Solid catalyst for preparing ethylene carbonate and preparation method thereof

Abstract

The invention relates to the technical field of ethylene carbonate preparation, and discloses a solid catalyst for preparing ethylene carbonate and a preparation method thereof. The solid catalyst comprises a carrier, an active component and a halogen-containing compound, the active component and the halogen-containing compound are loaded on the carrier, and the active component is silver. The method comprises the following steps: (1) impregnating a carrier in a solution containing an active component precursor, and then sequentially standing in a dark place, drying and reducing to obtain a catalyst intermediate; and (2) loading a halogen-containing compound on the catalyst intermediate to obtain the solid catalyst. By adopting the solid catalyst disclosed by the invention, ethylene carbonate can be synthesized from ethylene, O2 and CO2 in one step in the same fixed bed reactor by adopting a continuous synthesis process, and the selectivity of ethylene carbonate is relatively high.

Description

Technical Field

[0001] The invention relates to the technical field of ethylene carbonate preparation, and in particular to a solid catalyst for preparing ethylene carbonate and a preparation method thereof. Background Art

[0002] Ethylene carbonate is an important cyclic organic carbonate product in the field of new energy. It has the advantages of low toxicity, high boiling point and good stability. It is widely used in key industries such as special environmentally friendly battery fluids and biodegradable materials. It is also used to produce high-end chemical products such as dimethyl carbonate and ethylene glycol. With the urgent demand for special electronic chemicals in my country's electric vehicle industry and the rapid development of the biodegradable materials industry, the new output value of ethylene carbonate and its derivatives will reach hundreds of billions of yuan in the next five years.

[0003] At present, my country's ethylene carbonate synthesis process faces the following technical difficulties: (1) The phosgene method is accompanied by the generation of a large amount of HCl, which seriously corrodes the equipment and has been eliminated; (2) The traditional urea alcoholysis method uses ethylene glycol as the raw material, and low-temperature synthesis is limited by thermodynamics, while high-temperature conditions have high energy consumption; (3) The carbon dioxide-ethylene oxide cycloaddition method is the most widely used, but the raw material ethylene oxide is expensive, and its separation, purification, storage and transportation costs are also high. In addition, ethylene oxide is flammable and explosive, and the safety risk is relatively large. How to reduce the energy consumption and pollution of ethylene carbonate synthesis and improve the process economy and environmental protection are major problems that the industry needs to solve urgently. In view of the above technical difficulties, it is urgent to develop a new generation of low-energy, high-efficiency, and environmentally friendly ethylene carbonate synthesis technology to improve my country's global competitiveness in the field of high-end chemical materials.

[0004] The continuous reaction process of synthesizing ethylene carbonate directly from ethylene with oxygen and carbon dioxide belongs to the new generation of ethylene carbonate synthesis technology. This technical route adopts a one-step continuous reaction process, which significantly simplifies the process, eliminates the separation, purification, storage and transportation of ethylene oxide, significantly reduces process energy consumption, and improves the economy and safety of the whole process. In addition, the whole process generates nearly zero waste. After ethylene is epoxidized to generate ethylene oxide, it is immediately cycloadded with carbon dioxide to generate ethylene carbonate, which solves the problems of poor selectivity of ethylene oxide synthesis, high separation cost and high risk of explosion in storage and transportation, as well as the high energy consumption of urea alcoholysis, poor intrinsic safety of epoxidation and cycloaddition reactions and complex processes.

[0005] Patent application CN114768694A discloses a device for preparing ethylene carbonate and a process thereof, which realizes the synthesis of ethylene carbonate by epoxidation of ethylene and cycloaddition of ethylene oxide and carbon dioxide in series. However, the device is actually used to synthesize ethylene carbonate in two steps, firstly oxidizing ethylene into ethylene oxide under epoxidation conditions, and then synthesizing ethylene carbonate by reacting the obtained ethylene oxide with carbon dioxide under the action of a catalyst.

[0006] Patent application CN112480058A discloses a production system for directly preparing cyclic carbonate from olefins and its application, wherein olefins, oxygen and carbon dioxide are mixed and fed from the lower part of the reactor side wall, and a homogeneous composite catalyst is fed from the upper part of the reactor side wall, so that olefin epoxidation to epoxide and epoxide and carbon dioxide cycloaddition to synthesize cyclic carbonate in series are realized in the same reactor. However, it can be concluded from the embodiments that the system is mainly used for directly synthesizing styrene carbonate from styrene and carbon dioxide. In addition, since the reaction raw materials are all fed from the lower part of the reactor side wall, it is not suitable for gaseous olefin reactions such as ethylene and propylene because of easy flooding.

