Continuous synthesis and purification method of 1, 1, 2, 2-tetrafluoroethyl-2, 2, 2-trifluoroethyl ether
By constructing a continuous process system and using multi-solvent targeted washing technology, the problem of catalyst recycling has been solved, enabling efficient and low-cost production of hydrofluoroethers with electronic-grade purity, suitable for high-end applications.
Patent Information
- Application Number
- CN202511653305.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-12
- Publication Date
- 2026-03-20
AI Technical Summary
In existing technologies, catalysts are difficult to recover and recycle during the production of hydrofluoroethers, resulting in resource waste and high costs. At the same time, the preparation of composite catalysts is complicated, generating a large amount of solid waste and increasing post-treatment costs.
By employing inexpensive alkaline catalysts and constructing a continuous process system that includes partial discharge of the reaction liquid, initial evaporation separation, and material recycling, the catalysts can be recovered in situ and reused multiple times. Combined with multi-solvent targeted washing and precision distillation technology, high-purity products can be produced continuously.
It enables the recycling of catalysts, reduces production costs, improves production efficiency and equipment utilization, and achieves a product purity of over 99.95%, making it suitable for high-end applications.
Smart Images
Figure CN121698728A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of chemical production, in particular to a continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether. BACKGROUND
[0002] Hydrofluoroethers (HFE) are a class of compounds containing fluorine, carbon, hydrogen, oxygen and other elements, with ODP (ozone depletion potential) of 0 and GWP (global warming potential) far lower than PFAS and other fluorine-containing compounds. Therefore, HFE has the dual advantages of protecting the ozone layer and carbon emission reduction, and is a new generation of ODS (ozone-depleting substances) substitute, which can be widely used in refrigerants, blowing agents, cleaning agents and heat transfer agents, etc.
[0003] Generally, the catalyst used in the production of hydrofluoroethers (HFE) is one or more of potassium hydroxide, sodium hydroxide, sodium ethoxide and potassium ethoxide; a combination of one of sodium hydroxide, potassium hydroxide, sodium ethoxide and potassium ethoxide and calcium hydroxide; a composite catalyst prepared from strong basic anion exchange resin, water, N-hydroxyethyl perfluorooctylsulfonamide, 1,8-diazabicyclo(5,4,0)undec-7-ene, and ethylenediaminetetraacetic acid disodium; a eutectic solvent catalyst DBU-ChCl prepared from 1,8-diazabicycloundec-7-ene (DBU) and choline chloride (ChCl).
[0004] However, in actual production process, if a single component catalyst is used, it is difficult to recover and recycle, causing resource waste; the composite catalyst needs to be prepared and used immediately, and the preparation steps are complicated, also difficult to realize recovery and recycling, and easy to form a large amount of catalyst solid waste, increasing the cost of post-treatment. SUMMARY
[0005] I. Technical problems to be solved The present application proposes a continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, which utilizes the fact that the boiling point of the target product is much lower than that of the raw material and solvent, and the product and the raw material and solvent cannot form azeotrope. After a certain period of time, the reaction liquid is discharged and distilled, and the raw material is returned to the reaction kettle to continue to participate in the reaction, thereby realizing the continuous synthesis of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether.
[0006] II. Specific technical solutions A continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, comprising the following steps: S1. In a reaction kettle, trifluoroethanol and tetrafluoroethylene are subjected to addition reaction in the presence of a catalyst and a solvent; S2. A part of the reaction liquid obtained in step S1 is discharged and subjected to initial distillation to obtain a crude product rich in 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether and an initial distillation kettle bottom material rich in catalyst, trifluoroethanol and solvent; S3. At least part of the initial distillation kettle bottom material is returned to the reaction kettle, and new trifluoroethanol and tetrafluoroethylene are continuously added to the reaction kettle to realize continuous reaction; S4. The crude product obtained in step S2 is subjected to washing and rectification to obtain a high-purity 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether product.
