Continuous production process and device of vinylene carbonate

Abstract

The invention relates to a continuous production process and device of vinylene carbonate, chloroethylene carbonate, tertiary amine and a solvent are continuously fed in a reactor for dechlorination reaction, and temperature is controlled by a tubular heat exchanger; the reaction liquid continuously overflows from a side overflow port to enter a middle receiving tank, a vinylene carbonate crude product is obtained after desolvation, the vinylene carbonate crude product enters a melt crystallizer for melt crystallization after being purified by a low-component removal tower, a high-component removal tower and a rectifying tower, and a vinylene carbonate product with the purity of 99.99% or above is obtained; a reaction by-product tertiary amine hydrochloride settles to the lower part of the reactor, is discharged from the bottom of the reactor after being subjected to countercurrent washing by inputting a solvent through a salt leaching cavity, enters a neutralization kettle, is neutralized by liquid caustic soda and then is subjected to liquid separation, an organic phase enters a recovery system to be dehydrated, and then sequentially passes through a solvent recovery tower to recover the solvent and a tertiary amine recovery tower to recover tertiary amine; and the solvent and the tertiary amine can be recycled. The continuous production of the vinylene carbonate is realized, the consumption of raw materials is reduced, and the yield and the production efficiency are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium ion battery additives, and in particular relates to a continuous production process and device for vinylene carbonate. Background Art

[0002] Vinylene carbonate, with its high dielectric constant and low viscosity, is currently the most commonly used electrolyte additive. It can significantly improve the electrochemical performance of electrolytes, increasing coulombic efficiency and charge capacity retention. With the rapid development of new energy vehicles and energy storage in recent years, the importance of vinylene carbonate has become increasingly prominent.

[0003] Currently, the main principles of the industrial production methods of vinylene carbonate are similar. They all use vinylene carbonate as a raw material, react with chlorine under ultraviolet light to synthesize vinyl chloride carbonate; then, in an organic solvent, the vinyl chloride carbonate reacts with a tertiary amine to remove hydrogen chloride to produce crude vinylene carbonate; the obtained crude vinylene carbonate is then purified by distillation and crystallization to finally produce vinylene carbonate with higher purity.

[0004] Research has found that the reaction of tertiary amines with chloroethylene carbonate is a typical dehydrohalogenation reaction, but during the reaction process, the tertiary amine will cause the generated vinylene carbonate to further generate polymers, resulting in the loss of vinylene carbonate and a reduction in yield. In the prior art, the synthesis process of vinylene carbonate is mainly a kettle-type dropwise addition reaction, which is an intermittent operation. That is, a quantitative tertiary amine is added dropwise to a substrate previously composed of chloroethylene carbonate, a solvent, and a polymerization inhibitor, and the reaction is filtered after a period of time. The filtrate is subjected to precipitation and purification to obtain vinylene carbonate. Since the dechlorination reaction is a highly exothermic reaction, a violent and highly exothermic reaction will occur after the tertiary amine is added dropwise and accumulated to a certain amount, resulting in a "flyaway" phenomenon, which is prone to solvent boiling out of control and poses a great safety hazard. Therefore, it is difficult to increase the volume of the reactor. In addition, during the intermittent reaction process, the tertiary amine added dropwise in the early stage cannot be consumed in time, resulting in a large excess of tertiary amine in the reaction system relative to the product vinylene carbonate, which leads to instability of the vinylene carbonate, an increased probability of side reactions, and an increase in polymers, thereby resulting in a decrease in yield. The polymers produced by side reactions are viscous, tarry, or pitch-like, which further contaminate the reaction system, making filtration and post-processing of the reaction liquid difficult. This results in a reaction yield of only around 60%, low production efficiency, a high concentration of waste products, and high energy consumption. Particularly in the later stages of the crude distillation process, a large amount of asphalt-like polymer, with high viscosity, forms at the bottom of the crude distillation equipment. This not only affects the purity of the vinylene carbonate but also severely impairs the heat transfer efficiency of the distillation equipment's inner walls, making them difficult to clean. This ultimately reduces the overall heat transfer efficiency of the distillation process.

[0005] In addition, the existing industrial production processes for vinylene carbonate are all intermittent production processes, which have a large amount of heat accumulated in the reaction and low production efficiency. At the same time, due to the long reaction time and the large amount of polymer generated, the yield of vinylene carbonate is low, which is difficult to meet the requirements of large-scale industrial production. Summary of the Invention

[0006] One of the problems to be solved by the present invention is that the traditional synthesis process of vinylene carbonate is mainly a kettle-type dropwise reaction, intermittent operation, low production efficiency, a lot of three wastes, high energy consumption and other problems;

[0007] The second problem to be solved by the present invention is that as the reaction proceeds, the generated polymer accumulates and wraps around the tertiary amine hydrochloride generated by the reaction, and adheres to the wall of the reactor. After the reaction is completed, the reactor is difficult to clean, and the cleaning solution will also cause an increase in the three wastes.

