CN116253710A - High-conversion continuous production process and system for fluoroethylene carbonate - Google Patents

High-conversion continuous production process and system for fluoroethylene carbonate Download PDF

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CN116253710A
CN116253710A CN202211658372.4A CN202211658372A CN116253710A CN 116253710 A CN116253710 A CN 116253710A CN 202211658372 A CN202211658372 A CN 202211658372A CN 116253710 A CN116253710 A CN 116253710A
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reaction
gas
tower
fluoroethylene carbonate
product
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丁永良
李明全
张飞
钟显威
唐倩
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Shanghai Donggeng Chemical Technology Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
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    • C07D317/00—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms
    • C07D317/08—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3
    • C07D317/10—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3 not condensed with other rings
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D9/00—Crystallisation
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0053—Details of the reactor
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
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Abstract

The invention relates to the technical field of chemical industry, in particular to a high-conversion continuous production process and a system of fluoroethylene carbonate, wherein the high-conversion continuous production process of fluoroethylene carbonate comprises the following steps: s1, chlorination reaction: mixing ethylene carbonate and a chloro reagent, and carrying out chloro reaction under the action of illumination to obtain a chloro product; s2, fluorination reaction: adding a fluorination reagent into the chlorinated product to carry out a fluorination reaction to obtain a reaction product, wherein the fluorination reagent is nano-scale potassium fluoride, and the fluorination reaction is carried out in at least one stage of micro-channel reactor; s3, purifying: and (3) carrying out solid-liquid separation on the reaction product, and then sequentially removing the solvent and crystallizing by falling film to obtain the product fluoroethylene carbonate. The invention adopts nano-scale potassium fluoride as a fluorination reagent and a chlorination product to carry out fluorination reaction in the microchannel reactor, so that the fluorination reaction can be carried out continuously, the purity of the product is ensured, the reaction time is shortened, the raw materials are saved, and the production efficiency and the economy are improved.

Description

High-conversion continuous production process and system for fluoroethylene carbonate
Technical Field
The application relates to the technical field of chemical industry, in particular to a fluoroethylene carbonate high-conversion continuous production process and system.
Background
In recent years, with the high emphasis on environmental protection of various countries, the demand of new energy automobiles is increasing, and the demand of lithium ion batteries is rapidly increasing when lithium ion batteries are used as power sources for supplying power to new energy electric automobiles.
Fluoroethylene carbonate (FEC) is a main lithium ion battery electrolyte additive, has excellent film forming performance, better SEI film forming performance, compact structure layer forming but no impedance increase, can prevent electrolyte from further decomposition, and improves the low temperature performance of the electrolyte. Therefore, fluoroethylene carbonate can be used as an additive of the electrolyte of the lithium ion secondary battery, so that the cycle performance of the lithium battery can be improved, and the safety performance of the lithium battery can be remarkably improved because fluorine atoms contained in the fluoroethylene carbonate have flame retardant performance. In addition, fluoroethylene carbonate can be used as an intermediate of medicines and pesticides, and has good application prospect.
Currently, there are mainly 3 methods for synthesizing fluoroethylene carbonate. Firstly, a direct fluoro method using Ethylene Carbonate (EC) as a raw material, but the direct fluoro method contains fluorine in the raw material, and because of the characteristics of high toxicity and high reaction activity of the fluorine, the system has great potential safety hazard and the product purity is low; secondly, an electrochemical fluorination method, which can react under the conditions of safety and relatively simple equipment, is still in the theoretical research stage of a laboratory at present; the third is the halogen exchange method using chloroethylene carbonate as raw material, the halogen exchange method is the most widely used method, the method is divided into two steps, EC reacts with excessive chlorine to produce chloroethylene carbonate (CEC), purified CEC reacts with fluoridation reagent (KF) and solvent in the reaction kettle, filter, rectify to get pure FEC product.
The energy-saving production process and system of the ultra-pure fluoroethylene carbonate disclosed in the patent CN114736185A comprise the following steps: chloridizing the chloridizing reagent with excessive EC to generate CEC under the action of light, wherein chloridizing reaction products comprise CEC and unreacted EC; using EC as solvent, and reacting CE with fluoridation reagent to generate fluoroethylene carbonate (FEC); and (3) carrying out solid-liquid separation on the fluoro reaction product to obtain solid mixed salt and liquid, and purifying the liquid to obtain the target product fluoroethylene carbonate. The production process and the system have the defects that the fluorination reaction cannot be continuously carried out, so that the time of the fluorination reaction is too long (7-9 h), a large amount of heat released by the fluorination reaction cannot be utilized, the utilization rate of raw materials is not high, secondary treatment of byproducts is needed, and the like.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, the present invention aims to provide a process and a system for high-conversion continuous production of fluoroethylene carbonate, which can reduce byproducts, shorten reaction time, save raw materials, continuously react, reduce production energy consumption, improve production efficiency and economy, and easily realize industrial capacity amplification and continuous production while ensuring product purity.
To achieve the above and other related objects, in a first aspect, the present invention provides a high conversion continuous production process of fluoroethylene carbonate, comprising the steps of:
s1, chlorination reaction: mixing ethylene carbonate and a chloro reagent, and carrying out chloro reaction under the action of illumination to obtain a chloro product;
s2, fluorination reaction: adding a fluorination reagent into the chlorinated product to carry out fluorination reaction to obtain a reaction product, wherein the fluorination reagent is nano-scale potassium fluoride, and the fluorination reaction is carried out in at least one stage of microchannel reactor;
s3, purifying: and (3) carrying out solid-liquid separation on the reaction product, and then sequentially removing the solvent and crystallizing by falling film to obtain the product fluoroethylene carbonate.
Optionally, in step S1, the chloro reagent uses chlorine gas.
Optionally, in step S1, the molar ratio of the ethylene carbonate to the chloro reagent is 1-2:0.4 to 0.6, preferably 1.5 to 2:0.4-0.6.
Optionally, in step S1, the illumination uses violet light or blue light.
Optionally, in step S1, the reaction temperature of the chlorination reaction is 60-80 ℃, preferably 65-70 ℃, and the time of the chlorination reaction is 0.5-2.5h, preferably 1.5-2h.
Optionally, in step S1, the chlorinated product includes vinyl monochlorocarbonate and vinyl carbonate, and the vinyl carbonate is used as a solvent.
Optionally, in step S2, the molar ratio of the chloroethylene carbonate in the chloro product to the nanoscale potassium fluoride is 1:1.05-1.15.
Optionally, in step S2, the reaction temperature of the fluorination reaction is 60-80 ℃, preferably 65-70 ℃, and the time of the fluorination reaction is 10-120S, preferably 60-90S.
