Background
The vinylene carbonate is synthesized by three main process routes, and each process route takes the vinylene carbonate as a starting material. The method comprises the following steps: ethylene carbonate is used as a raw material, hydrogen atoms on the ethylene carbonate are substituted with chlorine gas to produce dichloroethylene carbonate, and chlorine is eliminated to produce vinylene carbonate. The method 2 comprises the following steps: using ethylene carbonate as a raw material, and using sulfuryl chloride or chlorine gas as a chlorinating agent, substituting hydrogen atoms on the ethylene carbonate to generate monochloroethylene carbonate, and then eliminating chlorine to generate vinylene carbonate. The method 3 comprises the following steps: the ethylene carbonate is taken as a raw material, and catalytic dehydrogenation is directly carried out to generate vinylene carbonate. After the vinylene carbonate crude product is prepared, the vinylene carbonate product is obtained by separation means such as filtration, reduced pressure rectification and the like.
Currently, the method 2 is mostly used in industry for producing vinylene carbonate, and the reaction process is shown in fig. 2.
In the process of synthesizing chloroethylene carbonate, chloroethylene carbonate serving as a reaction product can further react with chlorine to generate dichloroethylene carbonate, the boiling point of the dichloroethylene carbonate is close to that of the chloroethylene carbonate, the dichloroethylene carbonate is difficult to separate, and acetylene carbonate can be generated in the subsequent synthesis of vinylene carbonate, so that the product purity is reduced, and the overall yield is reduced. Meanwhile, ethylene carbonate is chlorinated into a strong exothermic reaction, and the reaction rate is gradually accelerated along with the rise of the problem, so that in the traditional process for carrying out the reaction in a reaction kettle, if heat is not transferred in time, temperature runaway in the reaction kettle can be caused, and potential safety hazards are caused.
For example, the chinese patent web publication CN105859677A discloses a method for preparing monochloroethylene carbonate, which comprises: in the tower reactor, a packing layer is arranged every 1 m along the height direction of the tower, a bracket is arranged, the bottom of each bracket is provided with a first mercury immersion lamp, and a liquid uniform distributor and a second mercury immersion lamp are respectively arranged above each layer of packing; preheating ethylene carbonate to 60 ℃, adding an initiator and a catalyst, and heating to 60 ℃ to obtain ethylene carbonate liquid containing the initiator and the catalyst; introducing nitrogen from the tower bottom, replacing air in the tower, and emptying nitrogen tail gas; drying and dehydrating chlorine, heating to 65 ℃, introducing chlorine into the bottom and the middle of the tower respectively, adding ethylene carbonate liquid containing an initiator and a catalyst from the top of the tower, carrying out gas-liquid countercurrent contact reaction, collecting liquid monochloroethylene carbonate at the bottom of the tower, and treating tail gas at the top of the tower to obtain hydrochloric acid and chlorinated paraffin.
The chlorine gas in the tower reactor mentioned in the above patent enters the tower from the bottom of the tower, and the reaction product chloroethylene carbonate is also produced from the bottom of the rectifying tower, and from the view point of the concentration distribution of the materials in the tower reactor, the concentration gradient of the chloroethylene carbonate is gradually increased from the top to the bottom, and the concentration gradient of the chlorine gas is also gradually increased from the top to the bottom, so that the chloroethylene carbonate in the lower part of the reactor is further reacted with the chlorine gas to generate dichloroethylene carbonate and trichloroethylene carbonate, and the yield of the reaction is reduced.
For another example, chinese patent network publication No. CN109942536A discloses a method for preparing high-purity chloroethylene carbonate by reactive distillation, which adopts a reactive distillation apparatus, and the structure of the apparatus comprises: the output pipe at the top of the reaction rectifying kettle is connected with the input end of a condenser, the output end of the condenser is connected with a storage tank, a finished product tank and a tail gas absorption tank, a return pipe is arranged on the storage tank, and the return pipe is connected to the upper end part of the reaction rectifying kettle; sampling and detecting the bottom of the reaction rectifying still, rectifying the product when the mass fraction of the dichloroethylene carbonate obtained by detection is less than or equal to 1%, and refluxing the distillate at the top of the reaction rectifying still into the reaction rectifying still through a storage tank and a reflux pipe after the distillate enters a condenser to be cooled; and sampling and detecting the output end of the condenser, and collecting the liquid material separated by cooling in the condenser into a finished product tank when the mass fraction of the chloroethylene carbonate in the distillate is greater than or equal to 95%.
