of 99-99.9%, and a yield of 60-90%. A process (300) for preparing TFMAP includes preparing a diazonium solution from reacting 3-aminotrifluorotoluene with sulfuric acid, then adding the diazonium solution in batches with acetaldehyde oxime to obtain 3 '-(trifluoromethyl) acetophenone oxime, which is further treated with a 30% HCl solution and distilled to obtain 3'-(trifluoromethyl) acetophenone with improved yield and purity.

Description

[0001] Cross-references to related applications and priorities

[0002] This application claims priority to Indian Patent Application No. 202221028493 filed on May 18, 2022, which is incorporated herein by reference. Technical Field

[0003] The subject matter described herein generally relates to methods for preparing 3'-(trifluoromethyl)acetophenone (TFMAP). In particular, the subject matter of the present application relates to the preparation of high purity 3'-(trifluoromethyl)acetophenone (TFMAP) with improved yield and purity. Background Art

[0004] Acetophenone derivatives such as 3'-(trifluoromethyl)acetophenone (hereinafter alternatively referred to as "TFMAP") are useful as intermediates in the synthesis of agrochemical compounds such as insecticidal and fungicidal compounds. TFMAP is used as an intermediate in the preparation of trifloxystrobin, which is used as an insecticide.

[0005]

[0006] In the prior art, conventional methods for preparing TFMAP have deficiencies in many aspects, such as product loss, reactant and reaction intermediate loss, time consumption and large amount of energy consumption.

[0007] Several patents have been filed to prepare 3'-(trifluoromethyl)acetophenone using trifluoromethylbenzene and n-butyllithium as starting materials. However, trifluoromethylbenzene and n-butyllithium are pyrophoric in nature, making it challenging to manage them on an industrial scale. Furthermore, handling trifluoromethylbenzene and n-butyllithium on a commercial scale raises serious safety concerns, as they can severely decompose if exposed to air or moisture. Therefore, such techniques are neither practical nor safe to use on a large scale.

[0008] In addition, some processes use 60% sulfuric acid in the hydrolysis step, resulting in lower yields due to increased pollutant production and higher COD in the waste effluent. The use of concentrated sulfuric acid results in higher caustic consumption standards to maintain the pH of the reaction mass, thereby increasing production costs.

[0009] Therefore, there has long been a need to develop an economical process for preparing 3'-(trifluoromethyl)acetophenone (TFMAP) product, which minimizes reactant consumption, reactant and reaction intermediate losses, thereby improving the overall purity and yield of the final product, i.e., 3'-(trifluoromethyl)acetophenone (TFMAP).

[0010] Purpose of the Invention

[0011] The main purpose of the present application is to provide a system for preparing 3'-(trifluoromethyl)acetophenone (TFMAP), which can provide TFMAP with high yield and high purity.

[0012] Another object of the present application is to provide a method capable of providing high yield and high purity TFMAP.

[0013] Yet another object of the present application is to provide a process capable of selectively using AAO (50% solution in water) for easy and safe handling at commercial scale.

[0014] Another object of the present application is to provide a method for simultaneously recovering solvent and by-products such as 3-hydroxytrifluorotoluene.

[0015] Yet another object of the present application is to provide a method for preparing 3'-(trifluoromethyl)acetophenone (TFMAP) with minimal effluent generation. Summary of the invention

[0016] This Summary is provided to introduce concepts related to systems and methods for preparing 3'-(trifluoromethyl)acetophenone (TFMAP).This Summary is not intended to identify essential features of the claimed subject matter, nor is it intended to be used to determine or limit the scope of the disclosed subject matter.

[0017] According to an embodiment of the present subject matter, a system and method are disclosed that can provide high yield and high purity TFMAP.