[0008] The third problem to be solved by the present invention is that the polymerization of vinylene carbonate itself and the reaction with excess tertiary amine result in a reduced yield of vinylene carbonate and a purity that does not meet the requirements.

[0009] The object of the present invention is to overcome the defects in the prior art and provide a continuous production process and apparatus for vinylene carbonate, which can improve production efficiency, reduce the generation of three wastes, reduce energy consumption and costs, reduce material polymerization, and improve the yield of vinylene carbonate products.

[0010] In order to solve one of the above problems, the technical solution adopted by the present invention is: designing the intermittent synthesis process into a continuous process, eliminating the accumulation of reaction heat, reducing the number of equipment and the number of workers, thereby improving production efficiency, reducing the amount of three wastes generated, reducing energy consumption and costs, and improving the inherent safety of the process.

[0011] In order to solve the second problem mentioned above, the technical solution adopted by the present invention is: in the production process, the solvent and tertiary amine hydrochloride are separated in time. The relative density of tertiary amine hydrochloride is greater than that of the liquid, and it will be precipitated and separated from the reaction system, thereby reducing the occurrence of side reactions and improving the product yield.

[0012] In order to solve the third problem mentioned above, the technical solution adopted by the present invention is to continuously input solvent from the bottom of the reactor, countercurrently wash the sinking tertiary amine hydrochloride, bring the vinylene carbonate product entrained by the tertiary amine hydrochloride slurry into the reaction liquid, and wash off the polymer entrained by the tertiary amine hydrochloride to avoid the accumulation of polymer on the surface of the tertiary amine hydrochloride to cause viscosity, thereby improving the yield of vinylene carbonate; at the same time, adding a high-efficiency polymerization inhibitor to the reaction system can prevent the polymerization of vinylene carbonate itself and the reaction with the tertiary amine, thereby further improving the yield.

[0013] A continuous production process for vinylene carbonate comprises the following steps:

[0014] S1: Use a delivery pump to continuously preheat the solvent through the preheater and then feed it into the reactor. When the solvent feed amount reaches a certain mass, start warm water to preheat the shell side of the reactor tube heat exchanger;

[0015] Chloroethylene carbonate, polymerization inhibitor and tertiary amine are continuously added to the reactor in proportion through the reaction material inlet in the reactor, and a dechlorination reaction occurs in the reactor; the products of this reaction are vinylene carbonate and tertiary amine hydrochloride. Vinylene carbonate dissolves in the solvent and continues to rise with the solvent; tertiary amine hydrochloride has low solubility in the solvent and a relative density greater than that of the solvent, precipitates to form particles and gradually sinks. The reaction is exothermic and is discharged into the outer cavity of the reaction chamber through the lower outlet of the central tube, and heat is transferred through the mass transfer process; the solvent in the outer cavity of the reaction chamber absorbs the reaction heat and evaporates, and evaporates from the gas phase port at the top of the reactor; the reaction speed is controlled by evaporation of the solvent, adjusting the flow rate of hot water and cooling water in the shell and tube heat exchanger, and by adjusting the reaction material feed rate and the solvent entry rate, the residence time of the reaction material in the reaction chamber is controlled, so that the reaction is complete when the reaction material rises from the bottom of the reactor to the top. The product dissolves in the solvent, continues to rise, overflows from the side overflow port and flows into the intermediate receiving tank, and then undergoes distillation treatment;

[0016] S2: The tertiary amine hydrochloride by-product produced by the reaction is a solid with a relative density greater than that of the solvent. It is continuously produced during the reaction and continues to settle to the bottom of the reaction device; the washing solvent is continuously pumped into the lower part of the salt washing chamber, and the sinking tertiary amine hydrochloride forms a countercurrent with the rising washing solvent. The products and polymers entrained by the tertiary amine hydrochloride are washed away by the solvent. The slurry formed by the cleaned tertiary amine hydrochloride and the washing solvent is continuously discharged from the system through the bottom valve opened at the bottom and enters the neutralization kettle;

[0017] S3: The reaction liquid flows from the side overflow into an intermediate receiving tank. Then, it is pumped through a desolventizing tower, a low-boiling point desulfurization tower, and a high-boiling point desulfurization tower for distillation. After the solvent evaporates and condenses, it enters a solvent recovery tank and returns to S1 or S2 for recycling. The crude vinylene carbonate, free of solvent, low-boiling substances, and high-boiling substances, enters the next distillation step.

