Method and system for preparing trifluoroacetone acid ester by high gravity method

Abstract

The application provides a method and system for preparing trifluoro pyruvic ester by using high gravity method, and relates to the technical field of organic fluorine chemical synthesis. The method for preparing trifluoro pyruvic ester by using high gravity method comprises the following steps: in a high gravity reactor, an alcohol ether solution containing an aldehyde compound and a catalyst is circulated and sprayed, and hexafluoropropylene oxide is introduced, so that the aldehyde compound and the hexafluoropropylene oxide are subjected to catalytic reaction to obtain a reaction product; the reaction product is subjected to gas-liquid separation, and the gaseous product is subjected to rectification separation to obtain trifluoro pyruvic fluoride and a hydrogen fluoride hydrocarbon; the trifluoro pyruvic fluoride and alcohol are subjected to esterification reaction in a micro-channel reactor to obtain trifluoro pyruvic ester. The method for preparing trifluoro pyruvic ester by using high gravity method has the advantages of simple and easily obtained raw materials, mild reaction conditions, high conversion rate and high yield.

Description

Technical Field

[0001] This invention relates to the field of organofluorine chemical synthesis technology, and in particular to a method and system for preparing trifluoropyruvate by a supergravity method. Background Technology

[0002] Trifluoropyruvate esters (methyl trifluoropyruvate, ethyl trifluoropyruvate, etc.) have two reaction centers, namely carbonyl and ester groups, and are important trifluoromethylating agents. They are widely used in the pharmaceutical and pesticide industries, mainly for the synthesis of anti-inflammatory drugs, anticancer and antiviral drugs.

[0003] The main synthetic routes for trifluoropyruvate are as follows: 1) The intermediate 2-fluoro-2-alkoxy-trifluoropropionate is first synthesized from hexafluoropropylene oxide and alcohol. Then, under the catalysis of concentrated sulfuric acid or a solid superacid, hydrogen fluoride is removed to generate the target product, trifluoropyruvate. Using concentrated sulfuric acid not only generates a large amount of waste acid that pollutes the environment, but also produces numerous byproducts that are difficult to separate. Using a solid superacid (nickel sulfate and ferric sulfate supported on alumina, titanium dioxide, and zirconium oxide, etc.) results in a long reaction time, low yield, and complex preparation process for the solid acid catalyst.

[0004] 2) Using trifluorobromomethane and its ester as raw materials, an intermediate is synthesized using a zinc powder-pyridine complex catalyst, followed by acid hydrolysis to obtain trifluoropyruvate. This route involves a long reaction time, many steps, complex reaction operations, and relatively harsh operating conditions, resulting in a large amount of waste and making it unsuitable for large-scale production.

[0005] 3) Trifluoropyruvate is synthesized by reacting trifluoropyruvate with alcohol or diazomethane as raw materials. This route has high raw material prices and low reaction conversion rate, making it unsuitable for large-scale production.

[0006] CN102391113A discloses a method for synthesizing trifluoroacetate compounds. The method involves adding 96-98% concentrated sulfuric acid, 2-fluoro-2-alkoxy-trifluoropropionate, silica, and phosphorus pentoxide to a reaction vessel under stirring. The reaction temperature is controlled at 90-145℃, and the reaction vessel pressure is 0-0.1 MPa. After reactive distillation for 15-45 minutes, the product is collected by vacuum distillation with a reflux ratio of 0.2:1-5:1. The molar ratio of sulfuric acid to 2-fluoro-2-alkoxy-trifluoropropionate is 0.9:1-1.2:1, the molar ratio of phosphorus pentoxide to 2-fluoro-2-alkoxy-trifluoropropionate is 0.03:1-0.3:1, and the molar ratio of silica to 1,2-fluoro-2-alkoxy-trifluoropropionate is 0.2:1-1:1. This invention first prepares a solid acid catalyst by exchanging an activator with a metal oxide under heating conditions. Then, using 2-fluoro-2-alkoxy-trifluoropropionate as a raw material, it undergoes a gas-phase catalytic reaction with the prepared solid acid catalyst at 140-300°C to produce trifluoroacetone ester. Although this method avoids the generation of large amounts of waste sulfuric acid, it suffers from high raw material costs and high reaction temperatures.

[0007] CN109776319A discloses a production process for ethyl trifluoropyruvate, comprising the following steps: adding zinc powder, pyridine, diethyl oxalate, and a catalyst into a three-necked flask equipped with a mechanical stirrer, starting the stirrer, drawing a vacuum, and introducing trifluorobromomethane gas at a certain temperature, controlling the gas flow rate to maintain atmospheric pressure, until all the zinc powder in the flask has reacted, and continuing stirring for 4 hours; then pouring the reaction solution into glacial hydrochloric acid for hydrolysis; and finally obtaining the finished product, ethyl trifluoropyruvate, through extraction, drying, distillation, and rectification. This process uses a Grignard reaction involving zinc powder and needs to be carried out in steps: firstly, the activation of zinc powder and the introduction of trifluorobromomethane gas into the reaction are time-consuming, and after the reaction is completed, stirring needs to continue for 4 hours; subsequently, multiple post-processing steps such as hydrolysis with glacial hydrochloric acid, extraction, drying, distillation, and rectification are required. The entire process involves a gas-liquid-solid three-phase reaction, resulting in low mass transfer efficiency. Furthermore, the reactivity of zinc powder is difficult to control, the intermittent operation steps are cumbersome, and the equipment utilization rate is low, making it difficult to achieve continuous production. Therefore, it is not conducive to industrial scale-up.

