Preparation method of vinylene carbonate

Abstract

The invention discloses a preparation method of vinylene carbonate, which comprises the following step: reacting chloroethylene carbonate under the action of a catalyst to generate vinylene carbonate, wherein the catalyst comprises a modified titanium silicalite molecular sieve and a metal salt loaded on the modified titanium silicalite molecular sieve, the modified titanium silicalite molecular sieve is obtained by calcining the titanium silicalite molecular sieve and then etching the titanium silicalite molecular sieve with tetraalkyl ammonium hydroxide, and metal elements in the metal salt have d orbital electrons; practice shows that the method can directly remove hydrogen chloride from chloroethylene carbonate to generate vinylene carbonate, the reaction temperature is unexpectedly reduced and can be reduced to 200 DEG C or even below 180 DEG C, the energy consumption and the safety performance in the production process are greatly reduced, a solvent is not needed in the reaction process, and the method is suitable for industrial production. And no solid waste is generated.

Description

Technical Field

[0001] The invention relates to the technical field of synthesis, in particular to the synthesis of lithium battery electrolyte additives, and specifically to a method for preparing vinylene carbonate. Background Art

[0002] Vinylene carbonate (VC), also known as Vinylene Carbonate in English, has a chemical formula of C3H2O3 and is a colorless and transparent liquid. Vinylene carbonate, also known as 1,3-dioxol-2-one and ethylene carbonate, is often used as a new organic film-forming additive and overcharge protection additive for lithium-ion batteries. It has good high and low temperature performance and anti-flatulence function, which can improve the capacity and cycle life of the battery. Vinylene carbonate can also be used as a monomer for the preparation of polyvinyl carbonate. At present, the mainstream synthesis process of vinylene carbonate is as follows: vinylene carbonate is chlorinated with chlorine to generate chloroethylene carbonate, and then one molecule of hydrogen chloride is eliminated under the action of an organic base (generally triethylamine, also known as an acid binding agent) to obtain vinylene carbonate; in this process, the elimination reaction is generally carried out in a solvent, and after the reaction is completed, it is concentrated, distilled, and crystallized to obtain a high-purity finished product of vinylene carbonate. The defects of this process are: (1) the amount of triethylamine used is large and the cost is high, and triethylamine can promote the polymerization of vinylene carbonate, resulting in a low yield of vinylene carbonate; (2) a large amount of solid salt is produced in the process, and the post-treatment process is complicated; (3) liquid alkali is used in the triethylamine recovery process, which is not only costly but also produces a large amount of wastewater and waste salt sodium chloride. Summary of the invention

[0003] The object of the present invention is to overcome one or more deficiencies in the prior art and to provide an improved method for preparing vinylene esters to solve at least one problem in the prior art.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for preparing vinylene carbonate comprises: reacting vinyl chlorocarbonate in the presence of a catalyst to generate vinylene carbonate; wherein the catalyst comprises a modified titanium silicalite and a metal salt supported on the modified titanium silicalite, wherein the modified titanium silicalite is obtained by first calcining the titanium silicalite and then etching it with tetraalkylammonium hydroxide, and the metal element in the metal salt has d-orbital electrons.

[0006] The present invention also provides a catalyst, which includes a modified titanium silicon molecular sieve and a metal salt supported on the modified titanium silicon molecular sieve, wherein the modified titanium silicon molecular sieve is obtained by first calcining the titanium silicon molecular sieve and then etching it with tetraalkylammonium hydroxide, and the metal element in the metal salt has d orbital electrons. Further, the catalyst is used for removing hydrogen chloride from chloroethylene carbonate to prepare vinylene carbonate.

[0007] In some embodiments of the present invention, the calcination temperature is controlled to be 400-600°C. Further, the calcination temperature is controlled to be 400-550°C.

[0008] In some embodiments of the present invention, the tetraalkylammonium hydroxide is tetramethylammonium hydroxide and / or tetrapropylammonium hydroxide.

[0009] In some embodiments of the present invention, the preparation method of the modified titanium silicalite comprises: calcining the titanium silicalite at 400-600° C. for 0.5-20 h, and then soaking it in an aqueous solution of tetramethylammonium hydroxide and / or tetrapropylammonium hydroxide for 1-30 min.