[0018] S4: Purifying the crude vinylene carbonate by distillation in a primary distillation tower and a secondary distillation tower to obtain refined vinylene carbonate;

[0019] S5: The finished vinylene carbonate product passes through a primary melting crystallizer and a secondary melting crystallizer to finally obtain a finished vinylene carbonate product with a purity of more than 99.99%, which enters a finished vinylene carbonate product receiving tank;

[0020] S6: The tertiary amine hydrochloride slurry discharged into the neutralization kettle is neutralized and separated by adding liquid caustic soda. The upper organic phase enters the dehydration tower of the recovery system for dehydration, and then enters the solvent recovery tower for distillation to recover the solvent and the tertiary amine recovery tower for distillation to recover the tertiary amine. The recovered solvent and tertiary amine enter the solvent tank and tertiary amine tank respectively, and are returned to S1 for recycling. The recovered solvent can also be returned to step S2 for washing the tertiary amine hydrochloride;

[0021] S7: The water phase discharged from S6 is transferred to the brine evaporation system, waste salt incineration system and sewage treatment system to treat the waste salt and wastewater.

[0022] Preferably, the solvent is a hydrocarbon, ether, ester, or nitrile compound, more typically selected from one or more mixtures of n-hexane, cyclohexane, n-heptane, petroleum ether, dichloromethane, dichloroethane, methyl propyl ether, ethyl propyl ether, methyl tert-butyl ether, n-propyl ether, isopropyl ether, ethyl formate, n-propyl formate, isopropyl formate, n-butyl formate, isobutyl formate, tert-butyl formate, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and acetonitrile.

[0023] Preferably, the tertiary amine is selected from N,N-dimethylethylamine, N,N-dimethyl-n-propylamine, N,N-dimethylisopropylamine, N,N-dimethylbutylamine, N,N-dimethylhexylamine, N,N-dimethylcyclohexylamine, N,N-dimethylaniline, diethylmethylamine, di-n-propylmethylamine, diisopropylmethylamine, triethylamine, triisopropylamine, tributylamine, pyridine, N-methylpyrrole, N-methylpyrrolidine, N-methylmorpholine, N-methyl One or more combinations of piperidine, imidazole, N-methylimidazole, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylbutanediamine, N,N,N',N'-tetramethylhexanediamine, N,N'-dimethylpiperazine, pentamethyldiethylenetriamine, triethylenediamine, 1,5-diazabis[4.3.0]non-5-ene, and 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0024] Preferably, the solvent contains 0.01 to 0.5% of a polymerization inhibitor, which is a combination of one or more of phenols, quinones, phenothiazines, phosphites, piperidinols, and piperidine nitrogen oxides. Typical polymerization inhibitors are hydroquinone, p-methoxyphenol, p-tert-butylcatechol, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butylhydroquinone, phenothiazine, 2,2,6,6-tetramethyl-4-hydroxy-piperidine nitrogen oxide, tris(2,2,6,6-tetramethyl-4-oxy-piperidine nitrogen oxide) phosphite, and bis(2,2,6,6-tetramethyl-4-oxy-piperidine nitrogen oxide) sebacate.

[0025] Preferably, the mass ratio of the solvent, chloroethylene carbonate, and tertiary amine is 2.0-10.0:1.0:0.8-1.5; the purity of chloroethylene carbonate is ≥70%; and the density of the solvent or mixed solvent at 25° C. is less than 1.0.

[0026] Preferably, in step S1, during the process of the delivery pump inputting materials, warm water is used to preheat the shell and tube temperature of the reaction tube to 55-105° C., so that the reaction is initiated by the heat.

[0027] Preferably, a temperature control device is provided on the pipes connecting the solvent preheater, the ethylene chloride preheater, the tertiary amine preheater and the pipeline mixer; thermometers are provided at the upper, middle and lower parts of the central tube to control the reaction temperature to be 50-100°C, and the residence time of the ethylene chloride and tertiary amine in the reaction chamber for the dechlorination reaction is 1-12 hours, and the residence time in the salt washing chamber is 0.5-5 hours.

[0028] A continuous production device for vinylene carbonate comprises: a solvent delivery pump, a chloroethylene carbonate delivery pump, a tertiary amine delivery pump, a washing solvent delivery pump, a solvent preheater, a chloroethylene carbonate preheater, a tertiary amine preheater, a pipeline mixer, a reactor, a condenser, a solvent receiving tank, an intermediate receiving tank, a desolventizing tower, a low-cost desolventizing tower, a high-cost desolventizing tower, a primary distillation tower and a secondary distillation tower, a primary melting crystallizer, a secondary melting crystallizer, a vinylene carbonate finished product receiving tank, a neutralization kettle, a liquid separator, a dehydration tower, a solvent recovery tower, a tertiary amine recovery tower, a solvent tank, and a tertiary amine tank.

