WO2018113628A1 - Rapid continuous-flow synthesis process for fluoroethylene carbonate. - Google Patents

Abstract

The present invention relates to a rapid continuous-flow synthesis process for fluoroethylene carbonate and an integrated continuous-flow reactor to implement the process. In the continuous-flow synthesis process, raw materials to be fluorinated and fluorine gas are taken as reactants, and are subjected to the steps of mixing and dispersing, fluorination reaction and gas-liquid separation continuously and successively to obtain the fluoroethylene ethylene carbonate. The synthesis process is carried out in an integrated continuous-flow reactor, wherein the raw materials to be fluorinated and fluorine gas are continuously fed to a feed inlet of the integrated continuous-flow reactor, the fluoroethylene carbonate is continuously obtained at a discharge outlet of the integrated continuous-flow reactor, and the reaction time is equal to or less than 600 seconds. The process is a fast, safe and efficient continuous synthesis process for fluoroethylene carbonate that has high versatility and easy for large-scale production.

Description

Rapid continuous flow synthesis process of fluoroethylene carbonate Technical field

The invention relates to the field of chemistry, in particular to a rapid continuous flow synthesis process of fluoroethylene carbonate.

Background technique

Fluorinated compounds (especially organofluorine compounds, ie partially and fully fluorinated organic compounds) are excellent and commercially valuable chemicals. The fluorine-containing compound can exhibit various properties such as inertness, nonpolarity, hydrophobicity, oleophobicity and the like, and thus has a very wide range of uses. Fluorinated organic carbonates are an important class of organic fluorine compounds (organic known as organic fluorides), which can be used as solvents and solvent additives for lithium ion batteries. Their performance in forming solid electrolyte interface films (SEI films) is better. The formation of the compact structure layer without increasing the impedance, at the same time can prevent the electrolyte from further decomposing and having a flame retarding effect, thereby improving the low temperature performance of the electrolyte, so that the cycle life of the battery is significantly increased, and the safety performance of the battery is improved. Among them, fluoroethylene carbonate is an important product.

The synthetic route of fluoroethylene carbonate mainly includes the following:

The electrochemical fluorination method for the industrial production of organofluorine compounds was first put into industrial production by 3M Company. This fluorination process is commonly referred to as "Simons electrochemical fluorination process", and the process requires electrolysis of an electrolyte solution containing liquid anhydrous hydrogen fluoride and an organic compound raw material, which is disadvantageous in that it consumes high energy and requires the use of anhydrous hydrogen fluoride. Another electrochemical fluorination process is electrolysis in a salt melt, such as a potassium fluoride/hydrogen fluoride melt, which is known as the Phillips process. BASF Europe has improved this method in CN103261484A by using a hydrogen fluoride complex instead of an anhydrous hydrogen fluoride or salt melt as a fluorinating agent in the electrolyte and applying it to the preparation of fluoroorganic carbonates, but still in the process It consumes a lot of power and costs a lot.

Another method of industrial production of fluoroorganocarbonates is the halogen exchange process, a process for the synthesis of fluoroorganocarbonates by Finkelstein Reaction. Such a method generally comprises first chlorinating an organic compound to obtain a chlorinated organic carbonate, and after purification, reacting with a fluorinating reagent (HF or KF) to obtain a fluorinated organic carbonate. For example, the route for the synthesis of monofluoroethylene carbonate by halogen exchange is as follows:

Among them, the first-stage chlorination reaction has been reported more, the process is relatively mature, and it is easy to operate and control relative to the fluorination reaction. However, since the route of synthesizing fluoroethylene carbonate requires a two-step reaction, and in order to reduce the impurities of the halogen exchange reaction, a high-purity fluoroorganic carbonate is obtained, and the intermediate chloroethylene carbonate needs to be washed and neutralized. The multi-step purification process, such as drying and rectification, makes the process cumbersome and reduces production efficiency. Further, according to the prior report, the total yield of the monofluorocarbonate produced by the two-step reaction is generally from 60 to 65%, which is not preferable.

Patent CN105541783A relates to a method for producing fluoroethylene carbonate, which is obtained by subjecting ethylene carbonate as a raw material to a three-step reaction of chlorination, elimination and addition to produce fluoroethylene carbonate. The process route is as follows, intermediate chlorination Both ethylene carbonate and vinylene carbonate need to be purified (required rectification to obtain vinyl chlorocarbonate and refined under reduced pressure to obtain vinylene carbonate) before being used in the next reaction, compared to direct fluorination, reaction step Both the process steps and the process steps were increased, the production efficiency was lowered, and the fluoroethylene carbonate yield was not improved compared with the halogen exchange method, which was only 56.5% based on the vinyl chlorocarbonate.

Another feasible route for the synthesis of fluoroethylene carbonate is the direct fluorination method, that is, the synthesis of fluoroethylene carbonate by direct substitution reaction of fluorine gas or a mixed gas of fluorine gas and an inert gas (for example, nitrogen) with ethylene carbonate. For example, the route for the synthesis of monofluoroethylene carbonate by direct fluorination is as follows:

Compared with the halogen exchange method, the method undergoes a one-step reaction, the process route is more concise, and the reaction is prone to mild conditions. Due to the high reactivity of the fluorine gas, the fluorination reaction can be theoretically completed at a relatively low temperature, and the production efficiency is more efficient. high. However, this method also has shortcomings. For example, the fluorine gas of the raw material is highly toxic; the high reactivity of the fluorine gas makes the process extremely exothermic, which tends to cause high pressure in the reactor and is dangerous; the fluorine gas is highly corrosive and requires high reaction equipment. . For these reasons, there are few reports on the direct fluorination process, and industrial applications are also greatly limited.

Fluorine gas is a highly toxic gas that can irritate the eyes, skin, and respiratory mucosa. When the concentration of fluorine is 5 to 10 ppm, it may cause irritation to the mucous membranes such as the eyes, nose, and throat, and may cause pulmonary edema when the action time is long. Contact with the skin can cause burning of the hair, coagulation necrosis at the contact site, carbonization of the epithelial tissue, and the like. Chronic contact can cause osteopetrosis and ligament calcification. To ensure personnel safety, the maximum allowable concentration in air is 0.1 ppm (0.2 mg/m3). Therefore, the direct fluorination method using fluorine gas requires high safety requirements for equipment and processes, and needs to include leak prevention and exhaust gas treatment facilities.

Elemental fluorine is the most electronegative element, and its chemical elemental fluorine gas is very reactive. Most of its elements, including some inert gases, can react with it to form compounds. Fluorine gas has strong oxidizing properties and can be burned in strong reaction with most oxidizable substances or organic substances at room temperature. For example, alkali metals will explode in fluorine gas, and many non-metals such as silicon, phosphorus and sulfur will also burn in fluorine gas. However, the reaction of most organic compounds with fluorine gas is highly prone to combustion explosion. The exothermic reaction of the organic compound with fluorine gas is very large. For example, if a fluorine reaction occurs with fluorine gas, the exotherm of the reaction is about 482 kJ/mol, and for the similar substitution reaction of chlorine and bromine, the reaction exotherm is respectively About 101kJ/mol and 34kJ/mol, that is, the exotherm of the fluorination reaction is nearly 5 times that of the chlorination reaction, and is an order of magnitude larger than the similar bromination reaction. If it is a polyfluorination reaction, the exotherm is multiplied. Increase (for example, the exotherm of the difluoro reaction is about 964 kJ/mol). Therefore, the fluorine reaction using fluorine gas or a mixed gas of fluorine gas and an inert gas as a raw material has a large heat release characteristic compared with a similar substitution reaction (for example, chlorination, bromine, etc.), and requires heat transfer to the process. Very high, increasing the difficulty of process development. In addition, the existing process for synthesizing fluoroethylene carbonate cannot realize the synthesis of a plurality of different fluoroethylene carbonates and mixtures thereof by simply adjusting the process parameters using the same set of reactors (for example, ethylene carbonate). The ester is used as a raw material to synthesize monofluoroethylene carbonate; or ethylene carbonate is used as a raw material to synthesize difluoroethylene carbonate; or monofluoroethylene carbonate is used as a raw material to synthesize vinyl trifluorocarbonate).

The substitution reaction of fluorine gas with organic compounds is easy to occur and the process is severe. If the control is not good, the reaction easily leads to excessive decrease in selectivity, and a mixture of products with different degrees of fluorination is produced, which reduces the yield of the target product and also increases the separation and purification. Difficulty. In general, the fluorine-substituted reaction selectivity of the fluorinated starting material is better than other fluorine-substituted (eg, difluoro, trifluoro, tetrafluoro) reactions, and the corresponding process conditions are also easy to control. For example, Chinese patents CN1810764A and CN201080042843A report that the selectivity of synthesizing monofluorocarbonate with ethylene carbonate as a raw material is more selective than the synthesis of difluoroethylene carbonate, trifluoroethylene carbonate, and tetrafluoroethylene carbonate. High, the former is greater than 95%, and the latter three are not more than 80%. Further, the proportion of the target product in the crude reaction product is also high, and it has been reported that the selectivity for preparing the monofluoroethylene carbonate is up to 95%, but the preparation of difluoroethene carbonate, trifluoroethylene carbonate, carbonic acid The highest level of tetrafluoroethene ester is no more than 75%. That is to say, the existing methods are not able to solve the problem of selectivity of direct fluorination reaction well.