[0010] Furthermore, the preparation method of the modified titanium silicalite comprises: calcining the titanium silicalite at 400-600° C. for 1-15 hours, and then soaking it in an aqueous solution of tetramethylammonium hydroxide and / or tetrapropylammonium hydroxide with a mass concentration of 1%-20% for 5-25 minutes.

[0011] In some embodiments of the present invention, the metal salt comprises a metal nitrate and / or a metal chloride.

[0012] In some embodiments of the present invention, the metal in the metal salt includes a combination of one or more of barium, iron, zinc and cesium.

[0013] In some embodiments of the present invention, the metal salt is a combination of one or more selected from barium nitrate, zinc nitrate, cesium nitrate, barium chloride, and zinc chloride.

[0014] In some embodiments of the present invention, in the catalyst, the loading amount of the metal salt is 0.01-0.5 parts per part of the modified titanium silicalite molecular sieve.

[0015] In some embodiments of the present invention, the preparation method of the catalyst includes: soaking the modified titanium silicon molecular sieve in an aqueous solution of a metal salt, separating the solid (for example, by filtering), and drying (for example, at 120-170° C.). Furthermore, the soaking process is accompanied by stirring.

[0016] In some embodiments of the present invention, the reaction temperature is controlled to be 150-180°C.

[0017] In some embodiments of the present invention, the reaction is controlled to be carried out at a pressure of 0.1-0.3 MPa.

[0018] In some embodiments of the present invention, the method for preparing vinylene carbonate comprises: heating vinylene carbonate to form steam, and then passing the steam through a fixed bed reactor containing the catalyst under the driving of a carrier gas to react and generate vinylene carbonate.

[0019] In some embodiments of the present invention, the carrier gas is nitrogen or an inert gas.

[0020] In some embodiments of the present invention, the feed space velocity of the chloroethylene carbonate is 0.1-10h -1 .

[0021] In some embodiments of the present invention, during the preparation of the vinylene carbonate, the reaction product is cooled to obtain crude vinylene carbonate and hydrogen chloride gas. The crude vinylene carbonate can be distilled and crystallized to obtain refined vinylene carbonate. The hydrogen chloride gas is buffered in a buffer tank and then absorbed by water to obtain hydrochloric acid.

[0022] In the present invention, compared with other conventional carriers or unmodified titanium silicalite, the use of modified titanium silicalite as a carrier can obtain better effects. For example, compared with activated carbon, although the catalyst using activated carbon as a carrier has a certain particle size, perhaps due to the insufficient strength of the activated carbon itself, as the reaction proceeds, when the material gas flow passes through quickly, the catalyst particles are easier to break, and the generated powder blocks the micropores of the catalyst, resulting in a decrease in the specific surface area of ​​the catalyst and deactivation; for example, compared with conventional mesoporous silica materials, the catalyst using mesoporous silica materials as a carrier has certain reactivity, but it may be because the surface of the mesoporous silica material contains a large number of hydroxyl groups and has a high surface energy. It is easy to agglomerate under the drive of the material gas flow, affecting the dispersion and uniformity of the metal salt, resulting in a decrease in the catalytic reaction effect; for example, compared with unmodified titanium silicalite, practice shows that under the same temperature conditions, the catalyst prepared using unmodified titanium silicalite as a carrier has a lower yield when used to remove hydrogen chloride from ethylene chlorocarbonate, while the modified titanium silicalite of the present invention can achieve a higher yield under milder conditions.

[0023] In the present invention, the principle of vinyl chloride carbonate reacting to generate vinylene carbonate under the action of a catalyst is roughly as follows:

[0024]

[0025] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0026] Based on the existing problems of low yield and large amount of triethylamine used in the process of synthesizing vinylene carbonate, which not only has high cost, but also produces a large amount of wastewater and waste salt such as sodium chloride, and the formation of solid salt causes complicated post-treatment, the inventors of the present invention innovatively provide a new catalyst, which includes a modified titanium silicon molecular sieve and a metal salt supported on the modified titanium silicon molecular sieve. Practice shows that the catalyst can not only directly remove hydrogen chloride from vinyl chlorocarbonate to generate vinylene carbonate, but also the reaction temperature is unexpectedly reduced to 200°C or even below 180°C, which greatly reduces energy consumption and improves safety performance in the production process.