[0029] Preferably, the reactor of the production device is composed of an upper reaction chamber, a middle shell and tube heat exchanger, and a lower salt washing chamber.

[0030] Preferably, there is a central tube in the reaction chamber with a lower opening extending to the upper part of the shell and tube heat exchanger, which divides the reaction chamber into an inner cavity and an outer cavity. The inner cavity is inside the central tube, and the annular space between the central tube and the outer cylinder wall of the reaction chamber is the outer cavity. The diameter of the central tube is 300-2000 mm, the diameter of the outer cylinder wall of the reaction chamber is 500-4000 mm, and the height of the reaction chamber cylinder is 1000-10000 mm. The central opening of the reaction chamber top cover is used to insert the central tube, which is installed and fixed perpendicular to the cross-section of the reaction chamber. The upper end of the central tube is connected to the pipeline from the pipeline mixer, and the elliptical head corresponding to the outer cavity of the reaction chamber is provided with a gas phase port, which is connected to the condenser. A side overflow port is provided on the upper part of the outer cylinder wall of the reaction chamber, and the side overflow port is not lower than the bottom of the central tube.

[0031] Preferably, the reactor is provided with a shell and tube heat exchanger at the lower part of the reaction chamber, and the shell and tube heat exchanger is connected to the reaction chamber by welding or flange. The diameter of the tubes of the shell and tube heat exchanger is 25 to 100 mm, the height of the tubes is 300 to 2000 mm, and the heat exchange area of the shell and tube heat exchanger is 50 to 500 m2. At least one heat exchange medium inlet and heat exchange medium outlet are respectively provided at the upper and lower parts of the shell side of the shell and tube heat exchanger. The heat exchange medium includes but is not limited to steam, thermal oil, chilled water, and circulating water.

[0032] Preferably, the salt washing chamber includes at least two straight cylindrical salt washing sections with gradually decreasing diameters. The lower end of the shell and tube heat exchanger and the barrel of each salt washing section are connected by welding or flange through a diameter change, and the aspect ratio of the barrel of the salt washing section is 1 to 5:1.

[0033] Preferably, a washing solvent inlet is provided in the middle and lower part of the deposition section, and the solvent feed flow rate can be adjusted in real time according to the feed flow rate of the reaction material; an automatic switching valve is installed at the bottom of the salt washing chamber, which controls the tertiary amine hydrochloride slurry to be intermittently discharged to the tertiary amine hydrochloride neutralization kettle at a certain flow rate and frequency by adjusting the opening and closing time and frequency.

[0034] Preferably, the tertiary amine hydrochloride slurry is discharged into the neutralization kettle through the automatic switch valve at the bottom of the reaction device and then directly enters the alkaline water. The mixed organic phase of the tertiary amine and the solvent is separated from the brine phase to achieve tertiary amine recovery. The tertiary amine recovered after distillation and dehydration can be recycled.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. Continuous process, the conversion rate of vinyl chloride carbonate is ≥98%, and the total yield of vinylene carbonate relative to vinyl chloride carbonate is ≥70%, which greatly improves production efficiency and target product yield, reduces the generation of three wastes, and reduces energy consumption and labor costs.

[0037] 2. The boiling point of the solvent is lower than that of the tertiary amine, the relative density is less than 1.0, and the solubility of the tertiary amine hydrochloride is low, which is conducive to separation.

[0038] 3. Add special high-efficiency polymerization inhibitor to prevent material polymerization and improve product yield.

[0039] 4. The tertiary amine hydrochloride produced by the reaction has a high density and settles at the bottom of the reactor. It is separated while reacting, maintaining a homogeneous reaction, reducing side reactions, and improving product purity and yield.

[0040] 5. The tertiary amine hydrochloride is taken out of the system through the washing solvent at the bottom of the reactor. After separation, the tertiary amine hydrochloride directly enters the neutralization kettle and reacts with liquid alkali to replace the tertiary amine, thus realizing tertiary amine recovery with a short process and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a process flow chart for the continuous production of vinylene carbonate according to the present invention;

[0042] Figure 2 It is a schematic diagram of the continuous production device of vinylene carbonate of the present invention.

