CN112778101B - Method for preparing perfluoroalkyl vinyl ether by taking carboxylate solution as raw material - Google Patents

Abstract

The invention discloses a method for preparing perfluoroalkyl vinyl ether by using a carboxylate solution as a raw material. The carboxylate solution is continuously discharged from a raw material reactor to the upper end of a sloping plate in a decarboxylation reactor. Under the action of the small baffle assembly, it is evenly distributed on the inclined plate and forms a thin layer of flow. The inclined plate heats the thin layer to make the carboxylate in it undergo a decarboxylation reaction. The reaction process generates perfluoroalkyl vinyl ether products, Carbon dioxide and alkali metal fluorides, perfluoroalkyl vinyl ether products and carbon dioxide are discharged from the gas phase outlet driven by nitrogen, and the products are condensed and collected by a condenser, and carbon dioxide and nitrogen are discharged. The generated alkali metal fluorides flow into the solvent and receive Tank, the solvent in the tank is pumped back to the raw material reactor for reuse. The invention greatly reduces the residence time of the product in the solvent, reduces the generation of by-products, and because the liquid phase decarboxylation is adopted, the decarboxylation temperature is low, and problems such as carbon deposition are not generated.

Description

A kind of method for preparing perfluoroalkyl vinyl ether with carboxylate solution as raw material

The patent application of the present invention is a divisional application entitled "a method and reaction system for preparing perfluoroalkyl vinyl ether", the application date of the original application is March 23, 2018, and the application number is 201810246092X.

technical field

The present invention relates to fluorine chemical technology, in particular to the preparation technology of perfluoroalkyl vinyl ether.

Background technique

Perfluoroalkyl vinyl ether is a versatile fluorine-containing monomer with the general formula:

Because of the large bond energy of C-F bond, perfluoroalkyl vinyl ether makes the π bond in the double bond contained more relaxed, and it is easy to polymerize with other monomers. Special functional polymer materials can be obtained by copolymerizing fluorine-containing olefins such as polymers. In addition, due to the copolymerization of perfluoroalkyl vinyl ether, flexible branches are introduced into the original polymer chain, which reduces the crystallinity of the polymer, so the polymerization can be improved without changing the original excellent properties of the fluoropolymer. Other properties of the material, such as: low temperature resistance, solvent resistance, toughness, tear resistance, adhesion to the substrate, etc.

There are many preparation methods of perfluoroalkyl vinyl ether, mainly through the reaction of acyl fluoride and metal salt compound to form carboxylate and then thermal cracking to remove CO ₂ and metal fluoride. The methods of preparing perfluoroalkyl vinyl ethers by salt formation and decarboxylation of acyl fluoride can be mainly divided into two categories:

The first type is a one-step method, that is, the acyl fluoride is directly reacted and decarboxylated with a metal carbonate in a reactor higher than the decarboxylation temperature of the intermediate carboxylate to obtain an alkenyl ether.

US patent US3321532 uses acid fluoride and sodium carbonate to directly form salt and decarboxylation in a tubular reactor, the decarboxylation temperature is 300 ° C, and the yield is up to 95%; US patent US3291843 also uses a tubular reactor, and the acid fluoride and silicon oxide are at 390 ° C. When cracked into ether, the yield is up to 85%; the Chinese patent CN101213168A of 3M Innovation Co., Ltd. uses acyl fluoride and metal carbonate to decarboxylate at high temperature in a stirred bed reactor, the decarboxylation temperature is 100 ~ 300 ℃, and the yield is about 70% The Chinese patent CN1196666C of Asahi Glass Company adopts the method of high temperature decarboxylation of acyl fluoride and metal carbonate in a fluidized bed, and its conversion rate is 100%, but the yield is only 55%; the patent CN102702035B of Juhua Group Company describes a In the method of continuously preparing fluorinated vinyl ether by using a twin-screw extruder, the front-stage of the twin-screw is decarboxylated after salt formation, and the temperature of the decarboxylation stage is 180°C to 320°C, and the highest conversion rate is 88.2%. It can be seen from the above-mentioned patent that the yield of alkenyl ether prepared by one-step decarboxylation is not high. The main problem is that during the solid-phase decarboxylation process, the alkenyl ether product will react with the residual raw material acyl fluoride to form by-products, reducing the product yield; , Due to the high temperature of solid phase decarboxylation and uneven heating, it is easy to cause the decomposition and carbonization of the alkene ether product, resulting in the problems of carbon deposition and sticking to the wall, which will not only cause the reactor to be difficult to clean, but also reduce the heat transfer effect of the reactor wall.