[0008] US2018050976 describes a process in which ethyl trifluoroacetate is oxidized with sodium hypochlorite in acetonitrile solvent, excess oxidant is quenched with sodium thiosulfate pentahydrate, sodium bicarbonate and sodium sulfate are added and stirred, and the solids are removed by filtration to obtain trifluoropyruvate hydrate. However, the yield is low, only 69%, and trifluoroacetic acid is easily generated as a byproduct.

[0009] CN121270372A discloses a trifluoropyruvate and a method for preparing trifluoropyruvate from trifluoroacetone, comprising: firstly, dissolving trifluoroacetone in a chlorinated solvent, then adding a catalyst, introducing chlorine gas and sealing the reaction, controlling the reaction temperature, and cooling to room temperature after the reaction to obtain a 1,1,1-trichlorotrifluoroacetone reaction mixture, adding alkaline solution to carry out a hydrolysis reaction, separating the aqueous phase after the reaction, continuing to reuse the chlorinated solvent, adding acid to the aqueous phase to adjust the pH to 3-4 to obtain an aqueous trifluoropyruvate solution, and finally obtaining wet trifluoropyruvate by extraction and pulping, and obtaining pure trifluoropyruvate by air purging. This process uses trifluoroacetone as raw material and requires multiple reaction steps, including chlorination, hydrolysis, acidification, extraction, pulping, and drying, making the process lengthy. The chlorination step uses highly toxic chlorine gas, posing serious safety hazards and environmental pressures, and requires extremely high equipment sealing. After the reaction, complex post-processing such as separation, pH adjustment, and extraction is required, and the solvent needs to be reused, making the operation cumbersome. Overall, the atom economy is poor, the amount of waste generated is large, and the industrial implementation is risky and costly.

[0010] In summary, existing methods for synthesizing trifluoropyruvate compounds are complex, time-consuming, produce numerous byproducts, generate large amounts of waste, require expensive catalysts, and are unsuitable for large-scale production. To address these issues, this invention proposes a novel centrifugal method for preparing trifluoropyruvate compounds.

[0011] In view of this, the present invention is hereby proposed. Summary of the Invention

[0012] The purpose of this invention is to provide a method and system for preparing trifluoropyruvate by supergravity, aiming to solve the core problems existing in the current trifluoropyruvate synthesis process, such as harsh reaction conditions, many by-products, large amount of waste, expensive / difficult-to-recover catalysts, low mass transfer efficiency leading to low conversion and yield, and difficulty in continuous scale-up production.

[0013] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a method for preparing trifluoropyruvate by a hypergravity method, the method comprising: In a hypergravity reactor, an alcohol-ether solution containing aldehydes and catalysts is circulated and sprayed, and hexafluoropropylene oxide is introduced to catalyze the reaction between the aldehydes and hexafluoropropylene oxide, yielding the reaction products. The reaction products were subjected to gas-liquid separation, and the gas phase products were separated by distillation to obtain trifluoroacetone fluoride and hydrofluorocarbons. Trifluoroacetone fluoride and alcohol were esterified in a microchannel reactor to obtain the esterified product. The esterification product is subjected to gas-liquid separation. The liquid phase product is trifluoroacetone ester, and the gas phase hydrogen fluoride is absorbed by water to obtain hydrofluoric acid solution.

[0014] Furthermore, the molar ratio of the aldehyde compound to hexafluoropropylene oxide is (1~3):1.

[0015] Furthermore, the aldehyde compounds include any one of acetaldehyde, propionaldehyde, and butyraldehyde.

[0016] Furthermore, the mass ratio of the solvent to the aldehyde compound is (3~8):1.

[0017] Furthermore, the catalyst comprises methanesulfonic acid and / or trifluoromethanesulfonic acid.

[0018] Furthermore, the amount of catalyst added is 0.01 to 0.1% of the mass of hexafluoropropylene oxide.

[0019] Furthermore, the solvent in the alcohol ether solution containing aldehydes and catalyst is an alcohol ether compound.

[0020] Furthermore, in the catalytic reaction of the aldehyde compound and hexafluoropropylene oxide, the reaction temperature is 10~40℃, the reaction pressure is 0~0.2 MPa, and the reaction time is 5~20 min.

[0021] Furthermore, the rotational speed of the supergravity reactor is 200~2000 rpm.

[0022] Furthermore, the alcohol ether solution containing aldehydes and catalyst is circulated and sprayed in a hypergravity reactor by a pump, and is countercurrently contacted with the introduced hexafluoropropylene oxide to carry out the catalytic reaction.

[0023] Furthermore, the ratio of the circulating flow rate of the alcohol ether solution containing aldehydes and catalyst to the feed flow rate of hexafluoropropylene oxide is (2~6):1.

[0024] Furthermore, the temperature of the gas-liquid separation is 10~40℃, and the pressure of the gas-liquid separation is 0~0.2 MPa.