[0007] Principle of implementation, working principle: The core principle of the scheme is to construct a continuous process system characterized by "partial discharge of reaction liquid, initial distillation separation, material circulation"; by continuously discharging the reaction liquid, the limitations of batch kettle reaction are broken, and the continuous operation characteristics of "discharge-initial distillation-return" realize the continuous production in essence, greatly improving the production efficiency and device utilization rate; and the initial distillation column is used to realize the rapid and online separation of the product and the reactant / catalyst; most importantly, by returning the initial distillation kettle bottom material rich in catalyst and raw material to the reaction kettle and combining it with the continuously added new raw material, a dynamic balance material circulation loop is formed, realizing the fundamental change from batch to continuous production, and the material circulation keeps the relative stability of the catalyst and raw material concentration in the reaction system, which is beneficial to the smooth and efficient reaction and improves the consistency of product quality.
[0008] As a preferred, in step S2, when the content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the initial distillation kettle bottom material is lower than a preset threshold value, it is discharged to a raw material storage tank and returned to the reaction kettle together with the newly added trifluoroethanol, solvent and catalyst; the beneficial effect of this preferred is that the preset threshold value realizes the accurate and optimized circulation of materials, avoids the infinite accumulation of products in the system, and ensures the long-term stable operation of the continuous process; the raw material storage tank facilitates the centralized addition and adjustment of raw materials, solvents and catalysts, so that the material mixing is more uniform and the feed composition is more controllable.
[0009] Preferably, the catalyst is a basic compound, or a co-solubilized catalyst formed by the basic compound and a metal oxide; the basic compound is selected from one or more of the group consisting of sodium hydroxide, potassium hydroxide, sodium ethoxide, potassium ethoxide, calcium hydroxide, lithium hydroxide, cesium hydroxide, and magnesium hydroxide. The beneficial effect of this preferred option is that choosing a "basic compound" as a catalyst makes the catalyst cost extremely low and easy to obtain, eliminating the dependence on special and expensive catalytic materials. Moreover, by utilizing the characteristics of these basic compounds, the protons of trifluoroethanol are efficiently captured to generate highly reactive trifluoroethanol anions, which nucleophilically attack the double bonds of tetrafluoroethylene to complete the addition reaction. It also provides the possibility of subsequent recycling and reuse of the catalyst in a homogeneous system.
[0010] Preferably, the catalyst can be recovered and reused through the recycling of the bottom material of the primary distillation vessel. The beneficial effect of this preferred method is that by directly recycling the bottom material back to the reactor, the catalyst is naturally and physically transported back to the reaction zone without the need for additional separation, purification or regeneration activation steps, thereby achieving recycling and reducing the generation of solid waste from the source and solving the environmental protection and treatment problems caused by the single use of catalysts in the prior art.
[0011] Preferably, in step S4, the washing is performed using a variety of solvents, which are selected from one or more of the group consisting of ethanol, saturated sodium bicarbonate solution and deionized water. The advantage of this preferred method is that the multi-step washing technology of "ethanol-sodium bicarbonate-water" can target and remove various impurities in the crude product, resulting in a comprehensive and thorough purification effect.
[0012] Preferably, the high-purity 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether product obtained in step S4 has a purity of not less than 99.95% and a water content of less than 30 ppm. The beneficial effect of this preferred option is that the purity and water content of the product are set to these parameters, so that the product reaches the electronic grade and meets the requirements of high purity.
[0013] Preferably, the solvent is selected from one or more of the group consisting of polyether glycol dialkyl ether, dimethylformamide, dimethyl sulfoxide, 1,8-diazabicycloundec-7-ene, dimethylacetamide, and alcohol solvents; in step S1, the weight ratio of the solvent to trifluoroethanol is 5:1 to 50:1; and / or the weight ratio of the catalyst to trifluoroethanol is 1:10 to 1:100; the molar ratio of tetrafluoroethylene to trifluoroethanol is 1:0.1 to 1:100; in step S1, the reaction temperature is 40°C to 100°C, and the reaction pressure is 0.5 MPa to 1.0 MPa; the beneficial effect of this preferred method is that operating under these preferred process parameters can ensure that the reaction proceeds steadily at a high rate and with high selectivity, thereby stably obtaining products with high yield and high purity, and has obvious feasibility and reproducibility.