The second type is a two-step method, including two-step solid-phase decarboxylation and two-step liquid-phase decarboxylation: the former refers to first decarboxylation of acyl fluoride in a mixture of organic solvent and carbonate or sodium hydroxide, potassium hydroxide or sodium carbonate Reaction in an aqueous solution of acetic acid to form a salt, then remove the solvent to obtain a dry salt, and then directly decarboxylate the dry salt at a high temperature to obtain an alkenyl ether product; the latter refers to the use of acyl fluoride to form a salt at a low temperature in a mixture of a solvent and carbonate, and then high-temperature decarboxylation to obtain the product .

The patent CN101659602B of Zhonghao Chenguang Chemical Research Institute adopts the method of first removing the solvent and then solid-phase decarboxylation in the reactor or cracking furnace. The patent states that this method can reduce the amount of by-product hydrogen-containing ether, and the product yield is less than 80% ; The Chinese patent CN100338013C of Asahi Kasei Co., Ltd. reported a similar method for preparing fluorine-containing vinyl ethers by first forming salts and desolvating solvents and then solid-phase decarboxylation; The process route of fluorovinyl ether and the cylindrical decarboxylation equipment with scraper, that is, the acyl fluoride is first salted, the solvent is removed, and then it is coated in the scraper cylinder for heating and decarboxylation, and the decarboxylation temperature is 120℃～250℃. Another patent CN203803486U discloses a reaction device for continuous decarboxylation, which improves the aforementioned decarboxylation equipment and improves the product yield, up to 98%. All of these schemes belong to two-step solid-phase decarboxylation, which have the common problems of solid-phase decarboxylation, namely, high decarboxylation temperature, easy occurrence of side reactions and difficult cleaning of residues such as generated fluoride salts. In addition, two-step solid-phase decarboxylation also has the Disadvantages of complexity and difficulty in solvent removal.

The patent CN101215225B of Zhonghao Chenguang Chemical Research Institute discloses a kind of adding organic amine as a catalyst in a polar solvent, perfluoroalkoxy propionyl fluoride and carbonate are salted at low temperature, and decarboxylated at 120℃～160℃ The method for obtaining perfluoroalkyl vinyl ether has a yield of 92.3%. Sinochem Lantian Group Co., Ltd. patent CN103965023B adopts perfluoroalkoxy propionyl fluoride and salt-forming agent under the action of catalyst to form salt at 20～80℃, and decarboxylate at 110～150℃ to prepare corresponding fluoroalkyl vinyl ether , the highest yield can reach 93.8% under a small amount of laboratory preparation. The above schemes are all two-step liquid-phase decarboxylation, and they all use a one-pot reaction in a reactor. After industrial scale-up, the decarboxylation product caused by the increase in the amount of solvent and the increase in the viscosity of the liquid phase during the reaction process is not considered and caused by the retention of the decarboxylation product in the liquid phase. The problem of side reactions is because when the product stays in the solvent, it will further react with the product itself and the residual acyl fluoride raw material in the solvent to generate by-products, and when using this one-pot liquid phase decarboxylation, there are many intermittent operations, which cannot be continuous. In addition, the solvent and catalyst used in liquid phase decarboxylation cannot be recycled, which has a great impact on the environment.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for preparing perfluoroalkyl vinyl ether by using carboxylate solution as raw material, so as to speed up the reaction, avoid the long stay of the decarboxylation reaction product in the solvent, and improve the solid-phase decarboxylation High temperature, easy to stick to the wall and difficult to clean the residue.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions: a method for preparing perfluoroalkyl vinyl ether with carboxylate solution as raw material,

The reaction system includes a raw material reactor for preparing a carboxylate solution, a decarboxylation reactor for decarboxylation of the carboxylate, a solvent receiving tank for collecting and reusing the solvent after decarboxylation, and the raw material reactor and the decarboxylation reactor are connected by pipelines, The solvent receiving tank is connected with the decarboxylation reactor through a pipeline, and the solvent in the solvent receiving tank is sent back to the raw material reactor by a solvent delivery pump. The inner cavity of the shell is divided into an upper decarboxylation reaction chamber and a lower heating chamber, the inclined plate is inclined downward, the decarboxylation reaction chamber is provided with a raw material inlet and a nitrogen inlet at the upper position of the corresponding inclined plate, and the decarboxylation reaction chamber is A gas phase outlet and a solvent outlet are arranged at the lower part of the corresponding inclined plate. The heating chamber is used to heat the inclined plate and to heat the carboxylate solution flowing along the inclined plate. A small baffle assembly for the solution to flow evenly on the inclined plate;