In a second aspect, the invention provides a fluoroethylene carbonate high-conversion continuous production system, which comprises a primary reaction unit, a secondary reaction unit and a purification unit;
the first-stage reaction unit comprises a gas-liquid mixer and a baffling photolysis tower, wherein the gas-liquid mixer is provided with a liquid inlet, a gas inlet and an outlet, the lower part of the baffling photolysis tower is provided with a feed inlet, the upper part of the baffling photolysis tower is provided with a discharge outlet, the outlet of the gas-liquid mixer is communicated with the feed inlet of the baffling photolysis tower, and the discharge outlet of the baffling photolysis tower is communicated with the liquid inlet of the gas-liquid mixer;
the second-stage reaction unit comprises at least one first-stage micro-channel reactor, all the micro-channel reactors are provided with inlets and outlets, the first-stage micro-channel reactor is also provided with a material inlet, the inlet of the first-stage micro-channel reactor is communicated with the discharge port of the baffling photolysis tower, the outlet of the last-stage micro-channel reactor is communicated with the inlet of the first-stage micro-channel reactor, and the at least one first-stage micro-channel reactor is connected with a heat pump system;
The purification unit comprises a desolventizing tower and a falling film crystallizer which are sequentially arranged and communicated along the production direction of the product, the desolventizing tower is communicated with the outlet of the last stage microchannel reactor, and the falling film crystallizer is connected with the heat pump system.
Optionally, the baffling photolysis tower comprises a shell, and the inside of the shell is sequentially divided into a baffling photolysis reaction cavity, an air collecting cavity and an exhaust gas cavity from bottom to top.
Optionally, a baffling device is arranged in the baffling photolysis reaction cavity, the baffling device comprises a plurality of baffles which are sequentially arranged, preferably a plurality of baffles which are sequentially arranged along the vertical direction, a baffling reaction channel is formed between adjacent baffles, and illumination devices extending along the channel are arranged on the inner wall of the baffling reaction channel.
Optionally, the gas collection cavity is communicated with the baffling photolysis reaction cavity, and the side wall of the gas collection cavity shell is provided with an exhaust port.
Optionally, a choke plate is arranged between the waste gas cavity and the gas collecting cavity, and a gas outlet is arranged at the top of the waste gas cavity shell.
Optionally, the exhaust port of the baffling photolysis tower is communicated with the gas inlet of the gas-liquid mixer.
Specifically, in the invention, the exhaust port of the baffling photolysis tower is communicated with the gas inlet of the gas-liquid mixer, so that chlorine which does not participate in the reaction can be circularly conveyed into the gas-liquid mixer, further the quantitative chlorine can complete the reaction as much as possible, and the consumption of the chlorine is reduced.
Optionally, the at least one stage microchannel reactor and the falling film crystallizer are coupled by the heat pump system.
Specifically, in the invention, the heat pump system can transfer the heat released by at least one stage of micro-channel reactor in the process of fluoro reaction to the falling film crystallizer for the sweating step and the melting step of melt crystallization in the falling film crystallization process, so that the energy consumption of production is reduced.
Optionally, the fluoroethylene carbonate production system further comprises an exhaust gas treatment unit, wherein the exhaust gas treatment unit comprises a water absorption tower and an alkali absorption tower which are communicated, the water absorption tower is provided with a feed inlet and a discharge outlet, the feed inlet of the water absorption tower is communicated with the air outlet of the exhaust gas cavity, and the discharge outlet of the water absorption tower is communicated with the alkali absorption tower.
Specifically, in the present invention, by providing a water absorption tower and an alkali absorption tower in communication, it is possible to absorb hydrogen chloride gas in the exhaust gas and recover by-product hydrochloric acid and chlorine gas in the exhaust gas and recover by-product sodium hypochlorite.
Optionally, a gas washing tower is arranged on a connecting passage between the inlet of the first-stage microchannel reactor and the discharge port of the baffling photolysis tower, the gas washing tower is provided with a gas inlet and a gas outlet, and the gas outlet of the gas washing tower is communicated with the inlet of the water absorption tower.
Specifically, in the invention, the gas scrubber is arranged on the connecting passage between the baffled photolysis tower and the first-stage micro-channel reactor, and the cleaning gas is introduced from the gas inlet of the gas scrubber, so that unreacted chlorine and impurities in the chlorination reaction can be removed.
Optionally, a solid-liquid separation device is arranged on a connecting passage between the desolventizing tower and the outlet of the last stage microchannel reactor.
Specifically, in the invention, the solid-liquid separation equipment is arranged on the connecting passage between the desolventizing tower and the outlet of the last stage microchannel reactor, so that the product fluoroethylene carbonate obtained by the fluorination reaction and impurities can be subjected to solid-liquid separation, and further the solid salt of potassium chloride is obtained.
Optionally, the desolventizing tower is in communication with the gas-liquid mixer.
Specifically, in the invention, the desolventizing tower is communicated with the gas-liquid mixer, so that the ethylene carbonate contained in the product can be separated out and returned to the gas-liquid mixer to be used as a reaction raw material, thereby improving the utilization rate of the raw material.
The invention has the beneficial effects that:
(1) According to the invention, the nano-scale potassium fluoride and the vinyl chloride carbonate are adopted to carry out the fluoro reaction in the micro-channel reactor with at least one stage of the micro-channel reactor sequentially communicated end to end, so that the raw material utilization rate is improved, byproducts are reduced, a large amount of reaction heat can be prevented from being emitted in a short time during the fluoro reaction, the reaction time is shortened, the fluorination reaction can be continuously carried out, and the production efficiency is improved.
(2) According to the invention, the gas-liquid mixer is communicated with the baffling photolysis tower, and the reaction liquid circulation and the gas circulation are realized, so that the raw material utilization rate can be improved, the chlorine-containing byproducts are reduced, the reaction condition is mild, and the safety is good.
(3) According to the invention, the micro-channel reactor and the falling film crystallizer are coupled by adopting the heat pump system, so that the heat released in the fluoro reaction process can be transferred to the falling film crystallizer for the sweating step and the melting step of melting crystallization in the falling film crystallization process, the production energy consumption is reduced, and the energy utilization rate is improved.
Drawings
FIG. 1 is a schematic structural diagram of a high conversion continuous production system for fluoroethylene carbonate in examples 1-4 and comparative example 1;
FIG. 2 is a schematic diagram showing the structure of a high conversion continuous production system for fluoroethylene carbonate in comparative example 2;
FIG. 3 is a schematic diagram of the structure of a microchannel reactor used in the high conversion continuous production system of fluoroethylene carbonate in examples 1-4 and comparative examples 1-2.
Description of the reference numerals
The gas-liquid mixer 11, the baffled photolysis tower 12, the water absorption tower 21, the alkali absorption tower 22, the gas washing tower 31, the first stage micro-channel reactor 41, the second stage micro-channel reactor 42, the centrifuge 51, the desolventizing tower 61, the falling film crystallizer 62, the heat pump system 71, the ethylene carbonate inlet A1, the chlorine inlet A2, the nitrogen inlet A3, the fluorinating agent inlet A4, the fluoroethylene carbonate outlet B1, the hydrochloric acid outlet B2, the sodium hypochlorite outlet B3 and the solid salt outlet B4.
Detailed Description
Further advantages and effects of the present invention will become readily apparent to those skilled in the art from the disclosure herein, by referring to the accompanying drawings and the preferred embodiments. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be understood that the preferred embodiments are presented by way of illustration only and not by way of limitation.