[0007] Patent application CN106966862B discloses a method for preparing propylene glycol and propylene carbonate simultaneously. The method is divided into two steps. First, propylene is oxidized to propylene oxide under epoxidation conditions, and then the obtained propylene oxide, water, carbon dioxide and another catalyst are contacted to synthesize propylene carbonate. The method adopts an intermittent reaction process and is divided into two steps. The process conditions need to be switched, which is time-consuming and labor-intensive. Although there is no need to separate and purify propylene oxide, the process is still relatively complicated. Summary of the invention

[0008] The purpose of the present invention is to provide a solid catalyst for preparing ethylene carbonate and a preparation method thereof. The solid catalyst of the present invention can be used to make ethylene, O 2 With CO 2 The direct continuous reaction to synthesize ethylene carbonate significantly simplifies the process, eliminates the steps of separation, purification, storage and transportation of ethylene oxide, and improves production efficiency through continuous production; significantly reduces process energy consumption and improves the economy of the entire process; the one-step direct synthesis has the same process conditions throughout the entire process, thus avoiding the problem of switching process conditions caused by different process conditions in the two-step method; and the solid catalyst is easy to separate, thus solving the limitation of difficult separation and high cost of homogeneous catalysts; the preparation system is simple, thus significantly reducing equipment investment.

[0009] In order to achieve the above object, the first aspect of the present invention provides a solid catalyst for preparing ethylene carbonate, the solid catalyst comprising a carrier and an active component and a halogen-containing compound loaded on the carrier, wherein the active component is silver.

[0010] Preferably, relative to 100 parts by weight of the carrier, the content of the active component is 0.1-5 parts by weight, preferably 1-4 parts by weight; the content of the halogen-containing compound in terms of halogen element is 0.1-5 parts by weight, preferably 1-3 parts by weight.

[0011] Preferably, the carrier is a catalyst carrier capable of providing acid and base active sites.

[0012] Preferably, the carrier is selected from at least one of a molecular sieve and a metal oxide.

[0013] Preferably, the molecular sieve is TS-1 titanium silicalite molecular sieve.

[0014] Preferably, the metal oxide is aluminum oxide, magnesium oxide, zinc oxide and mixed metal oxides thereof.

[0015] Preferably, the carrier is magnesium aluminum hydrotalcite.

[0016] Preferably, the halogen-containing compound is butylammonium bromide, propylammonium bromide, ZnBr 2 , KBr and KI.

[0017] The second aspect of the present invention provides a method for preparing the above-mentioned solid catalyst, the method comprising:

[0018] (1) immersing the support in a solution containing an active component precursor, and then sequentially placing the solution in a dark place, drying the solution, and reducing the solution to obtain a catalyst intermediate;

[0019] (2) Loading a halogen-containing compound on the catalyst intermediate to obtain the solid catalyst.

[0020] Preferably, the carrier is a catalyst carrier capable of providing acid and base active sites.

[0021] Preferably, the carrier is selected from at least one of a molecular sieve and a metal oxide.

[0022] Preferably, the molecular sieve is TS-1 titanium silicalite molecular sieve.

[0023] Preferably, the metal oxide is aluminum oxide, magnesium oxide, zinc oxide and mixed metal oxides thereof.

[0024] Preferably, the active component precursor is at least one of silver nitrate, silver acetate and silver chloride.

[0025] Preferably, when the halogen-containing compound is butylammonium bromide and / or propylammonium bromide, the process of loading the halogen-containing compound on the catalyst intermediate comprises: reacting the catalyst intermediate, 3-(aminopropyl)triethoxysilane and n-butyl bromide and / or n-propyl bromide under reflux conditions in the presence of an organic solvent, and collecting, washing and drying the solid after the reaction is completed.

[0026] Preferably, when the halogen-containing compound is ZnBr 2 When at least one of KBr and KI is present, the process of loading the halogen-containing compound on the catalyst intermediate comprises: placing the catalyst intermediate in an aqueous solution of the halogen-containing compound, stirring, filtering, washing and drying.

[0027] According to the technical solution of the present invention, the solid catalyst of the present invention can be used to make ethylene, O 2 With CO 2 Ethylene carbonate is directly and continuously synthesized through a one-step reaction, and the selectivity of ethylene carbonate is high; moreover, by adopting the solid catalyst of the present invention, ethylene carbonate can be directly synthesized in one reactor, while in the prior art, the reaction generally needs to be carried out in two steps, and the catalysts used in the two steps are different, the reaction conditions are different, and different reaction conditions need to be switched; furthermore, compared with the traditional two-step method for synthesizing ethylene carbonate, the solid catalyst of the present invention for synthesizing ethylene carbonate significantly simplifies the process, eliminates the steps of separation and purification of ethylene oxide and storage and transportation, significantly reduces the process energy consumption, and improves the economy of the whole process; in addition, the solid catalyst of the present invention is easy to separate and reuse, and the overall cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of an embodiment of a system for preparing ethylene carbonate by continuous reaction;

[0029] Figure 2 The present invention is a schematic diagram of another embodiment of a system for preparing ethylene carbonate by continuous reaction.

