System and process method for co-production of hexafluoropropylene oxide and trifluoroacetic acid

Abstract

The invention provides a system and a process method for co-production of hexafluoropropylene oxide and trifluoroacetic acid, and relates to the technical field of fluorine chemical industry. The system comprises a raw material storage device, a liquid phase oxidation reaction device, a rectifying tower, a hydrofluoric acid absorption tank, a trifluoroacetic acid absorption tank, a process water tank, a hydrofluoric acid concentration detector and a trifluoroacetic acid concentration detector. According to the method, the hydrofluoric acid and the trifluoroacetic acid are co-produced while the hexafluoropropylene oxide is produced, so that complex production processes such as use of non-renewable resources, high raw material price, use of a catalyst for catalysis, addition of an auxiliary agent and the like in the traditional hydrofluoric acid and trifluoroacetic acid production process are avoided; the technology for continuously producing hydrofluoric acid and trifluoroacetic acid, which is simple and efficient in technological process, low in raw material price and free of catalyst catalysis, is developed, and the technology is relatively high in technicality, low in safety risk and suitable for industrial application.

Description

Technical Field

[0001] The invention relates to the technical field of fluorine chemical industry, and in particular to a system and a process method for co-producing hexafluoropropylene oxide and trifluoroacetic acid. Background Art

[0002] The fluorine chemical industry has a rich variety of products with excellent performance, and has gradually occupied an important position. Fluorine chemical products are divided into inorganic fluorides and organic fluorides, among which hydrofluoric acid and trifluoroacetic acid are the basic fluorine chemical products of inorganic fluorides and organic fluorides respectively. Hydrofluoric acid (Hydrofluoric acid), also known as hydrogen fluoride solution, is clear and colorless, but has strong corrosiveness and can corrode metals, glass and other silicon-containing objects. Therefore, hydrofluoric acid is widely used in the chip manufacturing industry, and its product purity and quality directly affect the development of semiconductor technology. At the same time, hydrofluoric acid is also an important raw material for the production of fluorine refrigerants, fluorine resins, fluorine rubbers and fluorine-containing intermediates, and the market demand for hydrofluoric acid continues to expand. Trifluoroacetic acid (Trifluoroacetic acid) has a chemical formula of C2HF3O2, a boiling point of 72.4℃, and is a colorless and transparent liquid at room temperature. Because trifluoroacetic acid contains a special trifluoromethyl structure, it has excellent properties and can participate in a variety of organic synthesis reactions. It has been widely used in medicine, pesticides, dyes and other fields, and has become a very important fluorine-containing intermediate in the field of fluorine chemicals.

[0003] CN108163812A discloses a method for preparing hydrogen fluoride and hydrofluoric acid, which is 1) mixing a fluorosilicic acid solution and a saturated potassium carbonate solution and then heating the mixture to obtain a potassium fluorosilicate slurry, and filtering the mixture multiple times to obtain a relatively pure potassium fluorosilicate slurry; 2) heating the potassium fluorosilicate slurry and passing it through ammonia water for ammonia solution, filtering and adding potassium fluoride, and concentrating, heating under negative pressure, cooling and crystallizing to obtain a potassium hydrogen fluoride solid; 3) heating, decomposing and calcining the potassium hydrogen fluoride solid to obtain a crude hydrogen fluoride gas; 4) pressurizing the crude hydrogen fluoride gas, rectifying and purifying it, and filtering it through a membrane to obtain a hydrogen fluoride liquid. This method can absorb the hydrogen fluoride gas with high-purity water, thereby improving the purity of hydrofluoric acid. However, the process is relatively complicated, and more additives are added during production, which easily introduces impurities; and there are many filtering, heating and calcining procedures, which improves the product energy consumption and production cost.

[0004] The Chinese invention patent CN113816845A discloses a method for preparing trifluoroacetic acid, which comprises 1) adding an organic solvent solution of an alkali metal trifluoroacetate and a strong acid to a reactor for reaction to generate a mixture containing trifluoroacetic acid and an insoluble salt solid; 2) the mixture is transported, filtered, and accumulated through a sieve plate and collected to obtain a crude mixture; 3) the crude mixture is dried by extrusion and drying with a rake dryer to obtain a liquid phase material, and the trifluoroacetic acid product is obtained after distillation. The invention provides an innovative process for preparing trifluoroacetic acid, but the production process is cumbersome, more equipment is used, and the energy consumption of the product is increased. At the same time, the reliability and safety of the equipment are required to be high. In addition, solid waste is easily generated in the extrusion and filtration section, and further research is needed on the storage and disposal of solid waste. The equipment and materials in the transportation, filtration, drying and other sections are replaced frequently, which increases the frequency of manual maintenance operations and has certain production risks.

[0005] At present, fluorite is still one of the main raw materials for the production of hydrogen fluoride. The technology of producing hydrogen fluoride by fluorite-sulfuric acid method has been developed to be relatively mature, but it still has problems such as high energy consumption, high cost and serious environmental pollution when applied to industrial production. At the same time, fluorite is a non-renewable resource, and fluorite ore resources are becoming increasingly scarce. The development of new hydrogen fluoride production technology, the development of circular economy, and the realization of efficient, circular and economic development of fluorine chemical industry have become important issues to be solved urgently.

[0006] Traditional production of trifluoroacetic acid mainly includes the following processes: 1) Using trifluorodichloroethane as raw material, trichloroacetyl chloride and trifluoroacetic acid are generated under the action of a catalyst, and then separated and purified to obtain high-quality trifluoroacetic acid. Although this production process has a high conversion rate, it needs to be carried out under high temperature and high pressure conditions, has high requirements for equipment, and has certain production risks; 2) Using trifluoroethanol as raw material, trifluoroacetic acid is generated by liquid phase catalysis with hydrogen peroxide at low temperature. This process has a high raw material conversion rate and product yield, but the reaction involves a catalyst, and the raw materials trifluoroethanol and hydrogen peroxide are expensive, and the industrial application value is low.

[0007] In summary, the current process routes for producing hydrofluoric acid and trifluoroacetic acid have the following disadvantages: 1) the raw materials are non-renewable energy or are expensive, and the mining cost, production cost and environmental cost are high; 2) the reaction needs to be catalyzed by a catalyst, and the purchase, replacement and disposal of the catalyst increase the production cost; 3) a large number of additives are added, which are easy to bring in impurities and affect the purity of the product; 4) the production process is complicated, the operation procedures are cumbersome, the equipment requirements are high, and the cost of equipment consumables is high; 5) industrial application will generate a large amount of three wastes, the raw material utilization rate is low, and energy saving and consumption reduction and efficient resource utilization are not achieved.

[0008] In view of this, the present invention is proposed. Summary of the invention

[0009] The object of the present invention is to provide a system and process for the co-production of hexafluoropropylene oxide and trifluoroacetic acid. The present invention realizes the production of hydrofluoric acid and trifluoroacetic acid without using a catalyst; and no other additives are added in the process, so as to avoid the introduction of impurity elements and the like; the process is continuous and simple, the production cost is low, the equipment requirements are low, the manual operation frequency is low, the conversion rate and selectivity are high, and it is suitable for industrial production; it is green, economical, and circular production, reduces the amount of three wastes generated, and realizes energy saving and consumption reduction, and efficient production.

