Synthesis system of cyclic carbonate

Abstract

The utility model belongs to the field of chemical production equipment, and discloses a cyclic carbonate synthesis system which comprises a reaction unit, the reaction unit is provided with a first feed port, a second feed port and a first discharge port, the first feed port is communicated with a carbon dioxide supply unit, the second feed port is communicated with an epoxide supply unit, and the first discharge port is communicated with a second discharge port. The reaction unit comprises a first continuous reactor, the first continuous reactor is provided with a reaction channel, the outer surface of the first continuous reactor is sleeved with a jacket, the first feeding port, the second feeding port and the first discharging port are communicated with the reaction channel, and the first feeding port, the second feeding port and the second discharging port are communicated with the reaction channel. A containing cavity is formed between the jacket and the first continuous reactor, a heat transfer fluid is arranged in the containing cavity, through the design, the reaction units are evenly heated through hot oil in the containing cavity, and then the stability of the cyclic carbonate preparation process is improved.

Description

Technical Field

[0001] The present application relates to the field of chemical production equipment, and in particular to a synthesis system for cyclic carbonates. Background Art

[0002] Cyclic carbonate is a kind of organic chemical and chemical product with high added value. It can be prepared by phosgene method, transesterification method, urea alcoholysis method and CO2 cycloaddition reaction method. Five-membered and six-membered carbonates are more common. It not only has the "three highs" characteristics of high dipole moment, high boiling point and high flash point, but also has the biodegradability that contributes to green and sustainable development, thus avoiding serious damage to the natural environment. At the same time, cyclic carbonate has the advantages of low toxicity and high dielectric properties, and can be used to replace traditional polar aprotic solvents (such as DMF banned by European REACH regulations) as electrolytes in lithium-ion batteries. In addition to playing an important role directly in various industries, cyclic carbonates are also one of their important uses as intermediates for medicines and important chemicals. In the chemical industry, the traditional method of preparing polycarbonate and non-isocyanate polyurethane often uses highly toxic bisphenols, phosgene and isocyanates, while the use of cyclic carbonates as substitutes has better solved this problem; at the same time, with the unique advantages of cyclic carbonates, they have been industrialized by companies such as Shell and Asahi Kasei for the preparation of important chemicals such as ethylene glycol and dimethyl carbonate. In the biomedical field, aliphatic polycarbonates prepared from cyclic carbonates are particularly important in biomaterials, such as prepared drug delivery nanoparticles, hydrogels, and 3D printed stents. It can be seen that cyclic carbonates have an extremely wide range of applications, and in the production process, the reaction units involved in the current preparation process include intermittent reaction units and continuous reactors, but the intermittent reaction unit can be filled with limited CO2, and the intermittent reaction unit has a long reaction time, up to tens of hours. Moreover, compared with the traditional process, the continuous process has the advantages of fast reaction rate, short time, and good process safety.

[0003] Chinese patent application 202210742771.2 discloses a method and system for synthesizing carbonates by a three-phase method of alkylene oxide and carbon dioxide, the method comprising: contacting and reacting liquid alkylene oxide and gaseous carbon dioxide with a solid resin catalyst to obtain a contacted material; after stopping the contact for any period of time, the method further comprises:

[0004] 1) washing the contacted material with a washing solvent until the alkylene oxide concentration is less than 1wt% and the carbonate concentration is less than 5wt%, thereby obtaining a resin catalyst sealed with a washing solvent;

[0005] 2) Optionally, the method further comprises: discharging the washing solvent in the liquid-sealed resin catalyst by solid-liquid separation, purging the washing solvent entrained by the replacement resin catalyst under heating conditions in an inert atmosphere and / or a carbon dioxide atmosphere to obtain a solid resin catalyst, and the heated purged tail gas;

[0006] This solution can effectively realize synthesis, recovery, and storage in one reaction unit, and in the absence of steam and other heat sources, it provides good thermal insulation for the reaction unit, effectively reducing the problem of gradual catalyst cracking caused by loss of temperature in the reaction unit in the absence of a heat source.

[0007] However, it can be seen from the scheme that the purpose of the scheme is more to solve the problems of the catalyst being unable to be stored for a long time and losing temperature due to the temporary disappearance of the heat source in the cyclic carbonate heterogeneous catalyst process.