The carboxylate solution represented by the general formula (I) is continuously discharged from the raw material reactor to the upper end of the inclined plate in the decarboxylation reactor. Laminar flow, the inclined plate heats the thin layer, so that the carboxylate in it undergoes a decarboxylation reaction to form the perfluoroalkyl vinyl ether represented by formula (II), and the reaction formula is as follows:

Among them, M=Na, K; n=0, 1, 2;

The reaction process also produces carbon dioxide and alkali metal fluorides, perfluoroalkyl vinyl ether products and carbon dioxide are discharged from the gas phase outlet driven by nitrogen, and the products are collected by condensation in the condenser, and carbon dioxide and nitrogen are discharged, and the alkali metal fluorides are produced. With the solvent flowing into the solvent receiving tank, the solvent in the tank is pumped back to the raw material reactor for reuse.

Preferably, the carboxylate is obtained by converting the acid fluoride represented by the general formula (III),

n=0, 1, 2;

The obtained carboxylate is dissolved in an organic solvent to obtain the desired carboxylate solution.

Preferably, the mass ratio of the solvent to the carboxylate in the carboxylate solution is 0.1-3.0:1.

Preferably, the inclined plate is heated to 100°C to 160°C.

Preferably, the solvent is a combination of tetraethylene glycol dimethyl ether and diethylene glycol dimethyl ether, and the mass ratio of tetraethylene glycol dimethyl ether to diethylene glycol dimethyl ether is 0-0.2:1.

Preferably, the carboxylate is a combination of sodium salt and potassium salt, and the mass ratio of potassium salt to sodium salt is 0-0.1:1.

Preferably, the heating chamber is provided with a heat-conducting oil inlet and an outlet, the heat-conducting oil enters the heating chamber through the inlet and flows out of the heating chamber through the outlet, so as to realize the circulating flow of the heat-conducting oil in the heating chamber, the heating chamber is provided with a heater, and the The heater is connected to the thermostat, and the heater is controlled by the thermostat to ensure that the heat transfer oil in the heating chamber is at the set temperature.

Preferably, the small baffle assembly includes a row of middle small transverse plates located at the horizontal middle position of the inclined plate and two rows of side small transverse plates located on both sides of the inclined plate. It extends horizontally and is arranged in the longitudinal direction, and the two rows of side small transverse plates on both sides are aligned and distributed longitudinally with the middle row of small transverse plates.

Preferably, the small baffle assembly further comprises two rows of small inclined plates respectively located on both lateral sides of the inclined plate, the small inclined plates extending obliquely downward from the side to the middle and in the longitudinal direction with the middle small transverse plate and the side small transverse plates upper cross distribution.

Preferably, the small baffle assembly comprises two rows of middle small inclined plates in the middle and two rows of side small inclined plates on both sides, and the two rows of middle small inclined plates and the two rows of side small inclined plates are arranged in the longitudinal direction, The two rows of middle small inclined plates extend obliquely downward from the middle to the side, the two rows of side small inclined plates extend obliquely downward from the side to the middle, and the two rows of middle small inclined plates and the two rows of side small inclined plates are longitudinally cross distribution.

The present invention adopts the above technical scheme, and has the following beneficial effects: the carboxylate solution can form a thin-layer liquid phase flow on the inclined plate, so as to achieve the purpose of uniform heating of the reaction material and rapid decarboxylation, and at the same time, the decarboxylation product can quickly pass through the solvent It can greatly reduce the residence time of the product in the solvent, reduce the generation of by-products, and because the liquid phase decarboxylation is used, the decarboxylation temperature is low, and there will be no problems such as carbon deposition.

To sum up, the present invention has the advantages of fast reaction speed, low decarboxylation temperature, short product residence time, easy operation, recyclable solvent and high product yield. The shortcomings of continuous production also improve the problems of high decarboxylation temperature in solid phase method, easy sticking to the wall and difficult cleaning of residues.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

Fig. 1 is the structural representation of the reaction system that the present invention prepares perfluoroalkyl vinyl ether;

Fig. 2 is the structural representation of decarboxylation reactor;

Fig. 3 is the structural representation of inclined plate;

4 is a schematic diagram of the distribution structure of the first small baffle assembly on the inclined plate;

5 is a schematic diagram of the distribution structure of the second kind of small baffle assembly on the inclined plate;

FIG. 6 is a schematic diagram of the distribution structure of the third small baffle assembly on the inclined plate.