[0010] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0011] In a first aspect, the present invention provides a system for co-producing hexafluoropropylene oxide and trifluoroacetic acid, the system comprising a raw material storage device, a liquid phase oxidation reaction device, a distillation tower, a hydrofluoric acid absorption tank, a trifluoroacetic acid absorption tank, a process water tank, a hydrofluoric acid concentration detector, and a trifluoroacetic acid concentration detector;

[0012] The raw material storage device comprises a solvent storage tank, a hexafluoropropylene storage tank and an oxygen storage tank; and the raw material storage devices are all connected to the liquid phase oxidation reaction device;

[0013] The distillation tower comprises a tower top, an upper tower body, a middle tower body and a lower tower body; wherein the product of the tower top comprises carbonyl fluoride gas, the product of the upper tower body comprises trifluoroacetyl fluoride, the product of the middle tower body comprises hexafluoropropylene oxide, and the product of the lower tower body comprises a solvent;

[0014] The hydrofluoric acid absorption tank includes water and is connected to the top of the distillation tower, and is used to absorb carbonyl fluoride gas and convert it into hydrofluoric acid; and the hydrofluoric acid absorption tank is connected to a hydrofluoric acid concentration detector, which is used to display the concentration of hydrofluoric acid in the hydrofluoric acid absorption tank;

[0015] The trifluoroacetic acid absorption tank includes water and is connected to the upper tower body of the distillation tower, and is used to absorb trifluoroacetyl fluoride and convert it into trifluoroacetic acid; and the trifluoroacetic acid absorption tank is connected to a trifluoroacetic acid concentration detector, which is used to display the concentration of trifluoroacetic acid in the trifluoroacetic acid absorption tank;

[0016] The process water tank is connected to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank respectively, and is used to supply water to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank.

[0017] Preferably, the solvent in the solvent storage tank is selected from any one of FC-36, HFC-143a, HFC-142b, HFC-227a, R113, carbon tetrachloride or perfluoropolyether, or a combination of at least two thereof.

[0018] Preferably, the liquid phase oxidation reaction device is a reactor with a stirred tank.

[0019] Preferably, the temperature range of the liquid phase oxidation reaction device is 100-200° C., and the pressure range is 3-5 MPa.

[0020] Preferably, the distillation tower has a diameter ranging from 400 to 900 mm, a height ranging from 10 to 50 m, and a tower pressure ranging from 0.8 to 2.8 MPa.

[0021] Preferably, the distillation tower is selected from a plate tower and / or a packed tower.

[0022] Preferably, the plate type of the plate tower includes any one of a valve plate, a bubble cap plate, a sieve plate, a flow-through tray or a floating tongue plate, or a combination of at least two of them.

[0023] Preferably, the packing of the packed tower includes any one of Raschig ring packing, θ-ring packing, C-type packing or Y-type packing, or a combination of at least two of them.

[0024] Preferably, the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank are for normal pressure absorption and / or pressure absorption.

[0025] Preferably, the pressure of the pressure absorption is 0-1 MPa.

[0026] Preferably, the types of the hydrofluoric acid absorber and the trifluoroacetic acid absorber are independently selected from any one of a bubbling absorber, a gas phase spray absorber, a falling film absorber or a plate absorber.

[0027] Preferably, the lower tower body of the distillation tower is connected to a solvent storage tank, so as to return the solvent separated and removed by the distillation tower to the solvent tank for recycling.

[0028] In a second aspect, the present invention provides a process for co-producing hexafluoropropylene oxide and trifluoroacetic acid, wherein the process adopts the system as described in the first aspect, and the specific steps include:

[0029] The solvent, hexafluoropropylene and oxygen in the raw material storage device are mixed and then enter the liquid phase oxidation reaction device for liquid phase oxidation reaction to obtain a mixed material;

[0030] The mixed material is allowed to enter the distillation tower for separation; wherein the product from the top of the distillation tower includes carbonyl fluoride gas, the product from the upper tower body includes trifluoroacetyl fluoride, the product from the middle tower body includes hexafluoropropylene oxide, and the product from the lower tower body includes a solvent;

[0031] Filling water into the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank through a process water tank;

[0032] Allowing the carbonyl fluoride gas to enter the hydrofluoric acid absorption tank and react with water to generate hydrofluoric acid, and using a hydrofluoric acid concentration detector to monitor the concentration of the hydrofluoric acid;

[0033] The trifluoroacetyl fluoride is allowed to enter a trifluoroacetic acid absorption tank and react with water to generate trifluoroacetic acid, and a trifluoroacetic acid concentration detector is used to monitor the concentration of the trifluoroacetic acid.

[0034] Preferably, the mass ratio of the solvent to hexafluoropropylene is (1-10):1.

[0035] Preferably, the molar ratio of oxygen to hexafluoropropylene is (0.1-5):1.

[0036] Preferably, the ratio of the feed rates of the solvent storage tank, the hexafluoropropylene storage tank and the oxygen storage tank is (50-500):(5-50):(1-5).

[0037] Preferably, the temperature of the liquid phase oxidation reaction is 100-200° C. and the pressure is 3-5 MPa.

[0038] Preferably, the liquid phase oxidation reaction is carried out under stirring at a speed of 50 to 500 r / min.

[0039] Preferably, the top pressure of the distillation tower is 0.8-2.8 MPa, and the bottom temperature of the distillation tower is 80-90°C.

[0040] Preferably, the temperature of the middle tower body of the distillation tower is 50-70°C, the temperature of the upper tower body of the distillation tower is 10-20°C, and the temperature of the top of the distillation tower is -10-0°C.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The main technical problem solved by the present invention is to recycle the by-products carbonyl fluoride and trifluoroacetyl fluoride generated in the HFPO production process. An innovative by-product resource recovery process route is developed, which avoids the tail gas disposal of highly toxic carbonyl fluoride and trifluoroacetyl fluoride, improves the utilization rate of raw materials, and has high economic efficiency.

[0043] (2) The present invention produces hydrofluoric acid and trifluoroacetic acid simultaneously during the production of HFPO, thereby avoiding the use of non-renewable resources, expensive raw materials, the need for catalyst catalysis, the addition of additives and other complex production processes in the traditional production of hydrofluoric acid and trifluoroacetic acid. A process for the continuous production of hydrofluoric acid and trifluoroacetic acid has been developed, which has a simple and efficient process flow, low raw material prices, and no need for catalyst catalysis. The process is highly technical, has low safety risks, and is suitable for industrial applications.

[0044] (3) The present invention adopts continuous and automated control from raw material feeding to product output: the raw material feeding section sets the raw material ratio to stabilize the feeding, the reactor temperature and pressure are automatically controlled, and the raw materials continuously enter the HFPO distillation tower for further separation. The hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank are set to have an acid concentration, and after the acid concentration reaches the standard, the hydrofluoric acid and trifluoroacetic acid products are automatically collected. The lower tower body of the HFPO distillation tower recovers the solvent, and the automatic pump stroke automatically returns it to the solvent tank to achieve solvent reuse. The entire process flow is in continuous production, which greatly improves the production capacity of the device; the entire process flow realizes automated production, does not require manual operation, and has a low process safety risk.

[0045] (4) In the reactor of the present invention, the raw materials react directly without using a catalyst. In the whole process, only the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank need to be replenished with water. No auxiliary agent needs to be added, and no new impurities are introduced. While obtaining the HFPO product, hydrofluoric acid and trifluoroacetic acid are continuously produced. The process is simple and efficient, the production cost is low, and the product purity is high.