[0027] Specifically, in the present invention, titanium silicalite is selected as the basic carrier, which has a complex three-dimensional pore structure, usually composed of two sets of ten-membered ring pores and one set of nine-membered ring pores, and these pores are connected by four-coordinated atoms to form a staggered three-dimensional structure; usually, the first set of pores is composed of ten-membered rings composed of four-coordinated atoms, the second set of pores is also composed of ten-membered rings composed of four-coordinated atoms, and is perpendicularly staggered with the first set of pores, and the third set of pores is staggered with the first and second sets of pores, and is composed of nine-membered rings composed of four-coordinated atoms; the existence of these structures promotes the high activity of the titanium silicalite itself, and The present invention adopts calcination to further activate the carrier, and then uses a specific base-tetraalkylammonium hydroxide to etch and modify the carrier, which can further increase the generation of an ordered skeleton and produce more micropores of different levels, thereby not only allowing the metal salt to be better and stably loaded, but also the fully developed pore structure with a gradient pore size is also conducive to contact with ethylene chlorocarbonate, and has the effect of changing the flow state of ethylene chlorocarbonate in fluid form at the microscopic level, forming a flow mode closer to the "turbulent" form, and increasing the probability of ethylene chlorocarbonate contacting the catalyst, thereby greatly improving the catalytic efficiency and catalytic effect;

[0028] Furthermore, the metal salt in the present invention is preferably nitrate, which can obtain a relatively higher yield than chloride. Analysis shows that perhaps a special chemical bond is formed when the metal nitrate is loaded on the modified titanium silicalite molecular sieve. It is speculated that the oxygen in the nitrate ion may participate in the formation of functional bonds such as coordination bonds, and then combined with the adsorption of anions and cations, the metal salt is greatly immobilized on the carrier-modified titanium silicalite molecular sieve. In particular, in the preparation process of the present invention, ethylene chloride is converted into steam and then contacted with the catalyst. This preparation process puts higher requirements on the stability of the metal salt on the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of a production device used in an embodiment of the present invention;

[0030] Figure 2Gas chromatography-mass spectrometry (GC-MS) spectrum of vinylene carbonate obtained in Example 1 of the present invention;

[0031] In the accompanying drawings: 1. preheater; 2. reaction chamber; 21. fixed bed reactor; 3. cooler; 4. product collecting kettle; 5. buffer tank; 6. deacidification tank. DETAILED DESCRIPTION

[0032] The present invention provides a method for preparing vinylene carbonate. Figure 1 The process is further explained.

[0033] See also Figure 1 As shown, the raw material ethylene carbonate is introduced into the preheater 1 at a preset flow rate to form saturated steam through heating, and a carrier gas (such as nitrogen, etc.) is introduced at the same time, the carrier gas flow rate is adjusted, the reaction pressure is maintained, and then the carrier gas drives the ethylene carbonate gas to enter the fixed bed reactor 21 of the reaction chamber 2, contact and react with the catalyst, and the reaction temperature is controlled. After the reaction is completed, the reaction product is cooled through the cooler 3 to obtain crude vinyl carbonate and hydrogen chloride gas. The crude vinyl carbonate is collected by the product collecting kettle 4, and the remaining mixed gas (including carrier gas and hydrogen chloride gas) is introduced into the buffer tank 5, and then introduced into the deacidification tank 6 through the buffer tank 5 for deacidification. Water or liquid alkali can be used to absorb hydrogen chloride, and a single-stage or multi-stage absorption method can be used, and the gas after deacidification is discharged; wherein, the presence of the buffer tank 5 can prevent the liquid in the deacidification tank 6 from being sucked back.