The synthesis process of the reaction rectification device adopted in the patent is divided into two steps, wherein the first step is synthesis of chloroethylene carbonate, and the second step is rectification of chloroethylene carbonate, so that although the selectivity of the reaction is effectively improved, the occurrence of side reactions is reduced, the reaction and the rectification are realized in one device, but the continuous production of chloroethylene carbonate is not realized.
Based on the above, the invention designs a vinylene carbonate synthesis method for an electrolyte, so as to solve the above-mentioned problems.
Disclosure of Invention
The invention aims to provide a method for synthesizing vinylene carbonate for electrolyte, which solves the problems in the background technology.
In order to achieve the purpose, the invention provides the following technical scheme: a vinylene carbonate synthesis method for electrolyte realizes vinylene carbonate synthesis and purification through a synthesis and purification device, and specifically comprises the following steps:
s1, pumping raw material ethylene carbonate and an initiator into a raw material preheater through a metering pump, controlling the outlet temperature of the raw material preheater to be 40-70 ℃, and feeding the raw material ethylene carbonate and the initiator from the middle upper part of a reaction rectifying tower, wherein the adding mass of the initiator is 0.1-1% of the mass of the ethylene carbonate;
s2, feeding chlorine into the reactive distillation tower from the bottom of the tower, wherein the molar weight of the introduced chlorine is 1-1.1 times of that of ethylene carbonate, controlling the temperature of a tower kettle of the reactive distillation tower to be 50-80 ℃ by adjusting the heat conduction oil flow of a reboiler, and controlling the vacuum degree of the reactive distillation tower to be 2-10 Kpa by a vacuum pump;
s3, the chlorine and the ethylene carbonate react in countercurrent contact on the surface of a filler in the reactive distillation tower, the reaction heat is used for heating a liquid phase, the reaction products of the chlorinated ethylene carbonate and the hydrogen chloride rise together with the chlorine, and after the chlorine and the hydrogen chloride are cooled by a condenser at the top of the reactive distillation tower, part of the chlorine and the ethylene carbonate partially flow back and enter a chlorinated ethylene carbonate buffer tank;
s4, allowing excess chlorine and product hydrogen chloride to enter a vacuum pump through a gas phase outlet of a condenser, allowing the excess chlorine and the product hydrogen chloride to enter an acid absorption tower through an outlet of the vacuum pump, absorbing the product hydrogen chloride through desalted water to prepare a 30% hydrochloric acid aqueous solution, allowing the residual trace hydrogen chloride and the excess chlorine to enter an alkali absorption tower, allowing the trace hydrogen chloride and the excess chlorine to be treated by a 48% sodium hydroxide aqueous solution in the alkali absorption tower to prepare a sodium hypochlorite aqueous solution, and introducing the residual unabsorbed gas into an active carbon absorption tower for absorption;
s5, adding the chloroethylene carbonate into a vinylene carbonate synthesis kettle, starting stirring, adding the solvent, triethylamine and the antioxidant, controlling the reaction temperature to be 60-80 ℃, and reacting for 8 hours.
Preferably, synthetic purification device includes raw material preheater and reaction rectifying column, raw material preheater is connected with the reaction rectifying column middle part, reaction rectifying column bottom is equipped with the reboiler, reaction rectifying column top exit linkage has the condenser, the liquid phase exit linkage of condenser has chlorinated ethylene carbonate buffer tank, chlorinated ethylene carbonate buffer tank exit linkage has vinylene carbonate synthesis cauldron, the gaseous phase exit linkage of condenser has the vacuum pump, the export of vacuum pump is connected with the entry of acid absorption tower, the export of acid absorption tower is connected with the entry of alkali absorption tower, the export of alkali absorption tower is connected with the entry of active carbon adsorption tower, the export evacuation of active carbon adsorption tower.