[0030] Description of Reference Numerals

[0031] 1. Gas mixing unit; 2. Fixed bed reactor; 3. Gas-liquid separation unit; 4. Raw gas circulation unit. DETAILED DESCRIPTION

[0032] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0033] 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.

[0034] The solid catalyst of the present invention comprises a carrier and an active component and a halogen-containing compound loaded on the carrier, wherein the active component is silver.

[0035] In the solid catalyst, the content of the active component can be 0.1-5 parts by weight, preferably 1-4 parts by weight, relative to 100 parts by weight of the carrier. For example, it can be 1 part by weight, 1.3 parts by weight, 1.5 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.3 parts by weight, 2.5 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.2 parts by weight, 3.5 parts by weight, 3.7 parts by weight or 4 parts by weight.

[0036] In the solid catalyst, the content of the halogen-containing compound is calculated as halogen content. Relative to 100 parts by weight of the carrier, the content of the halogen-containing compound in terms of halogen element can be 0.1-5 parts by weight, preferably 1-3 parts by weight, and specifically, for example, can be 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.5 parts by weight, 1.7 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.4 parts by weight, 2.5 parts by weight, 2.7 parts by weight, 2.8 parts by weight or 3 parts by weight.

[0037] In the present invention, the carrier may be a catalyst carrier conventionally used in the art. Preferably, the carrier is a catalyst carrier capable of providing acid and base active sites. Further preferably, the carrier is at least one of a molecular sieve and a metal oxide.

[0038] In the present invention, the molecular sieve may be a titanium silicalite molecular sieve having a multi-level pore structure (such as micropores and mesopores). In a preferred embodiment, in order to obtain a higher selectivity for ethylene carbonate, the molecular sieve is a TS-1 titanium silicalite molecular sieve.

[0039] In the present invention, the metal oxide may be aluminum oxide, magnesium oxide, zinc oxide, and mixed metal oxides thereof. The mixed metal oxide may be, for example, magnesium aluminum hydrotalcite and / or zinc magnesium aluminum hydrotalcite.

[0040] In the present invention, the halogen-containing compound may be butylammonium bromide, propylammonium bromide, ZnBr 2 In a preferred embodiment, the halogen-containing compound is ZnBr 2 , KBr and KI.

[0041] In a preferred embodiment, the solid catalyst comprises a carrier and an active component and a halogen-containing compound supported on the carrier, wherein the carrier is magnesium aluminum hydrotalcite, the active component is silver, and the halogen-containing compound is ZnBr 2 According to the preferred embodiment, the solid catalyst is used to prepare ethylene carbonate, which can further improve the selectivity of ethylene carbonate.

[0042] The present invention also provides a method for preparing the solid catalyst, which comprises:

[0043] (1) immersing the support in a solution containing an active component precursor, and then sequentially placing the solution in a dark place, drying the solution, and reducing the solution to obtain a catalyst intermediate;

[0044] (2) Loading a halogen-containing compound on the catalyst intermediate to obtain the solid catalyst.

[0045] In the method of the present invention, the carrier can be a catalyst carrier conventionally used in the art. Preferably, the carrier is a catalyst carrier capable of providing acid-base active sites. Further preferably, the carrier is at least one of a molecular sieve and a metal oxide.

[0046] In the present invention, the molecular sieve may be a titanium silicalite molecular sieve having a multi-level pore structure (such as micropores and mesopores). In a preferred embodiment, in order to obtain a higher selectivity for ethylene carbonate, the molecular sieve is a TS-1 titanium silicalite molecular sieve.

[0047] In the present invention, the metal oxide may be aluminum oxide, magnesium oxide, zinc oxide, and mixed metal oxides thereof. The mixed metal oxide may be, for example, magnesium aluminum hydrotalcite and / or zinc magnesium aluminum hydrotalcite.

[0048] In the method of the present invention, the active component precursor may be at least one of silver nitrate, silver acetate and silver chloride.

[0049] In the method described in the present invention, in step (1), the process of standing in the dark is carried out at room temperature, and the time of standing in the dark can be 5-48 hours.