[0034] The above scheme is further described below in conjunction with specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions adopted in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0035] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0036] The titanium silicalite molecular sieve is TS-1 molecular sieve, purchased from Zhuoran Environmental Protection Technology (Dalian) Co., Ltd. Activated carbon was purchased from Shanghai Activated Carbon Factory Co., Ltd. Mesoporous silica material was purchased from Shijiazhuang Jingsheng Mineral Products Co., Ltd. In the following, the modified titanium silicalite molecular sieve is prepared by the following method: TS-1 molecular sieve is calcined at 500±10°C for 6h, and after cooling, it is placed in an aqueous solution of tetrapropylammonium hydroxide with a mass concentration of 10%, soaked for 20min, filtered, washed with deionized water, and vacuum dried to obtain the modified titanium silicalite molecular sieve.

[0037] Preparation Example 1

[0038] Take 50g of modified titanium silicalite molecular sieve, mix it with 200g of 7% barium nitrate aqueous solution, and stir it at room temperature for 20h. Filter out the excess aqueous solution to obtain the impregnated catalyst, and dry it at 160-165℃ for 10h to obtain the modified titanium silicalite molecular sieve loaded with barium nitrate catalyst, the grade of which is Cat-Ba(NO3)207S.

[0039] Preparation Example 2

[0040] Take 50g of modified titanium silicon molecular sieve, mix it with 100g of 20% zinc nitrate aqueous solution, and stir it for 20h at room temperature. Filter out the excess aqueous solution to obtain the impregnated catalyst, and dry it at 120-125℃ for 20h to obtain the modified titanium silicon molecular sieve loaded zinc nitrate catalyst, the grade is Cat-Zn(NO3)220S.

[0041] Preparation Example 3

[0042] Take 50g of modified titanium silicalite molecular sieve, mix it with 100g of cesium nitrate aqueous solution with a mass fraction of 20%, and stir it for 20h at room temperature. Filter out the excess aqueous solution to obtain the impregnated catalyst, and dry it at 140-145℃ for 18h to obtain the modified titanium silicalite molecular sieve loaded with cesium nitrate catalyst, the grade of which is Cat-CsNO320S.

[0043] Preparation Example 4

[0044] Take 50g of modified titanium silicalite, mix with 100g of 20% barium chloride aqueous solution, stir for 20h at room temperature. Filter to remove excess aqueous solution, obtain impregnated catalyst, dry at 160-165℃ for 18h, and obtain modified titanium silicalite loaded with barium chloride catalyst, the grade is Cat-BaCl220S.

[0045] Preparation Example 5

[0046] Take 50g of modified titanium silicon molecular sieve, mix with 100g of 20% by mass zinc chloride aqueous solution, stir for 20h at room temperature. Filter to remove excess aqueous solution, obtain impregnated catalyst, dry at 160-165℃ for 18h, and obtain modified titanium silicon molecular sieve loaded zinc chloride catalyst, the grade is Cat-ZnCl220S.

[0047] Preparation Example 6

[0048] Take 50g of activated carbon and mix it with 100g of 20% barium chloride aqueous solution, stir it at room temperature for 20h. Filter out the excess aqueous solution to obtain the impregnated catalyst, dry it at 160-165℃ for 18h, and obtain the activated carbon supported barium chloride catalyst, the grade is Cat-BaCl220C.

[0049] Preparation Example 7

[0050] Take 50g of mesoporous silica material, mix it with 100g of 20% barium chloride aqueous solution, and stir it for 20h at room temperature. Filter out the excess aqueous solution to obtain the impregnated catalyst, and dry it at 160-165℃ for 18h to obtain the mesoporous silica material loaded with barium chloride catalyst, which is designated as Cat-BaCl220SiO2.

[0051] Preparation Example 8

[0052] Take 50g of TS-1 molecular sieve, mix it with 100g of 20% barium chloride aqueous solution, and stir it for 20h at room temperature. Filter out the excess aqueous solution to obtain the impregnated catalyst, and dry it at 160-165℃ for 18h to obtain TS-1 molecular sieve supported barium chloride catalyst, with the brand Cat-BaCl220TS-1.

[0053] Example 1

[0054] This example provides a method for preparing vinylene carbonate, which combines Figure 1 The production device shown in the figure specifically comprises the following steps:

[0055] The catalyst of the brand Cat-Ba(NO3)207S was loaded into the fixed bed reactor, and the loading volume was 20 mL. After the loading was completed, nitrogen was used to purge and maintain the nitrogen atmosphere to remove moisture and air in the device.