[0018] In one embodiment, a system for preparing 3'-(trifluoromethyl)acetophenone (TFMAP) is disclosed. The system may include: a first reactor capable of reacting 3-aminobenzotrifluoride and sulfuric acid in the presence of toluene and sodium nitrite (NaNO2) solution to prepare a diazo solution; a second reactor capable of mixing and adding the acetaldehyde oxime solution and the diazo solution in lot-wise manner, and then adding other reactants to obtain an aqueous layer and an organic layer, i.e., 3'-(trifluoromethyl)acetophenone oxime; a third reactor capable of hydrolyzing 3'-(trifluoromethyl)acetophenone oxime with 30% HCl to obtain 3'-(trifluoromethyl)acetophenone (TFMAP); and a distillation unit associated with the third reactor, configured to obtain refined 3'-(trifluoromethyl)acetophenone (TFMAP).

[0019] In yet another embodiment, the 3'-(trifluoromethyl)acetophenone (TFMAP) product obtained by practicing the systems and methods disclosed herein includes: an appearance ranging from a colorless liquid to an orange liquid; a purity of 99-99.9%; and a yield of 60-90%.

[0020] In another embodiment, a method for preparing 3-(trifluoromethyl)acetophenone (TFMAP) is disclosed, comprising the following steps. The method may include the step of introducing water into a first reactor, and then reacting 3-aminotrifluorotoluene (3-ABTF) with sulfuric acid (H2SO4) in the presence of toluene and sodium nitrite (NaNO2) solution to obtain a reaction mass A. The next step may include adding aminosulfonic acid dissolved in water to the reaction mass A under continuous stirring, and then heating at 7-8°C to obtain a diazo solution in the first reactor. The method may include coupling the diazo solution and the acetaldehyde oxime solution in a batch manner in a second reactor, and continuously stirring for 4-5 hours, and then adding other reactants to obtain a reaction mass B having an aqueous layer and an organic layer of 3'-(trifluoromethyl)acetophenone oxime. The method may further include the steps of raising the temperature to 35-40°C to separate the organic layer from the aqueous layer in the reaction mass B, and then washing the organic layer with a 30% hydrochloric acid solution to obtain 3'-(trifluoromethyl)acetophenone oxime. In the next step, the method may include the step of feeding 3'-(trifluoromethyl)acetophenone oxime into the third reactor and then adding 30% hydrochloric acid solution under continuous stirring to obtain crude 3'-(trifluoromethyl)acetophenone (TFMAP) containing an aqueous effluent layer and a crude organic layer. The method may also include the step of distilling the crude organic layer of the reaction mass B in a distillation unit to obtain refined 3'-(trifluoromethyl)acetophenone (TFMAP).

[0021] In yet another embodiment, 3-(trifluoromethyl)acetophenone (TFMAP) is prepared by a batch process.

[0022] List of abbreviations

[0023] 3-ABTF: 3-aminobenzotrifluoromethane

[0024] H2SO4: sulfuric acid

[0025] NaNO2: Sodium Nitrite

[0026] ETP: Effluent plant treatment

[0027] TFMAP: 3'-(trifluoromethyl)acetophenone

[0028] AAO: acetaldehyde oxime

[0029] HCl: hydrochloric acid BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The specific embodiments will be described with reference to the accompanying drawings. In the accompanying drawings, the leftmost digit of a reference number identifies the drawing in which the reference number first appears. The same numerals are used throughout the drawings to refer to the same features and components.

[0031] Figure 1 A system (100) for preparing 3'-(trifluoromethyl)acetophenone according to an embodiment of the present application is shown.

[0032] Figure 2 A workflow diagram of a system (100) for preparing 3'-(trifluoromethyl)acetophenone according to an embodiment of the present application is shown.

[0033] Figure 3 A method (300) for preparing 3'-(trifluoromethyl)acetophenone according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0034] Throughout the specification, references to "various embodiments," "some embodiments," "one embodiment," or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the phrases "in various embodiments," "in some embodiments," "in one embodiment," or "in an embodiment" appearing throughout the specification do not necessarily all refer to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner.