[0008] The problem to be solved by the present application is: how to provide a cyclic carbonate production system with uniform heating during the reaction process. Utility Model Content

[0009] The purpose of the present application is to provide a synthesis system for cyclic carbonates, which synthesis system forms a containing chamber with the jacket and the reaction unit through a reaction channel arranged in a reaction unit and a jacket arranged on the outer surface of the reaction unit, and the reaction unit is uniformly heated by hot oil in the containing chamber, thereby improving the stability of the cyclic carbonate preparation process.

[0010] To achieve the above objectives, the technical solutions adopted in this application are:

[0011] A synthesis system for cyclic carbonates comprises a reaction unit, wherein the reaction unit is provided with a first feed port, a second feed port, and a first discharge port, wherein the first feed port is connected to a carbon dioxide supply unit, the second feed port is connected to an epoxide supply unit, and the first discharge port is connected to a condensation unit. The reaction unit comprises a first continuous reactor, wherein the first continuous reactor is provided with a reaction channel, and the outer surface of the first continuous reactor is provided with a jacket, wherein the first feed port, the second feed port, and the first discharge port are connected to the reaction channel, wherein a containing cavity is formed between the jacket and the first continuous reactor, and wherein a heat transfer fluid is provided in the containing cavity.

[0012] The beneficial effects of this application are:

[0013] The present application provides a synthesis system for cyclic carbonates. The synthesis system comprises a reaction channel arranged in a reaction unit and a jacket arranged on the outer surface of the reaction unit, so that the jacket and the reaction unit form a containing cavity, and the reaction unit is uniformly heated by hot oil in the containing cavity, thereby improving the stability of the cyclic carbonate preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the synthesis system of cyclic carbonate in Example 1;

[0015] Figure 2 is a cross-sectional view of the reaction channel in Example 1;

[0016] Figure 3 is a cross-sectional view of the reaction channel in Example 2;

[0017] Figure 4 is a cross-sectional view of the reaction channel in Example 2;

[0018] Figure 5 is a cross-sectional view of the reaction channel in Example 3;

[0019] Figure 6 This is a cross-sectional view of the reaction channel in Example 3. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. The components of the present application implemented as described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Example 1

[0022] refer to Figure 1-2 A synthesis system of cyclic carbonate comprises a reaction unit 1, wherein the reaction unit 1 is provided with a first feed port 2, a second feed port 3, and a first discharge port 4, wherein the first feed port 2 is connected to a carbon dioxide supply unit 5, the second feed port 3 is connected to an epoxide supply unit 6, and the first discharge port 4 is connected to a condensation unit 7, wherein the reaction unit 1 comprises a first continuous reactor 10, wherein the first continuous reactor 10 is provided with a reaction channel 9, and a jacket 8 is provided on the outer surface of the first continuous reactor 10, wherein the first feed port 2, the second feed port 3, and the first discharge port 4 are connected to the reaction channel 9, and a receiving cavity is formed between the jacket 8 and the first continuous reactor 10, and a heat transfer fluid is provided in the receiving cavity.

[0023] In actual use, two important raw materials for preparing cyclic carbonates: epoxide and carbon dioxide are fed into the reaction channel 9 of the reaction unit 1 through the epoxide supply unit 6 and the carbon dioxide supply unit 5 respectively. Then, after the carbon dioxide and epoxide are heated and reacted in the reaction unit 1, they flow out through the second continuous reactor 11 and flow into the condensation unit 7 for condensation to obtain cyclic carbonates.

[0024] During this process, a heat transfer fluid is filled into the accommodating cavity formed between the jacket 8 outside the reaction unit 1 and the reaction unit 1. The heat transfer fluid wraps around the outer surface of the reaction unit 1 to provide uniform and stable heat for the reaction unit 1, thereby improving the stability of the cyclic carbonate preparation process.

[0025] As a further preference of this embodiment, the reaction unit 1 also includes a second continuous reactor 11, one end of the second continuous reactor 11 is connected to the first discharge port 4, and the other end is connected to the condensation unit 7. Through continuous heat exchange and heat transfer between the first continuous reactor 10 and the second continuous reactor 11 and control of the flow rate of the carbon dioxide supply unit, the temperature and pressure of the carbon dioxide in the first continuous reactor 10 and the second continuous reactor 11 reach the conditions required for supercritical carbon dioxide, thereby making the carbon dioxide present a supercritical state. Since carbon dioxide in the supercritical state has the characteristics of both gas and liquid, the reaction rate can be effectively accelerated, and due to the continuous cycloaddition, the reaction time is effectively shortened and the production efficiency is improved.

