Catalyst and method of preparation and synthesis of vinylene carbonate

Abstract

The application provides a catalyst, a preparation method and a synthesis method of vinylene carbonate, and the preparation method of the catalyst is as follows: Al2O3 and Cr2O3 are used as carriers, the carriers are immersed in a metal impregnation solution containing platinum elements to obtain a first impregnation product, the first impregnation product is dried and calcined, then is immersed in a salt solution containing potassium elements to obtain a second impregnation product, and the second impregnation product is treated to obtain the catalyst. The application prepares a novel catalyst with high catalytic activity for the synthesis of vinylene carbonate, the salt solution containing potassium elements can change the first impregnation product from acidic to neutral, and the potassium elements and the platinum elements are loaded on the carrier as active elements; a new process for preparing vinylene carbonate is developed by using the specific catalyst and specific temperature and pressure conditions, the reaction temperature is relatively mild compared with the prior art, the safety is high, and the yield is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of lithium battery additives, more particularly to a catalyst, a preparation method and a synthesis method of vinylene carbonate. BACKGROUND

[0002] Vinylene carbonate is an additive of non-aqueous electrolyte of lithium ion battery, which can form a compact structure layer during use of the battery without increasing impedance, and can form a SEI film capable of preventing further decomposition of electrolyte, effectively improving high and low temperature resistance of lithium ion electrolyte, and improving fire resistance of lithium ion electrolyte, thereby improving cycle life of the battery and significantly increasing safety performance of the battery.

[0003] At present, the mainstream process for synthesizing vinylene carbonate in industry is to synthesize chloroethylene carbonate from vinyl carbonate and chlorine under catalytic conditions, and then to further synthesize vinylene carbonate from chloroethylene carbonate and triethylamine. However, this process has obvious problems. First, the reaction involves chlorine, which is highly dangerous and has high pollution, and requires high environmental protection and safety costs. Second, the reaction is a two-step reaction with many by-products to be separated, thereby leading to complex process, non-continuous production, many operation steps, and low product yield.

[0004] Based on the problems of the traditional synthesis route, some people have proposed a route of directly dehydrogenating vinyl carbonate to generate vinylene carbonate in one step. Although this method avoids environmental pollution and multiple reaction steps, the required reaction temperature is high. It is known that vinylene carbonate has poor stability under high temperature conditions and is easy to polymerize. Therefore, the realizability of this scheme needs to be verified. In addition, hydrogen is generated during the reaction process, which has high requirements for equipment and safety protection measures in actual production process. Therefore, further improvement and development are needed. SUMMARY

[0005] In view of the deficiencies of the prior art, in order to solve the above problems, a catalyst, a preparation method and a synthesis method of vinylene carbonate are proposed, and the following technical solutions are provided.

[0006] A preparation method of a catalyst, the preparation method being as follows: taking Al2O3 and Cr2O3 as carriers, immersing the carriers in a metal impregnation solution containing platinum elements to obtain a first impregnation product, drying and calcining the first impregnation product, and then immersing the first impregnation product in a salt solution containing potassium elements to obtain a second impregnation product, and obtaining the catalyst after post-treatment of the second impregnation product.

[0007] Further, the loading rate of the platinum elements on the carriers is 0.5%-0.8%, and the loading rate of the potassium elements on the carriers is 0.05%-0.3%.

[0008] Further, the impregnation time of the carrier in the metal impregnation solution containing the platinum element is 2-10h.

[0009] Further, the impregnation time of the first impregnation product in the salt solution containing the potassium element is 2-10h.

[0010] Further, the drying temperature of the first impregnation product is 80-180℃, and the drying time is 2-8h. The calcination temperature of the first impregnation product is 400-600℃, and the calcination time is 3-8h.

[0011] Further, the post-processing includes, in sequence, drying, calcination, reduction by hydrogen, and pressing under a pressure of 8-12MPa for 40-50s.

[0012] Further, the drying temperature of the second impregnation product is 80-180℃, and the drying time is 2-8h. The calcination temperature of the second impregnation product is 400-600℃, and the calcination time is 3-8h.

[0013] In addition, the application further provides a catalyst prepared by the above-mentioned catalyst preparation method.

[0014] In addition, the application further provides a synthesis method of vinylene carbonate. The synthesis method uses the above-mentioned catalyst to react under the conditions of a temperature of 70-100℃ and a vacuum degree of 5-30mbar to obtain vinylene carbonate.

[0015] Further, the molar ratio of the vinyl carbonate and the furan is 1-10.