[0025] Furthermore, the liquid product obtained by gas-liquid separation includes the solvent in the alcohol ether solution containing aldehyde compounds, and the solvent is returned to the hypergravity reactor for recycling.

[0026] Furthermore, the feed molar ratio of the trifluoroacetone fluoride to the alcohol is (1~1.2):1.

[0027] Furthermore, the esterification reaction is carried out at a temperature of 0~30℃, a pressure of 0.1~0.3 MPa, and a reaction time of 20~100 s.

[0028] Furthermore, the alcohol includes methanol or ethanol.

[0029] Further, the trifluoropyruvate esters include methyl trifluoropyruvate or ethyl trifluoropyruvate.

[0030] Secondly, the present invention provides a system for preparing trifluoropyruvate by a supergravity method, the system comprising a supergravity reactor, a gas-liquid separation device 1, a distillation separation device, a microchannel esterification reactor, a gas-liquid separation device 2, and a water absorption device that are sequentially fluidly connected. The top of the hypergravity reactor is provided with an inlet for an alcohol ether solution containing aldehydes and catalyst; the middle or lower part of one side is provided with an inlet for hexafluoropropylene oxide; and the bottom is provided with an outlet for solvent. The hypergravity reactor is equipped with a circulating spray distribution device and a stirring device. The middle or lower part of the other side of the hypergravity reactor is provided with a reaction product outlet, which is connected to the No. 1 gas-liquid separation device through a conveying pipeline. The liquid phase outlet of the gas-liquid separation device is connected to the solvent storage device under the supergravity reactor through a reflux pipeline to realize solvent recycling; the gas phase outlet of the No. 1 gas-liquid separation device is connected to the distillation separation device through a delivery pipeline. The distillation and separation device is equipped with a trifluoroacetone fluoride outlet and a by-product outlet, and the trifluoroacetone fluoride outlet is connected to the microchannel esterification reactor via a delivery pipeline; The microchannel esterification reactor is connected to gas-liquid separator #2, and the gas phase is connected to a water absorption device.

[0031] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention provides a new process for the catalytic synthesis of trifluoropyruvyl fluoride and by-product hydrofluorocarbons using aldehyde compounds and hexafluoropropylene oxide as raw materials and alcohol ether compounds as solvents. Compared with the existing technology which uses expensive raw materials, the raw materials of this invention are simple, readily available and inexpensive. The reaction path directly generates trifluoropyruvyl fluoride in one step, which is simple and avoids the complex steps of concentrated sulfuric acid catalytic defluorination or high-temperature gas phase catalysis of solid acid in traditional methods. This significantly simplifies the process flow, reduces equipment investment and operating costs, and has good prospects for industrial application.

[0032] (2) The present invention uses a supergravity reactor for continuous reaction, making full use of the supergravity field to enhance mass transfer and mixing efficiency. Compared with traditional reactors, the supergravity reactor reduces the catalytic reaction temperature to 10~40℃, making the reaction conditions milder and the reaction time significantly shorter. At the same time, it achieves efficient contact between aldehyde compounds and hexafluoropropylene oxide, thereby significantly improving the raw material conversion rate and product yield, and making it easy to achieve continuous and automated production.

[0033] (3) The present invention proposes to carry out microchannel esterification reaction of trifluoroacetone fluoride with alcohol, which has high efficiency in heat and mass transfer and high conversion rate; the by-product hydrogen fluoride is absorbed by water to form hydrofluoric acid solution, realizing comprehensive utilization of resources and improving the economic efficiency and safety of the process. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the process flow and system structure for preparing trifluoroacetone esters by the supergravity method provided by the present invention.

[0036] Among them, 100 is the supergravity reactor, 200 is the No. 1 gas-liquid separation device, 300 is the distillation separation device, 400 is the microchannel esterification reactor, 500 is the No. 2 gas-liquid separation device, 600 is the water absorption device, and 700 is the solvent storage device. Detailed Implementation

[0037] Unless otherwise defined herein, the scientific and technical terms used in conjunction with this invention shall have the meanings commonly understood by one of ordinary skill in the art. The meaning and scope of terms shall be clear; however, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or foreign definitions. In this application, unless otherwise stated, the use of "or" means "and / or". Furthermore, the use of the term "comprising" and other forms is non-limiting.

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Firstly, such as Figure 1 As shown, this invention provides a method for preparing trifluoropyruvate by a hypergravity method, the method comprising: In a hypergravity reactor, an alcohol-ether solution containing aldehydes and catalysts is circulated and sprayed, and hexafluoropropylene oxide is introduced to catalyze the reaction between the aldehydes and hexafluoropropylene oxide, yielding the reaction products. The reaction products were subjected to gas-liquid separation, and the gas phase products were separated by distillation to obtain trifluoroacetone fluoride and hydrofluorocarbons. Trifluoroacetone fluoride and alcohol were esterified in a microchannel reactor to obtain the esterified product. The esterification product is subjected to gas-liquid separation. The liquid phase product is used to obtain trifluoroacetone ester, and the gas phase hydrogen fluoride is absorbed by water to obtain hydrofluoric acid solution.