Preferably, the reactive distillation tower is provided with section fillers, each section of the fillers are filled with rice, the fillers are filled with silk screens, a distributor is arranged in the middle of each section of the fillers, an LED ultraviolet lamp is arranged on the distributor and used for irradiating the fillers, a tower kettle of the reactive distillation tower is provided with a reboiler, the tower top is provided with a condenser, and the power of the LED ultraviolet lamp is 50-500 KW.
Preferably, the initiator is one or more of peroxide, and the peroxide can be benzoyl peroxide, benzoyl tert-butyl peroxide, methyl ethyl ketone peroxide or azobisisobutyronitrile.
Preferably, the reflux ratio of S3 is 1 (1-3), the purity of chloroethylene carbonate is more than 99%, and the selectivity of chloroethylene carbonate is calculated to be more than 98%.
Preferably, the mass ratio of the chloroethylene carbonate, the solvent, the triethylamine and the antioxidant in the S5 is 1 (3-5): 0.5-1): 0.001-0.01.
Preferably, the antioxidant is one or more of 2, 6-tri-tert-butyl-4-methylphenol, bis (3, 5-tri-tert-butyl-4-hydroxyphenyl) thioether and tetra [ beta- (3, 5-tri-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester.
Preferably, the solvent is one or more of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl acetate, methyl tert-butyl ether, tetrahydrofuran, acetonitrile, chloroform and dichloromethane.
Compared with the prior art, the invention has the beneficial effects that:
the synthesis and rectification processes of the chloroethylene carbonate are integrated, the synthesis and the refining of the chloroethylene carbonate are simultaneously carried out through the reaction rectification tower, the reaction heat is released in the reaction process and is used for rectification, the equipment investment is reduced, the overall synthesis time is shortened, the process energy consumption is reduced, the continuous production of the chloroethylene carbonate is realized, the material back-mixing is effectively reduced through the design of the feeding position of the reaction rectification tower, the main reaction selectivity is obviously improved, and the occurrence of side reactions is reduced.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, the present invention provides a technical solution of a method for synthesizing vinylene carbonate for electrolyte, wherein vinylene carbonate is synthesized and purified by a synthesis and purification device, and the method specifically comprises the following steps:
s1, pumping raw material ethylene carbonate and an initiator into a raw material preheater 1 through a metering pump, controlling the outlet temperature of the raw material preheater to be 40-70 ℃, and feeding the raw material ethylene carbonate and the initiator from the middle upper part of a reaction rectifying tower 2, wherein the adding mass of the initiator is 0.1% -1% of the mass of the ethylene carbonate;
s2, feeding chlorine into the reactive distillation tower 2 from the bottom of the tower, wherein the molar weight of the introduced chlorine is 1-1.1 times of that of ethylene carbonate, controlling the temperature of a tower kettle of the reactive distillation tower 2 at 50-80 ℃ by adjusting the heat-conducting oil flow of the reboiler 3, and controlling the vacuum degree of the reactive distillation tower 2 at 2-10 Kpa by a vacuum pump 5;
s3, the chlorine and the ethylene carbonate react in countercurrent contact on the surface of the packing in the reactive distillation tower 2, the reaction heat is used for heating the liquid phase, so that the reaction products of chlorinated ethylene carbonate and hydrogen chloride rise together with the chlorine, and after being cooled by a condenser 4 at the top of the reactive distillation tower 2, part of the chlorine and the hydrogen chloride flow back to enter a chlorinated ethylene carbonate buffer tank 9;
s4, allowing excess chlorine and product hydrogen chloride to enter a vacuum pump 5 through a gas phase outlet of a condenser 4, allowing the excess chlorine and the product hydrogen chloride to enter an acid absorption tower 6 through an outlet of the vacuum pump 5, absorbing the product hydrogen chloride through desalted water to prepare a 30% hydrochloric acid aqueous solution, allowing the rest trace hydrogen chloride and the excess chlorine to enter an alkali absorption tower 7, allowing the trace hydrogen chloride and the excess chlorine to be prepared into a sodium hypochlorite aqueous solution through a 48% sodium hydroxide aqueous solution in the alkali absorption tower 7, and introducing the rest unabsorbed gas into an active carbon adsorption tower 8 for adsorption;
s5, adding the chloroethylene carbonate into a vinylene carbonate synthesis kettle 10, starting stirring, simultaneously adding a solvent, triethylamine and an antioxidant, controlling the reaction temperature to be 60-80 ℃, reacting for 8 hours to obtain a vinylene carbonate crude product, and purifying and separating to obtain a vinylene carbonate product.