Detailed ways

The technical solutions of the embodiments of the present invention will be explained and described below with reference to the accompanying drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the examples in the implementation manner, other examples obtained by those skilled in the art without creative work shall fall within the protection scope of the present invention.

Embodiment 1, as shown in FIG. 1 , a reaction system for preparing perfluoroalkyl vinyl ether includes a raw material reactor 1 for preparing a carboxylate solution, a decarboxylation reactor 2 for decarboxylating the carboxylate, and the decarboxylation is completed. The solvent is collected and reused in the solvent receiving tank 3, the raw material reactor 1 is connected with the decarboxylation reactor 2 through a pipeline, and the solvent receiving tank 3 is connected with the decarboxylation reactor 2 through a pipeline.

The raw material reactor 1 includes a first feed pipe 11 , a second feed pipe 12 and a discharge pipe 13 . The first feeding pipe 11 introduces the organic solvent into the raw material reactor 1, and the second feeding pipe 12 introduces the alkali metal carbonate and acid fluoride or the prepared carboxylate into the raw material reactor 1. Acyl fluoride and alkali metal carbonate are reacted in the raw material reactor to obtain a carboxylate solution, or the carboxylate is stirred and dissolved in an organic solvent in the raw material reactor to form a carboxylate solution.

2 and 3, the decarboxylation reactor 2 includes an outer shell 23 and an inclined plate 24 arranged in the outer shell, and the inclined plate 24 divides the inner cavity of the outer shell into an upper decarboxylation reaction chamber 26 and a lower heating chamber 29, The inclined plate 24 is inclined downward, the decarboxylation reaction chamber is provided with a raw material inlet 21 and a nitrogen inlet 22 at the upper part of the corresponding inclined plate, and the decarboxylation reaction chamber is provided with a gas phase outlet 27 and a solvent outlet at the lower position of the corresponding inclined plate. 28. The heating chamber is used to heat the inclined plate and to heat the carboxylate solution flowing along the inclined plate. The upper surface of the inclined plate is distributed with small baffle components that make the carboxylate solution flow evenly on the inclined plate. 25.

When the reaction system is in use, the carboxylate solution prepared in the raw material reactor flows from the raw material inlet 21 into the upper end of the inclined plate 24 in the decarboxylation reactor, and forms a thin layer downward under the action of the small baffle plate 25 on the inclined plate. Flow, under the contact with the heated inclined plate, the decarboxylation reaction occurs instantaneously to generate perfluoroalkyl vinyl ether, carbon dioxide and alkali metal fluoride. The perfluoroalkyl vinyl ether product and carbon dioxide are discharged from the gas phase outlet 27 driven by nitrogen, and the products are collected by condensation in a condenser, and carbon dioxide and nitrogen are discharged. The generated alkali metal fluoride flows into the solvent receiving tank with the solvent, and the solvent in the tank is pumped back to the raw material reactor for reuse.

The advantages of the decarboxylation reactor of the present invention are: the carboxylate solution can form a thin-layer liquid phase flow on the inclined plate, so as to achieve the purpose of uniform heating of the reaction material and rapid decarboxylation, and at the same time, the decarboxylation product can quickly pass through the solvent layer, and greatly The residence time of the product in the solvent is reduced, the generation of by-products is reduced, and the method is liquid-phase decarboxylation, the decarboxylation temperature is low, and problems such as carbon deposition will not occur.

The heating chamber 29 is provided with a heat transfer oil inlet 30 and an outlet 31, the heat transfer oil enters the heating chamber through the inlet and flows out of the heating chamber through the outlet, so as to realize the circulating flow of the heat transfer oil in the heating chamber. The heating chamber is provided with a heater, the heater is connected to a thermostat, and the heater is controlled to work by the thermostat so as to ensure that the heat-conducting oil in the heating chamber is at a set temperature.

Through the setting of the small baffle assembly 25, the carboxylic acid solution forms a thin layer flow on the inclined plate. Those skilled in the art can understand that the shape of the small baffle is not particularly limited, and can be any small baffle known in the art, such as a square baffle or a sawtooth baffle. Furthermore, the small baffle assemblies may be distributed regularly or irregularly. The material of the inclined plate and the small baffle plate is not particularly limited, and is usually the same as the material forming the decarboxylation reaction chamber, such as stainless steel.

Three specific structures of the small baffle assembly 25 are described below.