Spatially relative terms, such as "upper," "lower," "side wall," "top" and "bottom" may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. The device may also be positioned in other different ways and the spatially relative descriptions used herein are construed accordingly.
The invention provides a high-conversion continuous production process of fluoroethylene carbonate, which comprises the following steps:
S1, chlorination reaction: according to the mole ratio of the ethylene carbonate to the chlorinating agent of 1-2: mixing ethylene carbonate and a chlorinating reagent at 0.4-0.6, and carrying out chlorination reaction for 0.5-2.5h by adopting ultraviolet light or blue light irradiation at 60-80 ℃ to obtain a chlorination product;
s2, fluorination reaction: adding nano-scale potassium fluoride into the obtained chlorinated product, so that the molar ratio of the chloroethylene carbonate to the nano-scale potassium fluoride in the chlorinated product is 1:1.05-1.15, and carrying out fluorination reaction in at least one stage of micro-channel reactor at 60-80 ℃ for 10-120s to obtain a reaction product;
s3, purifying: and (3) carrying out solid-liquid separation on the obtained reaction product, and then sequentially removing the solvent ethylene carbonate and carrying out primary melt crystallization to obtain the product fluoroethylene carbonate.
In another embodiment of the invention, the obtained reaction product is subjected to solid-liquid separation, and then solvent ethylene carbonate is removed and twice melting crystallization are sequentially carried out, so that the product fluoroethylene carbonate is obtained.
The invention also provides a fluoroethylene carbonate high-conversion continuous production system which comprises a primary reaction unit, an exhaust gas treatment unit, a secondary reaction unit and a purification unit;
referring to fig. 1, the primary reaction unit includes a gas-liquid mixer 11 and a baffling photolysis tower 12, and is a place where ethylene carbonate and chlorine are mixed and chlorinated to generate ethylene chlorocarbonate.
With continued reference to fig. 1, the gas-liquid mixer is provided with a liquid inlet A1, a gas inlet and an outlet, the lower part of the shell of the baffling photolysis tower 11 is provided with a feed inlet, the upper part of the shell of the baffling photolysis tower 12 is provided with a discharge outlet, the outlet of the gas-liquid mixer 11 is communicated with the feed inlet of the baffling photolysis tower 12, and the discharge outlet of the baffling photolysis tower 12 is communicated with the liquid inlet A1 of the gas-liquid mixer 11.
Specifically, by communicating the outlet of the gas-liquid mixer 11 with the feed inlet of the baffling photolysis tower 12, and communicating the discharge outlet of the baffling photolysis tower 12 with the liquid inlet A1 of the gas-liquid mixer, the unreacted complete ethylene carbonate and chlorine can be circulated into the gas-liquid mixer 11 and the baffling photolysis tower 12 to continue the chlorination reaction; the exhaust port of the baffling photolysis tower 12 is communicated with the gas inlet of the gas-liquid mixer 11, so that chlorine which does not participate in the reaction can be circularly conveyed into the gas-liquid mixer 11, further, the quantitative chlorine can complete the reaction as much as possible, the consumption of the chlorine is reduced, and less chlorine-containing byproducts are generated.
With continued reference to fig. 1, the baffling photolysis tower 12 includes a housing, and the interior of the housing is divided into a baffling photolysis reaction chamber, an air collecting chamber, and an exhaust chamber in order from bottom to top.
With continued reference to fig. 1, the baffling photolysis reaction chamber is a place for performing chlorination reaction, a baffling device is arranged in the baffling photolysis reaction chamber, the baffling device comprises a plurality of baffles which are sequentially arranged along the vertical direction, a baffling reaction channel is formed between adjacent baffles, and illumination devices extending along the channel are arranged on the inner wall of the baffling reaction channel.
With continued reference to fig. 1, the gas collecting cavity is used for collecting unreacted gaseous raw materials, the gas collecting cavity is communicated with the baffling photolysis reaction cavity, the side wall of the gas collecting cavity shell is provided with a gas outlet, with continued reference to fig. 1, the waste gas cavity is used for collecting waste gas generated by chlorination reaction, the gas blocking plate is used for preventing the unreacted gaseous raw materials in the gas collecting cavity from entering the waste gas cavity, the gas blocking plate is arranged between the waste gas cavity and the gas collecting cavity, and the top of the waste gas cavity shell is provided with a gas outlet.
The light source of the illumination device adopts a purple light lamp, and a transparent protective sleeve (not shown in the figure) is arranged on the purple light lamp.
Specifically, set up transparent protective sheath on the purple light lamp, on the one hand, can make the purple light that the purple light lamp sent see through protective sheath catalytic chlorination, on the other hand, can avoid the purple light lamp to receive the pollution and the corruption of reaction material.
The choke plate is connected with an opening and closing control device, namely an electric push rod (not shown in the figure).
Specifically, the electric push rod can be used for opening and closing the choke plate, the electric push rod is used for closing the choke plate in the chlorination reaction process, and after the chlorination reaction is finished, the electric push rod is used for opening the choke plate, so that waste gas in the gas collection cavity smoothly enters the waste gas cavity.
With continued reference to fig. 1, the exhaust gas treatment unit includes a water absorber 21 and a base absorber 22 in communication.
With continued reference to fig. 1, the water absorber 21 is configured to absorb the hydrogen chloride gas in the exhaust gas and recover the byproduct hydrochloric acid through the hydrochloric acid outlet B2, the water absorber 21 is provided with a discharge port and a feed port, the bottom of the water absorber 21 is provided with the hydrochloric acid outlet B2, the feed port of the water absorber 21 is communicated with the gas outlet of the exhaust gas cavity Q3 in the baffling photolysis tower 12, and the discharge port of the water absorber 21 is communicated with the alkali absorber 22.
With continued reference to fig. 1, the alkali absorption tower 22 is configured to absorb chlorine in the exhaust gas and recover sodium hypochlorite as a byproduct through a sodium hypochlorite outlet B3, the bottom of the alkali absorption tower 22 is provided with the sodium hypochlorite outlet B3, and the top of the alkali absorption tower 22 is provided with an air outlet for evacuating gas inside the alkali absorption tower 22.
With continued reference to fig. 1, a gas scrubber 31 is disposed in a connection path between the baffled photolysis tower 12 and the first stage microchannel reactor 41, the gas scrubber 31 is configured to remove unreacted chlorine and impurities in the chlorination reaction, the gas scrubber 31 is provided with a nitrogen inlet A3 and a gas outlet, the nitrogen inlet A3 is configured to introduce nitrogen for scrubbing, and the gas outlet is connected to an inlet of the water absorber 21.
With continued reference to fig. 1, the secondary reaction unit includes two stages of microchannel reactors connected end to end, namely a first stage microchannel reactor 41 and a second stage microchannel reactor 42, wherein the first stage microchannel reactor 41 and the second stage microchannel reactor 42 are both provided with an inlet and an outlet, the inlet of the first stage microchannel reactor 41 is communicated with the discharge port of the baffled photolysis tower 12, the outlet of the last stage microchannel reactor 41 is communicated with the inlet of the first stage microchannel reactor 41, the first stage microchannel reactor 41 is further provided with a fluorinating agent inlet A4, and nano-scale potassium fluoride enters the first stage microchannel reactor 41 through the fluorinating agent inlet A4.