[0050] In the method of the present invention, in step (1), the drying temperature can be 60-100°C.

[0051] In the method of the present invention, in step (1), the reduction is carried out in an atmosphere containing hydrogen. The hydrogen-containing atmosphere can be a hydrogen-nitrogen mixed gas, and the content of hydrogen in the hydrogen-nitrogen mixed gas is 5 volume % or more, preferably 8-20 volume %. The reduction conditions may include: a temperature of 250-350° C. and a time of 1-10 hours.

[0052] In the method of the present invention, in the solid catalyst finally prepared, the halogen-containing compound can be butylammonium bromide, propylammonium bromide, ZnBr 2 In a preferred embodiment, the halogen-containing compound is ZnBr 2 , KBr and KI.

[0053] In some embodiments, when the halogen-containing compound is butylammonium bromide and / or propylammonium bromide, the process of loading the halogen-containing compound on the catalyst intermediate in step (2) includes: reacting the catalyst intermediate, 3-(aminopropyl)triethoxysilane and n-butyl bromide and / or n-propyl bromide under reflux conditions in the presence of an organic solvent, and collecting, washing and drying the solid after the reaction is completed.

[0054] In other embodiments, when the halogen-containing compound is ZnBr 2 When at least one of KBr and KI is present, the process of loading the halogen-containing compound on the catalyst intermediate in step (2) comprises: placing the catalyst intermediate in an aqueous solution of the halogen-containing compound, stirring, filtering, washing and drying.

[0055] According to a preferred embodiment of the present invention, the carrier is magnesium aluminum hydrotalcite, and the halogen-containing compound is ZnBr 2 , KBr and KI, the preparation method of the solid catalyst comprises: immersing magnesium aluminum hydrotalcite in a solution containing an active component precursor (such as silver nitrate), and then sequentially placing it in a dark place, drying and reducing it to obtain a catalyst intermediate; then placing the catalyst intermediate in a halogen-containing compound aqueous solution, stirring, filtering, washing and drying to obtain the solid catalyst.

[0056] In the method described in the present invention, the amounts of the carrier, the active component precursor and the raw material for providing the halogen-containing compound are such that in the prepared solid catalyst, the content of the active component can be 0.1-5 parts by weight, preferably 1-4 parts by weight, relative to 100 parts by weight of the carrier; the content of the halogen-containing compound in terms of halogen element can be 0.1-5 parts by weight, preferably 1-3 parts by weight.

[0057] The process of preparing ethylene carbonate using the solid catalyst of the present invention can be Figure 1 The system shown is implemented in the embodiment, specifically, the system includes:

[0058] The raw gas supply unit is used to supply ethylene, O 2 and CO 2 ;

[0059] A gas mixing unit 1 is used to mix ethylene, O 2 and CO 2 Mixing is performed;

[0060] A fixed bed reactor 2, which is filled with a solid catalyst, through which the mixed gas from the gas mixing unit is reacted, wherein the solid catalyst is the solid catalyst provided by the present invention;

[0061] A gas-liquid separation unit 3, used for performing gas-liquid separation on the reaction product of the fixed bed reactor;

[0062] The raw gas circulation unit 4 is used to return the gas phase components separated in the gas-liquid separation unit to the gas mixing unit and / or the fixed bed reactor for recycling.

[0063] In the system, the gas mixing unit 1 may be a static gas mixer or a tube-in-tube gas mixer. Figure 1 As shown, the gas mixing unit 1 is composed of two groups of static gas mixers. First, carbon dioxide and oxygen are mixed in the first static gas mixer to form a mixed gas of carbon dioxide and oxygen. Then, the mixed gas is mixed with ethylene in the second static gas mixer to achieve uniform mixing of ethylene, oxygen and carbon dioxide. When the gas mixing unit 1 is a tube-in-tube gas mixer, the tubes of the tube-in-tube gas mixer are oxygen permeable membrane tubes, such as Figure 2 As shown, ethylene and carbon dioxide are mixed through the pipeline and enter the shell side, and oxygen (for example, provided by air) enters the tube side. There is a positive pressure drop between the tube side and the shell side. Due to the pressure drop, oxygen passes through the membrane tube and enters the shell side to achieve mixing with ethylene and carbon dioxide. The oxygen permeation rate is adjusted by the pressure drop.

[0064] In the system, the fixed bed reactor 2 is a downward fixed bed reactor. The gas mixing unit 1 is connected to the fixed bed reactor 2 through a pipeline, and the mixed gas from the gas mixing unit 1 enters the downward fixed bed reactor by self-pressure, and passes through the catalyst bed in the fixed bed reactor from top to bottom. Preferably, a one-way valve is provided on the connecting pipeline between the gas mixing unit 1 and the fixed bed reactor 2 to prevent the material in the fixed bed reactor from being reversed.