Referring to FIG. 4 , the small baffle assembly includes a row of middle small transverse plates located at the horizontal middle position of the inclined plate and two rows of side small transverse plates located on both sides of the inclined plate. The transverse plates extend in the transverse direction and are arranged in the longitudinal direction, and the two rows of side small transverse plates on both sides are aligned and distributed longitudinally with the middle row of small transverse plates.

Referring to FIG. 5 , the small baffle assembly further includes two rows of small inclined plates located on both lateral sides of the inclined plate, the small inclined plates extend obliquely downward from the side to the middle and are connected to the middle small transverse plate and the side small transverse plates. The plates are cross-distributed in the longitudinal direction.

Referring to FIG. 6 , the small baffle assembly includes two rows of middle small inclined plates in the middle and two rows of side small inclined plates on both sides, and the two rows of middle small inclined plates and the two rows of side small inclined plates are longitudinal Arrangement, the two rows of middle small inclined plates extend obliquely downward from the middle to the side, the two rows of side small inclined plates extend obliquely downward from the side to the middle, and the two rows of middle small inclined plates are connected to the two rows of side small inclined plates. The inclined plates are distributed longitudinally.

The inclined plate needs to have a certain thickness to prevent the inclined plate from being bent and deformed under heating. Preferably, in this embodiment, the thickness of the inclined plate is 1-20 mm, and can be further selected at 3-15 mm, and further can be selected at 5-10 mm , those skilled in the art can make appropriate choices.

The inclined plate forms an included angle of 1° to 30° with the horizontal plane. Further, it can be selected from 2° to 20°, and further can be selected from 2° to 10°, and those skilled in the art can make appropriate choices.

The height of the small baffle assembly is 5-40 mm, preferably 10-20 mm, and those skilled in the art can make appropriate choices.

The carboxylate is heated and decarboxylated in the decarboxylation reactor 2, and the formed alkali metal fluoride enters the solvent receiving tank 3 with the solvent through the first pipeline 14, and the solvent in the solvent receiving tank 3 is sent to the raw material reactor 1 through the first pump 4 for reuse. The gas product that decarboxylation obtains enters in the condenser 5 via the first pipeline 15, and the condensed liquid is condensed by heat exchange with the condensing medium, and the liquid obtained by condensation enters the storage tank 6 through the second pipeline 16, and the liquid in the storage tank is by the second pump. 7 is sent to the rectification tower 8, and the perfluoroalkyl vinyl ether product is separated and purified by the rectification tower 8. A small amount of solvent and by-products are discharged from the second pipeline 18, and the perfluoroalkyl vinyl ether product is discharged from the third pipeline 17 and collected.

Those skilled in the art can understand that the raw material reactor suitable for the reaction system of the present invention is not particularly limited, and can be any jacketed reactor known in the art, such as a common jacketed stainless steel reactor with a stirring device Wait.

The decarboxylation reactor of the reaction system of the present invention is a hexahedral reactor. The applicable hexahedral reactor is not particularly limited, and can be any hexahedral reactor known in the art, as long as the hexahedral reactor is hollow. In the example of the present invention, the decarboxylation reactor is a cuboid decarboxylation reactor. The material used for preparing the hexahedral decarboxylation reactor of the present invention is not particularly limited, and may be any material known in the art. In a preferred embodiment of the present invention, the hexahedral decarboxylation reactor is made of stainless steel.

Those skilled in the art can understand that the solvent receiving tank suitable for the reaction system of the present invention is not particularly limited, and can be any solvent receiving tank known in the art, such as a common stainless steel tank and the like.

Those skilled in the art can understand that the solvent delivery pump suitable for the reaction system of the present invention is not particularly limited, and can be any solvent delivery pump known in the art, such as a diaphragm pump and the like.

The invention also relates to a method for preparing perfluoroalkyl vinyl ether by continuous thin-layer liquid-phase decarboxylation of carboxylate solution: the carboxylate solution represented by general formula (I) is continuously discharged from the raw material reactor to the decarboxylation reaction The upper end of the inclined plate in the device is evenly distributed on the inclined plate under the action of the small baffle plate on the surface of the inclined plate, and forms a thin layer of flow. For the perfluoroalkyl vinyl ether represented by formula (II), the relevant reaction formula is as follows:

Wherein, M is an alkali metal atom; n=0,1,2.

The carboxylate solution described in the present invention can be obtained by any method, wherein the carboxylate is preferably obtained by converting the acid fluoride represented by the general formula (III) because the method has a high yield. The specific method for the preparation of the carboxylate solution has been reported in many patents, for example: as described in patents CN101215225B, CN103965023B, etc., perfluoroalkoxy propionyl fluoride and carbonate are formed into salts at low temperature in polar solvents, directly Obtain the desired carboxylate solution; or obtain dry fluorine-containing carboxylate as described in patents CN101659602B, CN100338013C, CN102992969B, etc., and then dissolve it in a suitable organic solvent to obtain the desired carboxylate solution.

