Vinyl trifluoroacetate and synthesis method and synthesis device thereof

Abstract

The invention belongs to the technical field of fluorine chemical industry, and particularly relates to vinyl trifluoroacetate as well as a synthesis method and a synthesis device thereof. The trifluoroacetic acid vinyl ester disclosed by the invention is high in purity and suitable for the fields of high-end medicines and materials. The synthesis method of the vinyl trifluoroacetate comprises the following steps: firstly, reacting 2-chloroethanol with trifluoroacetyl chloride to generate 2-chlorine ethyl trifluoroacetate, then carrying out elimination reaction on the 2-chlorine ethyl trifluoroacetate in the presence of a catalyst and a polymerization inhibitor to generate a vinyl trifluoroacetate crude product, and finally rectifying to obtain the vinyl trifluoroacetate product. The synthesis method of the trifluoroacetic acid vinyl ester realizes efficient and green synthesis, and has the characteristics of mild conditions, high selectivity, continuous operation and environmental friendliness. According to the synthesis device of the trifluoroacetic acid vinyl ester, a continuous flow reaction system in modular design is adopted, integration and automatic control of esterification, elimination, rectification and tail gas recovery are achieved, and the production efficiency and the raw material utilization rate are effectively improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fluorinated chemicals, and particularly relates to vinyl trifluoroacetate and a synthesis method and device thereof. BACKGROUND

[0002] Vinyl trifluoroacetate (VTA) is an important fluorine-containing vinyl monomer, which contains both vinyl and trifluoroacetyl groups in its molecular structure. This special structure enables it to impart excellent chemical stability, weather resistance, low surface energy, and good biocompatibility to polymers after polymerization. Polyvinyl trifluoroacetate can be converted into functionalized polyvinyl alcohol derivatives through hydrolysis and other reactions, which have broad potential in the biomedical field such as drug delivery carriers, tissue engineering scaffolds, etc. In material science, it can be used to prepare high-performance thin films, optical coatings, and antifouling coatings, etc. In addition, this compound can also be used as a key intermediate in the synthesis of fluorine-containing silane polymers and thermal cyclization polymerization processes for the synthesis of high-performance fluorine-containing materials.

[0003] In the pharmaceutical field, vinyl trifluoroacetate is widely used as a synthetic intermediate in the molecular construction of anti-inflammatory drugs, antitumor drugs, and cardiovascular drugs. Its fluorine-containing group can significantly improve the liposolubility and metabolic stability of the drug. In agricultural chemicals, this compound can be used to develop high-efficiency, low-toxicity pesticides and herbicides, such as cell division inhibitors, to increase crop yields and reduce environmental pollution.

[0004] Currently, there are several methods for synthesizing vinyl trifluoroacetate. Among them, the direct addition method of trifluoroacetic acid and acetylene requires the use of highly toxic mercury oxide and mercury sulfate as catalysts, with harsh reaction conditions, many side reactions, low yield, and explosive risk of acetylene itself, which requires extremely high safety requirements for production. Another method is the condensation of trifluoroacetic anhydride and acetaldehyde, which is relatively mild, but prone to side reactions such as acetaldehyde polymerization or excessive dehydration of trifluoroacetic anhydride, resulting in low yield and complex by-product processing. In addition, Chinese patent CN117800841A discloses an indirect synthesis method based on 2-chloroethanol and trifluoroacetic acid. This method first synthesizes an intermediate under acid catalysis, and then performs an elimination reaction. However, this process generates a large amount of waste acid, the catalyst needs to be separated and recovered, and it is a batch operation with complex steps and high cost.

[0005] In summary, the existing synthesis methods generally have the disadvantages of low reaction selectivity, use of toxic reagents, discontinuous process, high environmental pollution, and poor economic efficiency. Therefore, it is of great industrial application value and scientific research significance to develop a continuous, mild, high-selectivity, low-cost, and environmentally friendly synthesis method and device for vinyl trifluoroacetate. SUMMARY

[0006] The technical problem solved by the present application is to overcome the above-mentioned defects existing in the prior art, and to provide a vinyl trifluoroacetate with high purity, which is suitable for high-end pharmaceutical and material fields.

[0007] The present application also provides a synthesis method of vinyl trifluoroacetate, which uses 2-chloroethanol and trifluoroacetyl chloride as raw materials, realizes efficient and green synthesis through two-step continuous reaction (esterification and catalytic elimination), and has the characteristics of mild conditions, high selectivity, continuous operation and environmental friendliness.

[0008] The present application also provides a synthesis device of vinyl trifluoroacetate, which adopts a continuous flow reaction system with modular design, realizes the integration and automatic control of esterification, elimination, rectification and tail gas recovery, and effectively improves the production efficiency and raw material utilization rate.

[0009] The synthesis method of vinyl trifluoroacetate provided by the present application comprises the following steps: first, 2-chloroethanol and trifluoroacetyl chloride are reacted to generate 2-chlorotrifluoroacetate; then, the 2-chlorotrifluoroacetate is subjected to an elimination reaction under the conditions of a catalyst and a polymerization inhibitor to generate a crude product of vinyl trifluoroacetate; finally, rectification is performed to obtain the product of vinyl trifluoroacetate.

[0010] The molar ratio of 2-chloroethanol to trifluoroacetyl chloride is 1:1~1:0.9.