[0065] In the system, the gas-liquid separation unit 3 can be a gas-liquid separation tank. The top and bottom of the gas-liquid separation tank are respectively provided with a discharge port, and the gas phase material is produced from the top discharge port, and the liquid phase material is produced from the bottom discharge port. Preferably, a defoamer is provided at the upper 1 / 5 of the gas-liquid separation tank to prevent the gas phase material from carrying liquid when the gas velocity is too fast.

[0066] In the system, the raw gas circulation unit 4 can be a high-pressure pump, which is used to inject the gaseous material extracted from the top outlet of the gas-liquid separation tank into the gas mixing unit and / or the fixed bed reactor to achieve the recycling of unreacted materials.

[0067] Preferably, each device in the system is made of 316L stainless steel.

[0068] In a specific embodiment, the process for preparing ethylene carbonate in the above system comprises:

[0069] Ethylene, O 2 and CO 2 The raw material is respectively transported to the gas mixing unit 1 through the raw material supply unit for mixing to obtain ethylene, O 2 and CO 2 A mixed gas of ethylene, O 2 and CO 2 The molar ratio is 1:(0.8-5):(4-20);

[0070] Passing the mixed gas from the gas mixing unit 1 into the fixed bed reactor 2 to react at 150-260° C., wherein the fixed bed reactor is filled with a solid catalyst as a catalyst bed, and the solid catalyst is the solid catalyst provided by the present invention;

[0071] The reaction product of the fixed bed reactor 2 is transported to the gas-liquid separation unit 3 for gas-liquid separation, and a crude ethylene carbonate product (i.e., a crude EC product) is obtained from the separated liquid phase;

[0072] The gas phase components separated from the gas-liquid separation unit 3 are returned to the gas mixing unit and / or the fixed bed reactor through the raw gas circulation unit 4 for recycling.

[0073] The solid catalyst for preparing ethylene carbonate and its preparation method of the present invention are further illustrated by examples. The examples are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following examples.

[0074] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.

[0075] Example 1

[0076] (1) Preparation of solid catalyst

[0077] Weigh 0.5g of silver nitrate and dissolve it in 10mL of water for later use, weigh 5g of magnesium aluminum hydrotalcite and place it in a 20mL brown glass bottle, use a pipette to take 5mL of silver nitrate aqueous solution and disperse it on the magnesium aluminum hydrotalcite in the brown bottle, cover the bottle cap, and stand it at room temperature in the dark for 12h, then place it in a 70℃ oven to dry. The obtained sample was reduced in a hydrogen-nitrogen mixed gas (hydrogen content is 10 volume %) at 300℃ for 5h to obtain a catalyst intermediate.

[0078] 2.0 g of the catalyst intermediate was weighed and placed in 300 mL of 0.8 mol / L potassium bromide aqueous solution and stirred for 4 h. The mixture was filtered and washed three times, and then dried at 70 ° C for 12 h to obtain a solid catalyst Cat-1, wherein the inductively coupled plasma emission spectrometer and ion chromatography tests showed that the silver content was 2.7 parts by weight relative to 100 parts by weight of magnesium aluminum hydrotalcite, and the content of potassium bromide in terms of bromine element was 2.1 parts by weight.

[0079] (2) Synthesis of Ethylene Carbonate

[0080] This embodiment Figure 1 The system shown is implemented, specifically, CO 2 and O 2 Mixing is achieved in a first static gas mixer according to a ratio to form a mixed gas; then the mixed gas and ethylene are mixed in a second static gas mixer according to a ratio to obtain a mixed raw gas, wherein ethylene / O 2 / CO 2 The molar ratio is 1 / 1 / 8, and the pressure of the gas mixing unit is 0.2MPa. The mixed raw material gas is pressed into the descending fixed bed reactor filled with solid catalyst Cat-1 by self-pressure. The outlet pressure of the fixed bed reactor is 0.1MPa, and the raw material space velocity is 8000mL / (g cat h), reaction temperature 200°C; the reaction products come out of the downward fixed bed reactor and enter the gas-liquid separation tank for separation, and the gas phase components (unreacted ethylene, O 2 and CO 2 ) are sampled and analyzed, and the rest are pumped into the gas mixing unit for recycling. The liquid component (crude ethylene carbonate) is taken from the bottom of the gas-liquid separation tank for analysis.

[0081] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 12.1% and the selectivity of ethylene carbonate was 92.2%.