[0043] Explanation of the reference numerals: A1, solvent preheater; A2, ethylene chlorocarbonate preheater; A3, tertiary amine preheater; W1, solvent delivery pump; W2, ethylene chlorocarbonate delivery pump; W3, tertiary amine delivery pump; W4, washing solvent delivery pump; B, pipeline mixer; C, reactor; C1, reaction chamber; C2, shell and tube heat exchanger; C3, salt washing chamber; C3-1, salt washing section; C3-2, salt washing section; D1, condenser; D2, condenser; E, solvent receiving tank; F, intermediate receiving tank; G, desolventizing tower; H, low-solvent desolventizing tower; J, high-solvent desolventizing tower; K1, primary distillation tower; K2, secondary distillation tower; M1, primary melt crystallizer; M2, secondary melt crystallizer; N, neutralization kettle; V, vinylene carbonate finished product receiving tank; N1, liquid caustic soda tank; P, separator tank; Q, dehydration tower; R, solvent recovery tower; R1, solvent tank; T, tertiary amine recovery tower; T1, tertiary amine tank; 11, side overflow port; 12, center pipe; 13, elliptical head; 14, feed port; 15, gas phase port; 16, washing solvent inlet; 17, automatic switch valve; 18, heat exchange medium inlet; 19, heat exchange medium outlet. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0045] A continuous production process and device for vinylene carbonate comprises the following steps: continuously pumping a solvent into a reaction device, and then continuously pumping in a proportion of reactants, vinylene carbonate, a polymerization inhibitor, and a tertiary amine, so that the reactants rise with the solvent in a reaction tube to undergo a dechlorination reaction; controlling the temperature and reaction speed by introducing warm water outside the reaction tube to ensure complete reaction; furthermore, circulating the solvent and continuously separating the tertiary amine hydrochloride by-product from the bottom of the reaction device, and circulating the tertiary amine, thereby maximizing the circulation effect, ensuring the implementation of the continuous process, and reducing material loss; and finally, obtaining the finished vinylene carbonate product through purification.

[0046] Example

[0047] This embodiment is used to illustrate a continuous production process flow chart of vinylene carbonate according to the present invention. Figure 1 shown.

[0048] This embodiment is used to illustrate a continuous production device for vinylene carbonate according to the present invention. Figure 2 The production device of this embodiment has the following dimensions: the diameter of the reaction chamber C1 is 1600 mm, the height of the cylinder is 2400 mm, the diameter of the central tube 12 inside the reaction chamber C1 is 500 mm, and the distance between the lower end of the central tube 12 and the upper surface of the shell-and-tube heat exchanger C2 is 800 mm; the height of the shell-and-tube heat exchanger C2 is 800 mm, and the inner diameter of the shell-and-tube heat exchanger is 50 mm; the diameter of the salt washing section C3-1 is 1000 mm, and the height of the cylinder is 1200 mm; the diameter of the salt washing section C3-2 is 600 mm, and the height of the cylinder is 800 mm.

[0049] The process flow for the continuous production of vinylene carbonate according to the present invention is described as follows:

[0050] S1: Isopropyl ether and methyl acetate were mixed in a volume ratio of 2:1, and a mixed organic solvent containing 0.3% 2,5-di-tert-butylhydroquinone and 0.1% p-methoxyphenol polymerization inhibitor was dissolved therein. The mixed organic solvent was heated to 60°C in preheater A1 through solvent delivery pump W1 and then fed into reactor C. A total of 6m 3 ;

[0051] Pass 70°C warm water into the shell side of the shell and tube heat exchanger C2 of reactor C to maintain the temperature of the organic solvent in reactor C at 60-65°C;

[0052] A mixed organic solvent containing 0.3% 2,5-di-tert-butylhydroquinone and 0.1% p-methoxyphenol as a polymerization inhibitor, ethylene chloride, and triethylamine delivery pumps W1, W2, and W3 are simultaneously started and preheated to 60°C via solvent, ethylene chloride, and triethylamine preheaters A1, A2, and A3, respectively, at flow rates of 440 kg / h, 180 kg / h, and 160 kg / h. The mixture is then combined and fed through feed port 14 of reactor C through pipeline mixer B into central tube 12 within reactor C. Triethylamine hydrochloride generated by the dechlorination reaction precipitates from the reactants, forming particles that gradually sink. Simultaneously, the reaction liquid flows from overflow port 11 at the upper side of reaction chamber C1 into intermediate receiving tank F. The reaction heat is taken away by the evaporation of the solvent, cooled by condensers D1 and D2, received by the solvent receiving tank E, and reused in S1. At the same time, the solvent evaporation rate is controlled by adjusting the flow of hot water or cooling water in the shell side of the shell and tube heat exchanger C2 to maintain the temperature of the reaction materials in the reaction chamber C1 at 60-70°C.