Example 1:
a technical scheme of a vinylene carbonate synthesis method for electrolyte is provided, which realizes vinylene carbonate synthesis and purification through a synthesis and purification device, and specifically comprises the following steps:
s1, pumping raw material ethylene carbonate and an initiator into a raw material preheater 1 through a metering pump, controlling the outlet temperature of the raw material preheater to be 40 ℃, and feeding the raw material ethylene carbonate and the initiator from the middle upper part of a reaction rectifying tower 2, wherein the adding mass of the initiator is 0.1 percent of the mass of the ethylene carbonate;
s2, chlorine enters the reaction rectifying tower 2 from the bottom of the tower, the introduced chlorine has the molar weight 1 time that of the ethylene carbonate, the temperature of the tower kettle of the reaction rectifying tower 2 is controlled at 50 ℃ by adjusting the heat conducting oil flow of the reboiler 3, and the vacuum degree of the reaction rectifying tower 2 is controlled at 2Kpa by the vacuum pump 5;
s3, the chlorine and the ethylene carbonate react in countercurrent contact on the surface of the packing in the reactive distillation tower 2, the reaction heat is used for heating the liquid phase, so that the reaction products of chlorinated ethylene carbonate and hydrogen chloride rise together with the chlorine, and after being cooled by a condenser 4 at the top of the reactive distillation tower 2, part of the chlorine and the hydrogen chloride flow back to enter a chlorinated ethylene carbonate buffer tank 9;
s4, allowing excess chlorine and product hydrogen chloride to enter a vacuum pump 5 through a gas phase outlet of a condenser 4, allowing the excess chlorine and the product hydrogen chloride to enter an acid absorption tower 6 through an outlet of the vacuum pump 5, absorbing the product hydrogen chloride through desalted water to prepare a 30% hydrochloric acid aqueous solution, allowing the rest trace hydrogen chloride and the excess chlorine to enter an alkali absorption tower 7, allowing the trace hydrogen chloride and the excess chlorine to be prepared into a sodium hypochlorite aqueous solution through a 48% sodium hydroxide aqueous solution in the alkali absorption tower 7, and introducing the rest unabsorbed gas into an active carbon adsorption tower 8 for adsorption;
s5, adding the chloroethylene carbonate into a vinylene carbonate synthesis kettle 10, starting stirring, simultaneously adding a solvent, triethylamine and an antioxidant, controlling the reaction temperature at 60 ℃, reacting for 8 hours to obtain a vinylene carbonate crude product, and purifying and separating to obtain a vinylene carbonate product.
Example 2:
a technical scheme of a vinylene carbonate synthesis method for electrolyte is provided, which realizes vinylene carbonate synthesis and purification through a synthesis and purification device, and specifically comprises the following steps:
s1, pumping raw material ethylene carbonate and an initiator into a raw material preheater 1 through a metering pump, controlling the outlet temperature of the raw material preheater to be 70 ℃, and feeding the raw material ethylene carbonate and the initiator from the middle upper part of a reaction rectifying tower 2, wherein the adding mass of the initiator is 1% of the mass of the ethylene carbonate;
s2, feeding chlorine into the reactive distillation tower 2 from the bottom of the tower, wherein the molar weight of the introduced chlorine is 1.1 times of that of the ethylene carbonate, controlling the temperature of a tower kettle of the reactive distillation tower 2 at 80 ℃ by adjusting the heat conduction oil flow of the reboiler 3, and controlling the vacuum degree of the reactive distillation tower 2 at 10Kpa by a vacuum pump 5;
s3, carrying out countercurrent contact on chlorine and ethylene carbonate on the surface of a filler in a reaction rectifying tower 2 for reaction, wherein the reaction heat is used for heating a liquid phase, so that the reaction products of chloroethylene carbonate and hydrogen chloride rise together with the chlorine, and after cooling through a condenser 4 at the top of the reaction rectifying tower 2, part of the chlorine is refluxed and enters a chloroethylene carbonate buffer tank 9, wherein the reflux ratio is 1 (1-3), the purity of the chloroethylene carbonate is more than 99%, and the selectivity of the chloroethylene carbonate is calculated to be more than 98%;
s4, allowing excess chlorine and product hydrogen chloride to enter a vacuum pump 5 through a gas phase outlet of a condenser 4, allowing the excess chlorine and the product hydrogen chloride to enter an acid absorption tower 6 through an outlet of the vacuum pump 5, absorbing the product hydrogen chloride through desalted water to prepare a 30% hydrochloric acid aqueous solution, allowing the rest trace hydrogen chloride and the excess chlorine to enter an alkali absorption tower 7, allowing the trace hydrogen chloride and the excess chlorine to be prepared into a sodium hypochlorite aqueous solution through a 48% sodium hydroxide aqueous solution in the alkali absorption tower 7, and introducing the rest unabsorbed gas into an active carbon adsorption tower 8 for adsorption;
s5, adding the chloroethylene carbonate into a vinylene carbonate synthesis kettle 10, starting stirring, simultaneously adding a solvent, triethylamine and an antioxidant, controlling the reaction temperature at 80 ℃, reacting for 8 hours to obtain a vinylene carbonate crude product, and purifying and separating to obtain a vinylene carbonate product.