Specifically, the first stage microchannel reactor 41 and the second stage microchannel reactor 42 are locations where potassium fluoride and ethylene chlorocarbonate undergo a fluorination reaction to generate ethylene chlorocarbonate, and by providing the first stage microchannel reactor 41 and the second stage microchannel reactor 42 in end-to-end communication, the reaction of nano-scale potassium fluoride and ethylene chlorocarbonate can be effectively avoided from being excessively severe, a large amount of reaction heat can be released in a short time, and the reaction can be continuously performed.
With continued reference to fig. 1, a solid-liquid separation apparatus is provided on a connection path between the second stage microchannel reactor 42 and the desolventizing tower 61, the solid-liquid separation apparatus being for solid-liquid separation of fluoroethylene carbonate and impurities, which are products obtained by the fluorination reaction, and the solid-liquid separation apparatus being provided with a solid salt outlet B4 through which solid salts of potassium chloride can be collected, specifically, the solid-liquid separation apparatus employing a centrifuge 51 or an automatic camera.
With continued reference to fig. 1, the purification unit includes a desolventizing column 61 and a falling film crystallizer 62 that are sequentially disposed and in communication along the product production direction.
With continued reference to fig. 1, a desolventizing tower 61 is provided for removing ethylene carbonate contained in the product and returning it to the gas-liquid mixer 11 as a reaction raw material, the desolventizing tower 61 being in communication with the outlet of the second stage microchannel reactor 42, the desolventizing tower 61 being also in communication with the gas-liquid mixer 11.
Specifically, by communicating the desolventizing tower 61 with the gas-liquid mixer 11, ethylene carbonate contained in the product can be separated and returned to the gas-liquid mixer 11 as a reaction raw material, so that the raw material utilization rate can be improved.
With continued reference to fig. 1, the falling film crystallizer 62 is used to further purify the reaction product fluoroethylene carbonate, and after the purification is completed, the product high-purity fluoroethylene carbonate is obtained through the fluoroethylene carbonate outlet B1.
With continued reference to FIG. 1, the falling film crystallizer 62 is coupled to the first stage microchannel reactor 41 and the second stage microchannel reactor 42 via a heat pump system 71.
Specifically, the heat pump system 71 can transfer the heat released from the first stage microchannel reactor 41 and the second stage microchannel reactor 42 during the fluorination reaction to the falling film crystallizer 62 for the sweating step and the melting step of the melting crystallization during the falling film crystallization, thereby reducing the production energy consumption.
All the communication lines are provided with on-off valves (not shown in the figure).
The present invention will be described in detail with reference to specific exemplary examples. It is also to be understood that the following examples are given solely for the purpose of illustration and are not to be construed as limitations upon the scope of the invention, as many insubstantial modifications and variations are within the scope of the invention as would be apparent to those skilled in the art in light of the foregoing disclosure. The specific process parameters and the like described below are also merely examples of suitable ranges, i.e., one skilled in the art can make a suitable selection from the description herein and are not intended to be limited to the specific values described below.
Example 1
The fluoroethylene carbonate high conversion continuous production system in this example is provided with a first-stage falling film crystallization.
Chlorination reaction: the ethylene carbonate and the chlorine (the molar ratio is 2:0.4) respectively enter a gas-liquid mixer 11 through a liquid inlet A1 and a gas inlet A2, are mixed and stirred into foam, then are introduced into a baffling photolysis tower 12, the temperature of a baffling photolysis reaction cavity in the baffling photolysis tower 12 is set to be 60 ℃, and the ethylene carbonate and the chlorine are subjected to chlorination reaction for 2.5 hours under the irradiation of a purple light lamp, so that a chlorinated product comprising ethylene carbonate monochloride and ethylene carbonate is obtained.
Opening a switch valve on a connecting pipeline between the baffling photolysis tower 12 and the gas washing tower 31, introducing the obtained chlorinated product and part of unreacted chlorine into the gas washing tower 31, introducing nitrogen into the gas washing tower 31 through a nitrogen inlet A3 to blow off redundant hydrogen chloride gas and chlorine, obtaining pure blending liquid of chloroethylene carbonate and ethylene carbonate at the bottom of the tower, sequentially passing the hydrogen chloride gas and the chlorine gas at the top of the tower and the hydrogen chloride gas discharged from an exhaust cavity in the baffling photolysis tower 12 through the water absorption tower 21 and the alkali absorption tower 22 together, obtaining byproduct hydrochloric acid from a hydrochloric acid outlet B2 of the water absorption tower 21, obtaining byproduct sodium hypochlorite from a sodium hypochlorite outlet B3 of the alkali absorption tower 22, and finally carrying out evacuation treatment on tail gas.
Fluorination reaction: the first stage micro-channel reactor 41 and the second stage micro-channel reactor 42 are cleaned by nitrogen replacement, the blend liquid of pure chloroethylene carbonate and ethylene carbonate is introduced into the first stage micro-channel reactor 41, nano-scale potassium fluoride (fluorinating agent) is added into the first stage micro-channel reactor 41 through a fluorinating agent inlet A4, and the molar ratio of the chloroethylene carbonate to the nano-scale potassium fluoride is 1:1.05, carrying out fluorination reaction for 120s at the temperature of 60 ℃, then sequentially circulating the reaction liquid to the second-stage micro-channel reactor 42 and the first-stage micro-channel reactor 41, continuously carrying out fluorination reaction on unreacted completely-nanoscale potassium fluoride and chloroethylene carbonate, collecting heat released by the first-stage micro-channel reactor 41 and the second-stage micro-channel reactor 42 in the fluorination reaction through a heat pump system, and obtaining a crude product fluoroethylene carbonate after the fluorination reaction is finished.
The obtained crude product fluoroethylene carbonate is added into a centrifuge 51, and the solid salt of potassium chloride is separated from fluoroethylene carbonate liquid through the centrifuge 51, so that the finished product potassium chloride is obtained.
Purifying the fluoroethylene carbonate liquid to obtain a high-purity fluoroethylene carbonate product, wherein the purification process comprises the following steps of:
(1) Removing ethylene carbonate: the desolventizing column 61 was set at 110℃and a flow rate of 380Kg/m 3 And (h) introducing fluoroethylene carbonate liquid into a desolventizing tower 61 for desolventizing under the pressure of 2kPa to obtain a crude fluoroethylene carbonate product.