[0035] The words "include," "have," "contain," and "comprises," and other forms thereof, are intended to be equivalent in meaning and to be open ended in that one or more items followed by any of these words are not meant to be an exhaustive list of the one or more items, or to be limited to only the listed one or more items. It must also be noted that the singular forms "a," "an," and "the" include the plural unless the context clearly dictates otherwise. Although the practice or testing of embodiments of the present disclosure may use any processes similar or equivalent to those described herein, exemplary processes are described. The disclosed embodiments are merely examples of the present disclosure, which may be embodied in various forms.

[0036] Various modifications to the embodiments may be apparent to those skilled in the art, and the general principles herein may be applied to other embodiments. However, it will be readily appreciated by those skilled in the art that the present disclosure is not intended to be limited to the embodiments shown, but rather to be given the widest scope consistent with the principles and features described herein. The specific embodiments of the present application will be described below with reference to the accompanying drawings.

[0037] In one embodiment of the present application, reference Figure 1, shows a system (100) for preparing 3'-(trifluoromethyl)acetophenone (TFMAP) according to an embodiment of the present application.

[0038] In one embodiment of the present application, by referring to Figure 1 and Figure 2 , a system (100) for preparing 3'-(trifluoromethyl)acetophenone (TFMAP) is disclosed. The system (100) may include a first reactor (104) capable of preparing a diazo solution by reacting 3-aminobenzotrifluoride (obtained from tank (101)) and sulfuric acid in the presence of toluene and sodium nitrite (NaNO2) solution obtained from tank (102). The system (100) may also include a second reactor (105) capable of batch-mixing the acetaldehyde oxime solution obtained from tank (103) with the diazo solution added to the second reactor (105) in batches in a predetermined amount, and then adding other reactants, i.e., a mixture of water, copper (II) sulfate, glacial acetic acid, and toluene obtained from tank (107) to obtain 3'-(trifluoromethyl)acetophenone oxime.

[0039] The system (100) may further include a third reactor (110) capable of hydrolyzing 3'-(trifluoromethyl)acetophenone oxime with 30% HCl from tank (108) to obtain 3'-(trifluoromethyl)acetophenone (TFMAP). The third reactor (110) is also configured to separate the aqueous effluent layer and the crude organic layer of 3'-(trifluoromethyl)acetophenone (TFMAP). In addition, the third reactor is configured to transfer the aqueous effluent layer to an effluent treatment device (112) capable of recovering additional 3'-(trifluoromethyl)acetophenone by treating the aqueous layer from the third reactor (105).

[0040] In one embodiment, the system (100) may include a tank (111) configured to perform alkaline washing on the crude organic layer of 3'-(trifluoromethyl)acetophenone (TFMAP) from the third reactor (110) using 3-10% and preferably 3-7% NaOH added to the alkaline washing tank (111) from the reactor (106) to remove residual acidity and transfer the crude organic layer of TFMAP to a distillation unit (113).

[0041] The system (100) may be further connected to a distillation unit (113) associated with the third reactor (110), which is configured to obtain refined and pure 3'-(trifluoromethyl)acetophenone (TFMAP).

[0042] In another embodiment of the present application, reference Figure 3, shows a method (300) for preparing 3'-(trifluoromethyl)acetophenone (TFMAP) according to an embodiment of the present application. The method (300) for preparing 3'-(trifluoromethyl)acetophenone (TFMAP) includes various steps and is further divided into four stages. In one embodiment, the method (300) is a batch process that is particularly capable of large-scale production of TFMAP.

[0043] In one embodiment of the present application, in the first stage A, the method (300) may include the step of diazotizing 3-aminotrifluorotoluene (3-ABTF) to obtain a diazo solution. In the second stage B, the method may include the step of coupling the diazo solution with an acetaldehyde oxime solution to obtain 3'-(trifluoromethyl)acetophenone oxime. In the third stage C, the method (300) may include hydrolyzing 3'-(trifluoromethyl)acetophenone oxime to obtain 3'-(trifluoromethyl)acetophenone (TFMAP). In the fourth stage D, the crude organic layer of 3'-(trifluoromethyl)acetophenone is distilled to obtain refined 3'-(trifluoromethyl)acetophenone (TFMAP).