[0011] The catalyst is polystyrene loaded with 1,8-diazabicycloundec-7-ene (DBU) or 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), and the loading amount is 15~30 mol%; the addition amount of the catalyst (calculated based on DBU or DBN) is 1.1~2.0 times the molar amount of the theoretical 2-chlorotrifluoroacetate. DBU is a strong alkaline pKa 12-13 and non-nucleophilic, which avoids attacking the carbonyl group or causing ester exchange side reactions, and efficiently promotes β-elimination.

[0012] The polymerization inhibitor is 3,5-di-tert-butylcatechol (TBC), and the addition amount of the polymerization inhibitor is 0.05%~0.1% of the theoretical 2-chlorotrifluoroacetate feed mass.

[0013] 2-chloroethanol and trifluoroacetyl chloride are reacted to obtain 2-chlorotrifluoroacetate, and hydrogen chloride is also generated, which is absorbed by water to obtain by-product hydrochloric acid.

[0014] The reaction temperature of 2-chloroethanol and trifluoroacetyl chloride is 60~80℃, and the reaction pressure is 0.05MPa~0.15MPa.

[0015] The elimination reaction temperature is 28~38℃, and the reaction pressure is 0.05MPa~0.15MPa.

[0016] A kind of vinyl trifluoroacetate is synthesized by the synthesis method of the vinyl trifluoroacetate.

[0017] The synthesis device for synthesizing the vinyl trifluoroacetate comprises at least one set of reaction systems, specifically comprising an esterification reactor, an elimination reactor and a rectifying tower, and the esterification reactor, the elimination reactor and the rectifying tower are sequentially connected through pipelines.

[0018] Specifically, the set of reaction systems comprises an esterification reactor A, an esterification reactor B, an elimination reactor A and an elimination reactor B, the liquid outlet of the esterification reactor A is connected with the liquid inlet of the esterification reactor B, the gas outlet of the esterification reactor B is connected with a gas-liquid separator B, the gas-liquid separator B is connected with the gas inlet of the esterification reactor A, the liquid outlet of the esterification reactor B is connected with a 2-chloroethyl trifluoroacetate storage tank, the 2-chloroethyl trifluoroacetate storage tank is connected with the elimination reactor A, the gas outlet of the elimination reactor A is connected with the gas inlet of the elimination reactor B, the elimination reactor B is connected with a crude vinyl trifluoroacetate storage tank, the crude vinyl trifluoroacetate storage tank is connected with the rectifying tower, and the discharge pipe of the elimination reactor B is connected with the bottom feed pipe of the elimination reactor A through a pump circulation pipeline.

[0019] The material inlet of the esterification reactor A is connected with a 2-chloroethanol storage tank through a metering pump, the gas outlet of the esterification reactor A is connected with a gas-liquid separator A, and the gas-liquid separator A is connected with a tail gas absorption tower.

[0020] The bottom liquid feed inlet of the esterification reactor B is connected with a trifluoroacetyl chloride storage tank.

[0021] The top gas outlet of the elimination reactor B is connected with a gas-liquid separator C, the gas-liquid separator C is connected with the tail gas absorption tower, and the tail gas absorption tower is connected with a dilute hydrochloric acid storage tank.

[0022] The top of the rectifying tower is connected with a refluxer, and the refluxer is connected with a vinyl trifluoroacetate product storage tank.

[0023] Compared with the prior art, the present application has the beneficial effects that: (1) The synthesis method of the present application uses 2-chloroethanol and trifluoroacetyl chloride as starting materials, avoiding the use of highly dangerous and toxic substances such as acetylene and mercury oxide, thereby improving the process safety from the source; using a supported non-nucleophilic strong base (such as DBU) as the elimination reaction catalyst, effectively inhibiting the carbonyl side reaction, the reaction selectivity is high, and the product purity and yield are significantly improved.

[0024] (2) The process of the present application realizes continuous operation, through multi-stage reactor series connection, material circulation and online detection control, solving the problems of low efficiency and complicated operation of traditional batch process; at the same time, the hydrogen chloride gas generated in the reaction is concentrated and absorbed as by-product hydrochloric acid, realizing the recycling of resources, reducing the discharge of three wastes, and having good environmental friendliness.

[0025] (3) The synthetic device of the present application is designed ingeniously, the series connection of esterification reactors A and B and the series connection and circulation of elimination reactors A and B ensure sufficient reaction of raw materials and effective heat transfer; the coupling design of the rectifying tower and the reaction system enables the unreacted raw materials to be recycled and reused, the whole device has high integration degree and stable operation. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a schematic view of the synthetic device of vinyl trifluoroacetate of the present application.

[0027] In the figure: 1, 2-chloroethanol storage tank; 2, metering pump; 3, esterification reactor A; 4, gas-liquid separator A; 5, esterification reactor B; 6, gas-liquid separator B; 7, trifluoroacetyl chloride storage tank; 8, 2-chloro trifluoroacetate ethyl ester storage tank; 9, elimination reactor A; 10, elimination reactor B; 11, gas-liquid separator C; 12, crude vinyl trifluoroacetate storage tank; 13, rectifying tower; 14, refluxer; 15, finished vinyl trifluoroacetate storage tank; 16, tail gas absorption tower; 17, dilute hydrochloric acid storage tank; 18, elimination reaction circulating pump; 19, discharge pump. DETAILED DESCRIPTION

[0028] The present application will be further described below in combination with specific examples.

[0029] The esterification reactor A and the esterification reactor B used in the present application are four-fluorine reactors with jacketed circulating heating lining on the basis of existing conventional esterification reactors.

[0030] The gas-liquid separator A, the gas-liquid separator B and the gas-liquid separator C are four-fluorine reactors with jacketed circulating refrigeration lining on the basis of existing conventional gas-liquid separators.