[0046] (5) The present invention uses hexafluoropropylene as raw material, which is relatively cheap. The solvent is separated in the lower tower of the HFPO distillation tower for reuse. The overall process has low energy consumption, high raw material conversion rate, and low amount of three wastes, which is suitable for industrial production.

[0047] (6) The present invention adopts a liquid phase oxidation method, in which oxygen and hexafluoropropylene are mixed and reacted in a suitable solvent to generate hexafluoropropylene oxide. The process is simple and the reaction is stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 The schematic diagram of the system for co-producing hexafluoropropylene oxide and trifluoroacetic acid according to the present invention.

[0050] Among them, 1 represents a solvent storage tank, 2 represents a hexafluoropropylene storage tank, 3 represents an oxygen storage tank, 4 represents a liquid phase oxidation reaction device, 5 represents a distillation tower, 6 represents a hydrofluoric acid absorption tank, 7 represents a trifluoroacetic acid absorption tank, 8 represents a process water tank, 9 represents a hydrofluoric acid concentration detector, and 10 represents a trifluoroacetic acid concentration detector. DETAILED DESCRIPTION

[0051] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear, however, in the case of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, unless otherwise stated, the use of "or" means "and / or". In addition, the use of the term "including" and other forms is non-limiting.

[0052] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0053] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0054] It should be noted that specific details are described in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0055] In a first aspect, the present invention provides a system for co-producing hexafluoropropylene oxide and trifluoroacetic acid, such as Figure 1 As shown, the system includes a raw material storage device, a liquid phase oxidation reaction device 4, a distillation tower 5, a hydrofluoric acid absorption tank 6, a trifluoroacetic acid absorption tank 7, a process water tank 8, a hydrofluoric acid concentration detector 9, and a trifluoroacetic acid concentration detector 10;

[0056] The raw material storage device comprises a solvent storage tank 1, a hexafluoropropylene storage tank 2 and an oxygen storage tank 3; and the raw material storage devices are all connected to a liquid phase oxidation reaction device 4;

[0057] The distillation tower 5 comprises a tower top, an upper tower body, a middle tower body and a lower tower body; wherein the product of the tower top comprises carbonyl fluoride gas, the product of the upper tower body comprises trifluoroacetyl fluoride, the product of the middle tower body comprises hexafluoropropylene oxide, and the product of the lower tower body comprises a solvent;

[0058] The hydrofluoric acid absorption tank 6 includes water and is connected to the top of the distillation tower 5, and is used to absorb carbonyl fluoride gas and convert it into hydrofluoric acid; and the hydrofluoric acid absorption tank 6 is connected to a hydrofluoric acid concentration detector 9, which is used to display the concentration of hydrofluoric acid in the hydrofluoric acid absorption tank 6;

[0059] The trifluoroacetic acid absorption tank 7 includes water and is connected to the upper tower body of the distillation tower 5, and is used to absorb trifluoroacetyl fluoride and convert it into trifluoroacetic acid; and the trifluoroacetic acid absorption tank 7 is connected to a trifluoroacetic acid concentration detector 10, which is used to display the concentration of trifluoroacetic acid in the trifluoroacetic acid absorption tank 7;

[0060] The process water tank 8 is connected to the hydrofluoric acid absorption tank 6 and the trifluoroacetic acid absorption tank 7 respectively, and is used to supply water to the hydrofluoric acid absorption tank 6 and the trifluoroacetic acid absorption tank 7.

[0061] In the present invention, a device for continuously producing hexafluoropropylene oxide (HFPO) and co-producing hydrofluoric acid and trifluoroacetic acid is provided. The device utilizes carbonyl fluoride and trifluoroacetyl fluoride, which are by-products produced in the process of producing HFPO, avoids the tail gas disposal of highly toxic carbonyl fluoride and trifluoroacetyl fluoride, and improves the utilization rate of raw materials. The device co-produces hydrofluoric acid and trifluoroacetic acid at the same time, avoids the complex production processes such as the use of catalysts and the addition of additives in the traditional production process of hydrofluoric acid and trifluoroacetic acid, and develops a process for continuously producing hydrofluoric acid and trifluoroacetic acid with a simple and efficient process flow and no need for catalysts.

[0062] like Figure 1 As shown, 1 represents a solvent storage tank. The solvent plays a role of dispersing raw materials in this process system. It is used as a reaction solvent for liquid phase oxidation in the reactor, and can be recovered and recycled after separation in a distillation tower. 2 represents a hexafluoropropylene storage tank, which stores and provides the reaction raw material hexafluoropropylene (HFP) to the liquid phase oxidation reaction device. 3 represents an oxygen storage tank, which stores and provides the reaction raw material oxygen (O2) to the liquid phase oxidation reaction device.

[0063] like Figure 1 As shown, 4 represents a liquid phase oxidation reaction device, and the raw materials HFP, oxygen and solvent are added to the reactor and heated to start the reaction;

[0064] Among them, the main reaction involved in the liquid phase oxidation reaction device is:

[0065]

[0066] Among them, the side reactions involved in the liquid phase oxidation reaction device are:

[0067] CF3CF=CF2+O2→CF3COF+COF2.

[0068] like Figure 1 As shown, 5 represents a distillation tower. After the liquid-phase oxidation reaction is completed, the mixture obtained by the reaction enters the distillation tower for separation. The product at the top of the tower includes carbonyl fluoride gas, the product at the upper tower body includes trifluoroacetyl fluoride, the product at the middle tower body includes hexafluoropropylene oxide (or also includes other products such as HFP), and the product at the lower tower body includes solvent.

[0069] like Figure 1 As shown, 6 represents a hydrofluoric acid absorption tank, 8 represents a process water tank, and 9 represents a hydrofluoric acid concentration detector. The top of the tower mainly produces carbonyl fluoride gas, which enters the hydrofluoric acid absorption tank 6 and begins to be absorbed. Carbonyl fluoride easily reacts with water to generate hydrogen fluoride, which is then absorbed by water to generate hydrofluoric acid. The reactions occurring in the hydrofluoric acid absorption tank are as follows:

[0070] COF2+H2O→CO2+2HF.

[0071] The water in the hydrofluoric acid absorption tank 6 is provided by a process water tank 8, and the hydrofluoric acid concentration detector 9 displays the hydrofluoric acid concentration. When the set acid output index is reached, the hydrofluoric acid product can be directly produced.

[0072] like Figure 1 As shown, 7 represents a trifluoroacetic acid absorption tank, 8 represents a process water tank, and 10 represents a trifluoroacetic acid concentration detector. The upper tower of the distillation tower mainly produces trifluoroacetyl fluoride, which enters the trifluoroacetic acid absorption tank 7 and begins to be absorbed. Trifluoroacetyl fluoride easily reacts with water to form trifluoroacetic acid. The main reactions occurring in the trifluoroacetic acid absorption tank are as follows:

[0073] CF3COF+H2O→CF3COOH(TFA).

[0074] The water in the trifluoroacetic acid absorption tank 7 is provided by a process water tank 8, and the trifluoroacetic acid concentration detector 9 displays the trifluoroacetic acid concentration. When the acid output index is reached, the trifluoroacetic acid product can be directly produced.

[0075] like Figure 1 As shown, HFPO, HFP and other products are discharged from the middle tower of the distillation tower and enter the rear system for separation. The solvent is discharged from the lower tower of the HFPO distillation tower and returned to the solvent tank for recycling.