[0056] Vinyl chloride carbonate (content 82.4%) enters the preheater at a speed of 3.0g / min to form saturated steam through heating, and the nitrogen flow is adjusted to maintain the pressure at 0.1-0.2MPa, and enters the fixed bed reactor to contact and react with the catalyst, and the reactor temperature is controlled at 155-165°C. The reaction product is cooled by a cooler to obtain a crude vinylene carbonate, and the generated hydrogen chloride gas is absorbed by the deacidification tank. After 2h, the feeding is stopped to obtain 279.6g of liquid, and after vacuum distillation, 206.4g of vinylene carbonate with a purity of 92.7% is obtained, and the yield is 91.9%.

[0057] Example 2

[0058] This example provides a method for preparing vinylene carbonate, which combines Figure 1 The production device shown in the figure specifically comprises the following steps:

[0059] The catalyst with the brand name Cat-Zn(NO3)220S was loaded into the fixed bed reactor, and the loading volume was 20 mL. After the loading was completed, nitrogen was used to purge and maintain the nitrogen atmosphere to remove moisture and air in the device.

[0060] Chloroethylene carbonate (content 82.4%) enters the preheater at a speed of 2.4g / min to form saturated steam through heating, adjusts the nitrogen flow rate, maintains the pressure at 0.1-0.2MPa, enters the fixed bed reactor, contacts and reacts with the catalyst, and the reactor temperature is controlled at 155-165°C. The reaction product is cooled by a cooler to obtain a crude vinylene carbonate, and the generated hydrogen chloride gas is absorbed by a deacidification tank. After 2h, the feeding is stopped to obtain 225.4g of liquid, and after vacuum distillation, 162.3g of vinylene carbonate with a purity of 93.2% is obtained, and the yield is 90.8%.

[0061] Example 3

[0062] This example provides a method for preparing vinylene carbonate, which combines Figure 1 The production device shown in the figure specifically comprises the following steps:

[0063] The catalyst with the brand name Cat-CsNO320S was loaded into the fixed bed reactor, and the loading volume was 20 mL. After the loading was completed, nitrogen was used to purge and maintain the nitrogen atmosphere to remove moisture and air in the device.

[0064] Chloroethylene carbonate (content 82.4%) enters the preheater at a speed of 2.7g / min to form saturated steam through heating, and the nitrogen flow is adjusted to maintain the pressure at 0.2-0.3MPa, and enters the fixed bed reactor to contact and react with the catalyst, and the reactor temperature is controlled at 155-165°C. The reaction product is cooled by a cooler to obtain a crude vinylene carbonate, and the generated hydrogen chloride gas is absorbed by a deacidification tank. After 2h, the feeding is stopped to obtain 268.2g of liquid, and after vacuum distillation, 190.6g of vinylene carbonate with a purity of 90.5% is obtained, and the yield is 92.0%.

[0065] Example 4

[0066] This example provides a method for preparing vinylene carbonate, which combines Figure 1 The production device shown in the figure specifically comprises the following steps:

[0067] The catalysts of Cat-Ba(NO3)207S, Cat-Zn(NO3)220S and Cat-CsNO320S were loaded into the fixed bed reactor at a volume ratio of 1:1:1, with a loading volume of 20 mL. After loading, nitrogen was used to purge and maintain the nitrogen atmosphere to remove moisture and air in the device.

[0068] Chloroethylene carbonate (content 82.4%) enters the preheater at a speed of 2.7g / min to form saturated steam through heating, and the nitrogen flow is adjusted to maintain the pressure at 0.2-0.3MPa, and enters the fixed bed reactor to contact and react with the catalyst, and the reactor temperature is controlled at 155-165°C. The reaction product is cooled by a cooler to obtain a crude vinylene carbonate, and the generated hydrogen chloride gas is absorbed by the deacidification tank. After 2h, the feeding is stopped to obtain 266.2g of liquid, and after vacuum distillation, 186.4g of vinylene carbonate with a purity of 91.9% is obtained, and the yield is 91.4%.