The definition of n is the same as that of general formulae (I) and (II).

In the carboxylate solution of the present invention, the mass ratio of the solvent to the carboxylate is 0.1-3.0:1, preferably 0.3-1.5:1. The applicable solvent is aprotic alcohol ether, which can be selected from one or more of diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether. Combination, preferably one or two combinations of tetraethylene glycol dimethyl ether and diethylene glycol dimethyl ether, the mass ratio of tetraethylene glycol dimethyl ether and diethylene glycol dimethyl ether is 0～0.2:1 . The applicable carboxylate is one or a combination of sodium salt or potassium salt, and the mass ratio of potassium salt to sodium salt is 0-0.1:1.

In the decarboxylation reaction of the present invention, the carboxylate is thermally decarboxylated under reduced pressure or inert gas.

During the pyrolysis decarboxylation of the present invention, under the action of the small baffle, the carboxylate solution forms a thin layer with a thickness of 1-30 mm, preferably a thin layer of 5-15 mm, on the inclined plate to flow. In addition, a thermal oil is passed through the heating chamber, and the inclined plate is heated to 100°C to 160°C, preferably 120°C to 140°C. At this temperature, the carboxylate in the solution is easily decarboxylated by heat, and because the solution forms a thin layer on the swash plate, the decarboxylated product can pass through the solvent layer very quickly, reducing the residence time of the product in the solvent. Reduce by-products.

As shown in FIG. 1 , the method of the present invention may further include condensation and collection of the gaseous product produced by the decarboxylation reaction and separation and purification of the product.

The present invention will be further elaborated below in conjunction with the examples.

Comparative ratio:

In a 2L three-necked flask with stirring and reflux condensing device, add 500g diethylene glycol dimethyl ether and 170g anhydrous sodium carbonate, slowly drip 500g perfluoro(2-methyl-3-oxa) under stirring hexyl) fluoride. After the addition was completed, the reaction was slowly heated up to 60°C, and the reaction was kept at 60°C for 1 h to complete the salt-forming reaction. Then the temperature was continued to rise to 130° C., and 362 g of liquid was collected through a reflux condensing device, wherein the content of perfluoro-n-propyl vinyl ether was 86.23%. The product yield of perfluoro-n-propyl vinyl ether was 77.9%.

Example 1:

The solvent diethylene glycol dimethyl ether 1000g and sodium carbonate 400g were added to the raw material reactor, and the raw material perfluoro(2-methyl-3-oxhexyl) fluoride 1200g was added dropwise to the raw material reactor. A salt-forming reaction occurred in the raw material reactor, the reaction temperature was 80°C, and the reaction time was 3.5h. After the reaction, a sodium carboxylate solution was obtained.

The obtained sodium carboxylate solution was continuously added to the decarboxylation reactor at a flow rate of 500g/h through a pipeline, and decarboxylation reaction occurred in the decarboxylation reactor. The reaction temperature was 130°C, and the crude product generated by the reaction was condensed by the condenser to obtain 932g of liquid product. , in which the content of perfluoro-n-propyl vinyl ether is 96.75%. The yield of perfluoro-n-propyl vinyl ether was 93.8%.

Example 2:

The solvent diethylene glycol dimethyl ether 1100g, tetraethylene glycol dimethyl ether 100g and sodium carbonate 500g were added to the raw material reactor, and the raw material perfluoro(2-methyl-3-oxhexyl) fluoride 1500g was dropped When added to the raw material reactor, the two react in the raw material reactor to form a salt. The reaction temperature is 80°C and the reaction time is 4h. After the reaction, a sodium carboxylate solution was obtained.

The obtained sodium carboxylate solution was continuously added to the decarboxylation reactor at a flow rate of 500g/h through the pipeline, and decarboxylation reaction occurred in the decarboxylation reactor. The reaction temperature was 140°C, and the crude product generated by the reaction was condensed by the condenser to obtain 1168g of liquid product. , in which the content of perfluoro-n-propyl vinyl ether is 97.12%. The product yield of perfluoro-n-propyl vinyl ether was 94.4%.