[0053] S2: While starting the mixed solvent, ethylene chloride, and triethylamine delivery pumps, start the washing solvent isopropyl ether delivery pump W4 and feed isopropyl ether from the washing solvent inlet 16 into the salt washing chamber C3 at a flow rate of 500 kg / h. Half an hour after the washing solvent isopropyl ether is fed, the automatic on-off valve 17 at the bottom of the salt washing chamber C3-2 is opened to discharge the material. By controlling the opening and closing time of the valve, the slurry of triethylamine hydrochloride is discharged into the neutralization reactor N at a discharge rate of 400-500 kg / h. The solid content of the slurry is controlled at 40-50%. The slurry is sampled and filtered to remove solids. Gas chromatography analysis shows that the vinylene carbonate content in the clear slurry is only 0.23%;

[0054] S3: The reaction liquid overflowing from the side overflow port 11 of reactor C is sampled and analyzed by gas chromatography. The vinyl chloride content is 0.37%. The content is controlled to be less than 0.5% and enters intermediate receiving tank F. It is then continuously distilled through desolventizing tower G to remove the solvent mixture of methyl acetate and isopropyl ether, low-boiling substances such as triethylamine and isopropyl ether are removed through low-boiling tower H, and high-boiling polymers are removed through high-boiling tower J to obtain crude vinylene carbonate. Gas chromatography analysis shows a vinylene carbonate content of 91.3%. The solvent and triethylamine are condensed and recovered and sent to the solvent and triethylamine storage tanks, respectively, for repeated use in S1 or S2.

[0055] S4: The crude vinylene carbonate obtained in S3 is continuously distilled through a primary distillation tower K1 and a secondary distillation tower K2 to obtain refined vinylene carbonate. Gas chromatography analysis shows that the purity of the vinylene carbonate is 99.52%.

[0056] S5: The refined vinylene carbonate product is sequentially passed through the primary melting crystallizer of M1 and the secondary melting crystallizer of M2 to obtain the finished vinylene carbonate product. Gas chromatography analysis shows that the purity of the vinylene carbonate reaches 99.993%.

[0057] S6: The triethylamine hydrochloride and isopropyl ether slurry discharged from S2 is treated with 32% liquid caustic soda in a neutralization tank N to adjust the pH of the aqueous phase to 9-11. The slurry is then transferred to a separatory tank P for stratification. The upper organic phase containing isopropyl ether and triethylamine is sequentially distilled through a dehydration tower Q, a solvent recovery tower P, and a tertiary amine recovery tower Q. The recovered isopropyl ether has a purity of 98.7% and a moisture content of 370 ppm; the recovered triethylamine has a purity of 99.3% and a moisture content of 410 ppm. The recovered tertiary amine is returned to S1 for recycling, and the isopropyl ether is returned to S2 for washing the tertiary amine hydrochloride.

[0058] S7: The brine separated from the lower layer of the separator tank passes through a three-effect evaporation system, and the evaporated wastewater enters the sewage treatment system for biochemical treatment; the salt slurry discharged by evaporation is transferred to the rotary kiln of the solid waste incinerator for high-temperature calcination to remove organic matter, and the obtained sodium chloride is sold as a by-product or treated as general solid waste.

[0059] The continuous production process and apparatus of vinylene carbonate provided in the embodiments of the present invention can not only effectively improve the purity and yield of the product and stabilize the product characteristics, but also reduce equipment investment and labor costs, lower production energy consumption, and have low production costs, and can be applied to the large-scale production of vinylene carbonate.