[0040] It should be noted that, firstly, in the hypergravity reactor, the alcohol-ether solution containing aldehydes and catalyst forms a liquid film or droplets with a huge specific surface area through circulating spraying, which comes into countercurrent contact with the introduced hexafluoropropylene oxide gas. The strong shear force generated by the hypergravity field continuously renews the gas-liquid interface, significantly enhancing the mass transfer coefficient and breaking through the mass transfer limitations of traditional reactors. This allows the gas and liquid phases to fully contact and quickly reach reaction equilibrium. At the same time, the short residence time effectively suppresses the occurrence of side reactions and improves the reaction selectivity. As a result, the temperature in this step is controlled at 10~40℃, the residence time is 5~20min, the reaction conditions are mild, and the conversion rate of hexafluoropropylene oxide is significantly improved.

[0041] Next, after gas-liquid separation, the reaction products are mainly composed of alcohol and ether solvents, which can be recycled back to the supergravity reactor to achieve closed-loop solvent circulation, reducing raw material consumption and waste emissions. The gaseous products are mainly trifluoroacetone fluoride and hydrofluorocarbons as byproducts. Obviously, this invention can achieve preliminary separation of solvent and product through simple gas-liquid separation, which reduces the difficulty of distillation operation, reduces energy consumption and equipment investment, and significantly reduces production costs.

[0042] Furthermore, the gaseous product is separated by distillation, utilizing the boiling point difference between hydrofluorocarbons and trifluoroacetone fluoride (boiling point 8-10℃). Pressurized distillation increases the operating temperature, avoiding the high energy consumption of cryogenic separation, while ensuring separation efficiency and product purity. This step yields trifluoroacetone fluoride with a purity ≥99%, meeting the requirements of subsequent esterification reactions. Simultaneously, the byproduct hydrofluorocarbons can be comprehensively utilized as refrigerants, foaming agents, or fluorine-containing intermediate raw materials, maximizing atom economy.

[0043] Finally, trifluoropyruvyl fluoride and alcohol undergo esterification in a microchannel reactor, which features efficient heat and mass transfer and a high conversion rate. After gas-liquid separation, the liquid phase is the product trifluoropyruvate, while the gas phase hydrogen fluoride is absorbed by water to form a hydrofluoric acid solution, thus realizing resource utilization.

[0044] In summary, the continuous process of supergravity reaction-gas-liquid separation-distillation purification-droplet esterification significantly reduces raw material costs and significantly improves overall yield compared to existing technologies. The reaction conditions are mild, with a temperature range of 10–40°C and a pressure range of 0–0.2 MPa. Furthermore, the entire process generates no waste acid, and all solvents, byproducts such as hydrofluorocarbons and HF are recovered, achieving green production. In particular, the introduction of supergravity technology not only enhances mass transfer efficiency and improves raw material conversion rate but also significantly reduces reaction residence time, solving the challenges of high yield and low cost in the industrial production of trifluoropyruvate.

[0045] As an optional implementation, the method for preparing trifluoropyruvate by the centrifugal method specifically includes the following steps: First, a certain amount of aldehyde compounds and catalysts are dissolved in the solvent alcohol ether, and then continuously sprayed and circulated in a hypergravity reactor; Then, hexafluoropropylene oxide (A) is introduced into the reactor, so that aldehydes (acetaldehyde, propionaldehyde, etc.) and hexafluoropropylene oxide undergo a catalytic reaction in the hypergravity reactor. The reaction equation is shown in (1). Then, the reaction products are separated into gas and liquid phases. The liquid phase, mainly the solvent, is returned to the reaction. The gas phase is separated by distillation into trifluoroacetone fluoride (B) and hydrofluorocarbons (C) as a byproduct. Finally, trifluoropyruvyl fluoride is added dropwise to react with alcohols (methanol, ethanol, etc.) to undergo an esterification reaction. The reaction equation is shown in (2) to obtain trifluoropyruvate (D). This invention has the advantages of simple and readily available raw materials, mild reaction conditions, and high conversion and yield.

[0046] Equation (1); Equation (2); Wherein, R1 is any one of -CH3, -CH2CH3, and -CH2CH2CH3; R2 is either -CH3 or -CH2CH3.

[0047] As an optional implementation, the molar ratio of the aldehyde compound to hexafluoropropylene oxide is (1~3):1, for example, it can be 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, etc.

[0048] In a preferred embodiment, the molar ratio of the aldehyde compound to hexafluoropropylene oxide is (1.5~3):1.

[0049] It should be noted that this ratio aims to balance reactivity and selectivity: a suitable excess of aldehydes can promote efficient ring-opening of hexafluoropropylene oxide and inhibit its decomposition or side reactions; however, excessive amounts can easily trigger self-condensation of aldehydes or multi-step side reactions with active intermediates, reducing the selectivity of the target product. Under hypergravity, this range can also maintain a favorable mass transfer concentration gradient, ensuring rapid and directional catalytic reactions while balancing conversion, yield, and operational stability.

[0050] In a preferred embodiment, the catalyst comprises methanesulfonic acid and / or trifluoromethanesulfonic acid.