[0031] The elimination reactor A and the elimination reactor B are four-fluorine reactors with jacketed circulating heating and cooling lining on the basis of existing conventional elimination reactors.

[0032] The tail gas absorption tower is a PP material spray absorption tower purchased from outside.

[0033] Polystyrene-supported DBU: chloromethyl polystyrene is treated by swelling, and then reacted with DBU catalyst by solidification, washed, vacuum dried and loaded to detect the loading amount, and the loading amount is 22 mol%.

[0034] Polystyrene-supported DBN: chloromethyl polystyrene is treated by swelling, and then reacted with DBN catalyst by solidification, washed, vacuum dried and loaded to detect the loading amount, and the loading amount is 20 mol%.

[0035] Polymerization inhibitor 3,5-di-tert-butyl catechol: commercially available, content ≥98.0%.

[0036] As shown in Figure 1 The reaction system comprises: esterification reactor A3, esterification reactor B5, elimination reactor A9, elimination reactor B10, the liquid outlet of the esterification reactor A3 is connected with the liquid inlet of the esterification reactor B5, the gas outlet of the esterification reactor B5 is connected with the gas-liquid separator B6, the gas-liquid separator B6 is connected with the gas inlet of the esterification reactor A3; the liquid outlet of the esterification reactor B5 is connected with the 2-chloroethyl trifluoroacetate storage tank 8, the 2-chloroethyl trifluoroacetate storage tank 8 is connected with the elimination reactor A9, the gas outlet of the elimination reactor A9 is connected with the gas inlet of the elimination reactor B10, the elimination reactor B10 is connected with the crude vinyl trifluoroacetate storage tank 12, the crude vinyl trifluoroacetate storage tank 12 is connected with the rectifying column 13. The discharge pipe of the elimination reactor B10 is connected to the bottom feed pipe of the elimination reactor A9 through a pump circulation pipeline.

[0037] The material inlet of the esterification reactor A3 is connected with the 2-chloroethanol storage tank 1 through the metering pump 2. The gas outlet of the esterification reactor A3 is connected with the gas-liquid separator A4, and the gas-liquid separator A4 is connected with the tail gas absorption tower 16.

[0038] The bottom liquid feed inlet of the esterification reactor B5 is connected with the trifluoroacetyl chloride storage tank 7.

[0039] The top gas outlet of the elimination reactor B10 is connected with the gas-liquid separator C11, the gas-liquid separator C11 is connected with the tail gas absorption tower 16, and the tail gas absorption tower 16 is connected with the dilute hydrochloric acid storage tank 17.

[0040] The top of the rectifying column 13 is connected with the refluxer 14, and the refluxer 14 is connected with the vinyl trifluoroacetate product storage tank 15.

[0041] The synthesis method of vinyl trifluoroacetate using the above synthesis device comprises the following steps: (1) Esterification reaction Material preparation and feed control: add 2-chloroethanol raw material with a purity of ≥99.5% into the 2-chloroethanol storage tank 1, open the metering pump 2, and pump the 2-chloroethanol into the esterification reactor A3; at the same time, open the gas phase outlet valve of the trifluoroacetyl chloride storage tank 7, control the pressure of the gas phase trifluoroacetyl chloride to be 0.3 MPa, and make it enter the gas distributor at the bottom of the esterification reactor B5. When the material liquid levels of the esterification reactor A3 and the esterification reactor B5 are consistent, stop the 2-chloroethanol feed first, and continue to pass the trifluoroacetyl chloride gas.

[0042] The esterification reaction of the segment: the gaseous trifluoroacetyl chloride is dispersed by the gas distributor at the bottom of the esterification reactor B5, and then fully contacts with the 2-chloroethanol pumped from the esterification reactor A3 (the pumping flow rate is consistent with the feeding flow rate of the metering pump 2) in the esterification reactor B5, the reaction temperature of the esterification reactor B5 is controlled at 60-80℃, and the reaction pressure is controlled at 0.05-0.15 MPa, so that the esterification reaction occurs between the two to generate 2-chlorotrifluoroethyl acetate, and hydrogen chloride gas and unreacted trifluoroacetyl chloride gas are simultaneously generated.

[0043] The tail gas recovery and secondary reaction: the mixed gas (hydrogen chloride + residual trifluoroacetyl chloride) generated in the esterification reactor B5 enters the gas-liquid separator B6, the condensation temperature of the gas-liquid separator B6 is controlled at 2-8℃, so that a small amount of condensed 2-chlorotrifluoroethyl acetate liquid in the mixed gas is separated and refluxed to the esterification reactor B5; the uncondensed gas (mainly hydrogen chloride and trifluoroacetyl chloride) enters the gas distributor at the bottom of the esterification reactor A3, and further reacts (the reaction temperature of the esterification reactor A3 is controlled at 60-80℃) with the 2-chloroethanol in the esterification reactor A3 to further generate 2-chlorotrifluoroethyl acetate and reduce the waste of raw materials.

[0044] The tail gas treatment and product temporary storage: the hydrogen chloride gas (almost no trifluoroacetyl chloride residue) generated in the esterification reactor A3 enters the gas-liquid separator A4, and the condensation temperature is controlled at 2-5℃, so that a small amount of 2-chloroethanol liquid entrained is separated and refluxed to the esterification reactor A3; the hydrogen chloride gas after the gas-liquid separation enters the tail gas absorption tower 16, fully contacts with the countercurrently sprayed deionized water in the tower, and is absorbed to generate dilute hydrochloric acid, which is transported by a pipeline to the dilute hydrochloric acid storage tank 17 for storage.