The fluorine gas is very corrosive, and most metals and non-metals are corroded. Therefore, the direct fluorination method requires high requirements on the material and structure of the reaction equipment, and at the same time requires that the fluorine gas in the process is consumed as completely as possible, and the conversion of fluorine gas is improved. Rate, reduce waste and reduce the risk of tail gas treatment.

The direct fluorination reaction of ethylene carbonate with fluorine gas is a gas-liquid two-phase heterogeneous reaction, and this kind of reaction is usually a combination of mass transfer process and reaction process, and its macroscopic reaction rate is affected by intrinsic reaction rate and mass transfer. The rate has a common impact. The fluorination reaction of ethylene carbonate with fluorine gas is a rapid reaction, so the macroscopic reaction rate is greatly affected by the mass transfer factor, and the good contact of the gas-liquid two phases is good, and it is advantageous to carry out the reaction quickly and completely. It is generally believed that in a heterogeneous reaction, two phases of close volume are mixed, and the mixing effect is better. However, in the gas-liquid two-phase reaction, the volume difference between the gas phase and the liquid phase is generally large. For example, ethylene carbonate undergoes a fluorination reaction with fluorine (pure fluorine gas), and the volume ratio of gas-liquid two phases is as high as 336:1 according to the theoretical molar ratio. If the polyfluorination reaction is carried out, the volume difference between the gas phase and the liquid phase will be multiplied. For example, the ethylene carbonate reacts with the fluorine element (pure fluorine gas) in a difluoro reaction. According to the theoretical molar ratio, the volume of the gas-liquid two phase The ratio is 672:1. Or the fluorinating reagent uses a mixed gas of fluorine gas and inert gas, and the volume difference between the gas phase and the liquid phase will be larger. For example, ethylene carbonate is subjected to a fluorination reaction with a mixed gas of a fluorine concentration of 20% and nitrogen gas. According to the theoretical molar ratio, the volume ratio of the gas-liquid two phases is as high as 1,680:1. Generally, the gas/liquid dispersion specific surface area is used to measure the mixing effect of the gas-liquid two-phase. The larger the gas/liquid dispersion specific surface area, the better the gas-liquid two-phase mixing.

In summary, the synthesis of fluoroethylene carbonate by direct fluorination has a theoretical reaction advantage (high reactivity of fluorine, rapid reaction at low temperatures, low production efficiency, and high production efficiency), but the method exists. The shortcomings are also obvious: 1) the controllability of the reaction is very poor, the heat release is very large, the reaction is easy to get out of control, and the risk is high; 2) due to the heterogeneous reaction of gas-liquid two-phase with huge volume difference, gas phase and It is difficult to achieve uniform mixing in the liquid phase. The reaction requires very high mass transfer of the reaction system, otherwise it is difficult to achieve sufficient reaction. 3) Poor process selectivity, low flexibility, and different degrees of fluorination of the same raw material (for example, The exotherm and gas-liquid phase volume ratios of the fluorination reaction, the difluoro reaction, the trifluoro reaction, the tetrafluoro reaction, etc. vary greatly, and the physical properties of different raw materials (for example, melting point, thermal conductivity, heat capacity) , solubility, etc.) and reactivity are also very different, so the conditions corresponding to the occurrence of fluorination reactions are also very different, it is difficult to control a certain degree of fluorination reaction to occur with high selectivity, and a reactor It is difficult to meet the synthesis conditions of a variety of fluoroproducts at the same time.

In the prior art, a process that can fully utilize the reaction advantages of the direct fluorination method and overcome the above three disadvantages of the method has not been developed, that is, the heat transfer and mass transfer problems are fully solved, and different raw material physics are also considered. Properties (eg, melting point, thermal conductivity, heat capacity, solubility, etc.) and reactivity differences, addressing process selectivity and flexibility issues, making direct fluorination reactions highly controllable, and high reaction efficiency (reactive, target product High yield), good universal applicability (using the same reactor can produce products with different degrees of fluorination with high efficiency).

In the existing industrial production, the direct fluorination method for synthesizing fluoroethylene carbonate mostly adopts a batch process, that is, into a reaction vessel containing a certain amount of raw materials, a fluorine gas or a mixed gas of fluorine gas and an inert gas is bubbled. The above-described batch-tank process is specifically described by way of example, for example, the patents CN1747946A, CN100343245C and JP2000309583A. In addition to the problems of low production efficiency and cumbersome operation inherent in the batch process, the gas-liquid two-phase reaction is carried out by means of bubbling with gas, and the reaction efficiency and the conversion rate of fluorine gas are both due to the limited contact between the gas and liquid phases. Low, poor reaction selectivity, and long reaction time. Chinese patent CN1810764A has improved this by using a bubble-adjusting column filled with a filler to adjust the size of the bubble and optimize the shape of the reactor when the F ₂ /N ₂ mixed gas is supplied to the ethylene carbonate, and the gas-liquid two-phase is increased. The contact time and contact area, the reaction efficiency increases, and the reaction time is correspondingly shortened. At 50 ° C, the FEC yield can reach 82%. However, this reaction is a batch process and the reaction time still takes several hours. After each batch of the reaction, N ₂ gas is required to remove the residual gas in the reactor, which limits the overall production efficiency of the fluoroethylene carbonate.

The batch process is to wait for a certain period of time after the raw materials are added to the reactor (including the reaction time of each step, the cooling time, the heating time, the holding time, and the waiting time of each operation, etc.), after the reaction reaches a certain requirement. The product is discharged at one time, ie the product is produced in batches, and only a limited number of products can be produced per batch (the number depends on the volume of the reactor). The total reaction time of the batch process refers to the total time from the raw material to the product, including the feeding time, reaction time, discharge time, transfer time, cooling time, heating time, holding time and interval of each operation. Waiting time, etc. During the batch process operation, the composition and temperature of the materials (including intermediate products and final products) in the reactor will change with time. It is an unsteady process, and the production process and product quality have great uncertainty, which directly leads to downstream. The quality of the product is unstable and difficult to control.

The most important characteristics of the batch process are two points. One is that there is “stay” or “interruption” in the process, and the second is that the production of the products is spaced apart, that is, the product has a batch and only one fixed quantity of product can be obtained in one batch. That is, for each batch of production, a fixed amount of the raw materials is reacted in the order of the reaction steps, resulting in a limited fixed amount of product (product); then a fixed amount of the raw material is put, and the same step is followed. The batch reacts to produce a limited fixed amount of product.

There are two ways to achieve a batch process: 1) using multiple reactors (eg, flasks, reactors, etc.), each step in one reactor; 2) using a reactor (eg, flask, reaction) In the reactor, etc., each step of the reaction is sequentially completed in the reactor, and a plurality of raw materials need to be sequentially added according to the progress of the reaction, that is, after each step of the reaction, there is a “stay”, waiting for further addition of the raw materials of the subsequent reaction. . Some literatures also refer to mode 2) as continuous, which is also intermittent in nature, because there is "stay" in the process, waiting for feeding, or adjusting to the appropriate temperature for the next reaction (for example, heating, cooling) Or keep warm).

Through the improvement of existing devices and process methods, there are some attempts in the continuous method of direct fluorination, which are only partially solved, but only solve the above three disadvantages to a certain extent, and still have long reaction time and low production efficiency. Process and equipment flexibility, poor selectivity.

Chinese patent CN1075313A relates to a method for directly fluorinating a fluorinated cyclic or acyclic carbonate to a corresponding fluorinated carbonate and reacting the produced fluorinated carbonate with an active nucleophile to synthesize a corresponding fluorinated functional compound. method. The process can be carried out in batch, semi-continuous or continuous manner, and the reaction apparatus is a temperature-controlled reactor which has not been described in detail, and the synthesis of fluoroethylene carbonate is not specifically mentioned. Due to the large differences in physical properties (eg, melting point, thermal conductivity, heat capacity, solubility, etc.) and reactivity of different raw materials, the process conditions and parameters corresponding to a certain raw material and a certain reaction process will be different. This method is not necessarily applicable to the synthesis of fluoroethylene carbonate. Although the method is continuous, the following main problems still exist: First, the process operation is cumbersome and complicated, and the reactor needs to contain an inert liquid reaction medium in advance, and the process needs to be filled in the reactor by replenishing liquid (recovered or new). The quality of the inert liquid medium is kept at a constant level; the second is that the reaction time is long and the reaction efficiency is low. The fluorination process of only the 100-gram sample needs to be injected for several hours or even ten hours, which greatly limits the expansion of the production scale. U.S. Patent No. 5,420, 359 A, US Pat. No. 2,020, 027, 172 A1, US Pat. No. 6,863, 211, B2, US Pat. In short, the process and its apparatus are essentially simply connecting the steps in the original batch. First, the problem of long process time, poor flexibility and low production efficiency cannot be solved, and it cannot be in a short time (10). The direct fluorination reaction is completed within a minute, and the problem of poor controllability, mass transfer, flexibility, and poor selectivity of the direct fluorination method is not solved; second, the process is not a continuous flow process, and the continuous flow process refers to production. In the process, the materials (ie, the reaction mixture containing raw materials, intermediates, products, solvents, etc.) are continuously flowing, and there is no waiting, that is, the products are continuously produced. Of course, it is mentioned in the text that continuous processes generally give higher yields, better product quality and more efficient use of fluorine than batch and semi-continuous processes.