[0051] In a preferred embodiment, the amount of catalyst added is 0.01 to 0.1% of the mass of hexafluoropropylene oxide, for example, it can be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.9%, 0.1%, etc.

[0052] It should be noted that the catalyst used is a protic acid liquid catalyst, which efficiently catalyzes the ring-opening of hexafluoropropylene oxide and reacts with aldehydes to form trifluoropyruvate, significantly improving the conversion efficiency and selectivity of the raw materials.

[0053] As an optional embodiment, the solvent in the alcohol ether solution containing aldehydes and catalyst is an alcohol ether compound.

[0054] As an optional implementation, the alcohol ether compound includes any one or a combination of at least two of diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and polyethylene glycol dimethyl ether.

[0055] As an optional implementation, the aldehyde compound includes any one of acetaldehyde, propionaldehyde, and butyraldehyde.

[0056] As an optional implementation, the solvent needs to be dried with molecular sieves to remove moisture before use, with a moisture content of 0~0.01%.

[0057] As an optional implementation, the mass ratio of the solvent to the total mass of the aldehyde compound and hexafluoropropylene oxide is (3~8):1, for example, it can be 3:1, 4:1, 5:1, 6:1, 7:1, or 8:1.

[0058] As an optional implementation, the temperature of the catalytic reaction is 10~40℃, for example, it can be 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, etc.

[0059] As an optional implementation, the pressure of the catalytic reaction is 0~0.2 MPa, for example, it can be 0 MPa, 0.12 MPa, 0.14 MPa, 0.16 MPa, 0.18 MPa, 0.2 MPa, etc.

[0060] As an optional implementation, the reaction time is 5 to 20 minutes, for example, 5 minutes, 6 minutes, 8 minutes, 10 minutes, 12 minutes, 14 minutes, 16 minutes, 18 minutes, 20 minutes, etc.

[0061] It should be noted that the reaction time must be sufficient to complete the reaction, but should not be too long, otherwise side reactions are likely to occur. Due to the significantly enhanced mass transfer and mixing under hypergravity, the reaction can approach equilibrium in a very short time; too short a time results in incomplete conversion, while too long a time leads to the accumulation of side reactions. This window represents the optimal dynamic response range that balances high conversion rate and high selectivity with equipment throughput and product stability. The reaction system is acidic; if the raw material hexafluoropropylene oxide remains in this system for too long, it will isomerize to hexafluoroacetone. Normally, the faster the reaction time, the better, but considering the conversion rate of hexafluoropropylene oxide, a certain residence time is required. Therefore, the main point is that a shorter residence time results in a lower conversion rate; a longer residence time makes hexafluoropropylene oxide prone to isomerization to hexafluoroacetone under acidic catalytic conditions, and to pentafluoropropionyl fluoride under alkaline and fluoride ion catalytic conditions.

[0062] As an optional implementation, the rotational speed of the hypergravity reactor is 200~2000 rpm, for example, it can be 200 rpm, 400 rpm, 600 rpm, 800 rpm, 1000 rpm, 1200 rpm, 1400 rpm, 1600 rpm, 1800 rpm, 2000 rpm, etc.

[0063] In a preferred embodiment, the rotational speed of the hypergravity reactor is 500~1000 rpm.

[0064] In a preferred embodiment, the alcohol ether solution containing aldehydes and catalyst is circulated and sprayed in a hypergravity reactor by a pump, and is countercurrently contacted with the introduced hexafluoropropylene oxide to carry out the catalytic reaction.

[0065] In a preferred embodiment, the ratio of the circulating flow rate of the alcohol ether solution containing aldehydes and catalyst to the feed flow rate of hexafluoropropylene oxide is (2~6):1.

[0066] It should be noted that this recirculation ratio aims to create a dynamic reaction environment with efficient countercurrent contact: a sufficiently high liquid-phase recirculation ratio can maintain stable concentrations of aldehydes and catalysts within the reactor, uniform heat distribution, and ensure sufficient capture and conversion of gaseous hexafluoropropylene oxide in the liquid phase; however, an excessively high ratio will increase energy consumption and dilute reactant concentrations, while an excessively low ratio will lead to insufficient gas-liquid contact, localized overheating, and uneven conversion. This range represents the optimal balance between enhanced mass transfer and process economy.

[0067] As an optional implementation, the temperature of the gas-liquid separation is 0~40℃, for example, it can be 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, etc., and the pressure of the gas-liquid separation is 0~0.2 MPa, for example, it can be 0MPa, 0.02 MPa, 0.04 MPa, 0.06 MPa, 0.08 MPa, 0.1 MPa, 0.12 MPa, 0.14 MPa, 0.16 MPa, 0.18 MPa, 0.2 MPa.

[0068] In a preferred embodiment, the liquid product obtained by gas-liquid separation includes the solvent in an alcohol ether solution containing aldehydes, and the solvent is returned to the hypergravity reactor for recycling.

[0069] In a preferred embodiment, the distillation separation is carried out by atmospheric or pressurized distillation.

[0070] As an optional implementation, the pressure of the distillation separation is 0~0.3 MPa, for example, it can be 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, 0.3 MPa, etc.