[0045] The reaction equilibrium control: the purity of 2-chlorotrifluoroethyl acetate in the esterification reactor B5 is detected every 30 min, when the purity is ≥98.5%, the discharge valve at the bottom of the esterification reactor B5 is opened, and the 2-chlorotrifluoroethyl acetate is transported to the 2-chlorotrifluoroethyl acetate storage tank 8; at the same time, the feeding flow rate of the metering pump 2 and the opening degree of the discharge valve of the esterification reactor B5 are adjusted, so that the liquid level of the materials in the esterification reactor A3 and the esterification reactor B5 is stably controlled at 85-95%, and the continuous and balanced operation of the esterification reaction is realized.

[0046] (II) Elimination reaction Feed and catalyst addition: Catalyst, which is polystyrene-supported DBU or DBN, was added to the elimination reactors A9 and B10, respectively. The amount of catalyst added (calculated as DBU / DBN) was 1.1-2.0 times the molar mass of the theoretical 2-chlorotrifluoroethyl acetate, and the amount of polymerization inhibitor TBC was 0.05%-0.1% of the amount of 2-chlorotrifluoroethyl acetate. The discharge pump of the 2-chlorotrifluoroethyl acetate storage tank 8 was started, and 2-chlorotrifluoroethyl acetate was pumped into the elimination reactors A9 and B10 (the amount of feed into the two reactors was equally divided), and at the same time, the elimination reaction circulating pump 18 was started to circulate the materials in the reactors, so as to ensure that the materials were in full contact with the catalyst.

[0047] Elimination reaction control: The reaction temperature of the elimination reactors A9 and B10 was controlled to be 28-38°C, and the reaction pressure was controlled to be 0.05-0.15 MPa. Under the action of the catalyst and the polymerization inhibitor, 2-chlorotrifluoroethyl acetate underwent elimination reaction to generate vinyl trifluoroacetate, and at the same time, hydrogen chloride gas was generated.

[0048] Tail gas treatment and product transfer: The hydrogen chloride gas generated in the elimination reaction entered the gas-liquid separator C11, and the condensation temperature was controlled to be 0-3°C. The liquid of vinyl trifluoroacetate entrained in the gas was separated and refluxed to the elimination reactor B10. The hydrogen chloride gas after condensation entered the tail gas absorption tower 16 (which was shared with the esterification reaction), was absorbed by deionized water to generate dilute hydrochloric acid, and was transported to the dilute hydrochloric acid storage tank 17. Every 20 min, the content of vinyl trifluoroacetate in the elimination reactor B10 was sampled and detected. When the content was ≥98.5%, the elimination reaction circulating pump 18 was stopped, the valve between the elimination reactor B10 and the vinyl trifluoroacetate crude product storage tank 12 was opened, and the reaction product was transported to the vinyl trifluoroacetate crude product storage tank 12. At the same time, the feed flow of 2-chlorotrifluoroethyl acetate and the opening degree of the feed valve of the vinyl trifluoroacetate crude product storage tank 12 were adjusted, so that the liquid level of the materials in the elimination reactors A9 and B10 was stably controlled at 85-95%, and the continuous and balanced operation of the elimination reaction was realized.

[0049] (III) Rectification step Rectification control: The discharge pump 19 of the vinyl trifluoroacetate crude product storage tank 12 was started, and the crude product was pumped into the rectification tower 13. The temperature of the tower bottom was 40-60°C, and the temperature of the tower top was 38-42°C. The condenser refluxer 14 was started, and the reflux ratio was adjusted to be 5:1. The vapor at the tower top was condensed, part of which was refluxed to the rectification tower, and part of which was output as qualified product.

[0050] Product collection: after the rectification of the purified vinyl trifluoroacetate vapor is separated by refluxer 14, the qualified product (purity ≥ 99.0%) enters the vinyl trifluoroacetate product storage tank 15; the heavy components produced in the rectification column 13 column (mainly unreacted 2-chloroethyl trifluoroacetate) are transported to the 2-chloroethyl trifluoroacetate storage tank 8 for secondary reaction to improve the utilization rate of raw materials.

[0051] Example 1 The synthesis method of the vinyl trifluoroacetate includes the following steps: Open the metering pump 2, and pump the 2-chloroethanol raw material with a purity ≥ 99.5% in the 2-chloroethanol storage tank 1 into the esterification reactor A3 at a flow rate of 160 g / h; at the same time, open the gas phase outlet valve of the trifluoroacetyl chloride storage tank 7, control the pressure of the gas phase trifluoroacetyl chloride to be 0.3 MPa, and make it enter the gas distributor at the bottom of the esterification reactor B5 at a flow rate of 200 g / h. When the material levels of the esterification reactor A3 and the esterification reactor B5 are consistent, first stop the 2-chloroethanol feeding, and continue to pass the trifluoroacetyl chloride gas. Control the reaction temperature of the esterification reactor B5 to be 70°C, and the reaction pressure to be 0.1 MPa.