Chinese patent CN1104930A relates to a method of directly fluorinating organic matter in a tubular reactor. The method is to mix the raw material and the inert liquid medium in the upstream pipeline, and then transport it to the tubular reactor through the fluid transfer device, and mix with the fluorine gas therein, and circulate for a long enough time to generate the desired fluorinated product. The examples do not mention the synthesis of fluoroethylene carbonate. The main problem is that the reaction mixture is fluorinated in the reactor for too long, and it takes several hours to several days, even several weeks, the reaction efficiency is very low, and the direct fluorination cannot be completed in a short time (within 10 minutes). The reaction also did not solve the problem of poor controllability, mass transfer, flexibility and poor selectivity in the direct fluorination process.

Chinese patent CN102548949A relates to a process for the continuous preparation of corresponding fluoroethylene carbonate and dimethyl fluorocarbonate from ethylene carbonate and dimethyl carbonate and a device for carrying out the process. During the reaction, the reactants are continuously introduced into the reactor cascade with the F ₂ /N ₂ mixed gas, and the reaction mixture is withdrawn from the reactor cascade and the target product is separated by continuous distillation. The conversion of the organic carbonate is up to 70% in the range of 10 to 70 °C. The process has the following main problems:

First, the core reaction equipment is a plurality of (2-5) reactor cascades with partition plates, that is, the so-called "continuous" of simple connections. In each reactor, the materials still have a waiting time, not a continuous flow. In addition, the apparatus includes an additional cooler to circulate a portion of the reaction mixture to remove a large amount of heat of reaction generated in the fluorination reaction; and in order to sufficiently mix the reaction mixture, it is necessary to pass the fluorine gas through a glass frit in advance. The finely dispersed form is introduced into the reactor. That is to say, the reaction device meets the requirements of heat and mass transfer of the fluorination reaction, and is equipped with various auxiliary equipments, with low integration degree and complicated structure. In summary, the reaction unit is not an integrated continuous flow reactor and must be cascaded by multiple reactors to complete the reaction.

Second, the residence time is still long, and the reaction time of the method is at least 30 minutes.

Third, the process operation is complicated. For example, when it is mentioned that each substance in the reaction mixture needs to reach a certain "quiescent concentration", the reaction can be carried out smoothly. The so-called "stationary concentration" refers to the substances in the reaction mixture when the reaction proceeds smoothly. The fixed concentration that needs to be maintained, it takes some time after the start of the reaction to reach this "stationary concentration" requirement; the reaction mixture needs to be withdrawn from each cascade reactor during the reaction, and the amount and composition of the mixture are withdrawn. The concentration needs to maintain a certain proportional relationship with the feed amount; in the process, the materials need to wait in each reactor and wait for different time, not continuous flow, not continuous flow process; the same reactor is synthesized When the fluorinated ethylene carbonates have different degrees of fluorination, the waiting time of the materials in which the heat is released is also different. In addition, these process requirements increase the overall process control difficulty and the difficulty of production site operations.

Chinese patent CN201080042843A relates to the synthesis of polyfluoro(difluoro, trifluoro and tetrafluoro) ethylene carbonate and corresponding mixtures using a reactor cascade similar to that described above, as well as the above three problems in the apparatus and process, for example The materials need to wait in each reactor and wait for different times, and the same reactor has different residence time in the synthesis of fluoroethylene carbonate with different degrees of fluorination. In summary, although the above process and its apparatus use reactor cascade to achieve continuous process, the reaction mixture still has a waiting flow in the cascade reactor, which is not a continuous flow, not a continuous flow process, and the reaction is not fast, and the reaction time is not fast. More than 30 minutes.

In addition, prior art processes, whether batch processes, semi-continuous, continuous processes, or reactor cascade processes, are inevitably subject to amplification effects, which introduces many uncertainties for further industrial applications. Scaling up effect refers to the research results obtained by using small equipment for chemical process (ie small-scale) experiments (such as laboratory scale), under the same operating conditions and large-scale production equipment (such as industrial scale) The results are often very different. The effect of these differences is called the amplification effect. The reason is mainly that the temperature, concentration, and material residence time distribution in small-scale experimental equipment are different from those in large-scale equipment. That is to say, under the same operating conditions, the results of small-scale experiments cannot be completely repeated on the industrial scale; if the results of the same or similar results as the small-scale experiments are obtained on the industrial scale, it is necessary to optimize the adjustment and change the process parameters and Operating conditions. For the chemical process, the amplification effect is a difficult and urgent problem to be solved. If it is not solved, it will lead to great uncertainty in the production process and product quality. First, it will directly lead to unstable quality of the downstream products, which is difficult to control. Second, uncertainty will lead to fluctuations in the process parameters of the production process, which will result in failure. Effective control of the production process, so that production safety can not be guaranteed, burying many safety hazards for the production process.

In summary, the direct fluorination reaction has strict requirements on mass transfer, heat transfer and safety of the device and process, and is limited by the device and the process. The prior art has problems of complicated installation and complicated process. In turn, the reaction time is too long, the production efficiency is low, the process and the device are flexible, and the selectivity is poor. For the synthesis of fluoroethylene carbonate with different degrees of fluorination, it has not been developed to develop a production process that can fully utilize the advantages of the direct fluorination process and overcome the above three disadvantages of the method, namely: fully solve the heat transfer The mass transfer problem also takes into account the flexibility and selectivity of the physical properties of different raw materials (eg, melting point, thermal conductivity, heat capacity, solubility, etc.) and differences in reactivity.

Summary of the invention

In view of the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a continuous flow synthesis process of fluoroethylene carbonate which is fast, flexible, efficient, safe and easy to mass-produce, and a device capable of realizing the process.

For the large amount of exothermic heat of direct fluorination reaction, the process development needs to optimize the physicochemical properties of the equipment material and structure, materials (raw materials, intermediates and products) and the process parameters matching the specific process, and the equilibrium reaction is exothermic. The relationship between system heat transfer and equipment heat transfer, in the premise of ensuring production safety and efficiency, timely remove a large amount of reaction heat, in order to prevent the system from overheating pressure, resulting in uncontrolled reaction. For example, physical properties of different raw materials (eg, melting point, thermal conductivity, heat capacity, solubility, etc.) and reactivity may vary greatly, and process parameters need to be adjusted and optimized according to specific materials and specific reaction processes. In order to be able to flexibly adapt to the production requirements of different raw material feeds and different levels of fluorinated products, process development needs to flexibly optimize reaction conditions and process parameters based on the reactivity of raw materials and intermediates, the target products produced and the reaction mechanism. Match the specific process of the reaction to improve the selectivity of the corresponding target product. For gas-liquid two-phase heterogeneous reaction, in the process development, it is necessary to optimize the equipment structure and process parameters to enhance the gas-liquid two-phase mixing effect, promote the two-phase mass transfer, and use the gas/liquid dispersed specific surface area to measure the gas-liquid two-phase in the reactor. The mass transfer effect, the larger the specific surface area, the better the mass transfer effect. In addition, in addition to being greatly affected by mass transfer factors, the fluorination reaction is also affected by kinetic factors, which mainly include various physical and chemical factors (eg, gas density, solubility, melting point, critical temperature, critical pressure, system temperature). , system pressure, concentration, medium in the reaction system, catalyst, flow field and temperature field distribution, residence time distribution, etc.) and the corresponding reaction mechanism, that is, the strengthening method based on these factors will also have a conversion rate and selectivity to the reaction. enhancement.

The continuous process (continuous process) refers to the connection between the production steps of the production system in the production process, and the continuous operation is ensured as a whole, but the waiting is allowed in each step. As a fast and efficient continuous process, the continuous-flow process (continuous-flow process) has the characteristics of short use time, high efficiency, easy operation, continuous uninterrupted addition of raw materials in the process, and continuous production. The product, the process material (that is, the reaction mixture containing raw materials, intermediates, products, solvents, etc.) is continuous flow, without interruption, without waiting, that is, the product is continuously produced, it is a kind of "pipeline" Chemical production process. When the process operation reaches a steady state, the state parameters such as composition and temperature of the material at any position in the reactor do not change with time, which is a steady state process, and thus the production process and product quality are stable. In a process involving multiple steps of reaction, if some of the steps are continuous or simply connect the steps in the original batch process, the process can be referred to as a continuous process; and only all steps are continuous. And the material is continuously flowing throughout the process, that is, the continuous addition of raw materials, continuous product, can be called continuous flow process.

Based on the difference between the above continuous flow process and the batch process and other continuous processes, the continuous flow process has much different control requirements and condition parameters than the latter. The batch process of the same product or other continuous process conditions cannot be used for reference. Or porting to a continuous flow process requires redesign and development. Therefore, continuous flow processes are completely new processes compared to batch processes and other continuous processes, and often continuous flow process conditions are not achievable in other processes.

The reaction time in a continuous process refers to the total time required from the feedstock to the reactor to the product output reactor. Different reaction time in continuous process will cause the control requirements and condition parameters of the process to vary greatly. The process conditions of long reaction time of the same product cannot be borrowed or transplanted into the process of short reaction time, and the reaction time of continuous process is shortened. Redesign the development process. Therefore, a continuous process with a short reaction time, especially a continuous flow process in which the reaction time is in seconds, is a completely new process with respect to a continuous process with a long reaction time, and often continuous flow process conditions are not realized in other processes.