[0071] As an optional implementation, when the aldehyde compound is acetaldehyde, the hydrofluorocarbon is 1,1-difluoroethane; when the aldehyde compound is propionaldehyde, the hydrofluorocarbon is 1,1-difluoropropane; when the aldehyde compound is butyraldehyde, the hydrofluorocarbon is 1,1-difluorobutane, etc.

[0072] It should be noted that the distillation separation of trifluoropyruvyl fluoride from the byproduct hydrofluorocarbon (e.g., 1,1-difluoroethane) involves the following steps: 1,1-difluoroethane has a boiling point of -25 to -26°C under normal pressure, while trifluoropyruvyl fluoride has a boiling point of 8 to 10°C. The trifluoropyruvyl fluoride is purified by distillation at a pressure of 0.1 to 0.3 MPa, yielding a purity ≥99%.

[0073] As an optional implementation, the byproduct 1,1-difluoroethane can be used to prepare other fluorinated chemicals, such as difluorochloroethane; it can also be used in the fields of refrigerants or foaming agents.

[0074] As an optional implementation, the esterification reaction is carried out in a microchannel esterification reactor.

[0075] As an optional implementation, the alcohol and trifluoropyruvyl fluoride undergo esterification in a microchannel esterification reactor. The feed molar ratio of alcohol to trifluoropyruvyl fluoride is 1:(1~1.05), for example, 1:1, 1:1.01, 1:1.02, 1:1.03, 1:1.04, 1:1.05, etc. A slight excess of trifluoropyruvyl fluoride is beneficial for the complete reaction of the alcohol and avoids residues in the product trifluoropyruvate.

[0076] As an optional implementation method, the esterification reaction temperature is 0~30℃, for example, 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, etc.; the esterification reaction time is 30~100s, for example, 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, etc.; because acyl fluoride has relatively strong reactivity, reacts quickly with alcohol, and no catalyst needs to be added.

[0077] As an optional implementation, the liquid phase separated in the No. 2 gas-liquid separator is the product trifluoroacetone ester, and the gas phase is mainly hydrogen fluoride, containing a small amount of unreacted trifluoropropionyl fluoride.

[0078] As an optional implementation, the hydrogen fluoride in the gas phase of the No. 2 gas-liquid separator is absorbed by water to form a hydrofluoric acid solution.

[0079] As an optional implementation, the alcohol is methanol or ethanol, and the target product is methyl trifluoropyruvate or ethyl trifluoropyruvate, respectively.

[0080] Secondly, such as Figure 1 As shown, the present invention provides a system for preparing trifluoropyruvate by a supergravity method. The system for preparing trifluoropyruvate by a supergravity method includes a supergravity reactor 100, a gas-liquid separation device 200, a distillation separation device 300, a microchannel esterification reactor 400, a gas-liquid separation device 500, and a water absorption device 600, which are connected in sequence in fluid communication. The top of the hypergravity reactor 100 is provided with an inlet for an alcohol ether solution containing aldehydes and catalyst; the middle or lower part of one side is provided with an inlet for hexafluoropropylene oxide; and the bottom is provided with an outlet for solvent. The hypergravity reactor is provided with a circulating spray distribution device and a stirring device. The middle or lower part of the other side of the hypergravity reactor is provided with a reaction product outlet, which is connected to the gas-liquid separation device through a conveying pipeline. The liquid phase outlet of the No. 1 gas-liquid separation device 200 is connected to the solvent storage device 700 under the supergravity reactor through a reflux pipeline to realize solvent recycling; the gas phase outlet of the No. 1 gas-liquid separation device is connected to the distillation separation device through a delivery pipeline. The distillation and separation device 300 is provided with a trifluoroacetone fluoride outlet and a by-product outlet, and the trifluoroacetone fluoride outlet is connected to the microchannel esterification reactor through a delivery pipeline; The microchannel esterification reactor 400 is connected to a gas-liquid separator #2. The gas phase of the gas-liquid separator is connected to a water absorption device, and the liquid phase is connected to a trifluoroacetate collection device.

[0081] The present invention will be further illustrated below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0082] Example 1 This embodiment provides a method for preparing trifluoropyruvate by a hypergravity method, the method comprising: 398 g of acetaldehyde and 0.5 g of trifluoromethanesulfonic acid were dissolved in 1988 g of diethylene glycol dimethyl ether dried in molecular sieves and circulated in a centrifugal reactor (1000 ml volume, 1000 rpm rotation speed) at a flow rate of 90 g / min. Then, 1000 g of hexafluoropropylene oxide (molar ratio of hexafluoropropylene oxide to acetaldehyde = 1.5:1) was slowly introduced into the centrifugal reactor at a feed flow rate of 30 g / min. The temperature was controlled at 20 °C, the pressure at 0.05 MPa, and the residence time at 9 min to obtain the reaction product. The reaction products were subjected to gas-liquid separation at 20 °C and 0.03 MPa to obtain gaseous and liquid products; wherein the liquid product was recycled back into the reaction as solvent; the gaseous product was separated by pressure distillation (0.1 MPa) to obtain trifluoroacetone fluoride and the byproduct 1,1-difluoroethane; wherein the conversion rate of hexafluoropropylene oxide was 95% and the yield of trifluoroacetone fluoride was 90%.