[0060] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. The above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A continuous production process and device for vinylene carbonate, characterized in that: The production process includes the following steps: S1: The solvent is continuously fed into the reactor through the preheater A1 by controlling the flow rate through the solvent delivery pump W1 and the flow meter. When the solvent feed reaches a certain mass, warm water is introduced into the shell side of the shell and tube heat exchanger C2 of the reactor C to preheat and keep the solvent warm. When the solvent in reactor C reaches the reaction temperature, the flow rates are controlled by solvent delivery pumps W1, W2, and W3 and flow meters, and the solvent, ethylene chloride, and tertiary amine are continuously fed at a predetermined flow rate through preheaters A1, A2, and A3 and pipeline mixer B, and then fed into reactor C from the upper portion of the central tube 12 for dechlorination reaction. The heat of reaction is transferred through the wall of the central tube 12 to the solvent in the outer cavity of reaction chamber C1. Furthermore, the material in the inner cavity of reaction chamber C1 is continuously discharged through the lower outlet of the central tube 12 into the outer cavity of reaction chamber C1, where heat is transferred through a mass transfer process. The solvent in the outer cavity of reaction chamber C1 absorbs the heat of reaction and evaporates, dissipating from the gas phase port 15 at the top of reactor C. After being cooled by circulating water and chilled water two-stage heat exchangers D1 and D2, it is collected in a solvent receiving tank E and recycled for synthesis. S2: The solvent is continuously fed into the washing solvent inlet 16 at the bottom of the washing chamber C3 connected to the lower part of the reactor C through the flow rate control of the delivery pump W4 and the flow meter to countercurrently wash the reaction by-product tertiary amine hydrochloride. At the same time, the automatic switch valve 17 at the bottom of the washing chamber C3 is opened to discharge the tertiary amine hydrochloride slurry continuously into the neutralization reactor N; S3: The reaction liquid continuously overflowing from the overflow port 11 on the upper side of the reactor C enters the intermediate receiving tank F, and then undergoes continuous distillation. The solvent is first separated and recovered by the desolventizing tower G, the low-boiling tower H, and the high-boiling tower J, and then returned to S1 or S2 for synthesis or washing, and the high-boiling substances are removed to obtain crude vinylene carbonate; S4: The crude vinylene carbonate is purified by distillation in the primary distillation tower K1 and the secondary distillation tower K2 to obtain refined vinylene carbonate; S5: The vinylene carbonate product is melt-crystallized in the primary melt crystallizer M1 and the secondary melt crystallizer M2 to obtain a vinylene carbonate product with a purity of more than 99.99%, which enters the vinylene carbonate product receiving tank V; S6: The tertiary amine hydrochloride slurry discharged into the neutralization kettle N is neutralized with liquid caustic soda and separated into layers in the separator P. The upper organic phase enters the dehydration tower Q of the recovery system for dehydration, and then enters the solvent recovery tower R for distillation to recover the solvent, and the tertiary amine recovery tower T for distillation to recover the tertiary amine. The recovered solvent and tertiary amine enter the solvent tank R1 and the tertiary amine tank T1 respectively, and are returned to S1 for recycling. The recovered solvent can also be returned to S2 for washing the tertiary amine hydrochloride; S7: The water phase discharged from S6 is transferred to the brine evaporation system, waste salt incineration system and sewage treatment system to treat the waste salt and wastewater.

2. A continuous production process and apparatus for vinylene carbonate according to claim 1, characterized in that: The solvent is a hydrocarbon, ether, ester, or nitrile compound, and is more typically selected from one or more mixtures of n-hexane, cyclohexane, n-heptane, petroleum ether, dichloromethane, dichloroethane, methyl propyl ether, ethyl propyl ether, methyl tert-butyl ether, n-propyl ether, isopropyl ether, ethyl formate, n-propyl formate, isopropyl formate, n-butyl formate, isobutyl formate, tert-butyl formate, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and acetonitrile. The density of the solvent or mixed solvent at 25°C is less than 1.0; the tertiary amine is selected from N,N-dimethylethylamine, N,N-dimethyl-n-propylamine, N,N-dimethylisopropylamine, N,N-dimethylbutylamine, N,N-dimethylhexylamine, N,N-dimethylcyclohexylamine, N,N-dimethylaniline, diethylmethylamine, di-n-propylmethylamine, diisopropylmethylamine, triethylamine, triisopropylamine, tributylamine, pyridine, N-methylpyrrole, N-methylpyrrolidine, N-methylmorpholine, N-methylpiperidine, imidazole, N-methylimidazole One or more combinations of oxazole, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylbutanediamine, N,N,N',N'-tetramethylhexanediamine, N,N'-dimethylpiperazine, pentamethyldiethylenetriamine, triethylenediamine, 1,5-diazabis[4.3.0]non-5-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene; the solvent contains 0.01-0.5% of a polymerization inhibitor, and the polymerization inhibitor is phenol, quinone, phenothiazine, phosphite , piperidinols, piperidine nitrogen oxides, and one or more combinations thereof. Typical polymerization inhibitors are hydroquinone, p-methoxyphenol, p-tert-butylcatechol, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butylhydroquinone, phenothiazine, 2,2,6,6-tetramethyl-4-hydroxy-piperidine nitrogen oxide, tris(2,2,6,6-tetramethyl-4-oxy-piperidine nitrogen oxide) phosphite, and bis(2,2,6,6-tetramethyl-4-oxy-piperidine nitrogen oxide) sebacate.

3. A continuous production process for vinylene carbonate according to claim 1, characterized in that: The mass ratio of the solvent, chloroethylene carbonate and tertiary amine is 2.0-10.0:1.0:0.8-1.

5.