[0076] In addition, it should be noted that the main process of the gas phase oxidation method is to generate hexafluoropropylene oxide by reacting oxygen and hexafluoropropylene through a reactor equipped with a solid catalyst, which requires the use of a catalyst and has a complex preparation process and a high production cost. The present invention adopts a liquid phase oxidation method, which is to generate hexafluoropropylene oxide by mixing oxygen and hexafluoropropylene in a suitable solvent, which has a simple process and a stable reaction.

[0077] As an optional embodiment, the solvent in the solvent storage tank is selected from any one of FC-36, HFC-143a, HFC-142b, HFC-227a, R113, carbon tetrachloride or perfluoropolyether, or a combination of at least two thereof.

[0078] As described above, the present invention adopts a liquid phase oxidation method, in which oxygen and hexafluoropropylene are mixed and reacted in a suitable solvent to generate hexafluoropropylene oxide. Therefore, the focus of the reaction is also on the selection of solvent. Hexafluoropropylene is difficult to dissolve in general solvents, but it has good solubility in chlorofluorocarbon and perfluorocarbon solvents. Therefore, the present invention selects the above solvent to be stored in a solvent storage tank so as to better play the role of dispersing raw materials in this process system.

[0079] As an optional embodiment, the liquid phase oxidation reaction device is a reactor with a stirred tank.

[0080] As an optional embodiment, the temperature range of the liquid phase oxidation reaction device is 100-200°C, for example, it can be 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, etc.

[0081] As an optional embodiment, the pressure range of the liquid phase oxidation reaction device is 3 to 5 MPa, for example, it can be 3 MPa, 3.2 MPa, 3.4 MPa, 3.6 MPa, 3.8 MPa, 4 MPa, 4.2 MPa, 4.4 MPa, 4.6 MPa, 4.8 MPa, 5 MPa, etc.

[0082] As an optional embodiment, the diameter of the distillation tower ranges from 100 to 500 mm, for example, it can be 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, 500 mm, etc.

[0083] As an optional embodiment, the height of the distillation tower is 10 to 50 m, for example, it can be 10 m, 15 m, 20 m, 25 m, 30 m, 35 m, 40 m, 45 m, 50 m, etc.

[0084] As an optional embodiment, the tower pressure range of the distillation tower is 2.0 to 3.5 MPa, for example, it can be 2.0 MPa, 2.2 MPa, 2.4 MPa, 2.6 MPa, 2.8 MPa, 3.0 MPa, 3.2 MPa, 3.4 MPa, 3.5 MPa, etc.

[0085] As an optional embodiment, the distillation tower is selected from a plate tower and / or a packed tower.

[0086] As an optional embodiment, the plate type of the plate tower includes any one of a valve plate, a bubble cap plate, a sieve plate, a flow-through tray or a floating tongue plate, or a combination of at least two of them.

[0087] As an optional embodiment, the packing of the packed tower includes any one of Raschig ring packing, θ-ring packing, C-type packing or Y-type packing, or a combination of at least two of them.

[0088] As an optional embodiment, the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank are for normal pressure absorption and / or pressure absorption.

[0089] As an optional embodiment, the pressure of the pressurized absorption is 0-1 MPa, for example, it can be 0 MPa, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa, etc.

[0090] It should be noted that in order to ensure that carbonyl fluoride or trifluoroacetyl fluoride is relatively completely absorbed, normal pressure absorption or pressure of the absorption tank can be maintained at about 0-1MPa for pressure absorption. In order to ensure that the gas phase enters the absorption system smoothly, one or more storage tanks can be added to temporarily store materials, and the regulating valve can be used to control the smooth feeding. The top of the absorption device is set with pressure control, which can release the unabsorbed or generated low boiling point into the tail gas system and discharge it after treatment.

[0091] As an optional embodiment, the types of the hydrofluoric acid absorber and the trifluoroacetic acid absorber are independently selected from any one of a bubbling absorber, a gas phase spray absorber, a falling film absorber or a plate absorber.

[0092] It should be noted that carbonyl fluoride and trifluoroacetyl fluoride react easily with water to generate hydrofluoric acid and trifluoroacetic acid. To improve the absorption effect, strengthening measures such as series multi-stage absorption, increased stirring, optimization of absorption tube diameter and number of bubbling holes can be adopted according to the actual process.

[0093] As an optional embodiment, the lower tower body of the distillation tower is connected to a solvent storage tank for returning the solvent separated and removed by the distillation tower to the solvent tank for recycling.

[0094] As an optional embodiment, the types of process water used in the process water tank 8 include but are not limited to softened water, distilled water, pure water or ultrapure water, any one or a combination of at least two of them.

[0095] In a second aspect, the present invention provides a process for co-producing hexafluoropropylene oxide and trifluoroacetic acid, wherein the process adopts the system as described in the first aspect, and the specific steps include:

[0096] The solvent, hexafluoropropylene and oxygen in the raw material storage device are mixed and then enter the liquid phase oxidation reaction device for liquid phase oxidation reaction to obtain a mixed material;

[0097] The mixed material is allowed to enter the distillation tower for separation; wherein the product from the top of the distillation tower includes carbonyl fluoride gas, the product from the upper tower body includes trifluoroacetyl fluoride, the product from the middle tower body includes hexafluoropropylene oxide, and the product from the lower tower body includes a solvent;

[0098] Filling water into the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank through a process water tank;

[0099] Allowing the carbonyl fluoride gas to enter the hydrofluoric acid absorption tank and react with water to generate hydrofluoric acid, and using a hydrofluoric acid concentration detector to monitor the concentration of the hydrofluoric acid;

[0100] The trifluoroacetyl fluoride is allowed to enter a trifluoroacetic acid absorption tank and react with water to generate trifluoroacetic acid, and a trifluoroacetic acid concentration detector is used to monitor the concentration of the trifluoroacetic acid.

[0101] As an optional embodiment, the mass ratio of the solvent to hexafluoropropylene is (1-10):1, for example, it can be 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, etc.

[0102] As an optional embodiment, the molar ratio of oxygen to hexafluoropropylene is (0.1-5):1, for example, it can be 0.1:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, etc.

[0103] As an optional embodiment, the ratio of the feed rates of the solvent storage tank, the hexafluoropropylene storage tank and the oxygen storage tank is (50-500):(5-50):(1-5);

[0104] Herein, “50-500” may be, for example, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, etc.;

[0105] Here, “5-50” can be, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, etc.;

[0106] Here, “1-5” can be, for example, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, etc.

[0107] As an optional embodiment, the temperature of the liquid-phase oxidation reaction is 100-200°C, for example, it can be 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, etc., and the pressure is 3-5Mpa, for example, it can be 3Mpa, 3.2Mpa, 3.4Mpa, 3.6Mpa, 3.8Mpa, 4Mpa, 4.2Mpa, 4.4Mpa, 4.6Mpa, 4.8Mpa, 5Mpa, etc.

[0108] As an optional embodiment, the liquid-phase oxidation reaction is carried out under stirring, and the stirring speed is 50 to 500 r / min, for example, it can be 50 r / min, 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, etc.