In order to solve the technical problem of the present invention, the present invention adopts the following technical solutions:

A continuous flow synthesis process of fluoroethylene carbonate, wherein the fluorinated raw material and fluorine gas are used as raw materials, and the fluoroethylene carbonate is obtained by successively mixing and dispersing, fluorination reaction and gas-liquid separation step, and the continuous flow is performed. A schematic diagram of the process route involved in the synthesis process is shown in Figure 1.

As shown in FIG. 1, the fluoroethylene carbonate continuous stream synthesis process and the corresponding integrated continuous flow reactor of the present invention can realize the following synthesis process:

Synthesis of monofluoroethylene carbonate and difluoroethene carbonate (ethylene-4,4-difluorovinyl carbonate, cis-4,5-difluorovinyl carbonate, transcarbonate) using ethylene carbonate as raw material Any one or any one of -4,5-difluorovinyl ester), trifluoroethylene carbonate, and tetrafluoroethylene carbonate;

Synthesis of difluoroethene carbonate (carbonic acid-4,4-difluorovinyl ester, cis-4,5-difluorovinyl carbonate, carbonic acid trans-4,5) using monofluoroethylene carbonate as raw material Any one or any of a plurality of -difluorovinyl esters, trifluoroethylene carbonate, and tetrafluoroethylene carbonate;

Synthesis of trifluorocarbonate from 4,4-difluorovinyl carbonate and/or cis-4,5-difluorovinyl carbonate and/or trans-4,5-difluorovinyl carbonate Any one or any of a plurality of vinyl esters and tetrafluoroethylene carbonate;

The tetrafluoroethylene carbonate is synthesized from trifluoroethylene carbonate.

As used herein, the term "fluorine gas" is understood to mean a fluorine element that is diluted with an inert gas or that is not diluted by an inert gas. Preferably, the fluorine gas of step (a) will be applied in the form of a dilution of fluorine. Preferred diluents are inert gases, especially selected from the group consisting of nitrogen, noble gases, or mixtures thereof. The mixed gas refers to a mixture of nitrogen and a rare gas, and the rare gas refers to a simple substance of a group 18 element of the periodic table. A mixed gas of fluorine gas and nitrogen gas is preferred. The concentration of fluorine gas is greater than 0% by volume. It is preferably equal to or greater than 5% by volume. More preferably, it is equal to or more than 12% by volume. The concentration of the fluorine gas is preferably equal to or less than 25% by volume. Preferably, it is equal to or less than 18% by volume. Preferably, the fluorine gas is contained in the gas mixture in a range of 12% to 18% by volume. Although it is possible to introduce different gas mixtures with different concentrations of fluorine or different inert gases, or diluted and undiluted fluorine gases into these different reactors, it is preferred for practical reasons to apply only to all reactors. A specific gas or mixture of gases.

As used herein, "degree of fluorination" refers to the number of fluorine atoms contained in a compound molecule, for example, the degree of fluorination of ethylene carbonate is 0, the degree of fluorination of monofluorocarbonate is 1, and difluorocarbonate Vinyl ester (-4,4-difluorovinyl carbonate, cis-4,5-difluorovinyl carbonate, trans-4,5-difluorovinyl carbonate) has a degree of fluorination of 2, The degree of fluorination of trifluoroethylene carbonate is 3, and the degree of fluorination of tetrafluoroethylene carbonate is 4.

Wherein the raw material to be fluorinated is reacted with elemental fluorine (F ₂ ) in a liquid phase to form a fluoroethylene carbonate, that is, the degree of fluorination of the raw material to be fluorinated is less than and/or equal to the degree of fluorination of the product, The fluorinated raw material is selected from the group consisting of ethylene carbonate, monofluoroethylene carbonate, difluorovinyl carbonate (-4,4-difluoroethylene carbonate, cis-4,5-difluorovinyl carbonate), Carbonic acid trans-4,5-difluorovinyl ester), trifluorovinyl carbonate, tetrafluoroethylene carbonate, or a mixture of any two or any combination thereof.

The "fluoroethylene carbonate" described herein is selected from the group consisting of: monofluoroethylene carbonate, difluorovinyl carbonate (-4,4-difluoroethylene carbonate, cis-4,5-difluorocarbonate) Any one or any of a variety of vinyl esters, trans-4,5-difluorovinyl carbonate, trifluoroethylene carbonate, and tetrafluoroethylene carbonate.

Preferably, the direct fluorination reaction can be carried out in the presence of a suitable inert solvent which is a solvent which does not react with fluorine gas, and the inert solvent may be a linear or cyclic perfluorocarbon such as Solvay Solexis Fluorinated ethers for sale, tetrafluoroethylene carbonate or hydrogen fluoride, and the like. The raw material to be fluorinated may or may not contain an inert solvent. Preferably, the fluorination to be carried out does not comprise an inert solvent.

The invention provides a versatile process for rapidly synthesizing fluoroethylene carbonate by using only one reactor, that is, the two reactants of the fluorinated raw material and the fluorine gas are continuously input into the reactor, and The reaction product was continuously collected. The fluoroethylene carbonate is selected from the group consisting of monofluoroethylene carbonate, difluorovinyl carbonate (-4,4-difluoroethylene carbonate, cis-4,5-difluorovinyl carbonate, Any one or any of a group of trans-4,5-difluorovinyl carbonate, trifluoroethylene carbonate, and tetrafluoroethylene carbonate. The reactor is an integrated continuous flow reactor, and the continuous flow reactor comprises three functional units: a mixed dispersion unit, a fluorination reaction unit, and a gas-liquid separation unit. By means of the optimization of the functional unit temperature zone and the optimization of the process conditions such as temperature and/or pressure and the synergy of the three functional units, no additional post-processing or purification steps are required in the intermediate process, and the total process time is shortened to 10 minutes. Greatly improved the efficiency of the process. In particular, it is possible to flexibly synthesize a plurality of fluorinated ethylene carbonates and mixtures thereof with different degrees of fluorination by simply adjusting the process parameters, and to highly synthesize various fluorination targets. The product has strong process applicability, which makes industrial production more adaptable to market demand.

The synthesis process of the fluoroethylene carbonate has no amplification effect, and the scale of the amplification reaction has no influence on the reaction conversion rate, the target product yield and the selectivity. The invention overcomes the defects of the prior art for preparing the fluorinated ethylene carbonate, and is very suitable for industrial large-scale production.

A first object of the present invention is to provide a rapid continuous flow synthesis process of fluoroethylene carbonate, which is characterized in that: the synthesis process uses a raw material to be fluorinated and fluorine gas as a reactant, and is successively mixed and dispersed, and fluorine. The reaction, gas-liquid separation step to obtain fluoroethylene carbonate, the synthesis process is carried out in an integrated continuous flow reactor, and the raw material to be fluorinated is continuously added to the feed port of the integrated continuous flow reactor And fluorine gas, the fluoroethylene carbonate is obtained continuously at the discharge port of the integrated continuous flow reactor, and the reaction time is equal to or less than 600 s.

Further, the reaction time is 20 to 600 s, preferably, the reaction time is 30 to 480 s, and more preferably, the reaction time is 40 to 300 s.

Further, the synthetic process has no amplification effect.

Further, the integrated continuous flow reactor comprises a mixing and dispersing unit, a fluorination reaction unit and a gas-liquid separation unit, and the mixing and dispersing unit is used for contacting and mixing fluorine gas with a fluorine-containing raw material or an inert solvent. Dispersing in a liquid phase, and then delivering the mixture to a fluorination reaction unit; or the mixed dispersion unit is used for contacting and mixing the raw material to be fluorinated with fluorine gas and dispersing the fluorine gas in the liquid phase while preliminary fluorination occurs. Reaction, and then conveying the mixture to a fluorination reaction unit; the fluorination reaction unit is used for reacting a raw material to be fluorinated with fluorine gas to form a fluoroethylene carbonate and transporting it to a gas-liquid separation unit; The liquid separation unit is used for the separation of liquid and gas.

Further, in the mixing and dispersing unit, the fluorine gas is only mixed with the raw material to be fluorinated or the inert solvent and dispersed in the liquid phase, and then enters the fluorination reaction unit to undergo a fluorination reaction; in the mixed dispersion unit, The fluorine gas is mixed with the raw material to be fluorinated and dispersed in the liquid phase, and the fluorine gas is initially fluorinated with the raw material to be fluorinated, and then further fluorinated by the fluorination reaction unit.

Further, the mixed dispersion unit or the fluorination reaction unit further has a separation function of liquid and gas. Among them, the gas after gas-liquid separation can be recycled and recycled, and can also enter the exhaust gas treatment device.

Further, the synthesis process is carried out at a pressure equal to or greater than the ambient pressure, preferably at a pressure equal to or greater than 5 bar, more preferably at a pressure equal to or greater than 10 bar, which are all relative pressures.

Further, the pressure of each unit may be the same or different.