[0044] The first stage of preparing the diazo solution (diazotization reaction) - stage (A)

[0045] In one embodiment of the present application, the method (300) may include a first stage (A): a stage of preparing a diazo solution in a first reactor (104). The first stage (A) may include the step of introducing (301) water into the first reactor (104), and then reacting 3-aminotrifluorotoluene (3-ABTF) with sulfuric acid (H2SO4) in the presence of toluene and sodium nitrite (NaNO2) solution to obtain a reaction substance A.

[0046] The first stage (A) may also include stirring the reaction mass obtained above for 1-4 hours, preferably a predetermined time of 30-45 minutes, and maintaining the temperature of the diazotization reaction at -5-10°C, preferably 0-2°C. The first stage (A) may also include adding (302) aminosulfonic acid dissolved in water to decompose excess sodium nitrite and remove excess NOx. In an optional embodiment, sodium silicate is added to the reaction to prevent vitrification of the reactor and ensure safety. In one embodiment, the first stage (A) is enabled to recover 90-98% of toluene from the reaction. The first stage (A) may also include the step of cooling the diazo solution and storing it at 7-8°C.

[0047] Second stage (coupling) for the preparation of 3'-(trifluoromethyl)acetophenone oxime - stage (B)

[0048] In another embodiment of the present application, the method (300) may include a second stage (B): coupling (303) the diazo solution with the acetaldehyde oxime solution from the tank (103) in the second reactor (105) to obtain B 3'-(trifluoromethyl)acetophenone oxime (reaction substance B). The second stage (B) may include the step of adding 0.8 to 1.5 molar equivalents of acetaldehyde oxime solution (50% solution in water) in batches to a reaction mixture comprising a diazo solution, water, copper (II) sulfate, glacial acetic acid and toluene at a constant temperature of 0-2°C and stirring for 4-5 hours. Acetaldehyde oxime (AAO) is sensitive to the pH of the reaction, and AAO will degrade simultaneously at acidic pH, resulting in a lower yield. The method of adding AAO in batches and then adding the diazo solution in batches can keep a specific concentration of AAO available and recover the product 3-hydroxytrifluorotoluene, thereby improving the yield and reducing pollution compared to conventional factory processes.

[0049] In addition, the second stage (B) may include the following steps: repeating the slow addition of 25% of the diazo solution in batches at least four times by maintaining the temperature at 0-2°C and the pH in the range of 2-2.5, and then adding the acetaldehyde oxime solution (50% solution in water) from the tank (103) during each slow addition, wherein during the addition of the acetaldehyde oxime solution, the pH of the reaction mass can be raised to 3-3.5 by adding 30% NaOH during each slow addition, wherein the reaction mass is stirred for another 4-5 hours. 4-5 parts of acetaldehyde oxime are added in the first addition, followed by 1-2 parts in the second and third additions, and finally 2-3 parts in the fourth addition, with the total addition amount divided into 8-12 parts. In one embodiment, for the batch addition of acetaldehyde oxime, the pH of the first and second batches is adjusted to between 2-2.5, and the pH of the third and fourth batches is adjusted to between 3-3.5.

[0050]

[0051] The second stage (B) may also include a step of separating the bottom aqueous layer and the remaining organic layer by increasing (304) the temperature to 35-40°C.