[0069] Example 5

[0070] This example provides a method for preparing vinylene carbonate, which combines Figure 1 The production device shown in the figure specifically comprises the following steps:

[0071] The catalyst of brand Cat-BaCl220S was loaded into the fixed bed reactor, and the loading volume was 20 mL. After the loading was completed, nitrogen was used to purge and maintain the nitrogen atmosphere to remove moisture and air in the device.

[0072] Chloroethylene carbonate (content 82.4%) enters the preheater at a speed of 3.0g / min to form saturated steam through heating, and the nitrogen flow is adjusted to maintain the pressure at 0.1-0.2MPa, and enters the fixed bed reactor to contact and react with the catalyst, and the reactor temperature is controlled at 155-165°C. The reaction product is cooled by a cooler to obtain a crude vinylene carbonate, and the generated hydrogen chloride gas is absorbed by the deacidification tank. After 2h, the feeding is stopped to obtain 286.4g of liquid, and after vacuum distillation, 185.9g of vinylene carbonate with a purity of 90.7% is obtained, and the yield is 80.9%.

[0073] Example 6

[0074] This example provides a method for preparing vinylene carbonate, which combines Figure 1 The production device shown in the figure specifically comprises the following steps:

[0075] The catalyst with the brand name Cat-ZnCl220S was loaded into the fixed bed reactor, and the loading volume was 20 mL. After the loading was completed, nitrogen was used to purge and maintain the nitrogen atmosphere to remove moisture and air in the device.

[0076] Chloroethylene carbonate (content 82.4%) enters the preheater at a speed of 2.4g / min to form saturated steam through heating, and the nitrogen flow is adjusted to maintain the pressure at 0.1-0.2MPa, and enters the fixed bed reactor to contact and react with the catalyst, and the reactor temperature is controlled at 155-165°C. The reaction product is cooled by a cooler to obtain a crude vinylene carbonate, and the generated hydrogen chloride gas is absorbed by a deacidification tank. After 2h, the feeding is stopped to obtain 229.6g of liquid, and after reduced pressure distillation, 150.1g of vinylene carbonate with a purity of 90.7% is obtained, and the yield is 81.7%.

[0077] Comparative Example 1

[0078] This example provides a method for preparing vinylene carbonate, which combines Figure 1 The production device shown in the figure specifically comprises the following steps:

[0079] The catalyst of brand Cat-BaCl220C was loaded into the fixed bed reactor, and the loading volume was 20 mL. After the loading was completed, nitrogen was used to purge and maintain the nitrogen atmosphere to remove moisture and air in the device.

[0080] Chloroethylene carbonate (content 82.4%) enters the preheater at a speed of 3.0g / min to form saturated steam through heating, and the nitrogen flow is adjusted to maintain the pressure at 0.1-0.2MPa, and enters the fixed bed reactor to contact and react with the catalyst, and the reactor temperature is controlled at 155-165°C. The reaction product is cooled by a cooler to obtain a crude vinylene carbonate, and the generated hydrogen chloride gas is absorbed by a deacidification tank. After 2h, the feeding is stopped to obtain 300.6g of liquid, and after vacuum distillation, 145g of vinylene carbonate with a purity of 89.4% is obtained, and the yield is 62.3%.

[0081] Comparative Example 2

[0082] This example provides a method for preparing vinylene carbonate, which combines Figure 1 The production device shown in the figure specifically comprises the following steps:

[0083] The catalyst of brand Cat-BaCl220SiO2 was loaded into the fixed bed reactor, and the loading volume was 20 mL. After the loading was completed, nitrogen was used to purge and maintain the nitrogen atmosphere to remove moisture and air in the device.

[0084] Chloroethylene carbonate (content 82.4%) enters the preheater at a speed of 3.0g / min to form saturated steam through heating, and the nitrogen flow is adjusted to maintain the pressure at 0.1-0.2MPa, and enters the fixed bed reactor to contact and react with the catalyst, and the reactor temperature is controlled at 155-165°C. The reaction product is cooled by a cooler to obtain a crude vinylene carbonate, and the generated hydrogen chloride gas is absorbed by the deacidification tank. After 2h, the feeding is stopped to obtain 312.5g of liquid, and after reduced pressure distillation, 132.1g of vinylene carbonate with a purity of 83.7% is obtained, and the yield is 53.1%.