Further, the synthesis process is performed under a gradient pressure, the mixed dispersion unit pressure is greater than the fluorination reaction unit pressure, and the fluorination reaction unit pressure is greater than the gas-liquid separation unit pressure. The high pressure of the mixing and dispersing unit pressure can increase the solubility of the fluorine gas in the liquid phase, reduce the gas phase volume of the fluorine gas, and promote the gas-liquid two-phase mixing of the raw material to be fluorinated and the fluorine gas, which is favorable for the fluorination reaction; The pressure of the fluorination reaction unit is lower than that of the mixed dispersion unit, and the solubility of the hydrogen fluoride gas generated in the reaction in the liquid phase can be lowered, and the pressure of the fluorination reaction unit cannot be too low to ensure sufficient solubility of the fluorine gas in the liquid phase, and the fluorination reaction unit is adopted. The pressure is to balance the two solubilityes to effectively promote the reaction; the gas-liquid separation unit uses a smaller pressure to further reduce the solubility of the hydrogen fluoride gas in the liquid phase, facilitating gas-liquid separation after completion of the reaction, and helping to reduce Residue of hydrogen fluoride in the product fluoroethylene carbonate improves product quality. Since the synthesis reaction of the present invention is a heterogeneous reaction, in order to promote the progress of the reaction, it is necessary to increase the solubility of the fluorine gas in the liquid phase, and on the other hand, it is necessary to reduce the solubility of the hydrogen fluoride gas generated in the reaction in the liquid phase, and to mix and disperse the unit. The gradient pressure formed by the fluorination reaction unit and the gas-liquid separation unit cooperates to achieve the best balance of solubility of fluorine gas and hydrogen fluoride gas in the liquid phase, promotes the reaction, and achieves sufficient reaction in a short time, high efficiency, The reaction is completed with high quality.

Further, the pressure of the mixing and dispersing unit is 5 to 18 bar, preferably 10 to 15 bar; the pressure of the fluorination reaction unit is 3 to 18 bar, preferably 5 to 15 bar; and the pressure of the gas-liquid separation unit is 0 to 10 bar, preferably 2 to 7bar.

Further, the integrated continuous flow reactor feed port is one or more, and the integrated continuous flow reactor discharge port is one or more.

Further, each of the units independently comprises more than one reactor module or a group of reactor modules, wherein the reactor module group is composed of a plurality of reactor modules connected in series or in parallel, and the units are connected in series with each other.

Further, each of the units corresponds to one temperature zone, and each temperature zone independently comprises more than one reactor module or a reactor module group, wherein the reactor module group is composed of a plurality of reactor modules connected in series or in parallel, each of which The temperature zones are connected in series.

Further, the reactor modules, the reactor module groups, the reactor modules and the reactor module groups are respectively connected in series or in parallel.

Further, the reactor module is selected from any one of the reaction devices capable of realizing a continuous flow process. Preferably, the reaction device is selected from the group consisting of a microreactor and a Tandem loop reactor. ), any one or any of a plurality of Tubular reactors. The microreactor, also known as a microstructure reactor or a microchannel reactor, is a device in which a chemical reaction occurs in a limited area with a general lateral dimension of 1 mm or less. The form is a miniature size channel. A tandem coil reactor, that is, a reactor in which a coil reactor is connected in series by a pipe, wherein the coil reactor is in the form of a tubular reactor. The tubular reactor is a continuous operation reactor with a tubular shape and a large aspect ratio which appeared in the middle of the last century. Such a reactor can be very long; it can be a single tube or a plurality of tubes in parallel; it can be an empty tube or a filling tube. Preferably, the reaction device may be one or more.

Further, the reaction device has a flow channel.

Further, the flow channel is made of a material resistant to F ₂ and HF, preferably a stainless steel, an alloy resistant to F ₂ and HF (monal gold, inconel, Hastelloy) ), polymer materials (partial or perfluorinated polymer poly, alkylene polymers), other types of polymers (polytetrafluoroethylene, perfluoroalkoxy alkane copolymers), ceramics (silicon carbide) or Painted with materials resistant to F ₂ and HF.

Further, the flow channel has a specific surface area greater than or equal to 2000 m ² /m ³ , a heat transfer coefficient greater than or equal to 1.5 MW/m ³ K, and a gas/liquid dispersion specific surface area greater than or equal to 47,000 m ² /m ³ . The flow channel has a large specific surface area (greater than or equal to 2000 m ² /m ³ ), and a heat transfer coefficient greater than or equal to 1.5 MW/m ³ K can be obtained, and the heat transfer performance of the system is excellent; the material flows throughout the flow channel. The process is forced to mix, the gas/liquid dispersion specific surface area can be as high as 47,000 m ² /m ³ , and the gas-liquid two-phase mass transfer performance is excellent.

Further, the raw material to be fluorinated is selected from the group consisting of ethylene carbonate, monofluoroethylene carbonate, difluorovinyl carbonate (-4,4-difluoroethylene carbonate, cis-4,5-di carbonate) Any one or any one of fluorovinyl ester, carbonic acid trans-4,5-difluorovinyl ester), trifluoroethylene carbonate, and tetrafluoroethylene carbonate, the raw material to be fluorinated The degree of fluorination is less than or equal to the product fluoroethylene carbonate.

Further, the raw material to be fluorinated contains an inert solvent, and the inert solvent refers to a solvent that does not chemically react with fluorine gas.

Further, the inert solvent is selected from a linear or cyclic perfluorocarbon, preferably any one or any of a fluorinated ether, a tetrafluoroethylene carbonate, and a hydrogen fluoride.

Further, the fluoroethylene carbonate is selected from the group consisting of monofluoroethylene carbonate, difluorovinyl carbonate (-4,4-difluoroethylene carbonate, cis-4,5-difluoroethylene carbonate) Any one or any combination of ester, carbonic acid trans-4,5-difluorovinyl ester, trifluoroethylene carbonate, and tetrafluoroethylene carbonate.

Further, the synthetic process can be carried out in the absence of an inert solvent.

Further, the continuous flow synthesis process is carried out in an integrated continuous flow reactor comprising three temperature zones, the mixed dispersion unit corresponding to the temperature zone 1, and the fluorination reaction zone corresponding to the temperature zone 2, The gas-liquid separation unit corresponds to the temperature zone 3, and the continuous flow synthesis process comprises the following steps:

(a) the fluorinated raw material or inert solvent is mixed with fluorine gas in the temperature zone 1 and the fluorine gas is dispersed in the liquid phase, and then the mixture is transported to the temperature zone 2; or the fluorinated raw material and the fluorine gas are in the temperature zone 1 contact mixing and dispersing fluorine gas in the liquid phase while preliminary fluorination reaction, and then transporting the mixture to the temperature zone 2;

(b) the fluorinated raw material and fluorine gas are reacted in the temperature zone 2 to form a fluoroethylene carbonate and the reaction mixture is sent to the temperature zone 3;

(c) The reaction mixture enters the temperature zone 3 for separation of the gas and the liquid.

Further, the temperature of the temperature zone 1 is -40 to 20 ° C, preferably -20 to 10 ° C.

Further, the temperature of the temperature zone 2 is 10 to 100 ° C, preferably 30 to 80 ° C, more preferably 40 to 60 ° C.

Further, the temperature of the temperature zone 3 is 30 to 80 ° C, preferably 40 to 60 ° C.

Further, the synthesis process is carried out at a pressure equal to or greater than the ambient pressure, preferably at a pressure equal to or greater than 5 bar, more preferably at a pressure equal to or greater than 10 bar.

Further, the pressure of each of the temperature zones may be the same or different.

Further, the synthesis process is performed under gradient pressure, the temperature of the temperature zone 1 is greater than the pressure of the temperature zone 2, and the pressure of the temperature zone 2 is greater than the pressure of the temperature zone 3. The gradient pressures of the three temperature zones cooperate to achieve the best balance of solubility of fluorine gas and hydrogen fluoride gas in the liquid phase, promote the reaction, achieve sufficient reaction in a short time, and complete the reaction with high efficiency and high quality. Preferably, the synergistic effect of the temperature distribution of the three temperature zones is further combined to complete the reaction more efficiently and with high quality.

Further, the pressure in the temperature zone 1 is 5 to 18 bar, preferably 10 to 15 bar; the pressure in the temperature zone 2 is 3 to 18 bar, preferably 5 to 15 bar; and the pressure in the temperature zone 3 is 0 to 10 bar, preferably 2 to 7 bar.

Further, the fluorine gas is a fluorine element diluted by an inert gas or diluted by an inert gas, and the inert gas is selected from nitrogen, a rare gas, or a mixed gas thereof, and the mixed gas means nitrogen and rare A mixture of gases, which is a simple substance of a group 18 element of the periodic table. The fluorine gas is preferably a mixed gas of a fluorine element and nitrogen.

Further, the concentration of the fluorine element in the fluorine gas is more than 0% by volume, preferably equal to or more than 5%, more preferably equal to or more than 12%; the concentration of the fluorine element in the fluorine gas is preferably equal to or less than 25% by volume, preferably Equally or less than 18%, most preferably, the concentration of fluorine in the fluorine gas is from 12% to 18%.