[0109] As an optional embodiment, the top pressure of the distillation tower is 0.8-2.8 MPa, for example, it can be 0.8 MPa, 1.0 MPa, 1.2 MPa, 1.4 MPa, 1.6 MPa, 1.8 MPa, 2.0 MPa, 2.2 MPa, 2.3 MPa, 2.4 MPa, 2.5 MPa, 2.6 MPa, 2.7 MPa, 2.8 MPa, etc.

[0110] As an optional embodiment, the temperature of the bottom of the distillation tower is 80-90°C, for example, it can be 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, etc.

[0111] As an optional embodiment, the temperature of the middle tower body of the distillation tower is 50-70°C, for example, it can be 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, etc.

[0112] As an optional embodiment, the temperature of the upper tower body of the distillation tower is 10-20°C, for example, it can be 10°C, 12°C, 14°C, 16°C, 18°C, 20°C, etc.

[0113] As an optional embodiment, the top temperature of the distillation tower is -10 to 0°C, for example, it can be -10°C, -9°C, -8°C, -7°C, -6°C, -5°C, -4°C, -3°C, -2°C, -1°C, 0°C, etc.

[0114] The technical solution of the present invention will be clearly and completely described below in conjunction with embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0115] Example 1

[0116] This embodiment provides a system for co-producing hexafluoropropylene oxide and trifluoroacetic acid, the system comprising a raw material storage device, a liquid phase oxidation reaction device, a distillation tower, a hydrofluoric acid absorption tank, a trifluoroacetic acid absorption tank, a process water tank, a hydrofluoric acid concentration detector, and a trifluoroacetic acid concentration detector;

[0117] The raw material storage device comprises a solvent storage tank, a hexafluoropropylene storage tank and an oxygen storage tank; and the raw material storage devices are all connected to a liquid phase oxidation reaction device; wherein the solvent in the solvent storage tank is HFC-227a.

[0118] The liquid phase oxidation reaction device is a reactor with a stirred tank.

[0119] The distillation tower comprises a tower top, an upper tower body, a middle tower body and a lower tower body; wherein the product of the tower top comprises carbonyl fluoride gas, the product of the upper tower body comprises trifluoroacetyl fluoride, the product of the middle tower body comprises hexafluoropropylene oxide, and the product of the lower tower body comprises a solvent;

[0120] The distillation tower has a diameter of 800 mm, a height of 25 m, and a pressure of 1.8 MPa; the distillation tower is a packed tower, and the packing type is a Y-type structured packing.

[0121] The hydrofluoric acid absorption tank includes water and is connected to the top of the distillation tower, and is used to absorb carbonyl fluoride gas and convert it into hydrofluoric acid; and the hydrofluoric acid absorption tank is connected to a hydrofluoric acid concentration detector, which is used to display the concentration of hydrofluoric acid in the hydrofluoric acid absorption tank;

[0122] The trifluoroacetic acid absorption tank includes water and is connected to the upper tower body of the distillation tower, and is used to absorb trifluoroacetyl fluoride and convert it into trifluoroacetic acid; and the trifluoroacetic acid absorption tank is connected to a trifluoroacetic acid concentration detector, which is used to display the concentration of trifluoroacetic acid in the trifluoroacetic acid absorption tank;

[0123] Wherein, the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank are subjected to 0.8 MPa pressure absorption; and the types of the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank are both bubbling absorption tanks.

[0124] The process water tank is connected to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank respectively, and is used to supply water to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank.

[0125] The lower tower body of the distillation tower is connected to the solvent storage tank, and is used to return the solvent separated and removed by the distillation tower to the solvent tank for recycling.

[0126] Example 2

[0127] This embodiment provides a system for co-producing hexafluoropropylene oxide and trifluoroacetic acid, the system comprising a raw material storage device, a liquid phase oxidation reaction device, a distillation tower, a hydrofluoric acid absorption tank, a trifluoroacetic acid absorption tank, a process water tank, a hydrofluoric acid concentration detector, and a trifluoroacetic acid concentration detector;

[0128] The raw material storage device comprises a solvent storage tank, a hexafluoropropylene storage tank and an oxygen storage tank; and the raw material storage devices are all connected to a liquid phase oxidation reaction device; wherein the solvent in the solvent storage tank is HFC-227a.

[0129] The liquid phase oxidation reaction device is a reactor with a stirred tank.

[0130] The distillation tower comprises a tower top, an upper tower body, a middle tower body and a lower tower body; wherein the product of the tower top comprises carbonyl fluoride gas, the product of the upper tower body comprises trifluoroacetyl fluoride, the product of the middle tower body comprises hexafluoropropylene oxide, and the product of the lower tower body comprises a solvent;

[0131] The distillation tower has a diameter of 800 mm, a height of 25 m, and a pressure of 1.8 MPa; the distillation tower is a packed tower, and the packing type is a Y-type structured packing.

[0132] The hydrofluoric acid absorption tank includes water and is connected to the top of the distillation tower, and is used to absorb carbonyl fluoride gas and convert it into hydrofluoric acid; and the hydrofluoric acid absorption tank is connected to a hydrofluoric acid concentration detector, which is used to display the concentration of hydrofluoric acid in the hydrofluoric acid absorption tank;

[0133] The trifluoroacetic acid absorption tank includes water and is connected to the upper tower body of the distillation tower, and is used to absorb trifluoroacetyl fluoride and convert it into trifluoroacetic acid; and the trifluoroacetic acid absorption tank is connected to a trifluoroacetic acid concentration detector, which is used to display the concentration of trifluoroacetic acid in the trifluoroacetic acid absorption tank;

[0134] Wherein, the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank are subjected to 0.6 MPa pressure absorption; and the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank are bubbling absorption tanks.

[0135] The process water tank is connected to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank respectively, and is used to supply water to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank.

[0136] The lower tower body of the distillation tower is connected to the solvent storage tank, and is used to return the solvent separated and removed by the distillation tower to the solvent tank for recycling.

[0137] Example 3

[0138] This embodiment provides a system for co-producing hexafluoropropylene oxide and trifluoroacetic acid, the system comprising a raw material storage device, a liquid phase oxidation reaction device, a distillation tower, a hydrofluoric acid absorption tank, a trifluoroacetic acid absorption tank, a process water tank, a hydrofluoric acid concentration detector, and a trifluoroacetic acid concentration detector;

[0139] The raw material storage device comprises a solvent storage tank, a hexafluoropropylene storage tank and an oxygen storage tank; and the raw material storage devices are all connected to a liquid phase oxidation reaction device; wherein the solvent in the solvent storage tank is HFC236fa.

[0140] The liquid phase oxidation reaction device is a reactor with a stirred tank.

[0141] The distillation tower comprises a tower top, an upper tower body, a middle tower body and a lower tower body; wherein the product of the tower top comprises carbonyl fluoride gas, the product of the upper tower body comprises trifluoroacetyl fluoride, the product of the middle tower body comprises hexafluoropropylene oxide, and the product of the lower tower body comprises a solvent;

[0142] The distillation tower has a diameter of 800 mm, a height of 25 m, and a pressure of 1.5 MPa; the distillation tower is a packed tower, and the packing type is a Y-type structured packing.