Example 3:

The solvent tetraethylene glycol dimethyl ether 1000g and sodium carbonate 280g were added to the raw material reactor, and the raw material 2,5-bis(trifluoromethyl)-3,6-dioxaundecafluorononanoyl fluoride was added to 1200g It is added dropwise to the raw material reactor, and the two undergo a salt-forming reaction in the raw material reactor. The reaction temperature is 90°C and the reaction time is 3h. After the reaction, a sodium carboxylate solution was obtained.

The obtained sodium carboxylate solution was continuously added to the decarboxylation reactor at a flow rate of 500 g/h through a pipeline, and a decarboxylation reaction occurred in the decarboxylation reactor. The reaction temperature was 150 ° C, and the crude ether generated by the reaction was condensed by the condenser to obtain a liquid product. 956g, wherein the content of 2-(heptafluoropropoxy)hexafluoropropyltrifluorovinyl ether is 92.16%. The yield of 2-(heptafluoropropoxy)hexafluoropropyltrifluorovinyl ether was 84.6%.

Example 4:

The solvent diethylene glycol dimethyl ether 1000g and potassium carbonate 450g were added to the raw material reactor, and the raw material perfluoro(2-methyl-3-oxhexyl) fluoride 1000g was added dropwise to the raw material reactor. A salt-forming reaction occurs in the raw material reactor, the reaction temperature is 60°C, and the reaction time is 3h. After the reaction, potassium carboxylate solution was obtained.

The obtained potassium carboxylate solution is continuously added to the decarboxylation reactor at a flow rate of 500g/h through the pipeline, and decarboxylation reaction occurs in the decarboxylation reactor. 765g, wherein the content of perfluoro-n-propyl vinyl ether is 94.65%. The product yield of perfluoro-n-propyl vinyl ether was 90.4%.

Example 5:

Add 803 g of 30% aqueous sodium hydroxide solution to a 2L three-necked flask with stirring and a reflux condensing device, place the flask in a cold water bath, and slowly drip perfluoro(2-methyl-3-oxa) under stirring. Hexyl) fluoride 1000g, reaction temperature 40 ℃, reaction time 2h. The reaction product was dried under vacuum at 90° C. to obtain 1186 g of dry solid.

1186 g of the prepared solid salt and 1000 g of diethylene glycol dimethyl ether were added to the raw material reactor for dissolution, the temperature was normal temperature, and the dissolution time was 0.5 h to obtain a sodium carboxylate solution.

The obtained sodium carboxylate solution is continuously added to the decarboxylation reactor at a flow rate of 500 g/h through a pipeline, and a decarboxylation reaction occurs in the reactor, and the reaction temperature is 130 ° C. After heat exchange of the condensation medium, 781 g of a liquid product is obtained by condensation, wherein the content of perfluoro-n-propyl vinyl ether is 97.28%. The product yield of perfluoro-n-propyl vinyl ether was 95.3%.

Example 6:

Add 30% sodium hydroxide aqueous solution 780g, 30% potassium hydroxide aqueous solution 33g in a 2L three-necked flask with stirring and reflux condensing device, the flask is placed in a cold water bath, and slowly dripped with perfluoro( 2-methyl-3-oxhexyl) fluoride 1000g, reaction temperature 40°C, reaction time 2h. The reaction product was dried under vacuum at 90° C. to obtain 1190 g of dry solid.

1190 g of the prepared solid salt mixture and 1000 g of diethylene glycol dimethyl ether were added to the raw material reactor for dissolution, the temperature was normal temperature, and the dissolution time was 0.5 h to obtain a sodium carboxylate solution.

The obtained sodium carboxylate solution is continuously added to the decarboxylation reactor at a flow rate of 500 g/h through a pipeline, and a decarboxylation reaction occurs in the reactor, and the reaction temperature is 130 ° C. After heat exchange of the condensation medium, 787 g of a liquid product is obtained by condensation, wherein the content of perfluoro-n-propyl vinyl ether is 97.87%. The product yield of perfluoro-n-propyl vinyl ether was 96.1%.