It must be noted that for each CF bond formed during the reaction of the CH bond with F ₂ , one molecule HF is formed. Therefore, assuming a stoichiometric reaction between ethylene carbonate (EC) and fluorine (F ₂ ), the F ₂ /EC ratio is required to be 4, that is, if 1 mole of ethylene carbonate is used as the raw material to be fluorinated, Then, 4 moles of F ₂ is required stoichiometrically to achieve complete fluorination of the ethylene carbonate. Therefore, in the present invention, for the sake of simplicity of description, the ratio of F ₂ /H is specified to represent the number of molecules of F ₂ corresponding to each H atom to be substituted to form a CF bond, that is, each The number of equivalents of F ₂ corresponding to the average of the H atoms in which the fluorine substitution reaction occurs. That is, the equivalent ratio of F ₂ to the raw material to be fluorinated is the ratio of the number of H atoms to be substituted multiplied by F ₂ /H, for example, the synthesis of trifluorovinyl carbonate using ethylene carbonate (EC) as a raw material, using F ₂ / H ratio of 1.15: condition 1, since the number of H atoms substituted by 3, then the equivalent ratio of F ₂ and F starting material to be fluorinated ₂ / EC of 3.45: 1.

Further, the ratio of F ₂ /H is from 1.0 to 2.0:1, preferably from 1.05 to 1.50:1, more preferably from 1.10 to 1.25:1.

The process of the present invention synthesizes fluoroethylene carbonate in a fast and highly versatile manner, the fluoroethylene carbonate being selected from the group consisting of monofluoroethylene carbonate and difluoroethylene carbonate (carbonic acid-4, 4-difluorovinyl ester, cis-4,5-difluorovinyl carbonate, trans-4,5-difluorovinyl carbonate), trifluoroethylene carbonate, tetrafluoroethylene carbonate Any one or any of a variety of them. In a preferred embodiment, selective manufacture of any one or any of a variety of monofluorocarbonate, difluoroethene carbonate, trifluoroethylene carbonate, and tetrafluoroethylene carbonate is possible.

The continuous flow synthesis process of the invention has great flexibility and versatility, and can rapidly synthesize fluoroethylene carbonate by using only one reactor, and can highly synthesize target products of various degrees of fluorination. Preferably, the reaction conversion rate of the synthesis process is 90% or more, and more preferably, the reaction conversion rate is 95% or more; the yield of the fluoroethylene carbonate is 85% or more, and more preferably, the fluorocarbonic acid The yield of vinyl ester is 90% or more.

It should be noted that the concentration of fluorine gas used in actual synthesis (including laboratory, pilot test, and actual production process) will have a deviation of body concentration of ±3 percentage points; the ratio of F ₂ /H will have a deviation of ±0.05. The temperature in the temperature zone will have a deviation of ±5 °C; the temperature in the temperature zone will have a deviation of ±1 bar; the reaction time will have a deviation of ±10 s.

A second object of the present invention is to provide an integrated reactor dedicated to a rapid continuous synthesis process of fluoroethylene carbonate. To meet the conditions of the continuous process, the present invention has developed a specialized integrated reactor. The reactor can be a modular structure, the organization mode and quantity of the design module, the modules included in each temperature zone, and the development of specific process conditions and parameters, including the division and temperature setting of each temperature zone, and pressure. The combination of pressure and temperature, combined with the above various factors, enables this continuous process to be realized. It is also possible to further combine the temperature and material concentration, the material ratio and the material flow rate to match the reaction progress, and obtain a better reaction effect. The material comprises each raw material and each intermediate product of the reaction process, wherein the material concentration comprises the concentration of each raw material and the concentration of each intermediate product, and the ratio of the materials comprises the ratio of each raw material and the concentration of each intermediate product. The material flow rate includes the flow rate of each raw material and the flow rate of each intermediate product.

An integrated reactor for a continuous flow synthesis process of fluoroethylene carbonate according to the present invention, the integrated reactor adopts a modular structure, and the integrated reactor adopts a modular structure including mixed dispersion a unit, a fluorination reaction unit and a gas-liquid separation unit, wherein the mixed dispersion unit is used for contacting and mixing the raw material to be fluorinated or the inert solvent with fluorine gas, and dispersing the fluorine gas in the liquid phase, and then delivering the mixture to the fluorination a reaction unit; or the mixed dispersion unit is used for contacting and mixing the raw material to be fluorinated with fluorine gas and dispersing fluorine gas in the liquid phase while preliminary fluorination reaction, and then conveying the mixture to the fluorination reaction unit; The fluorination reaction unit is used for reacting a raw material to be fluorinated with fluorine gas to form a fluoroethylene carbonate and transporting it to a gas-liquid separation unit; the gas-liquid separation unit is used for separation of liquid and gas.

Further, the mixed dispersion unit or the fluorination reaction unit further has a separation function of liquid and gas.

Further, the integrated continuous flow reactor feed port is one or more, and the integrated continuous flow reactor discharge port is one or more.

Further, each of the units independently comprises more than one reactor module or a group of reactor modules, wherein the reactor module group is composed of a plurality of reactor modules connected in series or in parallel, and the units are connected in series with each other.

Further, each of the units corresponds to one temperature zone, and each temperature zone independently comprises more than one reactor module or a reactor module group, wherein the reactor module group is composed of a plurality of reactor modules connected in series or in parallel, each of which The temperature zones are connected in series.

Further, the reactor modules, the reactor module groups, the reactor modules and the reactor module groups are respectively connected in series or in parallel.

Further, the reactor module is selected from any one of the reaction devices capable of realizing a continuous flow process. Preferably, the reaction device is selected from the group consisting of a microreactor, a tandem coil reactor, and a tubular reactor. One or any of a variety. Preferably, the reaction device may be one or more.

Further, the reaction device has a flow channel.

Further, the flow channel has a specific surface area greater than or equal to 2000 m ² /m ³ , a heat transfer coefficient greater than or equal to 1.5 MW/m ³ K, and a gas/liquid dispersion specific surface area greater than or equal to 47,000 m ² /m ³ .

Further, the flow channel is made of a material resistant to F ₂ and HF, preferably a stainless steel, an alloy resistant to F ₂ and HF (monal gold, inconel, Hastelloy) ), polymer materials (partial or perfluorinated polymer poly, alkylene polymers), other types of polymers (polytetrafluoroethylene, perfluoroalkoxy alkane copolymers), ceramics (silicon carbide) or Painted with materials resistant to F ₂ and HF.

Preferably, the mixing and dispersing unit corresponds to the temperature zone 1, the fluorination reaction unit corresponds to the temperature zone 2, and the gas-liquid separation unit corresponds to the temperature zone 3.

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

1. Efficient continuous flow synthesis of fluoroethylene carbonate in an integrated continuous flow reactor. That is, the reactants are continuously fed to the reactor without additional post-treatment or purification steps, and the reaction product is continuously collected. Thanks to the setting of the gradient pressure and the division of different temperature zones, the efficiency of the process is greatly improved. The reaction time is up to 10 minutes.

2. The process of the present invention allows for the selective manufacture of monofluoroethylene carbonate, difluoroethylene carbonate, trifluoroethylene carbonate, tetrafluoroethylene carbonate in a rapid and highly versatile manner. Any one or any of a variety. The process selectivity and the flexibility of the device are strong. The reactor can be flexibly synthesized by simply adjusting the process parameters, and the fluoroethylene carbonate and its mixture products can be flexibly synthesized. The process and the device have strong applicability. Industrial production is more adaptable to market demand.

3. The process safety is greatly improved. The relatively small liquid holding capacity of the continuous flow reactor and the excellent heat and mass transfer characteristics, combined with the short reaction time (within 10 minutes) make the process safer. The liquid holding capacity of the reactor refers to the total volume of the reaction materials stored in the reactor at any time when the operation reaches a steady state.

4. Fluorination reaction As a gas-liquid two-phase reaction, it is necessary to increase the gas-liquid two-phase contact to promote the reaction. In order to achieve an appropriate yield in the prior art process, it is necessary to reduce the flow rate of the raw material or the multiple cycles of the raw materials to increase the gas-liquid two. The probability of contact with the phase, which in turn increases the reaction time, but this obviously reduces the efficiency of the fluorination reaction. The process of the present invention can be carried out under a gradient pressure, the mixed dispersion unit pressure being greater than the fluorination reaction unit pressure, and the fluorination reaction unit pressure being greater than the gas-liquid separation unit pressure. The high pressure of the mixing and dispersing unit pressure can increase the solubility of fluorine gas in the liquid phase, reduce the gas phase volume of the fluorine gas, and promote the mixing of the gas to liquid and the fluorine gas, which is beneficial to the fluorination reaction; The pressure of the reaction unit is lower than that of the mixed dispersion unit, and the solubility of the hydrogen fluoride gas generated in the reaction in the liquid phase can be lowered, and the pressure of the fluorination reaction unit cannot be too low to ensure sufficient solubility of the fluorine gas in the liquid phase, and the pressure of the fluorination unit is used. In order to balance the two solubilityes, the reaction can be effectively promoted; the gas-liquid separation unit applies less pressure, further reduces the solubility of hydrogen fluoride gas in the liquid phase, facilitates gas-liquid separation after completion of the reaction, and helps to reduce product fluorine. Residue of hydrogen fluoride in vinyl carbonate to improve product quality. Since the synthesis reaction of the present invention is a heterogeneous reaction, in order to promote the progress of the reaction, it is necessary to increase the solubility of the fluorine gas in the liquid phase, and on the other hand, it is necessary to reduce the solubility of the hydrogen fluoride gas generated in the reaction in the liquid phase, and to mix and disperse the unit. The gradient pressure formed by the fluorination reaction unit and the gas-liquid separation unit cooperates to achieve the best balance of solubility of fluorine gas and hydrogen fluoride gas in the liquid phase, promotes the reaction, and achieves sufficient reaction in a short time, high efficiency, The reaction is completed with high quality.