[0083] Methanol and trifluoropyruvyl fluoride were introduced into a microchannel reactor at a molar ratio of 1:1.02 for esterification. The reaction temperature was 10℃, the reaction pressure was 0.2MPa, and the reaction time was 60s. The purity of methyl trifluoropyruvate was 99.2% as determined by chromatography, and the yield was 94%.

[0084] Example 2 This embodiment provides a method for preparing trifluoropyruvate by a supergravity method. The method for preparing trifluoropyruvate by a supergravity method differs from that in Example 1 in that the catalyst is methanesulfonic acid, the conversion rate of hexafluoropropylene oxide is 94%, and the yield of trifluoropyruvyl fluoride is 86%.

[0085] Example 3 This embodiment provides a method for preparing trifluoropyruvate esters using a centrifugal method. The difference between this method and Example 1 is that the catalyst used is anhydrous hydrofluoric acid. The conversion rate of hexafluoropropylene oxide is 89%, and the yield of trifluoropyruvate fluoride is 13%.

[0086] Example 4 This embodiment provides a method for preparing trifluoropyruvate esters using a centrifugal method. The difference between this method and Example 1 is that the catalyst used is sulfuric acid. The conversion rate of hexafluoropropylene oxide is 88%, and the yield of trifluoropyruvate fluoride is 48%.

[0087] Example 5 This embodiment provides a method for preparing trifluoropyruvate esters using a centrifugal method. The difference between this method and Example 1 is that the catalyst used is anhydrous hydrofluoric acid. The conversion rate of hexafluoropropylene oxide is 73%, and the yield of trifluoropyruvate fluoride is 33%.

[0088] Example 6 This embodiment provides a method for preparing trifluoropyruvate using a hypergravity method, the difference between this method and that of Example 1 being: 795 g of acetaldehyde was dissolved in 3976 g of diethylene glycol dimethyl ether dried over molecular sieves, and the solution was circulated and sprayed in a 1000 ml high-gravity reactor. The molar ratio of hexafluoropropylene oxide to acetaldehyde was 3:1. The conversion rate of hexafluoropropylene oxide was 97%, and the yield of trifluoroacetone fluoride was 92%.

[0089] Example 7 This embodiment provides a method for preparing trifluoropyruvate using a hypergravity method, the difference between this method and that of Example 1 being: 795 g of acetaldehyde was dissolved in 3976 g of diethylene glycol dimethyl ether dried over molecular sieves, and the solution was circulated and sprayed in a 1000 ml high-gravity reactor. The molar ratio of hexafluoropropylene oxide to acetaldehyde was 1:1. The conversion rate of hexafluoropropylene oxide was 90%, and the yield of trifluoroacetone fluoride was 86%.

[0090] Example 8 This embodiment provides a method for preparing trifluoropyruvate using a hypergravity method, the difference between this method and that of Example 1 being: The temperature of the centrifugal reactor was 10°C, and the pressure was 0.05 MPa. The conversion rate of hexafluoropropylene oxide was 91%, and the yield of trifluoroacetone fluoride was 86%.

[0091] Example 9 This embodiment provides a method for preparing trifluoropyruvate using a hypergravity method, the difference between this method and that of Example 1 being: The temperature of the centrifugal reactor was 40°C, and the pressure was 0.05 MPa. The conversion rate of hexafluoropropylene oxide was 92%, and the yield of trifluoroacetone fluoride was 85%.

[0092] Example 10 This embodiment provides a method for preparing trifluoropyruvate using a hypergravity method, the difference between this method and that of Example 1 being: 398 g of acetaldehyde was dissolved in 1988 g of diethylene glycol dimethyl ether dried over molecular sieves, and the solution was circulated and sprayed in a 1000 mL centrifugal reactor at a flow rate of 30 g / min for a residence time of 18 min. The conversion rate of hexafluoropropylene oxide was 85%, and the yield of trifluoroacetone fluoride was 69%.

[0093] Example 11 This embodiment provides a method for preparing trifluoropyruvate using a hypergravity method, the difference between this method and that of Example 1 being: 398 g of acetaldehyde was dissolved in 1988 g of diethylene glycol dimethyl ether dried over molecular sieves, and the solution was circulated and sprayed in a 1000 ml centrifugal reactor at a flow rate of 120 g / min for a residence time of 6.8 min. The conversion rate of hexafluoropropylene oxide was 93%, and the yield of trifluoroacetone fluoride was 89%.

[0094] Example 12 This embodiment provides a method for preparing trifluoropyruvate using a hypergravity method, the difference between this method and that of Example 1 being: The centrifugal reactor rotated at 200 rpm. The conversion rate of hexafluoropropylene oxide was 81%, and the yield of trifluoroacetone fluoride was 76%.

[0095] Example 13 This embodiment provides a method for preparing trifluoropyruvate using a hypergravity method, the difference between this method and that of Example 1 being: The centrifugal reactor rotated at 2000 rpm. The conversion rate of hexafluoropropylene oxide was 96%, and the yield of trifluoroacetone fluoride was 91%.