[0143] The hydrofluoric acid absorption tank includes water and is connected to the top of the distillation tower, and is used to absorb carbonyl fluoride gas and convert it into hydrofluoric acid; and the hydrofluoric acid absorption tank is connected to a hydrofluoric acid concentration detector, which is used to display the concentration of hydrofluoric acid in the hydrofluoric acid absorption tank;

[0144] The trifluoroacetic acid absorption tank includes water and is connected to the upper tower body of the distillation tower, and is used to absorb trifluoroacetyl fluoride and convert it into trifluoroacetic acid; and the trifluoroacetic acid absorption tank is connected to a trifluoroacetic acid concentration detector, which is used to display the concentration of trifluoroacetic acid in the trifluoroacetic acid absorption tank;

[0145] Wherein, the hydrofluoric acid absorber and the trifluoroacetic acid absorber are subjected to 0.8 MPa pressure absorption; and the types of the hydrofluoric acid absorber and the trifluoroacetic acid absorber are both circulating spray absorbers.

[0146] The process water tank is connected to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank respectively, and is used to supply water to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank.

[0147] The lower tower body of the distillation tower is connected to the solvent storage tank, and is used to return the solvent separated and removed by the distillation tower to the solvent tank for recycling.

[0148] Example 4

[0149] This embodiment provides a system for co-producing hexafluoropropylene oxide and trifluoroacetic acid, the system comprising a raw material storage device, a liquid phase oxidation reaction device, a distillation tower, a hydrofluoric acid absorption tank, a trifluoroacetic acid absorption tank, a process water tank, a hydrofluoric acid concentration detector, and a trifluoroacetic acid concentration detector;

[0150] The raw material storage device comprises a solvent storage tank, a hexafluoropropylene storage tank and an oxygen storage tank; and the raw material storage devices are all connected to a liquid phase oxidation reaction device; wherein the solvent in the solvent storage tank is selected from HFC236fa.

[0151] The liquid phase oxidation reaction device is a reactor with a stirred tank.

[0152] The distillation tower comprises a tower top, an upper tower body, a middle tower body and a lower tower body; wherein the product of the tower top comprises carbonyl fluoride gas, the product of the upper tower body comprises trifluoroacetyl fluoride, the product of the middle tower body comprises hexafluoropropylene oxide, and the product of the lower tower body comprises a solvent;

[0153] The distillation tower has a diameter of 800 mm, a height of 25 m, and a pressure of 1.8 MPa; the distillation tower is selected from a packed tower, and the packing type is a Y-type structured packing.

[0154] The hydrofluoric acid absorption tank includes water and is connected to the top of the distillation tower, and is used to absorb carbonyl fluoride gas and convert it into hydrofluoric acid; and the hydrofluoric acid absorption tank is connected to a hydrofluoric acid concentration detector, which is used to display the concentration of hydrofluoric acid in the hydrofluoric acid absorption tank;

[0155] The trifluoroacetic acid absorption tank includes water and is connected to the upper tower body of the distillation tower, and is used to absorb trifluoroacetyl fluoride and convert it into trifluoroacetic acid; and the trifluoroacetic acid absorption tank is connected to a trifluoroacetic acid concentration detector, which is used to display the concentration of trifluoroacetic acid in the trifluoroacetic acid absorption tank;

[0156] Wherein, the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank are subjected to 0.6MPa pressure absorption; and the types of the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank are both circulating spray absorption tanks.

[0157] The process water tank is connected to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank respectively, and is used to supply water to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank.

[0158] The lower tower body of the distillation tower is connected to the solvent storage tank, and is used to return the solvent separated and removed by the distillation tower to the solvent tank for recycling.

[0159] Example 5

[0160] This embodiment provides a system for co-producing hexafluoropropylene oxide and trifluoroacetic acid, the system comprising a raw material storage device, a liquid phase oxidation reaction device, a distillation tower, a hydrofluoric acid absorption tank, a trifluoroacetic acid absorption tank, a process water tank, a hydrofluoric acid concentration detector, and a trifluoroacetic acid concentration detector;

[0161] The raw material storage device comprises a solvent storage tank, a hexafluoropropylene storage tank and an oxygen storage tank; and the raw material storage devices are all connected to a liquid phase oxidation reaction device; wherein the solvent in the solvent storage tank is selected from HFC-143a.

[0162] The liquid phase oxidation reaction device is a reactor with a stirred tank.

[0163] The distillation tower comprises a tower top, an upper tower body, a middle tower body and a lower tower body; wherein the product of the tower top comprises carbonyl fluoride gas, the product of the upper tower body comprises trifluoroacetyl fluoride, the product of the middle tower body comprises hexafluoropropylene oxide, and the product of the lower tower body comprises a solvent;

[0164] The distillation tower has a diameter of 600 mm, a height of 30 m, and a pressure of 1.3 MPa; the distillation tower is a packed tower, and the packing type is a Y-type structured packing.

[0165] The hydrofluoric acid absorption tank includes water and is connected to the top of the distillation tower, and is used to absorb carbonyl fluoride gas and convert it into hydrofluoric acid; and the hydrofluoric acid absorption tank is connected to a hydrofluoric acid concentration detector, which is used to display the concentration of hydrofluoric acid in the hydrofluoric acid absorption tank;

[0166] The trifluoroacetic acid absorption tank includes water and is connected to the upper tower body of the distillation tower, and is used to absorb trifluoroacetyl fluoride and convert it into trifluoroacetic acid; and the trifluoroacetic acid absorption tank is connected to a trifluoroacetic acid concentration detector, which is used to display the concentration of trifluoroacetic acid in the trifluoroacetic acid absorption tank;

[0167] Wherein, the hydrofluoric acid absorber and the trifluoroacetic acid absorber are subjected to 0.8 MPa pressure absorption; and the hydrofluoric acid absorber and the trifluoroacetic acid absorber are both falling film absorbers.

[0168] The process water tank is connected to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank respectively, and is used to supply water to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank.

[0169] The lower tower body of the distillation tower is connected to the solvent storage tank, and is used to return the solvent separated and removed by the distillation tower to the solvent tank for recycling.

[0170] Application Example 1

[0171] This application example provides a process for co-producing hexafluoropropylene oxide and trifluoroacetic acid. The process is carried out using the system provided in Example 1. The specific steps are as follows:

[0172] The feed rate of the solvent tank is 50kg / h, the feed rate of the HFP storage tank is 20kg / h, and the feed rate of oxygen is 1kg / h. After the three materials are mixed, they enter the reactor for reaction. During the reaction, the reactor is stirred at a stirring rate of 50r / min, heated to 100°C, and the pressure is maintained at 3.2Mpa. After the raw materials are fully reacted in the reactor, the mixed materials enter the HFPO distillation tower for separation. The top pressure of the HFPO distillation tower is maintained at 2Mpa, the bottom temperature is 80°C, the middle tower temperature is 60°C, the upper tower temperature is 20°C, and the top temperature is -5°C. Carbonyl fluoride is discharged from the top of the HFPO distillation tower to the hydrofluoric acid absorption tank, and the process water tank is replenished with water in the hydrofluoric acid absorption tank in advance, and the hydrofluoric acid output concentration is set to 20%. Trifluoroacetyl fluoride is discharged from the upper tower of the HFPO distillation tower and enters the trifluoroacetic acid absorption tank for absorption. The process water tank is replenished with water in the trifluoroacetic acid absorption tank in advance, and the trifluoroacetic acid output concentration is set to 40%. After 24 hours, hydrofluoric acid with a concentration of 20% and trifluoroacetic acid with a concentration of 40% began to be produced continuously.