[0052] Take a sample every 30 min to detect the purity of 2-chloroethyl trifluoroacetate in the esterification reactor B5, when the purity is ≥ 98.5%, open the discharge valve at the bottom of the esterification reactor B5, and transport the 2-chloroethyl trifluoroacetate to the 2-chloroethyl trifluoroacetate storage tank 8; at the same time, adjust the feeding flow rate of the metering pump 2, the opening degree of the discharge valve of the esterification reactor B5, and the opening degree of the trifluoroacetyl chloride valve, so that the molar ratio of 2-chloroethanol and trifluoroacetyl chloride participating in the reaction is controlled to be 1:0.95, and the material levels in the esterification reactor A3 and the esterification reactor B5 are stably controlled at 85-95%, so as to realize the continuous and balanced operation of the esterification reaction. The esterification reaction of 2-chloroethanol is 1610 g, the trifluoroacetyl chloride is 2517 g, and the reaction collects 2-chloroethyl trifluoroacetate 3220 g (molar ratio 1:0.95).

[0053] The reaction temperature of the esterification reactor A3 and the esterification reactor B5 is controlled at 70°C, and the reaction pressure is controlled at 0.1 MPa.

[0054] The product collection: the vinyl trifluoroacetate vapor after the rectification is separated by the refluxer 14, and the qualified product (purity ≥ 99.2%) enters the vinyl trifluoroacetate product storage tank 15.

[0055] The total amount of the trifluoroacetyl chloride added in the example is 2517 g, the amount of 2-chloroethanol is 1610 g, and the amount of the vinyl trifluoroacetate product after the rectification is 2440 g, with a purity of 99.7% and a yield of 91.7% (calculated based on the trifluoroacetyl chloride).

[0056] Example 2 The synthesis method of the vinyl trifluoroacetate includes the following steps: The metering pump 2 is opened, and the 2-chloroethanol raw material with a purity of ≥ 99.5% in the 2-chloroethanol storage tank 1 is pumped into the esterification reactor A3 at a flow rate of 160 g / h; at the same time, the gas phase outlet valve of the trifluoroacetyl chloride storage tank 7 is opened, the pressure of the gas phase trifluoroacetyl chloride is controlled at 0.3 MPa, and the trifluoroacetyl chloride is made to enter the gas distributor at the bottom of the esterification reactor B5 at a flow rate of 200 g / h. When the liquid levels of the esterification reactor A3 and the esterification reactor B5 are consistent, the 2-chloroethanol feeding is stopped first, and the trifluoroacetyl chloride gas is continuously fed. The reaction temperature of the esterification reactor B5 is controlled at 70°C, and the reaction pressure is controlled at 0.1 MPa.

[0057] The purity of the ethyl 2-chlorotrifluoroacetate in the esterification reactor B5 is detected every 30 minutes. When the purity is greater than or equal to 98.5%, the discharge valve at the bottom of the esterification reactor B5 is opened, and the ethyl 2-chlorotrifluoroacetate is transported to the ethyl 2-chlorotrifluoroacetate storage tank 8. At the same time, the mass ratio of the 2-chloroethanol and the acetyl chloride participating in the reaction is controlled to be 1:0.95 by adjusting the feed flow rate of the metering pump 2, the opening degree of the esterification reactor B5 discharge valve and the acetyl chloride valve opening degree, so that the liquid level of the materials in the esterification reactor A3 and the esterification reactor B5 is stabilized at 85-95%, and the continuous and balanced operation of the esterification reaction is realized. The esterification reaction is carried out with 1680g of 2-chloroethanol and 2626g of acetyl chloride (mass ratio 1:0.95), and 3289g of ethyl 2-chlorotrifluoroacetate is collected.

[0058] The reaction temperature of the elimination reactors A9 and B10 is controlled to be 33°C, and the reaction pressure is 0.08MPa. The content of the vinyl trifluoroacetate in the elimination reactors is detected every 20 minutes. When the content is greater than or equal to 98.5%, the elimination reaction circulating pump 18 is stopped, the valve between the elimination reactor B10 and the crude vinyl trifluoroacetate storage tank 12 is opened, and the reaction product is transported to the crude vinyl trifluoroacetate storage tank 12. The discharge pump of the crude vinyl trifluoroacetate storage tank 12 is opened, the crude product is pumped into the rectification tower 13, the tower bottom temperature is 50°C, and the tower top temperature is 40°C. The refluxer 14 is opened, and the reflux ratio is adjusted to be 5:1. After the tower top vapor is condensed, part of it is refluxed to the rectification tower 13, and part of it is output as qualified product.

[0059] The reaction temperature of the elimination reactors A9 and B10 is controlled to be 33°C, and the reaction pressure is 0.08MPa. The content of the vinyl trifluoroacetate in the elimination reactors is detected every 20 minutes. When the content is greater than or equal to 98.5%, the elimination reaction circulating pump 18 is stopped, the valve between the elimination reactor B10 and the crude vinyl trifluoroacetate storage tank 12 is opened, and the reaction product is transported to the crude vinyl trifluoroacetate storage tank 12. The discharge pump of the crude vinyl trifluoroacetate storage tank 12 is opened, the crude product is pumped into the rectification tower 13, the tower bottom temperature is 50°C, and the tower top temperature is 40°C. The refluxer 14 is opened, and the reflux ratio is adjusted to be 5:1. After the tower top vapor is condensed, part of it is refluxed to the rectification tower 13, and part of it is output as qualified product.