Example 3:
a technical scheme of a vinylene carbonate synthesis method for electrolyte is provided, which realizes vinylene carbonate synthesis and purification through a synthesis and purification device, and specifically comprises the following steps:
s1, pumping raw material ethylene carbonate and an initiator into a raw material preheater 1 through a metering pump, controlling the outlet temperature of the raw material preheater to be 50 ℃, and feeding the raw material ethylene carbonate and the initiator from the middle upper part of a reaction rectifying tower 2, wherein the adding mass of the initiator is 0.1-1% of the mass of the ethylene carbonate;
s2, feeding chlorine into the reactive distillation tower 2 from the bottom of the tower, wherein the molar weight of the introduced chlorine is 1.05 times of that of the ethylene carbonate, controlling the temperature of a tower kettle of the reactive distillation tower 2 at 70 ℃ by adjusting the heat-conducting oil flow of the reboiler 3, and controlling the vacuum degree of the reactive distillation tower 2 at 6Kpa by a vacuum pump 5;
s3, the chlorine and the ethylene carbonate react in countercurrent contact on the surface of the packing in the reactive distillation tower 2, the reaction heat is used for heating the liquid phase, so that the reaction products of chlorinated ethylene carbonate and hydrogen chloride rise together with the chlorine, and after being cooled by a condenser 4 at the top of the reactive distillation tower 2, part of the chlorine and the hydrogen chloride flow back to enter a chlorinated ethylene carbonate buffer tank 9;
s4, allowing excess chlorine and product hydrogen chloride to enter a vacuum pump 5 through a gas phase outlet of a condenser 4, allowing the excess chlorine and the product hydrogen chloride to enter an acid absorption tower 6 through an outlet of the vacuum pump 5, absorbing the product hydrogen chloride through desalted water to prepare a 30% hydrochloric acid aqueous solution, allowing the rest trace hydrogen chloride and the excess chlorine to enter an alkali absorption tower 7, allowing the trace hydrogen chloride and the excess chlorine to be prepared into a sodium hypochlorite aqueous solution through a 48% sodium hydroxide aqueous solution in the alkali absorption tower 7, and introducing the rest unabsorbed gas into an active carbon adsorption tower 8 for adsorption;
s5, adding chloroethylene carbonate into a vinylene carbonate synthesis kettle 10, starting stirring, adding a solvent, triethylamine and an antioxidant, controlling the reaction temperature at 70 ℃, reacting for 8 hours to obtain a vinylene carbonate crude product, and purifying and separating to obtain a vinylene carbonate product, wherein the mass ratio of chloroethylene carbonate to the solvent to the triethylamine to the antioxidant is (3-5) to (0.5-1) to (0.001-0.01).