[0016] Due to the adoption of the above technical solutions, the application has the following beneficial technical effects:

[0017] 1. The application prepares a new high-catalytic-activity catalyst for the synthesis of vinylene carbonate.

[0018] On the one hand, Al2O3 and Cr2O3 are used as the common carrier to inhibit sintering and prevent the carbon-carbon bond from being easily broken. On the other hand, the salt solution containing the potassium element can change the first impregnation product from acidic to neutral, and the potassium element is loaded on the carrier together with the platinum element as the active element.

[0019] 2. The application develops a new process for preparing vinylene carbonate by using a specific catalyst and specific temperature and pressure conditions. Compared with the prior art, the reaction temperature is relatively mild, and the safety is high. DETAILED DESCRIPTION

[0020] In order for the personnel in the art to better understand the technical solutions of the present application, the technical solutions of the present application will be clearly and completely described below in combination with the embodiments of the present application, and other similar embodiments obtained by the personnel in the art without creative labor based on the embodiments in the present application shall all belong to the scope of protection of the present application.

[0021] A preparation method of a catalyst, comprising the following steps: taking Al2O3 and Cr2O3 as carriers, impregnating the carriers in a metal impregnation solution containing platinum elements to obtain a first impregnation product, impregnating the first impregnation product in a salt solution containing potassium elements after drying and calcining to obtain a second impregnation product, and obtaining the catalyst after post-treatment of the second impregnation product.

[0022] Al2O3 is a neutral carrier, has acidity and alkalinity, has good affinity with active components, and can inhibit sintering, but C-C bonds are easy to crack, and Cr2O3 is also an amphoteric carrier, can inhibit sintering, and C-C bonds are not easy to crack, so Cr2O3 is used as a supplement of Al2O3.

[0023] The Al2O3 / Cr2O3 carrier is prepared by using a mixed solution of sulfuric acid and aluminate and chromate as raw materials, and by adopting a ph swing method or a calcining process. Specifically, the ph swing method is: sulfuric acid, chromium salt and aluminum salt are alternately added and neutralized to precipitate chromium sesquioxide and aluminum sesquioxide. In addition, the carrier is impregnated twice to realize the loading of two active components, and the platinum element and the potassium element synergistically act, the potassium element can improve the adsorption structure of the platinum element on the carrier, improve the catalytic activity of the platinum element, and make the platinum element more easily transfer electrons.

[0024] By controlling the time of the two impregnations, the loading amount of the two elements is adjusted, the loading rate of the platinum element on the carrier is 0.5%-0.8%, and the loading rate of the potassium element on the carrier is 0.05%-0.3%. On the one hand, the total amount of platinum and potassium elements affects the overall catalytic performance of the catalyst, and on the other hand, by controlling the time of the two impregnations, the loading amount of the two elements is adjusted, the loading rate of the platinum element on the carrier is 0.5%-0.8%, and the loading rate of the potassium element on the carrier is 0.05%-0.3%. On the one hand, the total amount of platinum and potassium elements affects the overall catalytic performance of the catalyst, and on the other hand, the ratio between the platinum element and the potassium element needs to be controlled between 2:1 and 10:1. Among them, the platinum element is the main catalytically active component. The catalyst is used for catalytic reaction, and the auxiliary potassium element is adsorbed on the active sites on the surface of the catalyst to change the surface configuration, thereby improving the selectivity, carbon deposition resistance and sintering resistance of the catalyst, and inhibiting the tar formation of the reaction, but too high a proportion will cover the active sites of platinum, reducing the catalytic activity.

[0025] The present scheme uses a special catalyst to prepare vinylene carbonate, the reaction temperature is relatively mild, the safety is strong, and the continuous production is realized. In the preparation method of the vinylene carbonate, the temperature is creatively set to 70-100 DEG C, and the vacuum degree is 5-30 mbar, so that the production conditions are optimized.

[0026] Example 1: Preparation of catalyst

[0027] Step 1: Under the condition of water bath, the pH value is oscillated between 3-10 by alternately adding 0.5 mol / L sulfuric acid solution and potassium aluminate and potassium chromate mixed solution in the flask with stirring, the ph range is monitored by using Ph test paper, the reaction time of acid side and alkaline side is 5 min, after the reaction is completed, the precipitate is aged for 4h, and washed until SO4 2- is not detected. Then the precipitate is placed in a muffle furnace for drying at 80 DEG C for 2h and calcination at 550 DEG C for 4h to obtain γ-Al2O3 / Cr2O3.