(2) The primary falling film crystallization, namely primary melting crystallization, simultaneously transmits the heat collected by the heat pump system to the falling film crystallizer 62 for the melting step and the sweating step in the melting crystallization process, and the specific operation steps are as follows:
s1: pouring the desolventized fluoroethylene carbonate crude product into a raw material tank, starting a falling film crystallizer 62, and controlling the temperature of a cold and hot medium to be 23 ℃ through cold and hot medium preheating equipment of a circulating heat preservation system;
s2: starting a crystallization circulating pump, controlling the flow to be 0.2m 3 And/h, the pressure is 0.02MPa, and the motor frequency is 13Hz;
s3: the temperature of the cold and hot media of the falling film crystallizer 62 is regulated, the temperature of the primary crystallization is rapidly reduced to 30 ℃, and the temperature of the primary crystallization is slowly reduced to 22 ℃; controlling the crystallization time to be 80min, stopping the crystallization circulating pump, discharging the mother solution, weighing and sampling;
s4: the temperature of the cold medium and the hot medium of the falling film crystallizer 62 is regulated by sweating, the temperature of primary sweating is quickly increased to 18 ℃ and the temperature of primary sweating is slowly increased to 22.5 ℃; controlling the sweating time to be 40min, obtaining first-class sweat after the sweating is finished, discharging, weighing and sampling the first-class sweat;
S5: and regulating the temperature of the cooling medium of the falling film crystallizer 62 to 35 ℃, carrying out primary melting, controlling the melting time to 30min, obtaining a primary product fluoroethylene carbonate through a fluoroethylene carbonate outlet B1 after the melting is finished, and weighing and sampling the primary product fluoroethylene carbonate.
Through detection, the purity of the first-grade sweat is 92%, and the purity of the first-grade fluoroethylene carbonate product is 93.5%.
Example 2
The fluoroethylene carbonate high conversion continuous production system in this example is provided with a first-stage falling film crystallization.
Chlorination reaction: the ethylene carbonate and the chlorine (the molar ratio is 1.5:0.5) respectively enter a gas-liquid mixer 11 through a liquid inlet A1 and a gas inlet A2, are mixed and stirred into foam, then are introduced into a baffling photolysis tower 12, the temperature of a baffling photolysis reaction cavity in the baffling photolysis tower 12 is set to be 70 ℃, and the ethylene carbonate and the chlorine are subjected to chlorination reaction for 1.5h under the irradiation of a ultraviolet lamp, so that a chlorinated product comprising ethylene carbonate monochloride and ethylene carbonate is obtained.
Opening a switch valve on a connecting pipeline between the baffling photolysis tower 12 and the gas washing tower 31, introducing the obtained chlorinated product and part of unreacted chlorine into the gas washing tower 31, introducing nitrogen into the gas washing tower 31 through a nitrogen inlet A3 to blow off redundant hydrogen chloride gas and chlorine, obtaining pure blending liquid of chloroethylene carbonate and ethylene carbonate at the bottom of the tower, sequentially passing the hydrogen chloride gas and the chlorine gas at the top of the tower and the hydrogen chloride gas discharged from an exhaust cavity in the baffling photolysis tower 12 through the water absorption tower 21 and the alkali absorption tower 22 together, obtaining byproduct hydrochloric acid from a hydrochloric acid outlet B2 of the water absorption tower 21, obtaining byproduct sodium hypochlorite from a sodium hypochlorite outlet B3 of the alkali absorption tower 22, and finally carrying out evacuation treatment on tail gas.
Fluorination reaction: the first stage micro-channel reactor 41 and the second stage micro-channel reactor 42 are cleaned by nitrogen replacement, the blend liquid of pure chloroethylene carbonate and ethylene carbonate is introduced into the first stage micro-channel reactor 41, nano-scale potassium fluoride (fluorinating agent) is added into the first stage micro-channel reactor 41 through a fluorinating agent inlet A4, and the molar ratio of the chloroethylene carbonate to the nano-scale potassium fluoride is 1:1.1, carrying out fluorination reaction at 70 ℃ for 60 seconds, then sequentially circulating the reaction liquid to the second-stage micro-channel reactor 42 and the first-stage micro-channel reactor 41, continuously carrying out fluorination reaction on unreacted completely nano-scale potassium fluoride and chloroethylene carbonate, collecting heat released by the first-stage micro-channel reactor 41 and the second-stage micro-channel reactor 42 in the fluorination reaction through a heat pump system, and obtaining a crude product fluoroethylene carbonate after the fluorination reaction is finished.
The obtained crude product fluoroethylene carbonate is added into a centrifuge 51, and the solid salt of potassium chloride is separated from fluoroethylene carbonate liquid through the centrifuge 51, so that the finished product potassium chloride is obtained.
Purifying the fluoroethylene carbonate liquid to obtain a high-purity fluoroethylene carbonate product, wherein the purification process comprises the following steps of:
(1) Removing ethylene carbonate: the desolventizing column 61 was set to 120℃and a flow rate of 410Kg/m 3 And (h) introducing fluoroethylene carbonate liquid into a desolventizing tower 61 for desolventizing under the pressure of 1.5kPa to obtain a crude fluoroethylene carbonate product.
(2) The primary falling film crystallization, namely primary melting crystallization, simultaneously transmits the heat collected by the heat pump system to the falling film crystallizer 62 for the melting step and the sweating step in the melting crystallization process, and the specific operation steps are as follows:
s1: pouring the desolventized fluoroethylene carbonate crude product into a raw material tank, starting a falling film crystallizer 62, and controlling the temperature of a cold and hot medium to be 26 ℃ through cold and hot medium preheating equipment of a circulating heat preservation system;
s2: starting a crystallization circulating pump, controlling the flow to be 0.4m 3 And/h, the pressure is 0.04MPa, and the motor frequency is 15Hz;
s3: the temperature of the cold and hot media of the falling film crystallizer 62 is regulated, the temperature of the primary crystallization is rapidly reduced to 26 ℃, and the temperature of the primary crystallization is slowly reduced to 11 ℃; controlling the crystallization time at 85min, stopping the crystallization circulating pump, discharging the mother liquor, weighing and sampling;
s4: the temperature of the cold medium and the hot medium of the falling film crystallizer 62 is regulated by sweating, the temperature of the primary sweating is quickly increased to 9 ℃ and the temperature of the primary sweating is slowly increased to 20 ℃; controlling the sweating time to be 45min, obtaining first-class sweat after the sweating is finished, discharging, weighing and sampling the first-class sweat;
S5: the temperature of the cooling medium of the falling film crystallizer 62 is regulated to be 32 ℃, primary melting is carried out, the melting time is controlled to be 30min, after the melting is completed, the primary product fluoroethylene carbonate is obtained through the fluoroethylene carbonate outlet B1, and weighing and sampling are carried out.
The detection shows that the purity of the first-grade sweat is 92.9%, and the purity of the first-grade fluoroethylene carbonate is 95.4%.
Example 3
The fluoroethylene carbonate high conversion continuous production system in this example is provided with a first-stage falling film crystallization.
Chlorination reaction: the ethylene carbonate and the chlorine (the molar ratio is 1:0.6) respectively enter a gas-liquid mixer 11 through a liquid inlet A1 and a gas inlet A2, are mixed and stirred into foam, then are introduced into a baffling photolysis tower 12, the temperature of a baffling photolysis reaction cavity in the baffling photolysis tower 12 is set to be 80 ℃, and the ethylene carbonate and the chlorine undergo a chlorination reaction for 0.5h under the irradiation of a purple light lamp, so that a chlorinated product comprising ethylene carbonate monochloride and ethylene carbonate is obtained.