4. A continuous production process and apparatus for vinylene carbonate according to claim 1, characterized in that: A temperature control device is provided on the pipes connecting the solvent preheater A1, the ethylene chlorocarbonate preheater A2, the tertiary amine preheater A3 and the pipeline mixer B. The central tube 12 is provided with thermometers at the upper, middle and lower parts to control the reaction temperature to be 50-100° C. The residence time of the ethylene chlorocarbonate and tertiary amine in the reaction chamber C1 for the dechlorination reaction is 1-12 hours, and the residence time in the salt washing chamber C3 is 0.5-5 hours.

5. A continuous production process and apparatus for vinylene carbonate according to claim 1, characterized in that: The production device includes: a solvent delivery pump W1, a chloroethylene carbonate delivery pump W2, a tertiary amine delivery pump W3, a solvent preheater A1, a chloroethylene carbonate preheater A2, a tertiary amine preheater A3, a washing solvent delivery pump W4, a pipeline mixer B, a reactor C, condensers D1 and D2, a solvent receiving tank E, an intermediate receiving tank F, a desolventizing tower G, a low-pressure desolventizing tower H, a high-pressure desolventizing tower J, a primary distillation tower K1 and a secondary distillation tower K2, a primary melt crystallizer M1, a secondary melt crystallizer M2, a vinylene carbonate finished product receiving tank V, a neutralization kettle N, a separatory tank P, a dehydration tower Q, a solvent recovery tower R, a tertiary amine recovery tower T, a solvent tank R1, and a tertiary amine tank T1.

6. A continuous production process and apparatus for vinylene carbonate according to claim 5, characterized in that: The reactor C of the production device is composed of an upper reaction chamber C1, a middle shell and tube heat exchanger C2, and a lower salt washing chamber C3.

7. A continuous production process and apparatus for vinylene carbonate according to claim 6, characterized in that: The reaction chamber C1 is provided with a central tube 12 with a lower opening extending to the upper part of the shell-and-tube heat exchanger C2, dividing the reaction chamber C1 into an inner cavity and an outer cavity. The inner cavity is within the central tube 12, and the annular space between the central tube 12 and the outer cylinder wall of the reaction chamber C1 is the outer cavity. The diameter of the central tube 12 is 300-2000 mm, the diameter of the outer cylinder wall of the reaction chamber C1 is 500-4000 mm, and the height of the cylinder of the reaction chamber C1 is 1000-10000 mm. The central opening of the elliptical head 13 on the reaction chamber C1 is used to insert the central tube 12 and fix it perpendicularly to the cross section of the reaction chamber. The upper end of the central tube 12 is connected to the pipeline from the pipeline mixer B. The elliptical head 13 corresponding to the outer cavity is provided with a gas phase port (15) connected to the condenser D1. The upper part of the outer cylinder wall of the reaction chamber C1 is provided with a side overflow port 11, and the side overflow port is not lower than the bottom of the central tube 12.

8. A continuous production process and apparatus for vinylene carbonate according to claim 6, characterized in that: The reactor C is provided with a shell and tube heat exchanger C2 at the lower part of the reaction chamber C1. The shell and tube heat exchanger C2 is connected to the reaction chamber C1 by welding or flange. The inner diameter of the tubes of the shell and tube heat exchanger C2 is 25-100 mm, the height of the tubes is 300-2000 mm, and the heat exchange area of the shell and tube heat exchanger C2 is 50-500 m2. At least one heat exchange medium inlet 18 and heat exchange medium outlet 19 are respectively provided at the upper and lower parts of the shell side of the shell and tube heat exchanger C2. The heat exchange medium includes but is not limited to steam, thermal oil, chilled water, and circulating water.

9. A continuous production process and apparatus for vinylene carbonate according to claim 6, characterized in that: The salt washing chamber C3 includes at least two straight cylindrical salt washing sections C3-1 and C3-2 with gradually decreasing diameters. The lower end of the shell and tube heat exchanger C2 and the barrels of each salt washing section are connected by reducing the diameter, welding or flanges. The aspect ratio of the barrel of each salt washing section is 1 to 5:

1.

10. A continuous production process and apparatus for vinylene carbonate according to claim 9, characterized in that: A washing solvent inlet 16 is provided in the middle and lower part of the salt washing section C3-2, and the solvent feed flow rate can be adjusted in real time according to the feed flow rate of the reaction material; an automatic switching valve 17 is installed at the bottom of the salt washing chamber, which controls the tertiary amine hydrochloride slurry to be intermittently discharged to the tertiary amine hydrochloride neutralization kettle N at a certain flow rate and frequency by adjusting the switching time.

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