[0028] Step 2: The γ-Al2O3 / Cr2O3 carrier is impregnated with 0.5 mol / L H2PtCl6 solution for 2h, then dried at 80 DEG C for 2h, calcined at 550 DEG C for 4h, placed at room temperature, then impregnated with 0.5ml / L KNO3 solution for 2h, then dried at 80 DEG C for 2h, calcined at 550 DEG C for 4h, and then placed in a hydrogen environment for 20h.

[0029] Step 3: 1g of the catalyst is weighed in a tablet press, maintained at 10MPa pressure for 40s, and then sieved into powder using a 50 mesh sieve.

[0030] Example 2: Preparation of catalyst

[0031] Step 1: Under the condition of water bath, the pH value is oscillated between 3-10 by alternately adding 0.5 mol / L sulfuric acid solution and potassium aluminate and potassium chromate mixed solution in the flask with stirring, the ph range is monitored by using Ph test paper, the reaction time of acid side and alkaline side is 5 min, after the reaction is completed, the precipitate is aged for 4h, and washed until SO4 2- is not detected. Then the precipitate is placed in a muffle furnace for drying at 120 DEG C for 5h and calcination at 400 DEG C for 8h to obtain γ-Al2O3 / Cr2O3.

[0032] Step 2: The γ-Al2O3 / Cr2O3 carrier is impregnated with 0.5 mol / L H2PtCl6 solution for 6h, then dried at 100 DEG C, calcined at 400 DEG C for 8h, placed at room temperature, then impregnated with 0.5ml / L KNO3 solution for 6h, then dried at 80 DEG C for 5h, calcined at 400 DEG C for 8h, and then placed in a hydrogen environment for 20h.

[0033] Step 3: 1 g of catalyst was weighed in a tablet press, and after maintaining a pressure of 8 MPa for 45 s, it was sieved into powder using a 50-mesh sieve.

[0034] Example 3: Preparation of catalyst

[0035] Step 1: Under water bath conditions, a flask was stirred by alternately adding 0.5 mol / L sulfuric acid solution and a mixed solution of potassium aluminate and potassium chromate, so that the pH value oscillated between 3 and 10 for 10 times. Ph test paper was used to monitor the ph range, and the reaction time was 5 min on both the acidic side and the basic side. After the reaction was completed, the precipitate was aged for 4 h, washed, and SO4was not detected. 2- Then the precipitate was placed in a muffle furnace for drying at 180°C and calcination at 600°C for 3 h to obtain γ-Al2O3 / Cr2O3.

[0036] Step 2: The γ-Al2O3 / Cr2O3support was impregnated with 0.5 mol / L H2PtCl6solution for 10 h, then dried at 100°C for 8 h, calcined at 600°C for 3 h, and after standing at room temperature, it was impregnated with 0.5 ml / L KNO3solution for 10 h, then dried at 100°C for 2 h, calcined at 400°C for 8 h, and then placed in a hydrogen environment for 20 h.

[0037] Step 3: 1 g of catalyst was weighed in a tablet press, and after maintaining a pressure of 12 MPa for 50 s, it was sieved into powder using a 50-mesh sieve.

[0038] Example 4: Preparation of vinylene carbonate

[0039] The catalyst of Example 1 was fixed in the constant temperature zone of the reaction tube using quartz wool and quartz sand. The pipeline was heated to 40°C, the reaction tube was heated to 70°C, the pressure was stabilized at 10 mbar, and then the feed pump was started. Vinyl carbonate and furan were introduced into the reaction tube in a molar ratio of 1:1. During the synthesis process, distillation separation was carried out simultaneously. The reaction products were collected by atmospheric condensation device and detected by gas chromatography. The conversion rate of vinyl carbonate was 30%. After separation, the raw materials were returned to the reaction tube for continuous reaction. The total yield of the product was 80%.

[0040] Example 5: Preparation of vinylene carbonate

[0041] The catalyst of Example 1 was fixed in the constant temperature zone of the reaction tube with quartz wool and quartz sand. The pipeline insulation was opened, helium was purged, heating was turned on, the pipeline insulation was 40°C, the reaction tube was heated to 80°C, the pressure was 10 mbar and stable, then the feed pump was turned on, the amount of ethylene carbonate and furan according to the molar ratio of 1:2 was introduced into the reaction tube for reaction, the separation was carried out at the same time during the synthesis, the reaction product was collected by the normal pressure condensation device, and gas chromatography detection was carried out, the conversion rate of ethylene carbonate was 35%, after separation, the raw material returned to the reaction tube for continuous reaction, and the total yield of the product was 75%.