Opening a switch valve on a connecting pipeline between the baffling photolysis tower 12 and the gas washing tower 31, introducing the obtained chlorinated product and part of unreacted chlorine into the gas washing tower 31, introducing nitrogen into the gas washing tower 31 through a nitrogen inlet A3 to blow off redundant hydrogen chloride gas and chlorine, obtaining pure blending liquid of chloroethylene carbonate and ethylene carbonate at the bottom of the tower, sequentially passing the hydrogen chloride gas and the chlorine gas at the top of the tower and the hydrogen chloride gas discharged from an exhaust cavity in the baffling photolysis tower 12 through the water absorption tower 21 and the alkali absorption tower 22 together, obtaining byproduct hydrochloric acid from a hydrochloric acid outlet B2 of the water absorption tower 21, obtaining byproduct sodium hypochlorite from a sodium hypochlorite outlet B3 of the alkali absorption tower 22, and finally carrying out evacuation treatment on tail gas.
Fluorination reaction: the first stage micro-channel reactor 41 and the second stage micro-channel reactor 42 are cleaned by nitrogen replacement, the blend liquid of pure chloroethylene carbonate and ethylene carbonate is introduced into the first stage micro-channel reactor 41, nano-scale potassium fluoride (fluorinating agent) is added into the first stage micro-channel reactor 41 through a fluorinating agent inlet A4, and the molar ratio of the chloroethylene carbonate to the nano-scale potassium fluoride is 1:1.15, carrying out fluorination reaction for 10s at the temperature of 80 ℃, then sequentially circulating the reaction liquid to the second-stage micro-channel reactor 42 and the first-stage micro-channel reactor 41, continuously carrying out fluorination reaction on unreacted completely nano-scale potassium fluoride and chloroethylene carbonate, collecting heat released by the first-stage micro-channel reactor 41 and the second-stage micro-channel reactor 42 in the fluorination reaction through a heat pump system, and obtaining a crude product fluoroethylene carbonate after the fluorination reaction is finished.
The obtained crude product fluoroethylene carbonate is added into a centrifuge 51, and the solid salt of potassium chloride is separated from fluoroethylene carbonate liquid through the centrifuge 51, so that the finished product potassium chloride is obtained.
Purifying the fluoroethylene carbonate liquid to obtain a high-purity fluoroethylene carbonate product, wherein the purification process comprises the following steps of:
(1) Removing ethylene carbonate: the desolventizing column 61 was set to 130℃and a flow rate of 450Kg/m 3 Introducing fluoroethylene carbonate liquid into a desolventizing tower 61 for desolventizing under the pressure of 1kPa to obtain crude fluoroethylene carbonateThe product is obtained.
(2) The primary falling film crystallization, namely primary melting crystallization, simultaneously transmits the heat collected by the heat pump system to the falling film crystallizer 62 for the melting step and the sweating step in the melting crystallization process, and the specific operation steps are as follows:
s1: pouring the desolventized fluoroethylene carbonate crude product into a raw material tank, starting a falling film crystallizer 62, and controlling the temperature of a cold and hot medium to be 30 ℃ through cold and hot medium preheating equipment of a circulating heat preservation system;
s2: starting a crystallization circulating pump, controlling the flow to be 0.6m 3 And/h, the pressure is 0.07MPa, and the motor frequency is 18Hz;
s3: the temperature of the cold and hot media of the falling film crystallizer 62 is regulated, the temperature of the primary crystallization is quickly reduced to 22 ℃, and the temperature of the primary crystallization is slowly reduced to 0 ℃; controlling the crystallization time to be 90min, stopping the crystallization circulating pump, discharging the mother solution, weighing and sampling;
s4: the temperature of the cold medium and the hot medium of the falling film crystallizer 62 is regulated by sweating, the temperature of primary sweating is quickly increased to 5 ℃, and the temperature of primary sweating is slowly increased to 18 ℃; controlling the sweating time to be 50min, obtaining first-class sweat after the sweating is finished, discharging, weighing and sampling the first-class sweat;
S5: the temperature of the cooling medium of the falling film crystallizer 62 is regulated to be 30 ℃, primary melting is carried out, the melting time is controlled to be 30min, after the melting is completed, the primary product fluoroethylene carbonate is obtained through the fluoroethylene carbonate outlet B1, and weighing and sampling are carried out.
The detection shows that the purity of the first-grade sweat is 92.5%, and the purity of the first-grade fluoroethylene carbonate is 94.6%.
Example 4
The fluoroethylene carbonate high conversion continuous production system in this example is provided with a secondary falling film crystallization.
Chlorination reaction: the ethylene carbonate and the chlorine (the molar ratio is 2:0.5) respectively enter a gas-liquid mixer 11 through a liquid inlet A1 and a gas inlet A2, are mixed and stirred into foam, then are introduced into a baffling photolysis tower 12, the temperature of a baffling photolysis reaction cavity in the baffling photolysis tower 12 is set to 65 ℃, and the ethylene carbonate and the chlorine are subjected to chlorination reaction for 2 hours under the irradiation of a purple light lamp, so that a chlorinated product comprising ethylene carbonate monochloride and ethylene carbonate is obtained.
Opening a switch valve on a connecting pipeline between the baffling photolysis tower 12 and the gas washing tower 31, introducing the obtained chlorinated product and part of unreacted chlorine into the gas washing tower 31, introducing nitrogen into the gas washing tower 31 through a nitrogen inlet A3 to blow off redundant hydrogen chloride gas and chlorine, obtaining pure blending liquid of chloroethylene carbonate and ethylene carbonate at the bottom of the tower, sequentially passing the hydrogen chloride gas and the chlorine gas at the top of the tower and the hydrogen chloride gas discharged from an exhaust cavity in the baffling photolysis tower 12 through the water absorption tower 21 and the alkali absorption tower 22 together, obtaining byproduct hydrochloric acid from a hydrochloric acid outlet B2 of the water absorption tower 21, obtaining byproduct sodium hypochlorite from a sodium hypochlorite outlet B3 of the alkali absorption tower 22, and finally carrying out evacuation treatment on tail gas.
Fluorination reaction: the first stage micro-channel reactor 41 and the second stage micro-channel reactor 42 are cleaned by nitrogen replacement, the blend liquid of pure chloroethylene carbonate and ethylene carbonate is introduced into the first stage micro-channel reactor 41, nano-scale potassium fluoride (fluorinating agent) is added into the first stage micro-channel reactor 41 through a fluorinating agent inlet A4, and the molar ratio of the chloroethylene carbonate to the nano-scale potassium fluoride is 1:1.1, carrying out fluorination reaction for 90s at the temperature of 65 ℃, then sequentially circulating the reaction liquid to the second-stage micro-channel reactor 42 and the first-stage micro-channel reactor 41, continuously carrying out fluorination reaction on unreacted completely nano-scale potassium fluoride and chloroethylene carbonate, collecting heat released by the first-stage micro-channel reactor 41 and the second-stage micro-channel reactor 42 in the fluorination reaction through a heat pump system, and obtaining a crude product fluoroethylene carbonate after the fluorination reaction is finished.
The obtained crude product fluoroethylene carbonate is added into a centrifuge 51, and the solid salt of potassium chloride is separated from fluoroethylene carbonate liquid through the centrifuge 51, so that the finished product potassium chloride is obtained.