[0014] The beneficial effects of this invention are as follows: 1. By selecting a simple and inexpensive alkaline catalyst and utilizing the core technical feature of "recycling the bottom material of the primary distillation vessel", the catalyst can be recovered in situ and reused multiple times within the reaction system. This completely changes the existing technology's "one-time use" or "prepared and used on the spot" model of catalysts, significantly reducing the generation of solid waste and the high procurement cost of catalysts from the source, making the entire production process more economical and environmentally friendly.
[0015] 2. By constructing a continuous process system of "continuous discharge of reaction liquid - initial evaporation separation - material circulation", the traditional batch operation is transformed into a continuous steady-state process. This technology greatly improves equipment utilization and production efficiency, avoids the energy consumption and operational intensity caused by frequent start-up and shutdown, and makes the production process easier to control, significantly improving the inherent safety of the process and the stability of large-scale production.
[0016] 3. By adopting a post-treatment technology solution that combines "multi-solvent targeted washing" with precision distillation, various organic, acidic and inorganic impurities in the crude product are systematically removed. This optimization ensures that the purity of the final product is as high as 99.95% or more and the water content is less than 30ppm. Key indicators meet electronic grade standards, thus breaking through the limitation that traditional products can only be used in general fields, and enabling them to be applied to high-end fields such as semiconductor cleaning that have stringent purity requirements. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the process flow according to an embodiment of the present invention. Detailed Implementation
[0018] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0019] like Figure 1 As shown: The present invention provides a continuous synthesis and purification method for 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, the specific implementation method of which and the beneficial effects of each step are described below: S1. Addition reaction step: In a high-pressure reactor equipped with a stirrer, temperature control jacket and pressure control, the following operations are carried out: a catalyst, trifluoroethanol and solvent are added; wherein the catalyst is potassium hydroxide, and its weight ratio with trifluoroethanol is 1:20; the solvent is polyether glycol dialkyl ether, and its weight ratio with trifluoroethanol is 10:1.
[0020] After shutting down the reactor and replacing the air inside with nitrogen, the temperature was raised to 60°C. Tetrafluoroethylene gas was continuously introduced into the reactor, controlling the molar ratio of tetrafluoroethylene to trifluoroethanol at 1:2, and maintaining the reaction pressure at 0.7 MPa. Under these conditions, trifluoroethanol and tetrafluoroethylene underwent a catalytic addition reaction. In this process, inexpensive and readily available potassium hydroxide was selected as the catalyst, eliminating the complex and pre-prepared catalyst system of existing technologies. This significantly reduced the cost and complexity of catalyst preparation from the source, laying the foundation for the subsequent recycling of the catalyst.
[0021] S2. Discharge and Pre-distillation Step: After the above reaction has proceeded for 3 hours, the discharge pump is started to continuously discharge the reaction liquid from the reactor at a constant flow rate and transport it to the pre-distillation tower. In the pre-distillation tower, the temperature of the bottom of the tower is controlled at 110℃ and the temperature of the top of the tower is controlled at about 65℃ for atmospheric distillation. The crude product rich in 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is collected from the top of the tower; the bottom of the tower yields the pre-distillation bottom material rich in unreacted trifluoroethanol, solvent, and catalyst. "Reaction liquid discharge and pre-distillation" is the key to achieving continuous production. This step separates the product from the reaction system online, breaking the limitations of traditional batch reactions and creating conditions for building a material circulation loop, which is the core link to improve production efficiency.
[0022] S3. Material recycling and continuous reaction steps: At least most of the pre-distillation reactor bottom material obtained in step S2 is directly returned to the reactor in step S1 via a transfer pump. Simultaneously, new trifluoroethanol and tetrafluoroethylene are continuously added to the reactor at a flow rate matching the discharge rate and material consumption. This step, through "pre-distillation reactor bottom material recycling," achieves in-situ recovery and recycling of catalyst and unreacted raw materials, significantly reducing solid waste generation and raw material consumption. Furthermore, combined with continuous feeding, it constructs a highly efficient continuous production process, significantly improving production efficiency and equipment utilization, while reducing safety risks.