[0060] The reaction temperature of the elimination reactors A9 and B10 is controlled to be 33°C, and the reaction pressure is 0.08MPa. The content of the vinyl trifluoroacetate in the elimination reactors is detected every 20 minutes. When the content is greater than or equal to 98.5%, the elimination reaction circulating pump 18 is stopped, the valve between the elimination reactor B10 and the crude vinyl trifluoroacetate storage tank 12 is opened, and the reaction product is transported to the crude vinyl trifluoroacetate storage tank 12. The discharge pump of the crude vinyl trifluoroacetate storage tank 12 is opened, the crude product is pumped into the rectification tower 13, the tower bottom temperature is 50°C, and the tower top temperature is 40°C. The refluxer 14 is opened, and the reflux ratio is adjusted to be 5:1. After the tower top vapor is condensed, part of it is refluxed to the rectification tower 13, and part of it is output as qualified product.

[0061] Example 3 The synthesis method of the vinyl trifluoroacetate comprises the following steps: The metering pump 2 is opened, and 2-chloroethanol raw material with purity ≥ 99.5% in the 2-chloroethanol storage tank 1 is pumped into the esterification reactor A3 at a flow rate of 160 g / h; at the same time, the gas phase outlet valve of the trifluoroacetyl chloride storage tank 7 is opened, and the pressure of the gas phase trifluoroacetyl chloride is controlled to be 0.3 MPa, so that it enters the gas distributor at the bottom of the esterification reactor B5 at a flow rate of 200 g / h. When the material levels of the esterification reactor A3 and the esterification reactor B5 are consistent, the 2-chloroethanol feeding is stopped first, and the trifluoroacetyl chloride gas is continuously fed. The reaction temperature of the esterification reactor B5 is controlled to be 60°C, and the reaction pressure is 0.1 MPa.

[0062] The purity of 2-chlorotrifluoroethyl acetate in the esterification reactor B5 is detected every 30 min, and when the purity ≥ 98.5%, the discharge valve at the bottom of the esterification reactor B5 is opened, and the 2-chlorotrifluoroethyl acetate is transported to the 2-chlorotrifluoroethyl acetate storage tank 8; at the same time, by adjusting the feeding flow rate of the metering pump 2, the opening degree of the discharge valve of the esterification reactor B5 and the opening degree of the trifluoroacetyl chloride valve, the mass ratio of 2-chloroethanol and trifluoroacetyl chloride participating in the reaction is controlled to be 1:0.9, so that the material levels in the esterification reactor A3 and the esterification reactor B5 are stably controlled in the range of 85-95%, and the continuous and balanced operation of the esterification reaction is realized. The esterification reaction of 2-chloroethanol is 1702 g, the trifluoroacetyl chloride is 2520 g, and the reaction of 2-chlorotrifluoroethyl acetate is 3123 g (mass ratio 1:0.9).

[0063] The elimination reaction: the catalyst of polystyrene loaded DBU and the polymerization inhibitor are added into the elimination reactor A9 and the elimination reactor B10 respectively, the catalyst amount is 1.1 times of the pre-reaction 2-chlorotrifluoroethyl acetate, and the amount of the polymerization inhibitor 3,5-di-tert-butyl catechol is 0.05wt% of the feeding amount of 2-chlorotrifluoroethyl acetate; the discharge pump of the 2-chlorotrifluoroethyl acetate storage tank 8 is opened, and the 2-chlorotrifluoroethyl acetate is pumped into the elimination reactor A9 and the elimination reactor B10 at a flow rate of 350 g / h respectively, and the elimination reaction circulating pump 18 is opened at the same time, so that the material in the reactor circulates to ensure that the material and the catalyst are in full contact. The reaction temperature of the elimination reactor A9 and the elimination reactor B10 is controlled to be 28°C, and the reaction pressure is 0.05 MPa, the content of vinyl trifluoroacetate in the elimination reactor is detected every 20 min, and when the content ≥ 98.5%, the elimination reaction circulating pump 18 is stopped, the valve between the elimination reactor B10 and the crude vinyl trifluoroacetate storage tank 12 is opened, and the reaction product is transported to the crude vinyl trifluoroacetate storage tank 12. The discharge pump of the crude vinyl trifluoroacetate storage tank 12 is opened, and the crude product is pumped into the rectifying column 13, the column bottom temperature is 50°C, and the column top temperature is 40°C; the refluxer 14 is opened, and the reflux ratio is adjusted to be 5:1, so that the column top vapor is condensed, part of which is refluxed to the rectifying column 13, and part of which is output as qualified product.

[0064] Product collection: after the rectification of the purified vinyl trifluoroacetate steam through refluxer 14, the qualified product (purity ≥ 99.2%) enters the vinyl trifluoroacetate product storage tank 15.

[0065] The total amount of trifluoroacetyl chloride added in this example is 2520g, the amount of 2-chloroethanol is 1702g, the amount of vinyl trifluoroacetate product after rectification is 2401g, the purity is 99.5%, and the yield is 90.1% (calculated based on trifluoroacetyl chloride).

[0066] Example 4 The synthesis method of the vinyl trifluoroacetate includes the following steps: Open the metering pump 2 to pump the 2-chloroethanol raw material with a purity of ≥99.5% from the 2-chloroethanol storage tank 1 into the esterification reactor A3 at a flow rate of 160g / h; at the same time, open the gas phase outlet valve of the trifluoroacetyl chloride storage tank 7 and control the pressure of the gas phase trifluoroacetyl chloride to be 0.3MPa, so that it enters the gas distributor at the bottom of the esterification reactor B5 at a flow rate of 200g / h. When the liquid levels of the esterification reactor A3 and the esterification reactor B5 are consistent, stop the 2-chloroethanol feed first and continue to pass the trifluoroacetyl chloride gas. Control the reaction temperature of the esterification reactor B5 to be 80℃ and the reaction pressure to be 0.1MPa.