[0052] The third stage (hydrolysis) of the preparation of 3'-(trifluoromethyl)acetophenone (TFMAP) - stage (C)

[0053] In another embodiment of the present application, the method (300) may include a third stage (C) of hydrolyzing 3'-(trifluoromethyl)acetophenone oxime to obtain 3'-(trifluoromethyl)acetophenone (TFMAP). The third stage (C) may include the step of feeding 3'-(trifluoromethyl)acetophenone oxime (305) into the third reactor (110). The third stage may further include adding a predetermined amount of 30% hydrochloric acid (HCl) obtained from the tank (108) and water from the tank (109), and heating to a predetermined temperature between 70-110°C, preferably between 90-95°C and for a predetermined time of 3-7 hours, preferably 5-6 hours, while continuously stirring to obtain a crude 3'-(trifluoromethyl)acetophenone (TFMAP) containing an aqueous effluent layer and a crude organic layer. The third stage (C) may further comprise a step of alkaline washing (306) the crude organic layer of TFMAP in an alkaline washing tank (111) with water and a 3-10%, preferably 3-7% sodium hydroxide (NaOH) solution added from the tank (106). The alkaline washing (306) of the crude organic layer of TFMAP enables the removal of residual acidity before distillation. The third stage (C) may further comprise a step of distilling (307) the crude organic layer of TFMAP in a distillation unit (113) to obtain pure 3'-(trifluoromethyl)acetophenone (TFMAP). Additional recovery of 3'-(trifluoromethyl) The fourth stage of (TFMAP) - stage (D)

[0054] In another embodiment of the present application, the method (300) may include a fourth stage (D) for additionally recovering 3'-(trifluoromethyl)acetophenone (TFMAP) from the effluent. The fourth stage (D) may include the step of transferring the bottom aqueous layer separated in the second stage B to an effluent treatment unit (ETP) (112). The fourth stage (D) may also optionally include transferring the aqueous effluent layer to an effluent treatment unit (112), which is capable of recovering additional 3'-(trifluoromethyl)acetophenone by treating the aqueous layer from the third reactor (105).

[0055] In one embodiment of the present application, the purity of 3'-(trifluoromethyl)acetophenone (TFMAP) obtained by the method (300) may be between 99-99.9%, and the yield may be between 60-90%, particularly between 70-86%.

[0056] The following experiments further illustrate the present application. Unless expressly stated otherwise, all parts and percentages are by weight.

[0057] Example

[0058] Example 1: Preparation of Diazo Solution

[0059]

[0060] Under continuous stirring, sulfuric acid is introduced into the first reactor, followed by addition of 500 g of 3-aminotrifluorotoluene (exothermic reaction) to obtain a reaction mass. The reaction mass is cooled to 0-2 ° C. In addition, 135 g of toluene is added to the reaction mass, and then a sodium nitrite solution (225.6 g dissolved in 341.6 g of water) is slowly added over 2-2.5 hours, and continuous stirring is performed at a temperature of 0-2 ° C. After stirring the reaction mass for 30 minutes, 17.5 g of sulfamic acid dissolved in 92.5 g of water is added to obtain a diazo solution. Example 2: Preparation of 3'-(Trifluoromethyl)acetophenone oxime

[0061] Under continuous stirring, 730 g of water, 46 gm of copper (II) sulfate, 62 gm of glacial acetic acid, 930 gm of toluene were introduced into the second reactor, and then 295 g of acetaldehyde oxime (50% solution in water) and 25% amount of diazo solution were added in batches by keeping the temperature at 0-2° C. and pH at 2-2.5. After the addition of the diazo solution, the pH was raised to 3-3.5, and then 73 g of acetaldehyde oxime (50% solution in water) and 25% amount of diazo solution were added twice. In the next step, 110 g of acetaldehyde oxime and 25% diazo solution were added under continuous stirring for 1 hour. In the subsequent step, the temperature was raised to 35-40° C. to separate the aqueous layer from the organic layer. In addition, the aqueous layer was transferred to an effluent treatment device, while the organic layer was washed with 40 g of 30% HCl solution to obtain 3'-(trifluoromethyl)acetophenone oxime.

[0062] Example 3: Preparation of crude 3'-(trifluoromethyl)acetophenone (TFMAP)

[0063] In the third reactor, 3'-(trifluoromethyl)acetophenone oxime was introduced, and then 637 g of 30% hydrochloric acid was added under continuous stirring to obtain a reaction mass. The reaction mass was heated to 90-95° C. for 5-6 hours and then cooled to room temperature to obtain an aqueous layer and an organic layer. The aqueous layer was transferred to an effluent treatment unit, and the organic layer was washed with 125 g of water and 227 g of 3% sodium hydroxide to obtain 86% of crude 3'-(trifluoromethyl)acetophenone.