[0023] S4. Washing and Distillation Steps The crude product obtained in step S2. was purified as follows: the crude product was washed once with an equal volume of saturated sodium bicarbonate solution to neutralize acidic impurities; then washed three times with an equal volume of deionized water to remove inorganic salts and residual alkali; the washed organic layer was then distilled into a precision distillation column, the reflux ratio was controlled, and the fraction at 59-60℃ was collected; finally, high-purity 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether was obtained; analysis showed that its purity reached 99.96% and the water content was 15 ppm. The combined purification scheme of "multi-solvent targeted washing" and "precision distillation" systematically removed various impurities; this improved post-treatment process directly ensured that the product purity reached 99.96% and the water content was less than 30 ppm, meeting electronic-grade standards and satisfying the stringent requirements of the high-end electronic cleaning field, greatly enhancing the product value.
[0024] In summary, this implementation method, through the orderly connection and synergistic effect of four core steps, fully realizes the three major beneficial effects of "cost reduction through catalyst recycling", "efficiency improvement through continuous production" and "upgrading of product purity".
[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims.
Claims
1. A continuous synthesis and purification method for 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, characterized in that, Includes the following steps: S1. In a reaction vessel, trifluoroethanol and tetrafluoroethylene undergo an addition reaction in the presence of a catalyst and a solvent; S2. A portion of the reaction liquid obtained in step S1 is discharged and subjected to initial distillation to obtain a crude product rich in 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether and a bottom material of the initial distillation vessel rich in catalyst, trifluoroethanol and solvent. S3. At least a portion of the pre-distillation kettle bottom material is returned to the reactor, and new trifluoroethanol and tetrafluoroethylene are continuously added to the reactor to achieve a continuous reaction; S4. The crude product obtained in step S2 is washed and distilled to obtain a high-purity 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether product.
2. The continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether according to claim 1, characterized in that, In step S2, when the content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the bottom material of the primary distillation vessel is lower than a preset threshold, it is discharged to a raw material storage tank and returned to the reaction vessel together with the newly added trifluoroethanol, solvent and catalyst.
3. The continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether according to claim 1, characterized in that, The catalyst is an alkaline compound, or a co-solubilized catalyst formed by the alkaline compound and a metal oxide; the alkaline compound is selected from one or more of the group consisting of sodium hydroxide, potassium hydroxide, sodium ethoxide, potassium ethoxide, calcium hydroxide, lithium hydroxide, cesium hydroxide and magnesium hydroxide.
4. The continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether according to claim 3, characterized in that, The catalyst can be recovered and reused through the recycling of the bottom material of the primary steamer.
5. The continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether according to claim 1, characterized in that, In step S4, the washing is performed using a variety of solvents, which are selected from one or more of the group consisting of ethanol, saturated sodium bicarbonate solution and deionized water.
6. The continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether according to claim 1, characterized in that, The high-purity 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether product obtained in step S4 has a purity of not less than 99.95% and a water content of less than 30 ppm.
7. The continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether according to claim 1, characterized in that, The solvent is selected from one or more of the group consisting of polyether glycol dialkyl ethers, dimethylformamide, dimethyl sulfoxide, 1,8-diazabicycloundec-7-ene, dimethylacetamide, and alcohol solvents.
8. The continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether according to claim 1, characterized in that, In step S1, the weight ratio of the solvent to trifluoroethanol is 5:1 to 50:1; and / or, the weight ratio of the catalyst to trifluoroethanol is 1:10 to 1:
100.
9. The continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether according to claim 1, characterized in that, In step S1, the molar ratio of tetrafluoroethylene to trifluoroethanol is 1:0.1 to 1:
100.
10. The continuous synthesis and purification method of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether according to claim 1, characterized in that, In step S1, the reaction temperature is 40°C to 100°C and the reaction pressure is 0.5 MPa to 1.0 MPa.