[0042] Example 6: Preparation of vinylene carbonate

[0043] The catalyst of Example 2 was fixed in the constant temperature zone of the reaction tube with quartz wool and quartz sand. The pipeline insulation was opened, helium was purged, heating was turned on, the pipeline insulation was 40°C, the reaction tube was heated to 100°C, the pressure was 5 mbar and stable, then the feed pump was turned on, the amount of ethylene carbonate and furan according to the molar ratio of 1:5 was introduced into the reaction tube for reaction, the separation was carried out at the same time during the synthesis, the reaction product was collected by the normal pressure condensation device, and gas chromatography detection was carried out, the conversion rate of ethylene carbonate was 50%, after separation, the raw material returned to the reaction tube for continuous reaction, and the total yield of the product was 70%.

[0044] Example 7: Preparation of vinylene carbonate

[0045] The catalyst of Example 3 was fixed in the constant temperature zone of the reaction tube with quartz wool and quartz sand. The pipeline insulation was opened, helium was purged, heating was turned on, the pipeline insulation was 40°C, the reaction tube was heated to 100°C, the pressure was 30 mbar and stable, then the feed pump was turned on, the amount of ethylene carbonate and furan according to the molar ratio of 1:10 was introduced into the reaction tube for reaction, the separation was carried out at the same time during the synthesis, the reaction product was collected by the normal pressure condensation device, and gas chromatography detection was carried out, the conversion rate of ethylene carbonate was 60%, after separation, the raw material returned to the reaction tube for continuous reaction, and the total yield of the product was 40%.

[0046] Comparative Example 1: Preparation of catalyst

[0047] Step 1: Under water bath conditions, 0.5 mol / L sulfuric acid solution and potassium aluminate and potassium chromate mixed solution were alternately added in a flask with stirring, so that the pH value oscillated between 3-10 for 10 times, the ph range was monitored using ph test paper, the reaction time of acidic side and basic side was 5 min, after the reaction was completed, the precipitate was aged for 4 h, washed, and SO4 2- was not detected. Then the precipitate was placed in a muffle furnace and dried at 80°C for 2 h and calcined at 550°C for 4 h to obtain γ-Al2O3 / Cr2O3.

[0048] Step 2: The γ-Al2O3 / Cr2O3 support was impregnated with 0.5 mol / L H2PtCl6 solution for 2 h, then dried at 80°C for 2 h, calcined at 550°C for 4 h, and then placed in a hydrogen environment for 20 h.

[0049] Step 3: 1 g of the catalyst was weighed into a tablet press, maintained at a pressure of 10 MPa for 40 s, and then sieved into powder using a 50 mesh sieve.

[0050] Preparation of Catalyst

[0051] Step 1: A 0.5 mol / L sulfuric acid solution and a mixed solution of potassium aluminate and potassium chromate were added to a flask under water bath conditions. After the reaction was completed, the precipitate was aged for 4 h, washed, and SO4was not detected. 2- The precipitate was then placed in a muffle furnace and dried at 80°C for 2 h and calcined at 550°C for 4 h to obtain Al2O3 / Cr2O3.

[0052] Step 2: The γ-Al2O3 / Cr2O3 support was impregnated with 0.5 mol / L H2PtCl6 solution for 2 h, then dried at 80°C for 2 h, calcined at 550°C for 4 h, and then placed in a hydrogen environment for 20 h.

[0053] Step 3: 1 g of the catalyst was weighed into a tablet press, maintained at a pressure of 10 MPa for 40 s, and then sieved into powder using a 50 mesh sieve.

[0054] Preparation of Ethylene Carbonate

[0055] The catalyst of Example 1 was fixed in the constant temperature zone of the reaction tube using quartz wool and quartz sand. The pipeline was heated to 40°C, the reaction tube was heated to 60°C, the pressure was stabilized at 10 mbar, and then the feed pump was started. The reaction was carried out in the reaction tube, and the reaction product was collected using a normal pressure condensation device and subjected to gas chromatography detection. The conversion rate of ethylene carbonate was 20%, and the total yield of the product was 50%.

[0056] Preparation of Ethylene Carbonate

[0057] The catalyst of Comparative Example 1 was used, and the catalyst was fixed in the constant temperature zone of the reaction tube with quartz wool and quartz sand. The pipeline was heated, helium was introduced for purging, and heating was started. The pipeline was heated to 40°C, the reaction tube was heated to 60°C, the pressure was 10 mbar and stabilized, and then the feed pump was started. Ethylene carbonate and furan were introduced into the reaction tube in a molar ratio of 1:1. During the synthesis, separation was carried out simultaneously, the reaction products were collected by a normal pressure condensation device, and gas chromatography detection was carried out. The conversion rate of ethylene carbonate was 20%, and after separation, the raw materials were returned to the reaction tube for continuous reaction. The total yield of the product was 50%.