5. In the process, the temperature zone is combined with the gradient pressure setting to accelerate the reaction speed and shorten the reaction time. In the mixed dispersing unit, the solubility of the fluorine gas in the liquid phase is increased by the low temperature combined with the high pressure, and the high pressure increases the concentration of the fluorine gas in the unit volume of the reactor, and promotes the mixed mass transfer of the raw material to be fluorinated with the fluorine gas, and can obtain up to 95. The high conversion rate of % and the yield of 90%, so that the reaction time is greatly shortened, usually within 10 minutes, the reaction is complete, and the production is more efficient.

6. According to the mass transfer and kinetic requirements of the fluorination reaction and the physical and chemical properties of the raw materials (including the raw materials to be fluorinated and fluorine gas), three functional units are designed in an integrated continuous flow reactor. Wherein the mixed dispersion unit is used for contacting the raw material to be fluorinated or the inert solvent with fluorine gas and dispersing the fluorine gas in the liquid phase, and then conveying the mixture to the fluorination reaction unit; or the mixed dispersion unit is used for The fluorinated raw material is mixed with fluorine gas and the fluorine gas is dispersed in the liquid phase while a preliminary fluorination reaction occurs, and then the mixture is sent to the fluorination reaction unit; the fluorination reaction unit is used for the fluorination reaction unit and The fluorine gas reacts to produce fluoroethylene carbonate and is sent to a gas-liquid separation unit; the gas-liquid separation unit is used for separation of liquid and gas. By combining the three functional units, the reaction takes only 10 minutes or less to complete. Only one reactor is required to complete the reaction process, and the degree of integration is high.

7. In the integrated continuous flow reactor, the product quality is stable and reproducible due to stable flow rate and stable production process.

8. The process is still completed in 10 minutes on the industrial scale. The product content and yield are basically the same as those in the laboratory scale. No amplification effect is found, which solves the problem of industrialized amplification of the continuous flow of fluoroethylene carbonate.

9. The reactor can meet the stringent requirements of the fluorination reaction on the mass transfer, heat transfer, safety and corrosion resistance of the device and process without additional cooling or gas dispersion adjusting equipment. The process operation is simple, energy saving and integration degree High, small size, small footprint, greatly saving plant land.

DRAWINGS

1 is a schematic view showing a continuous flow synthesis process of the fluoroethylene carbonate according to the present invention;

Figure 2 is a schematic illustration of the integrated reactor of the present invention.

Wherein, the temperature of the temperature zone 1 is T1; the temperature of the temperature zone 2 is T2; and the temperature of the temperature zone 3 is T3.

detailed description

The invention is further illustrated below in conjunction with specific embodiments. It is to be understood that the examples are not intended to limit the scope of the invention. In addition, it should be understood that various changes and modifications may be made by those skilled in the art in the form of the appended claims.

Example 1

Vinyl fluorocarbonate example:

The concentration of the raw material to be fluorinated in the present embodiment is the mass concentration, and the concentration of the fluorine element in the fluorine gas is the volume concentration, and the purity of the product is detected by gas chromatography (GC).

Wherein, the temperature of the temperature zone 1 is T1; the temperature of the temperature zone 2 is T2; and the temperature of the temperature zone 3 is T3.

The raw material 1 (ethylene carbonate) is transported by a constant flow pump, and the raw material 2 (20% F ₂ and 80% N ₂ mixed gas) is introduced through the pipeline, and the two are in contact with the temperature zone 1 and flow through the temperature zone 1 to fully mix and preliminary reaction. The mixture flowing out of the temperature zone 1 enters the temperature zone 2, and the fluorination reaction corresponding to the fluoroethylene carbonate occurs through the temperature zone 2 until the reaction is complete. The reaction liquid flowing out of the temperature zone 2 enters the temperature zone 3 to separate the gas liquid, and a reaction mother liquid containing monofluoroethylene carbonate is obtained. The reaction mother liquor was collected. The mother liquor is distilled, cooled, etc. to obtain monofluoroethylene carbonate. The reaction parameters and results are as follows:

*average value

Example 2-6

Using the method of Example 1, the preparation of monofluoroethylene carbonate under different reaction parameters was investigated. The conditions and results of each parameter are shown in the following table.

*average value

Example 7-11

Using the method of Example 1, the preparation of difluoroethene carbonate under different reaction parameters was investigated. The conditions and results of each parameter are shown in the following table.

*average value

Example 12-14

Using the method of Example 1, the preparation of trifluoroethylene carbonate under different reaction parameters was investigated. The conditions and results of each parameter are shown in the following table.

*average value

Example 15-18

Using the method of Example 1, the preparation of tetrafluoroethylene carbonate under different reaction parameters was investigated. The conditions and results of each parameter are shown in the following table.

*average value

Claims (45)