[0173] Application Example 2

[0174] This application example provides a process for co-producing hexafluoropropylene oxide and trifluoroacetic acid. The process is carried out using the system provided in Example 2. The specific steps are as follows:

[0175] The solvent tank feed rate is 500kg / h, the HFP storage tank feed rate is 200kg / h, and the oxygen feed rate is 15kg / h. After the three materials are mixed, they enter the reactor for reaction. During the reaction, the reactor is stirred at a stirring rate of 100r / min, heated to 100°C, and the pressure is maintained at 3.2Mpa. After the raw materials are fully reacted in the reactor, the mixed materials enter the HFPO distillation tower for separation. The top pressure of the HFPO distillation tower is maintained at 2Mpa, the bottom temperature is 85°C, the middle tower body temperature is 60°C, the upper tower body temperature is 20°C, and the top temperature is -5°C. The top of the HFPO distillation tower discharges carbonyl fluoride to the hydrofluoric acid absorption tank, and the hydrofluoric acid output concentration is set to 40%. The upper tower body of the HFPO distillation tower is absorbed in the trifluoroacetic acid absorption tank, and the trifluoroacetic acid output concentration is set to 80%. After 48h, hydrofluoric acid with a concentration of 40% and trifluoroacetic acid with a concentration of 80% begin to be continuously produced.

[0176] Application Example 3

[0177] This application example provides a process for co-producing hexafluoropropylene oxide and trifluoroacetic acid. The process is carried out using the system provided in Example 3. The specific steps are as follows:

[0178] The solvent tank feed rate is 900kg / h, the HFP storage tank feed rate is 300kg / h, and the oxygen feed rate is 20kg / h. After the three materials are mixed, they enter the reactor for reaction. During the reaction, the reactor is stirred at a stirring rate of 300r / min, heated to 120°C, and the pressure is maintained at 3.5Mpa. After the raw materials are fully reacted in the reactor, the mixed materials enter the HFPO distillation tower for separation. The top pressure of the HFPO distillation tower is maintained at 2.2Mpa, the bottom temperature is 85°C, the middle tower body temperature is 60°C, the upper tower body temperature is 20°C, and the top temperature is -10°C. The HFPO distillation tower top discharges carbonyl fluoride to the hydrofluoric acid absorption tank, and the hydrofluoric acid output concentration is set to 60%. The upper tower body of the HFPO distillation tower is discharged to the trifluoroacetic acid absorption tank for absorption, and the trifluoroacetic acid output concentration is set to 90%. After 48h, hydrofluoric acid with a concentration of 60% and trifluoroacetic acid with a concentration of 90% begin to be continuously produced.

[0179] Application Example 4

[0180] This application example provides a process for co-producing hexafluoropropylene oxide and trifluoroacetic acid. The process is carried out using the system provided in Example 4. The specific steps are as follows:

[0181] The solvent tank feed rate is 1500kg / h, the HFP storage tank feed rate is 500kg / h, and the oxygen feed rate is 35kg / h. After the three materials are mixed, they enter the reactor for reaction. During the reaction, the reactor is stirred at a stirring rate of 500r / min, heated to 150°C, and the pressure is maintained at 3.5Mpa. After the raw materials are fully reacted in the reactor, the mixed materials enter the HFPO distillation tower for separation. The top pressure of the HFPO distillation tower is maintained at 2.8Mpa, the bottom temperature is 90°C, the middle tower body temperature is 70°C, the upper tower body temperature is 10°C, and the top temperature is -10°C. The HFPO distillation tower top discharges carbonyl fluoride to the hydrofluoric acid absorption tank, and the hydrofluoric acid output concentration is set to 40%. The upper tower body of the HFPO distillation tower is discharged to the trifluoroacetic acid absorption tank for absorption, and the trifluoroacetic acid output concentration is set to 95%. After 48h, hydrofluoric acid with a concentration of 40% and trifluoroacetic acid with a concentration of 95% begin to be continuously produced.

[0182] Application Example 5

[0183] This application example provides a process for co-producing hexafluoropropylene oxide and trifluoroacetic acid. The process is carried out using the system provided in Example 5. The specific steps are as follows:

[0184] The solvent tank feed rate is 2000kg / h, the HFP storage tank feed rate is 500kg / h, and the oxygen feed rate is 35kg / h. After the three materials are mixed, they enter the reactor for reaction. During the reaction, the reactor is stirred at a stirring rate of 500r / min, heated to 150°C, and the pressure is maintained at 3.8Mpa. After the raw materials are fully reacted in the reactor, the mixed materials enter the HFPO distillation tower for separation. The top pressure of the HFPO distillation tower is maintained at 2.8Mpa, the bottom temperature is 90°C, the middle tower body temperature is 70°C, the upper tower body temperature is 10°C, and the top temperature is -10°C. The HFPO distillation tower top discharges carbonyl fluoride to the hydrofluoric acid absorption tank, and the hydrofluoric acid output concentration is set to 40%. The upper tower body of the HFPO distillation tower is discharged to the trifluoroacetic acid absorption tank for absorption, and the trifluoroacetic acid output concentration is set to 99.5%. After 48h, hydrofluoric acid with a concentration of 40% and trifluoroacetic acid with a concentration of 99.5% are continuously produced.

[0185] Application Example 6

[0186] This application example provides a process method for the co-production of hexafluoropropylene oxide and trifluoroacetic acid. The difference from Application Example 1 is that the temperature range of the liquid-phase oxidation reaction device is 90°C, the pressure range is 2.5Mpa, and the other settings are exactly the same as those in Application Example 1.

[0187] Application Example 7

[0188] This application example provides a process method for the co-production of hexafluoropropylene oxide and trifluoroacetic acid. The difference from Application Example 1 is that the temperature range of the liquid-phase oxidation reaction device is 210°C, the pressure range is 5.5Mpa, and the other settings are exactly the same as those in Application Example 1.

[0189] Application Example 8

[0190] This application example provides a process method for the co-production of hexafluoropropylene oxide and trifluoroacetic acid. The difference from Application Example 1 is that the distillation tower of Example 1 is replaced by a distillation tower of the same type with a tower diameter range of 700 mm, a tower height of 8 m, and a tower pressure range of 1.8 MPa. The other settings are exactly the same as those in Application Example 1.

[0191] Application Example 9

[0192] This application example provides a process method for the co-production of hexafluoropropylene oxide and trifluoroacetic acid. The difference from Application Example 1 is that the distillation tower of Example 1 is replaced by a distillation tower of the same type with a tower diameter range of 600 mm, a tower height of 60 m, and a tower pressure range of 4.0 MPa. The other settings are exactly the same as those in Application Example 1.

[0193] Application Example 10

[0194] This application example provides a process method for the co-production of hexafluoropropylene oxide and trifluoroacetic acid. The difference from Application Example 1 is that the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank in Example 1 are adjusted to normal pressure absorption, and the other settings are exactly the same as those in Application Example 1.

[0195] Application Example 11

[0196] This application example provides a process method for the co-production of hexafluoropropylene oxide and trifluoroacetic acid. The difference from Application Example 1 is that the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank of Example 1 are no longer provided with a bubbling absorption device, and ordinary absorption without assistance is directly carried out. The other settings are exactly the same as those of Application Example 1.