[0085] Comparative Example 3

[0086] This example provides a method for preparing vinylene carbonate, which combines Figure 1 The production device shown in the figure specifically comprises the following steps:

[0087] The catalyst of brand Cat-BaCl220TS-1 was loaded into the fixed bed reactor, and the loading volume was 20 mL. After the loading was completed, nitrogen was used to purge and maintain the nitrogen atmosphere to remove moisture and air in the device.

[0088] Chloroethylene carbonate (content 82.4%) enters the preheater at a speed of 3.0g / min to form saturated steam through heating, and the nitrogen flow is adjusted to maintain the pressure at 0.1-0.2MPa, and enters the fixed bed reactor to contact and react with the catalyst, and the reactor temperature is controlled at 155-165°C. The reaction product is cooled by a cooler to obtain a crude vinylene carbonate, and the generated hydrogen chloride gas is absorbed by a deacidification tank. After 2h, the feeding is stopped to obtain 279.7g of liquid, and after vacuum distillation, 149.6g of vinylene carbonate with a purity of 88.5% is obtained, and the yield is 63.6%.

[0089] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

[0090] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

Claims

1. A method for preparing vinylene carbonate, characterized in that: The preparation method comprises: reacting chloroethylene carbonate in the presence of a catalyst to generate vinylene carbonate; wherein the catalyst comprises a modified titanium silicalite and a metal salt supported on the modified titanium silicalite, wherein the modified titanium silicalite is obtained by first calcining the titanium silicalite and then etching it with tetraalkylammonium hydroxide, and the metal element in the metal salt has d-orbital electrons.

2. The method for preparing vinylene carbonate according to claim 1, characterized in that: The calcination temperature is controlled to be 400-600° C.; and / or the tetraalkylammonium hydroxide is tetramethylammonium hydroxide and / or tetrapropylammonium hydroxide.

3. The method for preparing vinylene carbonate according to claim 1, characterized in that: The preparation method of the modified titanium silicalite comprises: calcining the titanium silicalite at 400-600° C. for 0.5-20 hours, and then soaking the titanium silicalite in an aqueous solution of tetramethylammonium hydroxide and / or tetrapropylammonium hydroxide for 1-30 minutes.

4. The method for preparing vinylene carbonate according to claim 1, characterized in that: The metal salt includes metal nitrate and / or metal chloride; and / or the metal in the metal salt includes a combination of one or more of barium, iron, zinc and cesium.

5. The method for preparing vinylene carbonate according to claim 1, characterized in that: The metal salt is a combination of one or more selected from barium nitrate, zinc nitrate, cesium nitrate, barium chloride and zinc chloride.

6. The method for preparing vinylene carbonate according to claim 1, characterized in that: In the catalyst, the loading amount of the metal salt is 0.01-0.5 parts per part of the modified titanium silicalite molecular sieve; And / or, the preparation method of the catalyst comprises: immersing the modified titanium silicon molecular sieve in an aqueous solution of a metal salt, separating the solid, and drying.

7. The method for preparing vinylene carbonate according to claim 1, characterized in that: The reaction temperature of the reaction is controlled to be 150-180° C.; and / or, the reaction is controlled to be carried out under a pressure of 0.1-0.3 MPa.

8. The method for preparing vinylene carbonate according to claim 1, characterized in that: The method for preparing the vinylene carbonate comprises: heating chloroethylene carbonate to form steam, and then passing the steam through a fixed bed reactor equipped with the catalyst under the driving of a carrier gas to react and generate vinylene carbonate.

9. The method for preparing vinylene carbonate according to claim 8, characterized in that: The carrier gas is nitrogen or an inert gas; and / or the feed space velocity of the chloroethylene carbonate is 0.1-10h -1 .

10. The method for preparing vinylene carbonate according to claim 8, characterized in that: In the process of preparing the vinylene carbonate, the reaction product is cooled to obtain crude vinylene carbonate and hydrogen chloride gas. The crude vinylene carbonate can be distilled and crystallized to obtain refined vinylene carbonate. The hydrogen chloride gas is buffered in a buffer tank and then absorbed by water to obtain hydrochloric acid.

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