Claims (10)

1. a method for preparing perfluoroalkyl vinyl ether with carboxylate solution as raw material, is characterized in that: The reaction system includes a raw material reactor for preparing a carboxylate solution, a decarboxylation reactor for decarboxylation of the carboxylate, a solvent receiving tank for collecting and reusing the solvent after decarboxylation, and the raw material reactor and the decarboxylation reactor are connected by pipelines, The solvent receiving tank is connected with the decarboxylation reactor through a pipeline, and the solvent in the solvent receiving tank is sent back to the raw material reactor by a solvent delivery pump. The inner cavity of the shell is divided into an upper decarboxylation reaction chamber and a lower heating chamber, the inclined plate is inclined downward, the decarboxylation reaction chamber is provided with a raw material inlet and a nitrogen inlet at the upper position of the corresponding inclined plate, and the decarboxylation reaction chamber is A gas phase outlet and a solvent outlet are arranged at the lower part of the corresponding inclined plate. The heating chamber is used to heat the inclined plate and to heat the carboxylate solution flowing along the inclined plate. A small baffle assembly for the solution to flow evenly on the inclined plate; The carboxylate solution represented by the general formula (I) is continuously discharged from the raw material reactor to the upper end of the inclined plate in the decarboxylation reactor. Laminar flow, the inclined plate heats the thin layer, so that the carboxylate in it undergoes a decarboxylation reaction to form the perfluoroalkyl vinyl ether represented by formula (II), and the reaction formula is as follows:

Among them, M=Na, K; n=0, 1, 2; The reaction process also produces carbon dioxide and alkali metal fluorides, perfluoroalkyl vinyl ether products and carbon dioxide are discharged from the gas phase outlet driven by nitrogen, and the products are collected by condensation in the condenser, and carbon dioxide and nitrogen are discharged, and the alkali metal fluorides are produced. With the solvent flowing into the solvent receiving tank, the solvent in the tank is pumped back to the raw material reactor for reuse. 2. a kind of method for preparing perfluoroalkyl vinyl ether with carboxylate solution as raw material according to claim 1, is characterized in that: carboxylate is obtained by the acyl fluoride transformation represented by general formula (III),

n=0, 1, 2; The obtained carboxylate is dissolved in an organic solvent to obtain the desired carboxylate solution. 3. a kind of method for preparing perfluoroalkyl vinyl ether with carboxylate solution as raw material according to claim 2, is characterized in that: in the described carboxylate solution, the mass ratio of solvent and carboxylate is 0.1 ~3.0:1. 4 . The method for preparing perfluoroalkyl vinyl ether from carboxylate solution according to claim 1 , wherein the inclined plate is heated to 100° C. to 160° C. 5 . 5. a kind of method for preparing perfluoroalkyl vinyl ether with carboxylate solution as raw material according to claim 3, is characterized in that: described solvent is tetraethylene glycol dimethyl ether and diethylene glycol Dimethyl ether combination. 6. a kind of method for preparing perfluoroalkyl vinyl ether with carboxylate solution as raw material according to claim 3, is characterized in that: described carboxylate is the combination of sodium salt and potassium salt. 7. a kind of method for preparing perfluoroalkyl vinyl ether with carboxylate solution as raw material according to claim 1, is characterized in that, described heating chamber is provided with heat-conducting oil inlet and outlet, and heat-conducting oil enters through inlet The heating chamber flows out of the heating chamber through the outlet to realize the circulating flow of heat-conducting oil in the heating chamber. The heating chamber is provided with a heater, and the heater is connected to a temperature controller. Oil is at set temperature. 8. a kind of method for preparing perfluoroalkyl vinyl ether with carboxylate solution as raw material according to claim 1, is characterized in that, described small baffle plate assembly comprises a row of middle positions located in the horizontal middle position of inclined plate The small transverse boards and the two rows of side small transverse boards located on the lateral sides of the inclined board, the middle small transverse boards and the side small transverse boards extend laterally and are arranged in the longitudinal direction, and the two rows of side small transverse boards on both sides are aligned and aligned with the side small transverse boards. The middle row of small horizontal plates in the middle row are vertically crossed. 9. a kind of method for preparing perfluoroalkyl vinyl ether by taking carboxylate solution as raw material according to claim 8, is characterized in that, described small baffle plate assembly also comprises two rows respectively located on the lateral sides of inclined plate A small inclined plate, the small inclined plate extends obliquely downward from the side to the middle, and is distributed in the longitudinal direction with the middle small transverse plate and the side small transverse plates. 10. The method for preparing perfluoroalkyl vinyl ether with carboxylate solution as a raw material according to claim 1, wherein the small baffle plate assembly comprises two middle rows of middle small inclined plates and two middle sloping plates. The two rows of side small inclined plates on the side, the two rows of middle small inclined plates and the two rows of side small inclined plates are arranged in the longitudinal direction, the two rows of middle small inclined plates extend obliquely downward from the middle to the side, and the two rows of small inclined plates are arranged in the longitudinal direction. The side small inclined plates extend obliquely downward from the side to the middle, and the two rows of middle small inclined plates and the two rows of side small inclined plates are longitudinally distributed.

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