[0058] Comparative Example 5: Preparation of vinylene carbonate

[0059] The catalyst of Comparative Example 1 was used, and the catalyst was fixed in the constant temperature zone of the reaction tube with quartz wool and quartz sand. The pipeline was heated, helium was introduced for purging, and heating was started. The pipeline was heated to 40°C, the reaction tube was heated to 120°C, the pressure was 10 mbar and stabilized, and then the feed pump was started. Ethylene carbonate and furan were introduced into the reaction tube in a molar ratio of 3:1. During the synthesis, separation was carried out simultaneously, the reaction products were collected by a normal pressure condensation device, and gas chromatography detection was carried out. The conversion rate of ethylene carbonate was 30%, and after separation, the raw materials were returned to the reaction tube for continuous reaction. The total yield of the product was 30%.

[0060] Comparative Example 6: Preparation of vinylene carbonate

[0061] The catalyst of Comparative Example 2 was used, and the catalyst was fixed in the constant temperature zone of the reaction tube with quartz wool and quartz sand. The pipeline was heated, helium was introduced for purging, and heating was started. The pipeline was heated to 40°C, the reaction tube was heated to 50°C, the pressure was 10 mbar and stabilized, and then the feed pump was started. Ethylene carbonate and furan were introduced into the reaction tube in a molar ratio of 2:1. During the synthesis, separation was carried out simultaneously, the reaction products were collected by a normal pressure condensation device, and gas chromatography detection was carried out. The conversion rate of ethylene carbonate was 5%, and after separation, the raw materials were returned to the reaction tube for continuous reaction. The total yield of the product was 10%.

[0062] Comparative Example 7: Preparation of vinylene carbonate

[0063] The catalyst of Example 3 was used, and the catalyst was fixed in the constant temperature zone of the reaction tube with quartz wool and quartz sand. The pipeline was heated, helium was introduced for purging, and heating was started. The pipeline was heated to 40°C, the reaction tube was heated to 90°C, the pressure was 50 mbar and stabilized, and then the feed pump was started. Ethylene carbonate and furan were introduced into the reaction tube in a molar ratio of 1:10. Under the pressure and temperature conditions, the product and the raw materials could not be separated by evaporation.

[0064] Furthermore, it should be understood that although the specification is described in terms of embodiments, not every embodiment includes every feature described. The specification can include implicit combinations of explicitly mentioned features and / or explicit combinations of implicitely mentioned features. Each embodiment depends on the explicit combinations of features and / or the implicit combinations of features made specifically within that embodiment, and each such embodiment can be combined with every other such embodiment to create further embodiments.

Claims

1. A method for preparing a catalyst, characterized in that, Using Al2O3 and Cr2O3 as supports, the supports are impregnated in a metal impregnation solution containing platinum to obtain the first impregnation product. The first impregnation product is dried, calcined, and then impregnated in a salt solution containing potassium to obtain the second impregnation product. The second impregnation product is then post-treated to obtain the catalyst. The platinum element loading rate on the support is 0.5%-0.8%, and the potassium element loading rate on the support is 0.05%-0.3%.

2. The method for preparing a catalyst according to claim 1, characterized in that, The carrier is immersed in a platinum-containing metal impregnation solution for 2-10 hours.

3. The method for preparing a catalyst according to claim 1, characterized in that, The first impregnation product is impregnated in a potassium-containing salt solution for 2-10 hours.

4. The method for preparing a catalyst according to claim 1, characterized in that, The drying temperature of the first impregnated product is 80-180℃, and the drying time is 2-8h. The calcination temperature of the first impregnated product is 400-600℃, and the calcination time is 3-8h.

5. The method for preparing a catalyst according to claim 1, characterized in that, The post-processing includes drying, calcining, reducing with hydrogen, and pressing at 8-12 MPa for 40-50 seconds on the second impregnated product.

6. The method for preparing a catalyst according to claim 5, characterized in that, The drying temperature of the second impregnated product is 80-180℃, and the drying time is 2-8h. The calcination temperature of the second impregnated product is 400-600℃, and the calcination time is 3-8h.

7. A catalyst, characterized in that, It is prepared by the method of any one of claims 1-6.

8. A method for synthesizing vinylene carbonate, characterized in that, Vinyl carbonate is obtained by reacting ethylene carbonate and furan as raw materials with the catalyst described in claim 7 at a temperature of 70-100°C and a vacuum of 5-30 mbar.

9. The method for synthesizing vinylene carbonate according to claim 8, characterized in that, The molar ratio of ethylene carbonate to furan is 1:1-10.