[0082] Example 2

[0083] (1) Preparation of solid catalyst

[0084] A solid catalyst was prepared according to the method of Example 1, except that the amount of raw materials was adjusted so that in the prepared solid catalyst Cat-2, the silver content was 3.1 parts by weight relative to 100 parts by weight of magnesium aluminum hydrotalcite, and the potassium bromide content in terms of bromine element was 1.3 parts by weight.

[0085] (2) Synthesis of Ethylene Carbonate

[0086] This embodiment Figure 1 The system shown is implemented, specifically, CO 2 and O 2Mixing is achieved in a first static gas mixer according to a ratio to form a mixed gas; then the mixed gas and ethylene are mixed in a second static gas mixer according to a ratio to obtain a mixed raw gas, wherein ethylene / O 2 / CO 2 The molar ratio is 1 / 1 / 7, and the pressure of the gas mixing unit is 0.4 MPa. The mixed raw material gas is pressed into the descending fixed bed reactor filled with solid catalyst Cat-2 by self-pressure. The outlet pressure of the fixed bed reactor is 0.2 MPa, and the raw material space velocity is 6000 mL / (g cat h), reaction temperature 180°C; the reaction products come out of the downward fixed bed reactor and enter the gas-liquid separation tank for separation, and the gas phase components (unreacted ethylene, O 2 and CO 2 ) are sampled and analyzed, and the rest are pumped into the gas mixing unit for recycling. The liquid component (crude ethylene carbonate) is taken from the bottom of the gas-liquid separation tank for analysis.

[0087] Quantitative analysis and calculation by gas chromatography (with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 11.2% and the selectivity of ethylene carbonate was 91.3%.

[0088] Example 3

[0089] (1) Preparation of solid catalyst

[0090] A solid catalyst was prepared according to the method of Example 1, except that the amount of raw materials was adjusted so that in the prepared solid catalyst Cat-3, the silver content was 1.7 parts by weight relative to 100 parts by weight of magnesium aluminum hydrotalcite, and the potassium bromide content in terms of bromine element was 2.6 parts by weight.

[0091] (2) Synthesis of Ethylene Carbonate

[0092] This embodiment Figure 1 The system shown is implemented, specifically, CO 2 and O 2 Mixing is achieved in a first static gas mixer according to a ratio to form a mixed gas; then the mixed gas and ethylene are mixed in a second static gas mixer according to a ratio to obtain a mixed raw gas, wherein ethylene / O 2 / CO 2 The molar ratio is 1 / 1 / 6, and the pressure of the gas mixing unit is 0.5MPa; the mixed raw material gas is pressed into the descending fixed bed reactor filled with solid catalyst Cat-3 by self-pressure, the outlet pressure of the fixed bed reactor is 0.3MPa, and the raw material space velocity is 7000mL / (g cat h), reaction temperature 230°C; the reaction products come out of the downward fixed bed reactor and enter the gas-liquid separation tank for separation, and the gas phase components (unreacted ethylene, O 2 and CO2 ) are sampled and analyzed, and the rest are pumped into the gas mixing unit for recycling. The liquid component (crude ethylene carbonate) is taken from the bottom of the gas-liquid separation tank for analysis.

[0093] Quantitative analysis and calculation by gas chromatography (with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 10.1% and the selectivity of ethylene carbonate was 92.4%.

[0094] Example 4

[0095] (1) Preparation of solid catalyst

[0096] A solid catalyst was prepared according to the method of Example 1, except that potassium iodide aqueous solution was used instead of potassium bromide aqueous solution to prepare solid catalyst Cat-4, wherein the silver content was 2.1 parts by weight relative to 100 parts by weight of magnesium aluminum hydrotalcite, and the potassium iodide content in terms of iodine element was 2.2 parts by weight.

[0097] (2) Synthesis of Ethylene Carbonate

[0098] This embodiment Figure 1 The system shown is implemented, specifically, CO 2 and O 2 Mixing is achieved in a first static gas mixer according to a ratio to form a mixed gas; then the mixed gas and ethylene are mixed in a second static gas mixer according to a ratio to obtain a mixed raw gas, wherein ethylene / O 2 / CO 2 The molar ratio is 1 / 1 / 5, and the pressure of the gas mixing unit is 0.8MPa; the mixed raw material gas is pressed into the descending fixed bed reactor filled with solid catalyst Cat-4 by self-pressure, the outlet pressure of the fixed bed reactor is 0.5MPa, and the raw material space velocity is 10000mL / (g cat h), reaction temperature 210°C; the reaction products come out of the downward fixed bed reactor and enter the gas-liquid separation tank for separation, and the gas phase components (unreacted ethylene, O 2 and CO 2 ) are sampled and analyzed, and the rest are pumped into the gas mixing unit for recycling. The liquid component (crude ethylene carbonate) is taken from the bottom of the gas-liquid separation tank for analysis.