[0067] Take samples every 30min to detect the purity of 2-chlorotrifluoroacetate ethyl ester in the esterification reactor B5, when the purity is ≥98.5%, open the discharge valve at the bottom of the esterification reactor B5 to transport the 2-chlorotrifluoroacetate ethyl ester to the 2-chlorotrifluoroacetate ethyl ester storage tank 8; at the same time, adjust the feed flow rate of the metering pump 2, the opening degree of the discharge valve of the esterification reactor B5 and the opening degree of the trifluoroacetyl chloride valve to control the molar ratio of the 2-chloroethanol and the trifluoroacetyl chloride participating in the reaction to be 1:1, so that the liquid levels of the esterification reactor A3 and the esterification reactor B5 are stably controlled at 85-95%, realizing the continuous and balanced operation of the esterification reaction. The reaction of 2-chloroethanol is 1560g, the reaction of trifluoroacetyl chloride is 2567g (molar ratio 1:1), and the reaction collection of 2-chlorotrifluoroacetate ethyl ester is 3266g.

[0068] The degeneration reaction: the catalyst of polystyrene loaded DBN and the polymerization inhibitor were added into the degeneration reactor A9 and the degeneration reactor B10 respectively, the amount of the catalyst was 2.0 times of the 2-chloroethyl trifluoroacetate in the pre-reaction, and the amount of the polymerization inhibitor 3,5-di-tert-butyl catechol was 0.1wt% of the amount of the 2-chloroethyl trifluoroacetate; the discharge pump of the 2-chloroethyl trifluoroacetate storage tank 8 was opened, and the 2-chloroethyl trifluoroacetate was pumped into the degeneration reactor A9 and the degeneration reactor B10 at a flow rate of 350g / h, and the degeneration reaction circulating pump 18 was opened at the same time to make the material in the reactor circulate and ensure that the material and the catalyst were in sufficient contact. The reaction temperature of the degeneration reactor A9 and the degeneration reactor B10 was controlled at 38℃, and the reaction pressure was 0.15MPa. The content of the vinyl trifluoroacetate in the degeneration reactor was detected every 20min, and when the content was ≥98.5%, the degeneration reaction circulating pump 18 was stopped, the valve between the degeneration reactor B10 and the vinyl trifluoroacetate crude product storage tank 12 was opened, and the reaction product was transported to the vinyl trifluoroacetate crude product storage tank 12. The discharge pump of the vinyl trifluoroacetate crude product storage tank 12 was opened, and the crude product was pumped into the rectification tower 13, the temperature of the tower bottom was 50℃, and the temperature of the tower top was 40℃; the refluxer 14 was opened, and the reflux ratio was adjusted to 5:1, so that the tower top vapor was condensed, part of which was refluxed to the rectification tower 13, and part of which was output as qualified product.

[0069] Product collection: after the rectification and purification, the qualified product (purity ≥99.2%) was separated by the refluxer 14, and then entered the vinyl trifluoroacetate product storage tank 15.

[0070] In this embodiment, 2567g of trifluoroacetyl chloride, 1560g of 2-chloroethanol and 2461g of vinyl trifluoroacetate after rectification were added, the purity was 99.5%, and the yield was 90.7% (calculated based on trifluoroacetyl chloride).

[0071] Example 5 The synthesis method of the vinyl trifluoroacetate includes the following steps: The metering pump 2 was opened, and the 2-chloroethanol raw material with a purity ≥99.5% in the 2-chloroethanol storage tank 1 was pumped into the esterification reactor A3 at a flow rate of 160g / h; at the same time, the gas phase outlet valve of the trifluoroacetyl chloride storage tank 7 was opened, the pressure of the gas phase trifluoroacetyl chloride was controlled at 0.3MPa, and the trifluoroacetyl chloride was made to enter the gas distributor at the bottom of the esterification reactor B5 at a flow rate of 200g / h. When the liquid levels of the esterification reactor A3 and the esterification reactor B5 were consistent, the 2-chloroethanol feeding was stopped, and the trifluoroacetyl chloride gas was continued to be fed. The reaction temperature of the esterification reactor B5 was controlled at 80℃, and the reaction pressure was 0.1MPa.

[0072] The purity of ethyl 2-chlorotrifluoroacetate in esterification reactor B5 was sampled every 30 minutes, and when the purity was ≥98.5%, the discharge valve at the bottom of esterification reactor B5 was opened to transport the ethyl 2-chlorotrifluoroacetate to the ethyl 2-chlorotrifluoroacetate storage tank 8; at the same time, the mass ratio of 2-chloroethanol and trifluoroacetyl chloride participating in the reaction was controlled to be 1:1 by adjusting the feed flow rate of metering pump 2, the opening degree of the esterification reactor B5 discharge valve and the trifluoroacetyl chloride valve, and the liquid level of the materials in esterification reactor A3 and esterification reactor B5 was stabilized at 85-95%, so that the esterification reaction was continuously and balancedly operated, and the esterification reaction was 2-chloroethanol 1644g, trifluoroacetyl chloride 2705g, (mass ratio 1:1) and the reaction collected 2-chlorotrifluoroacetate 3460g.