A rapid continuous flow synthesis process of fluoroethylene carbonate, characterized in that: the synthesis process is carried out by mixing and dispersing, fluorination reaction and gas-liquid separation step by using a raw material to be fluorinated and fluorine gas as reactants. The fluoroethylene carbonate, the synthesis process is carried out in an integrated continuous flow reactor, and the raw material to be fluorinated and the fluorine gas are continuously added to the feed port of the integrated continuous flow reactor, The continuous discharge reactor outlet has uninterruptedly obtained fluoroethylene carbonate, and the reaction time is equal to or less than 600 s. The continuous flow synthesis process according to claim 1, wherein the reaction time is from 20 to 600 s, preferably from 30 to 480 s, more preferably from 40 to 300 s. The continuous flow synthesis process according to claim 1 or 2, wherein the synthesis process has no amplification effect. The continuous flow synthesis process according to any one of claims 1 to 3, wherein the integrated continuous flow reactor comprises a mixing and dispersing unit, a fluorination reaction unit and a gas-liquid separation unit, and the mixing and dispersing unit is used. Mixing the raw material to be fluorinated or the inert solvent with fluorine gas and dispersing the fluorine gas in the liquid phase, and then conveying the mixture to the fluorination reaction unit; or the mixed dispersion unit is used for the raw material to be fluorinated The fluorine gas is contact-mixed and the fluorine gas is dispersed in the liquid phase while the preliminary fluorination reaction occurs, and then the mixture is sent to the fluorination reaction unit; the fluorination reaction unit is used to react the fluorine-containing raw material with the fluorine gas to form fluorine. The ethylene carbonate is delivered to the gas-liquid separation unit; the gas-liquid separation unit is used for separation of the liquid and the gas. The continuous flow synthesis process according to claim 4, wherein said mixing and dispersing unit or fluorination reaction unit further has a separation function of liquid and gas. The continuous flow synthesis process according to any one of claims 1 to 5, characterized in that the synthesis process is carried out at a pressure equal to or greater than the ambient pressure, preferably at a pressure equal to or greater than 5 bar, more preferably at or equal to or It is carried out at a pressure greater than 10 bar, both of which are relative pressures. The continuous flow synthesis process according to claim 6, wherein the pressure of each unit may be the same or different. The continuous flow synthesis process according to claim 6, wherein the synthesis process is carried out under a gradient pressure, the mixed dispersion unit pressure is greater than the fluorination reaction unit pressure, and the fluorination reaction unit pressure is greater than the gas-liquid separation unit pressure. The continuous flow synthesis process according to claim 6, wherein the pressure of the mixing and dispersing unit is 5 to 18 bar, preferably 10 to 15 bar; the pressure of the fluorination reaction unit is 3 to 18 bar, preferably 5 to 15 bar; The pressure of the unit is from 0 to 10 bar, preferably from 2 to 7 bar. The continuous flow synthesis process according to any one of claims 1 to 9, wherein the integrated continuous flow reactor feed port is one or more, and the integrated continuous flow reactor discharge port is provided. It is one or more. The continuous flow synthesis process according to any one of claims 1 to 10, characterized in that each of the mixing and dispersing unit, the fluorination reaction unit and the gas-liquid separation unit independently comprises more than one reactor module or A reactor module group in which a reactor module group is composed of a plurality of reactor modules connected in series or in parallel, and the units are connected in series with each other. The continuous flow synthesis process according to any one of claims 1 to 10, wherein each of the mixing and dispersing unit, the fluorination reaction unit and the gas-liquid separation unit corresponds to a temperature zone, and each temperature zone is independent. The ground comprises more than one reactor module or group of reactor modules, wherein the reactor module group is composed of a plurality of reactor modules connected in series or in parallel, and the temperature zones are connected in series with each other. A continuous flow synthesis process according to any one of claims 10 to 12, wherein said reactor modules, between reactor module groups, between the reactor module and the reactor module group are respectively In series or in parallel. The continuous flow synthesis process according to any one of claims 11 to 13, characterized in that the reactor module is selected from any one of the reaction devices capable of realizing a continuous flow process, preferably, the reaction device It is selected from any one or any of a plurality of reactors, a tandem coil reactor, and a tubular reactor. The continuous flow synthesis process according to claim 14, wherein the reaction device is one or more. A continuous flow synthesis process according to claim 14 or 15, wherein said reaction means has a flow passage. The continuous flow synthesis process according to claim 16, wherein said flow passage has a specific surface area greater than or equal to 2000 m ² /m ³ and a heat transfer coefficient greater than or equal to 1.5 MW/m ³ K, gas/liquid dispersion ratio. The surface area is greater than or equal to 47,000 m ² /m ³ . The continuous flow synthesis process according to claim 16, wherein said flow passage is made of a material resistant to F ₂ and HF, said material being preferably stainless steel, an alloy resistant to F ₂ and HF (Monel) Gold-containing, Inconel, Hastelloy-based alloys, polymer materials (partial or perfluorinated polymer polyalkylene polymers), other types of polymers (polytetrafluoroethylene, perfluoroalkane) An oxyalkane copolymer), a ceramic (silicon carbide) or a material coated with F ₂ and HF. The continuous flow synthesis process according to any one of claims 1 to 18, wherein the raw material to be fluorinated is selected from the group consisting of ethylene carbonate, monofluoroethylene carbonate, difluoroethylene carbonate, and trifluorocarbonate. Any one or any one of vinyl acetate and tetrafluoroethylene carbonate, the fluorine to be fluorinated material having a degree of fluorination less than or equal to the product fluoroethylene carbonate. The continuous flow synthesis process according to claim 19, wherein said raw material to be fluorinated comprises an inert solvent, and said inert solvent means a solvent which does not chemically react with fluorine gas. The continuous flow synthesis process according to claim 20, wherein the inert solvent is selected from a linear or cyclic perfluorocarbon, preferably any of a fluorinated ether, a tetrafluoroethylene carbonate, and a hydrogen fluoride. One or any of a variety. The continuous flow synthesis process according to any one of claims 1 to 21, wherein the fluoroethylene carbonate is selected from the group consisting of monofluoroethylene carbonate, difluoroethylene carbonate, and trifluoroethylene carbonate. Any one or any of a plurality of tetrafluoroethylene carbonates. A continuous flow synthesis process according to any one of claims 1 to 22, characterized in that the synthesis process can be carried out in the absence of an inert solvent. The continuous stream synthesis process according to any one of claims 1 to 23, wherein said continuous stream synthesis process is carried out in an integrated continuous flow reactor comprising three temperature zones, said mixed dispersion unit Corresponding to the temperature zone 1, the fluorination reaction unit corresponds to the temperature zone 2, and the gas-liquid separation unit corresponds to the temperature zone 3, and the continuous flow synthesis process comprises the following steps: (a) the fluorinated raw material or inert solvent is mixed with fluorine gas in the temperature zone 1 and the fluorine gas is dispersed in the liquid phase, and then the mixture is transported to the temperature zone 2; or the fluorinated raw material and the fluorine gas are in the temperature zone 1 contact mixing and dispersing fluorine gas in the liquid phase while preliminary fluorination reaction, and then transporting the mixture to the temperature zone 2; (b) the fluorinated raw material and fluorine gas are reacted in the temperature zone 2 to form a fluoroethylene carbonate and the reaction mixture is sent to the temperature zone 3; (c) The reaction mixture enters the temperature zone 3 for separation of the gas and the liquid. The continuous flow synthesis process according to claim 24, wherein the temperature of the temperature zone 1 is -40 to 20 ° C, preferably -20 to 10 ° C. The continuous flow synthesis process according to claim 24, wherein the temperature of the temperature zone 2 is from 10 to 100 ° C, preferably from 30 to 80 ° C, more preferably from 40 to 60 ° C. The continuous flow synthesis process according to claim 24, wherein the temperature of the temperature zone 3 is 30 to 80 ° C, preferably 40 to 60 ° C. A continuous flow synthesis process according to any one of claims 23 to 27, wherein the synthesis process is carried out at a pressure equal to or greater than ambient pressure, preferably at a pressure equal to or greater than 5 bar, more preferably at or equal to or It is carried out at a pressure greater than 10 bar. The continuous flow synthesis process according to any one of claims 23-27, characterized in that the pressure of each of the temperature zones may be the same or different. The continuous flow synthesis process according to any one of claims 23-27, characterized in that the synthesis process is carried out under gradient pressure, the temperature of the temperature zone 1 is greater than the pressure of the temperature zone 2, and the pressure of the temperature zone 2 is greater than the temperature. Zone 3 pressure. The continuous flow synthesis process according to any one of claims 23-27, characterized in that the pressure in the temperature zone 1 is 5 to 18 bar, preferably 10 to 15 bar; the pressure in the temperature zone 2 is 3 to 18 bar, preferably 5 to 15 bar. The pressure in the temperature zone 3 is 0 to 10 bar, preferably 2 to 7 bar. The continuous flow synthesis process according to any one of claims 1 to 31, wherein the fluorine gas is a fluorine element diluted by an inert gas or diluted by an inert gas, and the inert gas is selected from the group consisting of nitrogen gas. a rare gas, or a mixed gas thereof, which is a mixture of nitrogen and a rare gas, the rare gas being a simple substance of a group 18 element of the periodic table; the fluorine gas is preferably a fluorine element and a nitrogen gas. mixed composition. The continuous flow synthesis process according to any one of claims 1 to 32, characterized in that the concentration of the fluorine element in the fluorine gas is more than 0% by volume, preferably equal to or more than 5%, more preferably equal to or more than 12%; The concentration of the fluorine element in the fluorine gas is preferably equal to or less than 25% by volume, preferably equal to or less than 18%, and most preferably, the concentration of the fluorine element in the fluorine gas is from 12% to 18%. The continuous flow synthesis process according to any one of claims 1 to 32, wherein the ratio of F ₂ /H is from 1.0 to 2.0:1, preferably from 1.05 to 1.50:1, more preferably from 1.10 to 1.25:1, The ratio of F ₂ /H refers to the number of molecules of F ₂ corresponding to each H atom to be substituted to form a CF bond in the raw material to be fluorinated. An integrated reactor dedicated to the continuous stream synthesis process of any of claims 1-34, characterized in that the integrated reactor adopts a modular structure comprising a mixing and dispersing unit, a fluorination reaction unit and a gas a liquid separation unit for mixing a raw material to be fluorinated or an inert solvent with fluorine gas and dispersing fluorine gas in a liquid phase, and then conveying the mixture to a fluorination reaction unit; or The mixing and dispersing unit is used for contacting and mixing the raw material to be fluorinated with fluorine gas and dispersing the fluorine gas in the liquid phase while preliminary fluorination reaction, and then conveying the mixture to the fluorination reaction unit; The fluorinated raw material is reacted with fluorine gas to form fluoroethylene carbonate and sent to a gas-liquid separation unit; the gas-liquid separation unit is used for separation of liquid and gas. A continuous flow synthesis process according to claim 35, wherein said mixed dispersion unit or fluorination reaction unit further has a separation function of liquid and gas. The integrated reactor according to claim 35 or 36, wherein the integrated continuous flow reactor feed port is one or more, and the integrated continuous flow reactor discharge port is one. Or multiple. A continuous flow synthesis process according to any one of claims 35 to 37, wherein each of said mixing and dispersing unit, fluorination reaction unit and gas-liquid separation unit independently comprises more than one reactor module or A reactor module group in which a reactor module group is composed of a plurality of reactor modules connected in series or in parallel, and the units are connected in series with each other. The continuous flow synthesis process according to any one of claims 35 to 37, characterized in that each of the mixing and dispersing unit, the fluorination reaction unit and the gas-liquid separation unit corresponds to a temperature zone, and each temperature zone is independent. The ground comprises more than one reactor module or group of reactor modules, wherein the reactor module group is composed of a plurality of reactor modules connected in series or in parallel, and the temperature zones are connected in series with each other. The integrated reactor according to any one of claims 35 to 39, wherein said reactor modules, between reactor module groups, between the reactor module and the reactor module group are respectively In series or in parallel. The integrated reactor according to any one of claims 35 to 40, wherein the reactor module is selected from any one of the reaction devices capable of realizing a continuous flow process, preferably, the reaction device It is selected from any one or any of a plurality of reactors, a tandem coil reactor, and a tubular reactor. The integrated reactor according to claim 41, wherein said reaction means is one or more. A continuous flow synthesis process according to claim 41 or claim 42, wherein said reaction means has a flow passage. The continuous flow synthesis process according to claim 43, wherein said flow passage has a specific surface area greater than or equal to 2000 m ² /m ³ and a heat transfer coefficient greater than or equal to 1.5 MW/m ³ K, gas/liquid dispersion ratio. The surface area is greater than or equal to 47,000 m ² /m ³ . A continuous flow synthesis process according to claim 43, wherein said flow passage is made of a material resistant to F ₂ and HF, said material being preferably stainless steel, alloy resistant to F ₂ and HF (Monel) Gold-containing, Inconel, Hastelloy-based alloys, polymer materials (partial or perfluorinated polymer polyalkylene polymers), other types of polymers (polytetrafluoroethylene, perfluoroalkane) An oxyalkane copolymer), a ceramic (silicon carbide) or a material coated with F ₂ and HF.

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