[0099] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 9.7% and the selectivity of ethylene carbonate was 91.1%.

[0100] Example 5

[0101] (1) Preparation of solid catalyst

[0102] A solid catalyst was prepared according to the method of Example 1, except that zinc-magnesium-aluminum hydrotalcite was used instead of magnesium-aluminum hydrotalcite, to prepare a solid catalyst Cat-5.

[0103] (2) Synthesis of Ethylene Carbonate

[0104] Ethylene carbonate was synthesized according to the method of Example 1, except that the solid catalyst Cat-5 was loaded in the descending fixed bed reactor.

[0105] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 11.9% and the selectivity of ethylene carbonate was 93.3%.

[0106] Example 6

[0107] (1) Preparation of solid catalyst

[0108] A solid catalyst was prepared according to the method of Example 1, except that the same molar amount of silver acetate was used instead of silver nitrate to obtain a solid catalyst Cat-6.

[0109] (2) Synthesis of Ethylene Carbonate

[0110] Ethylene carbonate was synthesized according to the method of Example 1, except that the solid catalyst Cat-6 was loaded in the descending fixed bed reactor.

[0111] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 11.6% and the selectivity of ethylene carbonate was 91.3%.

[0112] Example 7

[0113] (1) Preparation of solid catalyst

[0114] A solid catalyst was prepared according to the method of Example 1, except that the same molar amount of silver chloride was used instead of silver nitrate to obtain a solid catalyst Cat-7.

[0115] (2) Synthesis of Ethylene Carbonate

[0116] Ethylene carbonate was synthesized according to the method of Example 1, except that the solid catalyst Cat-7 was loaded in the descending fixed bed reactor.

[0117] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 11.8% and the selectivity of ethylene carbonate was 91.5%.

[0118] Example 8

[0119] (1) Preparation of solid catalyst

[0120] The catalyst intermediate was prepared according to the method of Example 1.

[0121] Weigh 2.0 g of the catalyst intermediate and place it in a 200 ml round-bottom flask. Add 50 ml of toluene and 1.2 g of 3-(Aminopropyl)triethoxysilane; a reflux condenser is inserted into the middle opening of a three-necked flask, one of the side openings is plugged with a stopper, and the other opening is plugged with a rubber stopper with an air guide tube, and nitrogen is introduced into the air guide tube to replace the air in the three-necked flask and the reflux condenser; the three-necked flask is heated in an oil bath, and the temperature is raised to 110°C and then refluxed at a constant temperature for 12 hours; 2.01g of n-butyl bromide is added to the three-necked flask, and refluxed at a constant temperature of 110°C for 24 hours; after the reaction is completed, the solid is collected, washed three times with dichloromethane and anhydrous ethanol in sequence, and dried at 70°C for 12 hours to obtain a solid catalyst Cat-8, wherein, according to the tests by inductively coupled plasma emission spectrometry and ion chromatography, the silver content is 2.7 parts by weight relative to 100 parts by weight of magnesium aluminum hydrotalcite, and the content of butyl ammonium bromide in terms of bromine element is 2.0 parts by weight.

[0122] (2) Synthesis of Ethylene Carbonate

[0123] Ethylene carbonate was synthesized according to the method of Example 1, except that the solid catalyst Cat-8 was loaded in the descending fixed bed reactor.

[0124] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 8.8% and the selectivity of ethylene carbonate was 85.4%.

[0125] Example 9

[0126] (1) Preparation of solid catalyst

[0127] A solid catalyst was prepared according to the method of Example 8, except that 1.80 g of n-propane bromide was used instead of n-butane bromide to obtain a solid catalyst Cat-9, wherein the silver content was 2.7 parts by weight relative to 100 parts by weight of magnesium aluminum hydrotalcite, and the content of propylammonium bromide in terms of bromine element was 2.0 parts by weight.

[0128] (2) Synthesis of Ethylene Carbonate

[0129] Ethylene carbonate was synthesized according to the method of Example 1, except that the solid catalyst Cat-9 was loaded in the descending fixed bed reactor.

[0130] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 8.5% and the selectivity of ethylene carbonate was 84.8%.

[0131] Example 10

[0132] (1) Preparation of solid catalyst

[0133] A solid catalyst was prepared according to the method of Example 1, except that the same mass of TS-1 titanium silicon molecular sieve was used instead of magnesium aluminum hydrotalcite to prepare a solid catalyst Cat-10.