[0073] Elimination reaction: polyphenylethylene supported DBU catalyst and polymerization inhibitor were added to the elimination reactor A9 and the elimination reactor B10, respectively, the amount of catalyst was 2.0 times of the pre-reaction ethyl 2-chlorotrifluoroacetate, and the amount of polymerization inhibitor 3,5-di-tert-butyl catechol was 0.1wt% of the amount of ethyl 2-chlorotrifluoroacetate feed; the discharge pump of the ethyl 2-chlorotrifluoroacetate storage tank 8 was opened, and the ethyl 2-chlorotrifluoroacetate was pumped into the elimination reactor A9 and the elimination reactor B10 at a flow rate of 350g / h, respectively, and the elimination reaction circulating pump 18 was opened at the same time to make the materials in the reactor circulate and ensure that the materials and the catalyst were in full contact. The reaction temperature of the elimination reactor A9 and the elimination reactor B10 was controlled at 38℃, and the reaction pressure was 0.15MPa, the content of vinyl trifluoroacetate in the elimination reactor was sampled every 20 minutes, when the content was ≥98.5%, the elimination reaction circulating pump 18 was stopped, the valve between the elimination reactor B10 and the crude vinyl trifluoroacetate storage tank 12 was opened, and the reaction product was transported to the crude vinyl trifluoroacetate storage tank 12. The discharge pump of the crude vinyl trifluoroacetate storage tank 12 was opened, and the crude product was pumped into the rectification tower 13, the tower bottom temperature was 50℃, and the tower top temperature was 40℃; the refluxer 14 was opened, and the reflux ratio was adjusted to 5:1, so that the tower top vapor was separated after condensation, part of which was refluxed to the rectification tower 13, and part of which was output as qualified product.

[0074] Finished product collection: after the rectification and purification, the qualified product (purity ≥99.2%) was transported to the vinyl trifluoroacetate finished product storage tank 15 after the vapor was separated by the refluxer 14.

[0075] In this example, 2705g of trifluoroacetyl chloride, 1644g of 2-chloroethanol and 2637g of vinyl trifluoroacetate after rectification were added, the purity was 99.6%, and the yield was 92.2% (calculated based on trifluoroacetyl chloride).

Claims

1. A method for the synthesis of vinyl trifluoroacetate, characterized in that: First, 2-chloroethanol and trifluoroacetyl chloride are reacted to generate 2-chloroethyl trifluoroacetate, then the 2-chloroethyl trifluoroacetate is subjected to an elimination reaction under the condition of a catalyst and a polymerization inhibitor to generate crude vinyl trifluoroacetate, and finally, the crude vinyl trifluoroacetate is rectified to obtain the vinyl trifluoroacetate product.

2. The method of synthesis of vinyl trifluoroacetate according to claim 1, characterized by that: The 2-chloroethanol and the trifluoroacetyl chloride are in a molar ratio of 1:1-1:0.

9.

3. The method of synthesis of vinyl trifluoroacetate according to claim 2, characterized by that: The catalyst is polystyrene loaded with 1,8-diazabicycloundec-7-ene or 1,5-diazabicyclo[4.3.0]non-5-ene, and the loading amount is 15-30 mol%; the catalyst is added in an amount of 1.1-2.0 times the molar amount of the theoretical 2-chloroethyl trifluoroacetate.

4. The method of synthesis of vinyl trifluoroacetate according to claim 3, characterized by that: The polymerization inhibitor is 3,5-di-tert-butylcatechol, and the polymerization inhibitor is added in an amount of 0.05%-0.1% of the mass of the theoretical 2-chloroethyl trifluoroacetate feed.

5. The method of synthesis of vinyl trifluoroacetate according to claim 1, characterized by that: 2-chloroethanol and trifluoroacetyl chloride are reacted to generate 2-chloroethyl trifluoroacetate, and hydrogen chloride is also generated, which is absorbed by water to obtain by-product hydrochloric acid.

6. The method of synthesis of vinyl trifluoroacetate according to claim 1, characterized by that: The reaction temperature of 2-chloroethanol and trifluoroacetyl chloride is 60-80°C, and the reaction pressure is 0.05-0.15 MPa.

7. The method of synthesis of vinyl trifluoroacetate according to claim 1, characterized by that: The elimination reaction temperature is 28-38°C, and the reaction pressure is 0.05-0.15 MPa.

8. A vinyl trifluoroacetate characterized by: The vinyl trifluoroacetate is synthesized by the synthesis method of the vinyl trifluoroacetate according to any one of claims 1-7.

9. A synthesis apparatus for use in a method of synthesizing vinyl trifluoroacetate according to any one of claims 1 to 7, characterized in that: The reaction system includes at least one set of reaction systems, specifically including an esterification reactor, an elimination reactor, and a rectification tower, and the esterification reactor, the elimination reactor, and the rectification tower are sequentially connected by pipelines.

10. The synthesis apparatus for use in the synthesis method of vinyl trifluoroacetate according to claim 9, characterized in that: The specific set of reaction systems includes an esterification reactor A (3), an esterification reactor B (5), an elimination reactor A (9), and an elimination reactor B (10), the liquid outlet of the esterification reactor A (3) is connected to the liquid inlet of the esterification reactor B (5), the gas outlet of the esterification reactor B (5) is connected to a gas-liquid separator B (6), the gas-liquid separator B (6) is connected to the gas inlet of the esterification reactor A (3); the liquid outlet of the esterification reactor B (5) is connected to a 2-chloroethyl trifluoroacetate storage tank (8), the 2-chloroethyl trifluoroacetate storage tank (8) is connected to the elimination reactor A (9), the gas outlet of the elimination reactor A (9) is connected to the gas inlet of the elimination reactor B (10), the elimination reactor B (10) is connected to a crude vinyl trifluoroacetate storage tank (12), and the crude vinyl trifluoroacetate storage tank (12) is connected to a rectification tower (13).

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