Purifying the fluoroethylene carbonate liquid to obtain a high-purity fluoroethylene carbonate product, wherein the purification process comprises the following steps of:
(1) Removing ethylene carbonate: the desolventizing column 61 was set at 125℃and a flow rate of 420Kg/m 3 Introducing fluoroethylene carbonate liquid into desolventizing at 1.6kPaDesolventizing in column 61 to obtain crude fluoroethylene carbonate.
(2) 2+1 falling film crystallization, namely secondary melting crystallization and primary recovery, and simultaneously, heat collected by a heat pump system is conveyed to a melting step and a sweating step in the melting crystallization process in a falling film crystallizer 62, and the specific operation steps are as follows:
s1: pouring the desolventized fluoroethylene carbonate crude product into a raw material tank, starting a falling film crystallizer 62, and controlling the temperature of a cold and hot medium to be 27 ℃ through cold and hot medium preheating equipment of a circulating heat preservation system;
s2: starting a crystallization circulating pump, controlling the flow to be 0.4m 3 And/h, the pressure is 0.05MPa, and the motor frequency is 16Hz;
s3: the temperature of the cold and hot media of the falling film crystallizer 62 is regulated, the temperature of the primary crystallization is rapidly reduced to 25 ℃, and the temperature of the primary crystallization is slowly reduced to 10 ℃; controlling the crystallization time at 85min, stopping the crystallization circulating pump, discharging the mother liquor, weighing and sampling;
s4: the temperature of the cold medium and the hot medium of the falling film crystallizer 62 is regulated by sweating, the primary sweating is rapidly heated to 10 ℃ and the primary sweating is slowly heated to 21 ℃; controlling the sweating time to be 45min, obtaining first-class sweat after the sweating is finished, discharging, weighing and sampling the first-class sweat;
S5: and regulating the temperature of the cooling medium and heating medium of the falling film crystallizer 62 to 33 ℃, carrying out primary melting, controlling the melting time to be 30min, obtaining a primary product after the melting is finished, and discharging, weighing and sampling the primary product.
S6: the temperature of the cold and hot media of the falling film crystallizer 62 is regulated, the temperature of the secondary crystallization is rapidly reduced to 25 ℃, and the temperature of the secondary crystallization is slowly reduced to 13 ℃; controlling the crystallization time at 88min, stopping the crystallization circulating pump, discharging the mother liquor, weighing and sampling;
s7: sweating regulates the temperature of the cooling medium of the falling film crystallizer 62, the second-stage sweating rapidly increases the temperature to 12 ℃ and slowly increases the temperature to 21 ℃; controlling the sweating time to 48min, obtaining secondary sweat after the sweating is finished, discharging, weighing and sampling the secondary sweat;
s8: the temperature of the cooling medium of the falling film crystallizer 62 is regulated to 33 ℃, secondary melting is carried out, the melting time is controlled to be 30min, after the melting is finished, the secondary product fluoroethylene carbonate is obtained through the fluoroethylene carbonate outlet B1, and weighing and sampling are carried out.
S9: and carrying out primary recovery on the primary product, wherein the primary recovery operation step is carried out according to the primary melting crystallization operation step, and the primary recovery product is obtained after the primary recovery is finished.
Through detection, the purity of the first-stage sweat is 93.2%, the purity of the first-stage product is 95.8%, the purity of the second-stage product fluoroethylene carbonate is 99.5%, and the purity of the first-stage recovery product is 96.4%.
Comparative example 1
This comparative example differs from example 2 in that: the nano-scale potassium fluoride is not adopted as a fluorination reagent to carry out a fluorination reaction with the generated chloroethylene carbonate, and the specific steps are as follows:
fluorination reaction: the first stage micro-channel reactor 41 and the second stage micro-channel reactor 42 are cleaned by nitrogen replacement, the blend liquid of pure chloroethylene carbonate and ethylene carbonate is introduced into the first stage micro-channel reactor 41, and common potassium fluoride (fluorinating agent) is added into the first stage micro-channel reactor 41 through a fluorinating agent inlet A4, so that the molar ratio of chloroethylene carbonate to common potassium fluoride is 1:1.5, carrying out fluorination reaction at 70 ℃ for 60 seconds, then sequentially circulating the reaction liquid to the second-stage micro-channel reactor 42 and the first-stage micro-channel reactor 41, continuously carrying out fluorination reaction on the unreacted complete common potassium fluoride and chloroethylene carbonate, collecting heat released by the first-stage micro-channel reactor 41 and the second-stage micro-channel reactor 42 in the fluorination reaction through a heat pump system,
adding the obtained crude fluoroethylene carbonate into a centrifuge 51, separating solid mixed salt of potassium fluoride and potassium chloride from fluoroethylene carbonate liquid by the centrifuge 51, obtaining solid mixed salt of potassium fluoride and potassium chloride by a solid mixed salt outlet B4, adding water into the obtained solid mixed salt, stirring and dissolving, then adsorbing organic matters by adopting activated carbon, filtering the activated carbon to remove the organic matters, and adding calcium chloride into filtrate to ensure that the molar ratio of the calcium chloride to fluorine ions is 1.02:1, stirring and reacting for 1h, filtering after the reaction is finished, washing filter residues, and continuously drying at 150 ℃ for about 1h to obtain calcium fluoride; and then distilling and crystallizing the filtrate to obtain potassium chloride.
The remaining steps of this comparative example were the same as in example 2.
The detection shows that the purity of the first-grade sweat is 90.6%, and the purity of the first-grade fluoroethylene carbonate is 91.8%.
Comparative example 2
This comparative example differs from example 2 in that: the coupling of the falling film crystallizer 62 with the first stage microchannel reactor 41 and the second stage microchannel reactor 42 is achieved without using a heat pump system, and the specific steps are as follows:
fluorination reaction: the first stage micro-channel reactor 41 and the second stage micro-channel reactor 42 are cleaned by nitrogen replacement, the blend liquid of pure chloroethylene carbonate and ethylene carbonate is introduced into the first stage micro-channel reactor 41, nano-scale potassium fluoride (fluorinating agent) is added into the first stage micro-channel reactor 41 through a fluorinating agent inlet A4, and the molar ratio of the chloroethylene carbonate to the nano-scale potassium fluoride is 1:1.1, carrying out fluorination reaction at 70 ℃ for 60 seconds, then sequentially circulating the reaction liquid to a second-stage micro-channel reactor 42 and a first-stage micro-channel reactor 41, and continuously carrying out fluorination reaction on unreacted completely nanoscale potassium fluoride and chloroethylene carbonate, and obtaining a crude product fluoroethylene carbonate after the fluorination reaction is finished.
And a heat pump system is not used for conveying heat in the falling film crystallization process.
The remaining steps of this comparative example were the same as in example 2.
The detection shows that the purity of the first-grade sweat is 92.6%, and the purity of the first-grade fluoroethylene carbonate is 94.5%.
In the above examples, the purity of sweat and products was measured using a gas chromatograph-mass spectrometer.