[0134] (2) Synthesis of Ethylene Carbonate

[0135] Ethylene carbonate was synthesized according to the method of Example 1, except that the solid catalyst Cat-10 was loaded in the descending fixed bed reactor.

[0136] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 9.2% and the selectivity of ethylene carbonate was 88.7%.

[0137] Comparative Example 1

[0138] The solid catalyst was prepared and ethylene carbonate was synthesized according to the method of Example 1, except that the catalyst intermediate prepared in Example 1 was directly used as the solid catalyst D1 (that is, the solid catalyst was not loaded with a halogen-containing compound); and in the process of synthesizing ethylene carbonate, the solid catalyst loaded in the fixed bed reactor was the solid catalyst D1.

[0139] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 11.7% and the selectivity of ethylene carbonate was 16.3%.

[0140] Comparative Example 2

[0141] The solid catalyst was prepared and ethylene carbonate was synthesized according to the method of Example 1, except that, in the process of preparing the solid catalyst, silver nitrate was not added to obtain solid catalyst D2 (i.e., the solid catalyst was not loaded with silver); and, in the process of synthesizing ethylene carbonate, the solid catalyst loaded in the fixed bed reactor was solid catalyst D2.

[0142] Quantitative analysis and calculation by gas chromatography (equipped with HP-1 chromatographic column) revealed that the single-pass conversion of ethylene was 0% and the selectivity of ethylene carbonate was 0%.

[0143] It can be seen from the results of the above examples and comparative examples that the solid catalyst of the present invention can be used to realize the continuous synthesis process of ethylene, O 2 With CO 2 Ethylene carbonate is synthesized in one step in the same fixed bed reactor with high selectivity for ethylene carbonate.

[0144] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A solid catalyst for preparing ethylene carbonate, It is characterized in that The solid catalyst comprises a carrier, and an active component and a halogen-containing compound loaded on the carrier, wherein the active component is silver.

2. The solid catalyst according to claim 1, It is characterized in that Relative to 100 parts by weight of the carrier, the content of the active component is 0.1-5 parts by weight, preferably 1-4 parts by weight; the content of the halogen-containing compound in terms of halogen element is 0.1-5 parts by weight, preferably 1-3 parts by weight.

3. The solid catalyst according to claim 1 or 2, It is characterized in that The carrier is a catalyst carrier capable of providing acid and base active sites; Preferably, the carrier is selected from at least one of a molecular sieve and a metal oxide; Preferably, the molecular sieve is TS-1 titanium silicalite molecular sieve; Preferably, the metal oxide is aluminum oxide, magnesium oxide, zinc oxide and mixed metal oxides thereof.

4. The solid catalyst according to claim 4, It is characterized in that The carrier is magnesium aluminum hydrotalcite.

5. The solid catalyst according to claim 1 or 2, It is characterized in that The halogen-containing compound is butylammonium bromide, propylammonium bromide, ZnBr 2 , KBr and KI.

6. A method for preparing the solid catalyst according to claim 1, It is characterized in that The method includes: (1) immersing the support in a solution containing an active component precursor, and then sequentially placing the solution in a dark place, drying the solution, and reducing the solution to obtain a catalyst intermediate; (2) Loading a halogen-containing compound on the catalyst intermediate to obtain the solid catalyst.

7. The method according to claim 6, It is characterized in that The carrier is a catalyst carrier capable of providing acid and base active sites; Preferably, the carrier is selected from at least one of a molecular sieve and a metal oxide; Preferably, the molecular sieve is TS-1 titanium silicalite molecular sieve; Preferably, the metal oxide is aluminum oxide, magnesium oxide, zinc oxide and mixed metal oxides thereof.

8. The method according to claim 6, It is characterized in that The active component precursor is at least one of silver nitrate, silver acetate and silver chloride.

9. The method according to any one of claims 6 to 8, It is characterized in that When the halogen-containing compound is butylammonium bromide and / or propylammonium bromide, the process of loading the halogen-containing compound on the catalyst intermediate comprises: reacting the catalyst intermediate, 3-(aminopropyl)triethoxysilane and n-butyl bromide and / or n-propyl bromide under reflux conditions in the presence of an organic solvent, and collecting, washing and drying the solid after the reaction is completed.

10. The method according to any one of claims 6 to 8, It is characterized in that When the halogen-containing compound is ZnBr 2 When at least one of KBr and KI is present, the process of loading the halogen-containing compound on the catalyst intermediate comprises: placing the catalyst intermediate in an aqueous solution of the halogen-containing compound, stirring, filtering, washing and drying.

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