[0197] Test Case

[0198] Test sample: the reaction product provided in Application Examples 1 to 11;

[0199] The test results are shown in Table 1 below:

[0200] Table 1

[0201]

[0202]

[0203] As shown in Table 1, the raw materials in the reactor of the present invention react directly without using a catalyst. In the entire process, only the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank need to be replenished with water, and no auxiliary agent needs to be added, and no new impurities are introduced. While obtaining the HFPO product, hydrofluoric acid and trifluoroacetic acid are continuously produced. The process is simple and efficient, and the product purity is high.

[0204] After the system of the present invention is used to carry out the process of co-producing hexafluoropropylene oxide and trifluoroacetic acid, the yield of hydrofluoric acid can reach more than 85%, the purity of hydrofluoric acid can reach more than 48%, the yield of trifluoroacetic acid can reach more than 94%, the purity of trifluoroacetic acid can reach more than 90%, the yield of hexafluoropropylene oxide can reach more than 60%, the purity of hexafluoropropylene oxide can reach more than 53%, and the solvent recovery rate in the whole process method can reach more than 99.99%. It is explained that the process method of the present invention co-produces hydrofluoric acid and trifluoroacetic acid while producing HFPO, and its process flow is simple, the reaction is stable, the raw material conversion rate is high, the product yield is high, the purity is high, and the lower tower body of the distillation tower recovers the solvent, and the automatic control pump stroke automatically returns to the solvent tank, so as to realize the high recovery rate of solvent reuse, and the amount of three wastes generated is small, which is suitable for industrial production.

[0205] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 system for co-producing hexafluoropropylene oxide and trifluoroacetic acid, characterized in that: The system includes a raw material storage device, a liquid phase oxidation reaction device, a distillation tower, a hydrofluoric acid absorption tank, a trifluoroacetic acid absorption tank, a process water tank, a hydrofluoric acid concentration detector, and a trifluoroacetic acid concentration detector; The raw material storage device comprises a solvent storage tank, a hexafluoropropylene storage tank and an oxygen storage tank; and the raw material storage devices are all connected to the liquid phase oxidation reaction device; The distillation tower comprises a tower top, an upper tower body, a middle tower body and a lower tower body; wherein the product of the tower top comprises carbonyl fluoride gas, the product of the upper tower body comprises trifluoroacetyl fluoride, the product of the middle tower body comprises hexafluoropropylene oxide, and the product of the lower tower body comprises a solvent; The hydrofluoric acid absorption tank includes water and is connected to the top of the distillation tower, and is used to absorb carbonyl fluoride gas and convert it into hydrofluoric acid; and the hydrofluoric acid absorption tank is connected to a hydrofluoric acid concentration detector, which is used to display the concentration of hydrofluoric acid in the hydrofluoric acid absorption tank; The trifluoroacetic acid absorption tank includes water and is connected to the upper tower body of the distillation tower, and is used to absorb trifluoroacetyl fluoride and convert it into trifluoroacetic acid; and the trifluoroacetic acid absorption tank is connected to a trifluoroacetic acid concentration detector, which is used to display the concentration of trifluoroacetic acid in the trifluoroacetic acid absorption tank; The process water tank is connected to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank respectively, and is used to supply water to the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank.

2. The system for co-producing hexafluoropropylene oxide and trifluoroacetic acid according to claim 1, characterized in that: The solvent in the solvent storage tank is selected from any one of HFC236fa, HFC-143a, HFC-142b, HFC-227a, R113, carbon tetrachloride or perfluoropolyether, or a combination of at least two thereof.

3. The system for co-producing hexafluoropropylene oxide and trifluoroacetic acid according to claim 1, characterized in that: The liquid phase oxidation reaction device is a reactor with a stirred tank; Preferably, the temperature range of the liquid phase oxidation reaction device is 100-200° C., and the pressure range is 3-5 MPa.

4. The system for co-producing hexafluoropropylene oxide and trifluoroacetic acid according to claim 1, characterized in that: The distillation tower has a diameter ranging from 100 to 1000 mm, a height ranging from 10 to 50 m, and a tower pressure ranging from 0.5 to 3.5 MPa; Preferably, the distillation tower is selected from a plate tower and / or a packed tower; Preferably, the plate type of the plate tower includes any one or a combination of at least two of a valve plate, a bubble cap plate, a sieve plate, a flow-through tray or a floating tongue plate; Preferably, the packing of the packed tower includes any one of Raschig ring packing, θ-ring packing, C-type packing or Y-type packing, or a combination of at least two of them.

5. The system for co-producing hexafluoropropylene oxide and trifluoroacetic acid according to claim 1, characterized in that: The hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank are for normal pressure absorption and / or pressure absorption; Preferably, the pressure of the pressure absorption is 0-1 MPa.

6. The system for co-producing hexafluoropropylene oxide and trifluoroacetic acid according to claim 1, characterized in that: The types of the hydrofluoric acid absorber and the trifluoroacetic acid absorber are independently selected from any one of a bubbling absorber, a gas phase spray absorber, a falling film absorber or a plate absorber.

7. The system for co-producing hexafluoropropylene oxide and trifluoroacetic acid according to claim 1, characterized in that: The lower tower body of the distillation tower is connected to the solvent storage tank, and is used for separating and removing solvents from the distillation tower and returning the solvent tank for recycling.

8. A process for co-producing hexafluoropropylene oxide and trifluoroacetic acid, characterized in that: The process method adopts the system as claimed in any one of claims 1 to 7, and the specific steps include: The solvent, hexafluoropropylene and oxygen in the raw material storage device are mixed and then enter the liquid phase oxidation reaction device for liquid phase oxidation reaction to obtain a mixed material; The mixed material is allowed to enter the distillation tower for separation; wherein the product from the top of the distillation tower includes carbonyl fluoride gas, the product from the upper tower body includes trifluoroacetyl fluoride, the product from the middle tower body includes hexafluoropropylene oxide, and the product from the lower tower body includes a solvent; Filling water into the hydrofluoric acid absorption tank and the trifluoroacetic acid absorption tank through a process water tank; Allowing the carbonyl fluoride gas to enter the hydrofluoric acid absorption tank and react with water to generate hydrofluoric acid, and using a hydrofluoric acid concentration detector to monitor the concentration of the hydrofluoric acid; The trifluoroacetyl fluoride is allowed to enter a trifluoroacetic acid absorption tank and react with water to generate trifluoroacetic acid, and a trifluoroacetic acid concentration detector is used to monitor the concentration of the trifluoroacetic acid.

9. The process for co-producing hexafluoropropylene oxide and trifluoroacetic acid according to claim 8, characterized in that: The mass ratio of the solvent to hexafluoropropylene is (1-10):1; Preferably, the molar ratio of oxygen to hexafluoropropylene is (0.1-5):1; Preferably, the ratio of the feed rates of the solvent storage tank, the hexafluoropropylene storage tank and the oxygen storage tank is (50-500):(5-50):(1-5); Preferably, the temperature of the liquid phase oxidation reaction is 100-200°C and the pressure is 3-5Mpa; Preferably, the liquid phase oxidation reaction is carried out under stirring at a speed of 50 to 500 r / min.

10. The process for co-producing hexafluoropropylene oxide and trifluoroacetic acid according to claim 8, characterized in that: The top pressure of the distillation tower is 0.8-2.8 MPa; Preferably, the temperature of the bottom of the distillation tower is 80-90°C, the temperature of the middle tower body of the distillation tower is 50-70°C, the temperature of the upper tower body of the distillation tower is 10-20°C, and the temperature of the top of the distillation tower is -10-0°C.

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