[0064] Example 4: Distillation of crude 3'-(trifluoromethyl)acetophenone (TFMAP) into refined 3'-(trifluoromethyl)acetophenone (TFMAP)

[0065] The crude 3'-(trifluoromethyl)acetophenone in toluene is transferred to a distillation unit (packed column) to separate the hydrolysis products such as trifluorotoluene from toluene and obtain refined 3'-(trifluoromethyl)acetophenone (TFMAP).

[0066] Example 5: Effluent Treatment Plant (ETP)

[0067] The aqueous effluent layer is transferred as effluent to an effluent treatment unit (112) and treated, and 3'-(trifluoromethyl)acetophenone (TFMAP) is additionally recovered from the effluent.

[0068] According to the embodiments of the present disclosure, the system (100) and method (300) for preparing 3'-(trifluoromethyl)acetophenone (TFMAP) have the following advantages, including but not limited to:

[0069] Reduce the loss of the final product, thereby increasing the final yield of 3'-(trifluoromethyl)acetophenone (TFMAP).

[0070] The purity of 3'-(trifluoromethyl)acetophenone (TFMAP) increased to 99.9% and the yield increased to 90%.

[0071] • To reduce the time and energy consumption of the whole process for obtaining 3'-(trifluoromethyl)acetophenone (TFMAP).

[0072] Reduced losses of reactants and reaction intermediates as they are recycled in the synthesis of 3'-(trifluoromethyl)acetophenone (TFMAP).

[0073] ·TFMAP production capacity increased by 20%.

[0074] The embodiments, examples and alternatives of the foregoing paragraphs or descriptions and drawings, including any of their various aspects or corresponding individual features, may be adopted independently or in any combination. Features described in conjunction with one embodiment are applicable to all embodiments, unless these features are incompatible.

[0075] Although embodiments of the system (100) and method (300) for preparing 3'-(trifluoromethyl)acetophenone (TFMAP) have been described in language specific to structural features and / or methods, it should be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of embodiments of the system (100) and method (300) for preparing 3'-(trifluoromethyl)acetophenone (TFMAP).

Claims

1. A system (100) for preparing 3'-(trifluoromethyl)acetophenone (TFMAP), comprising: a first reactor (104) capable of reacting 3-aminotrifluorotoluene and sulfuric acid in the presence of toluene and sodium nitrite (NaNO2) solution to prepare a diazo solution; a second reactor (105) capable of mixing and adding the acetaldehyde oxime solution and the diazo solution in batches, and then adding other reactants to obtain an aqueous layer and an organic layer, namely 3'-(trifluoromethyl)acetophenone oxime; a third reactor (110) capable of hydrolyzing 3'-(trifluoromethyl)acetophenone oxime with 30% HCl to obtain 3'-(trifluoromethyl)acetophenone (TFMAP); and A distillation unit (113) associated with the third reactor (110) is configured to obtain refined 3'-(trifluoromethyl)acetophenone (TFMAP).

2. The system (100) according to claim 1, wherein: The third reactor (110) is also configured to perform layer separation of the aqueous effluent layer of 3'-(trifluoromethyl)acetophenone (TFMAP) and the crude organic layer.

3. The system (100) of claim 1, wherein: The third reactor (110) is also configured to transfer the aqueous effluent layer to an effluent treatment unit (112) which is capable of recovering additional 3'-(trifluoromethyl)acetophenone by treating the aqueous layer from the third reactor (105).

4. The system (100) of claim 1, wherein: Tank (111) is configured to perform alkaline washing of the crude organic layer of 3'-(trifluoromethyl)acetophenone (TFMAP) from the third reactor (110) using 3-10% NaOH to remove residual acidity and transfer the crude organic layer of TFMAP to a distillation unit (113).