As is clear from the results of the tests in examples 1 to 4, the purity of the first-stage fluoroethylene carbonate in examples 1 to 3 was 93.5% or more, and the purity of the second-stage fluoroethylene carbonate in example 4 was 99.5%. The result shows that the fluoroethylene carbonate produced by the high-conversion continuous production process and system of the fluoroethylene carbonate can reach more than 93%, wherein the fluoroethylene carbonate produced by the secondary falling film crystallization can reach more than 99%.
From the results of the test of comparative example 1 and example 2, the primary product of example 2 was higher in purity than example 4. The result shows that the product fluoroethylene carbonate can be improved in purity by adopting the nano-scale potassium fluoride to carry out fluorination reaction with the chloroethylene carbonate in the microchannel reactor to produce the fluoroethylene carbonate. In addition, the purity of the solid salt potassium chloride obtained through solid-liquid separation reaches 99% or more, and the solid salt potassium chloride can be directly sold, so that the recovery treatment procedure of byproducts is reduced, and the economical efficiency is improved.
In the production of fluoroethylene carbonate of comparative example 2 and example 2, the energy consumption of example 2 was only 70% of that of comparative example 2. The results show that the use of a heat pump system to couple the falling film crystallizer 62 to the first stage microchannel reactor 41 and the second stage microchannel reactor 42 can reduce the energy consumption for the production of fluoroethylene carbonate.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. It is therefore intended that all equivalent modifications and changes made by those skilled in the art without departing from the spirit and technical spirit of the present invention shall be covered by the appended claims.

Claims (10)

1. A high-conversion continuous production process of fluoroethylene carbonate is characterized in that: the method comprises the following steps:
s1, chlorination reaction: mixing ethylene carbonate and a chloro reagent, and carrying out chloro reaction under the action of illumination to obtain a chloro product;
s2, fluorination reaction: adding a fluorination reagent into the chlorinated product to carry out fluorination reaction to obtain a reaction product, wherein the fluorination reagent is nano-scale potassium fluoride, and the fluorination reaction is carried out in at least one stage of microchannel reactor;
S3, purifying: and (3) carrying out solid-liquid separation on the reaction product, and then sequentially removing the solvent and crystallizing by falling film to obtain the product fluoroethylene carbonate.
2. The fluoroethylene carbonate high conversion continuous production process according to claim 1, characterized in that: in the step S1, the chloro reagent adopts chlorine;
and/or, in the step S1, the molar ratio of the ethylene carbonate to the chlorinating agent is 1-2:0.4-0.6;
and/or, in the step S1, the illumination adopts purple light or blue light;
and/or in the step S1, the reaction temperature of the chlorination reaction is 60-80 ℃, and the time of the chlorination reaction is 0.5-2.5h.
3. The fluoroethylene carbonate high conversion continuous production process according to claim 1, characterized in that: in step S1, the chlorinated product includes vinyl monochlorocarbonate and vinyl carbonate, and the vinyl carbonate is used as a solvent.
4. The fluoroethylene carbonate high conversion continuous production process according to claim 3, characterized in that: in the step S2, the molar ratio of the chloroethylene carbonate to the nanoscale potassium fluoride in the chloro product is 1:1.05-1.15;
and/or in the step S2, the reaction temperature of the fluorination reaction is 60-80 ℃, and the time of the fluorination reaction is 10-120S.
5. A fluoroethylene carbonate high-conversion continuous production system is characterized in that: the fluoroethylene carbonate high-conversion continuous production system comprises a primary reaction unit, a secondary reaction unit and a purification unit;
the first-stage reaction unit comprises a gas-liquid mixer and a baffling photolysis tower, wherein the gas-liquid mixer is provided with a liquid inlet, a gas inlet and an outlet, the lower part of the baffling photolysis tower is provided with a feed inlet, the upper part of the baffling photolysis tower is provided with a discharge outlet, the outlet of the gas-liquid mixer is communicated with the feed inlet of the baffling photolysis tower, and the discharge outlet of the baffling photolysis tower is communicated with the liquid inlet of the gas-liquid mixer;
the second-stage reaction unit comprises at least one first-stage micro-channel reactor, all the micro-channel reactors are provided with inlets and outlets, the first-stage micro-channel reactor is also provided with a material inlet, the inlet of the first-stage micro-channel reactor is communicated with the discharge port of the baffling photolysis tower, the outlet of the last-stage micro-channel reactor is communicated with the inlet of the first-stage micro-channel reactor, and the at least one first-stage micro-channel reactor is connected with a heat pump system;
the purification unit comprises a desolventizing tower and a falling film crystallizer which are sequentially arranged and communicated along the production direction of the product, the desolventizing tower is communicated with the outlet of the last stage microchannel reactor, and the falling film crystallizer is connected with the heat pump system.
6. The fluoroethylene carbonate high conversion continuous production system according to claim 5, characterized in that: the baffling photolysis tower comprises a shell, wherein the inside of the shell is sequentially divided into a baffling photolysis reaction cavity, an air collecting cavity and an exhaust gas cavity from bottom to top;
the device comprises a plurality of baffle plates which are sequentially arranged, a baffle reaction channel is formed between every two adjacent baffle plates, and illumination equipment extending along the channel is arranged on the inner wall of the baffle reaction channel;
the gas collecting cavity is communicated with the baffling photolysis reaction cavity, and the side wall of the gas collecting cavity shell is provided with a gas outlet;
an air blocking plate is arranged between the waste gas cavity and the gas collecting cavity, and an air outlet is arranged at the top of the waste gas cavity shell.
7. The fluoroethylene carbonate high conversion continuous production system according to claim 6, characterized in that: and the exhaust port of the baffling photolysis tower is communicated with the gas inlet of the gas-liquid mixer.
8. The fluoroethylene carbonate high conversion continuous production system according to claim 5, characterized in that: the at least one stage of micro-channel reactor and the falling film crystallizer are coupled through the heat pump system.
9. The fluoroethylene carbonate high conversion continuous production system according to claim 6, characterized in that: the fluoroethylene carbonate production system further comprises an exhaust gas treatment unit, wherein the exhaust gas treatment unit comprises a water absorption tower and an alkali absorption tower which are communicated, the water absorption tower is provided with a feed inlet and a discharge outlet, the feed inlet of the water absorption tower is communicated with the air outlet of the exhaust gas cavity, and the discharge outlet of the water absorption tower is communicated with the alkali absorption tower.
10. The fluoroethylene carbonate high conversion continuous production system according to claim 9, characterized in that: a gas washing tower is arranged on a connecting passage between an inlet of the first-stage microchannel reactor and a discharge port of the baffling photolysis tower, the gas washing tower is provided with a gas inlet and a gas outlet, and the gas outlet of the gas washing tower is communicated with the inlet of the water absorption tower;
and/or a solid-liquid separation device is arranged on a connecting passage between the desolventizing tower and the outlet of the last stage microchannel reactor;
and/or the desolventizing tower is communicated with the gas-liquid mixer.
CN202211658372.4A 2022-12-22 2022-12-22 High-conversion continuous production process and system for fluoroethylene carbonate Pending CN116253710A (en)

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