[0096] Example 14 This embodiment provides a method for preparing trifluoropyruvate using a hypergravity method, the difference between this method and that of Example 1 being: Methanol and trifluoropyruvyl fluoride were introduced into a microchannel reactor at a molar ratio of 1:1 for esterification. The reaction temperature was 10℃, the reaction pressure was 0.2MPa, and the reaction time was 60s. The purity of methyl trifluoropyruvate was 99.2% as determined by chromatography, and the yield was 94%.

[0097] Example 15 This embodiment provides a method for preparing trifluoropyruvate using a hypergravity method, the difference between this method and that of Example 1 being: Methanol and trifluoropyruvyl fluoride were introduced into a microchannel reactor at a molar ratio of 1:1.05 for esterification. The purity of methyl trifluoropyruvate was 99.4% and the yield was 92%.

[0098] Example 16 This embodiment provides a method for preparing trifluoropyruvate using a hypergravity method, the difference between this method and that of Example 1 being: Ethanol and trifluoropyruvyl fluoride were introduced into a microchannel reactor at a molar ratio of 1:1.02 for esterification. The purity of ethyl trifluoropyruvate was 98.9% and the yield was 94%.

[0099] Comparative Example 1 This comparative example provides a method for preparing trifluoropyruvate, differing from Example 1 only in that the centrifugal reactor is replaced with a conventional spray reaction tower. The conversion rate of hexafluoropropylene oxide is 65%, and the yield of trifluoropyruvate fluoride is 59%.

[0100] Comparative Example 2 This comparative example provides a method for preparing trifluoropyruvate, which differs from Example 1 only in that the reaction is carried out in a conventional batch reactor. Acetaldehyde and a catalyst are first added to the reactor, followed by the introduction of hexafluoropropylene oxide. The conversion rate of hexafluoropropylene oxide is 70%, and the yield of trifluoropyruvate fluoride is 64%.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing trifluoropyruvate by a supergravity method, characterized in that, The method for preparing trifluoropyruvate by centrifugation includes: In a hypergravity reactor, an alcohol-ether solution containing aldehydes and catalysts is circulated and sprayed, and hexafluoropropylene oxide is introduced to catalyze the reaction between the aldehydes and hexafluoropropylene oxide, yielding the reaction products. The reaction products were subjected to gas-liquid separation, and the gas phase products were separated by distillation to obtain trifluoroacetone fluoride and hydrofluorocarbons. Trifluoroacetone fluoride and alcohol were esterified in a microchannel reactor to obtain the esterified product. The esterification product is subjected to gas-liquid separation. The liquid phase product is used to obtain trifluoroacetate; the gas phase hydrogen fluoride is absorbed by water to obtain hydrofluoric acid solution. The catalyst includes methanesulfonic acid and / or trifluoromethanesulfonic acid; The alcohol-ether solution containing aldehydes and catalyst is circulated and sprayed in a supergravity reactor by a pump, and is countercurrently contacted with the introduced hexafluoropropylene oxide to carry out the catalytic reaction.

2. The method for preparing trifluoropyruvate by centrifugal force according to claim 1, characterized in that, The molar ratio of the aldehyde compound to hexafluoropropylene oxide is (1~3):1; And / or, the aldehyde compounds include any one of acetaldehyde, propionaldehyde, and butyraldehyde.

3. The method for preparing trifluoropyruvate by centrifugal force according to claim 1, characterized in that, The amount of catalyst added is 0.01 to 0.1% of the mass of hexafluoropropylene oxide.

4. The method for preparing trifluoropyruvate by centrifugal force according to claim 1, characterized in that, The solvent in the alcohol ether solution containing aldehydes and catalyst is an alcohol ether compound; And / or, the mass ratio of the solvent to the aldehyde compound is (3~8):

1.

5. The method for preparing trifluoropyruvate by centrifugal force according to claim 1, characterized in that, In the catalytic reaction of the aldehyde compound and hexafluoropropylene oxide, the reaction temperature is 10~40℃, the reaction pressure is 0.05~0.2 MPa, and the reaction time is 5~20 min.

6. The method for preparing trifluoropyruvate by centrifugal force according to claim 1, characterized in that, The rotational speed of the hypergravity reactor is 200~2000 rpm; And / or, the ratio of the circulating flow rate of the alcohol ether solution containing the aldehyde compound and the catalyst to the feed flow rate of hexafluoropropylene oxide is (2~6):

1.

7. The method for preparing trifluoropyruvate by centrifugal force according to claim 1, characterized in that, The temperature for gas-liquid separation is 10~40℃, and the pressure for gas-liquid separation is 0.03~0.2 MPa; And / or, the liquid product obtained by gas-liquid separation includes the solvent in an alcohol ether solution containing aldehydes, and the solvent is returned to the hypergravity reactor for recycling.

8. The method for preparing trifluoropyruvate by the centrifugal method according to claim 1, characterized in that, The feed molar ratio of the trifluoroacetone fluoride to the alcohol is (1~1.2):1; And / or, the esterification reaction is carried out at a temperature of 0~30℃, a pressure of 0.1~0.3 MPa, and a reaction time of 20~100 s.

9. The method for preparing trifluoropyruvate by centrifugal force according to claim 1, characterized in that, The alcohol includes methanol or ethanol; The trifluoropyruvate includes methyl trifluoropyruvate or ethyl trifluoropyruvate.

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