5. The system (100) of claim 1, wherein: The other reactants in the second reactor (105) are water, copper (II) sulfate, glacial acetic acid and toluene.

6. A method (300) for preparing 3-(trifluoromethyl)acetophenone (TFMAP), comprising the following steps: Introducing (301) water into the first reactor (104), and then reacting 3-aminotrifluorotoluene (3-ABTF) with sulfuric acid (H2SO4) in the presence of toluene and sodium nitrite (NaNO2) solution to obtain reaction mass A; Under constant stirring, sulfamic acid dissolved in water is added (302) to the reaction mass A, which is then heated at 7-8°C to obtain a diazo solution in the first reactor (104); The diazo solution and acetaldehyde oxime solution are coupled in a batch manner (303) in a second reactor (105) and stirred for 4-5 hours, and then other reactants are added to obtain a reaction mass B having an aqueous layer and an organic layer of 3'-(trifluoromethyl)acetophenone oxime; raising the temperature (304) to 35-40°C to separate the organic layer from the aqueous layer in the reaction mass B, and then washing the organic layer with a 30% hydrochloric acid solution to obtain 3'-(trifluoromethyl)acetophenone oxime; 3'-(trifluoromethyl)acetophenone oxime is fed (305) into the third reactor (110), and then a 30% hydrochloric acid solution is added under continuous stirring to obtain a crude 3'-(trifluoromethyl)acetophenone (TFMAP) containing an aqueous effluent layer and a crude organic layer; and The crude organic layer of TFMAP is distilled (307) in a distillation unit (113) to obtain refined 3'-(trifluoromethyl)acetophenone (TFMAP).

7. The method (300) of claim 6, wherein: The method includes the sub-step of alkaline washing (306) the crude organic layer of 3'-(trifluoromethyl)acetophenone oxime in tank (111) with 3-10% NaOH added from tank (106) to remove residual acidity prior to distillation.

8. The method (300) of claim 6, wherein: The reaction mass A in the first reactor (104) is mixed for 1-4 hours, and the temperature is maintained at -5 to 10°C.

9. The method (300) of claim 6, wherein: In step (302), the aminosulfonic acid is added to the reaction mass A to decompose excess NaNO2 and remove NOx.

10. The method (300) of claim 6, wherein: In the step of coupling (303) the diazo solution and the acetaldehyde oxime solution in the second reactor (105), the temperature is 0-2°C and the pH is 2-3.

5.

11. The method (300) of claim 6, wherein: The batchwise addition of the diazo solution and the acetaldehyde oxime solution is performed at least 4 times.

12. The method (300) of claim 11, wherein: The acetaldehyde oxime solution is added in 4-5 portions in the first batch addition, in 1-2 portions in the second and third additions, and then in 2-3 portions in the fourth addition, and the total addition amount is divided into 8-12 portions.

13. The method (300) of claim 10, wherein: For the acetaldehyde oxime added in batches, the pH of the first and second batches was adjusted between 2 and 2.5, and the pH of the third and fourth batches was adjusted between 3 and 3.

5.

14. The method (300) of claim 10, wherein: The pH in the second reactor (105) was maintained by adding 30% sodium hydroxide.

15. The method (300) of claim 6, wherein: The 30% hydrochloric acid is added into the third reactor (110) at 70-110°C for 3-7 hours.

16. The method (300) of claim 6, wherein: The aqueous effluent layer is transferred as effluent to an effluent treatment unit (112) and treated, and 3'-(trifluoromethyl)acetophenone (TFMAP) is additionally recovered from the effluent.

17. The method (300) of claim 6, wherein: The 3-(trifluoromethyl)acetophenone (TFMAP) was prepared by a batch process.

18. A 3'-(trifluoromethyl)acetophenone (TFMAP) product comprising: Appearance ranges from colorless liquid to orange liquid; 99-99.9% purity; and 60-90% yield.

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