Wherein, synthetic purification device includes raw material pre-heater 1 and reaction rectifying tower 2, raw material pre-heater 1 is connected with 2 middle parts of reaction rectifying tower, 2 bottoms of reaction rectifying tower are equipped with reboiler 3, 2 top exit linkage in reaction rectifying tower have condenser 4, the liquid phase exit linkage of condenser 4 has chlorinated ethylene carbonate buffer tank 9, 9 exit linkage in chlorinated ethylene carbonate buffer tank have vinylene carbonate synthetic kettle 10, the gaseous phase exit linkage of condenser 4 has vacuum pump 5, the export of vacuum pump 5 is connected with the entry of acid absorption tower 6, the export of acid absorption tower 6 is connected with the entry of alkali absorption tower 7, the export of alkali absorption tower 7 is connected with the entry of active carbon adsorption tower 8, the export evacuation of active carbon adsorption tower 8.
The reaction rectifying tower 2 is provided with 10 sections of fillers, each section of fillers is 2 meters, the fillers are filled by a silk screen, a distributor is arranged in the middle of each section of fillers, an LED ultraviolet lamp is arranged on the distributor and used for irradiating the fillers, a tower kettle of the rectifying tower is provided with a reboiler 3, a condenser 4 is arranged at the top of the tower, and the power of the LED ultraviolet lamp is 50-500 KW.
The initiator is one or more of peroxide, and the peroxide can be benzoyl peroxide, benzoyl peroxide tert-butyl ester, methyl ethyl ketone peroxide and azobisisobutyronitrile.
The reflux ratio of S3 is 1 (1-3), the purity of chloroethylene carbonate is more than 99%, and the selectivity of chloroethylene carbonate is calculated to be more than 98%.
Wherein the mass ratio of the chloroethylene carbonate, the solvent, the triethylamine and the antioxidant in the S5 is 1 (3-5) to (0.5-1) to (0.001-0.01).
Wherein the antioxidant is one or a mixture of more of 2, 6-tri-tert-butyl-4-methylphenol, bis (3, 5-tri-tert-butyl-4-hydroxyphenyl) thioether and tetra [ beta- (3, 5-tri-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester.
Wherein the solvent is one or more of dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, ethyl acetate, methyl tert-butyl ether, tetrahydrofuran, acetonitrile, chloroform and dichloromethane.
The specific embodiment is as follows:
the ethylene carbonate (500 KG/h) and the initiator azobisisobutyronitrile (5 KG/h) are pumped into the raw material preheater 1 through a metering pump, the outlet temperature of the raw material preheater 1 is controlled to be 60 ℃, the preheated material enters from the middle part of the reaction rectifying tower 2, and liquid chlorine is gasified by a chlorine gas generator and then is delivered in 138 m3The flow rate of chlorine gas continuously rises from the bottom of the reaction rectifying tower 2, the ethylene carbonate and the initiator which descend are reacted under the illumination condition of an LED ultraviolet lamp, the product chloroethylene carbonate rises along with the chlorine gas after being heated and gasified, the chlorine gas enters a condenser 4 from the top of the reaction rectifying tower 2, the condensed material is partially refluxed into the reaction rectifying tower 2 to continue reacting, and is partially extracted to a chloroethylene carbonate buffer tank 9, the chloroethylene carbonate buffers the ethylene carbonate, wherein the reflux ratio of the material is 1:1Regular sampling analysis is carried out in the flushing tank 9, the average content of the chlorinated ethylene carbonate is 99.4%, a gas phase outlet at the top of the condenser 4 sequentially enters the acid absorption tower 6, the alkali absorption tower 7 and the activated carbon adsorption tower 8, and the tail gas recovery efficiency is 100%. After the liquid level of the chlorinated ethylene carbonate buffer tank 9 reaches 80%, the chlorinated ethylene carbonate buffer tank is thrown into a vinylene carbonate synthesis kettle 10 at one time, and the metered addition amount is as follows: 3500 kg. Adding dimethyl carbonate (12250 kg) and 2, 6-tri-tert-butyl-4-methylphenol (12 kg) as solvents into a head tank, starting a vinylene carbonate synthesis kettle 10 to stir (300 r/min) and heat after the addition is finished, controlling the temperature in the kettle to be 75 ℃, dropwise adding triethylamine (580 kg/h) into the vinylene carbonate synthesis kettle 10 through the head tank after the temperature in the kettle reaches a preset temperature, stopping dropwise adding for 3h, continuing to react for 5 h, then sampling and analyzing, stopping reaction after the purity of chloroethylene carbonate in the kettle is less than 0.5%, and refining materials in the kettle in a rectification system.
In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.