[0026] Considering the heat exchange efficiency, the diameter of the reaction channel 9 in the present application increases and decreases alternately along its length direction. Such a setting increases the specific surface area of ​​the reaction channel 9, significantly improves its heat transfer efficiency, and further improves production efficiency.

[0027] Furthermore, since the carbon dioxide in the supercritical state needs to meet the temperature and pressure conditions of a minimum temperature of 31°C and a minimum pressure of 7.3 MPa, the carbon dioxide supply unit 5 is connected to the first feed port 2 through a first delivery pipe 13. The first delivery pipe 13 is provided with a first pump 14. The operator can control the flow rate of the first pump 14 to make the carbon dioxide in the reaction unit 1 reach the pressure conditions required for supercriticality, and combine the heat transfer and heat exchange between the heat transfer fluid and the reaction unit 1 to make the carbon dioxide reach the temperature conditions required for supercriticality, thereby realizing the supercriticality of carbon dioxide.

[0028] At the same time, as a conventional technical means in the art, the epoxide supply unit 6 is connected to the second feed port 3 through a second delivery pipe 15, and the second delivery pipe 15 is provided with a second pump 16;

[0029] The second continuous reactor 11 is connected to the condensing unit 7 through a third delivery pipe 17, and the third delivery pipe 17 is provided with a first valve 18. More preferably, it also includes a fourth delivery pipe 19, one end of the fourth delivery pipe 19 is connected to the epoxide supply unit 6, and the other end is connected to the second feed port 3. The fourth delivery pipe 19 is provided with a third pump 23, and the second feed port 3 is provided with a second valve 20. The second valve 20 is a three-way valve, and the three-way valve is used to switch the connection relationship between the second delivery pipe 15, the fourth delivery pipe 19 and the second feed port 3. The fourth delivery pipe 19 is used as a spare delivery pipe between the epoxide supply unit 6 and the second feed port 3. When the second delivery pipe 15 is overhauled or cannot be used, the spare pipeline can still be used through the three-way valve, so as to continue to achieve the production of cyclic carbonate.

[0030] As a further preferred embodiment of the present invention, in order to prevent the waste gas generated in the production process of cyclic carbonate from polluting the environment, the condensing unit 7 is provided with an air outlet 21 and a second outlet 22, the air outlet 21 is connected to an external waste gas treatment device, and the second outlet 22 is connected to an external product collection device.

[0031] As a conventional technical means in the art, the heat transfer fluid is selected from any one of thermal oil, steam, and ethylene glycol.

[0032] Considering production cost and production stability, it is further preferred that the heat transfer fluid is heat transfer oil, and the heat transfer oil is selected from any one of benzene ring type heat transfer oil, alkyl naphthalene type heat transfer oil, alkyl biphenyl type heat transfer oil, biphenyl and biphenyl ether low melting mixture type heat transfer oil, alkyl biphenyl ether type heat transfer oil, and mineral type heat transfer oil. As for the specific type of heat transfer oil to be selected, this application does not impose too many restrictions, and the operator can make further selections on the type of heat transfer oil according to the actual temperature and heat transfer efficiency requirements.

[0033] Example 2

[0034] refer to Figure 3-4 , which is basically the same as Example 1, except that the diameter of the reaction channel 9 varies periodically along its length. By making the diameter of the reaction channel 9 vary periodically along its length, the flow stability of the fluid in the reaction channel 9 during the transmission process can be effectively improved, and the sudden change of the fluid flow rate caused by excessive diameter change can be avoided. At the same time, it should be noted that the present application recommends that the diameter of the reaction channel 9 varies periodically along its length and does not recommend a sudden change in the channel diameter. The reason is that the sudden change in the diameter causes the reaction channel 9 to form a relatively sharp inner wall, and this inner wall is not conducive to the flow of the fluid in the reaction channel 9. The present application expects that the diameter of the reaction channel 9 presents a relatively gentle and smooth change trend, thereby alleviating the change in the fluid flow rate in the reaction channel 9.

[0035] Example 3

[0036] refer to Figure 5-6 , which is basically the same as Example 1, except that a baffle 12 is provided on the inner wall of the reaction channel 9. It should be noted that, although in the process of preparing cyclic carbonates in the synthesis system of cyclic carbonates, with the continuous input of carbon dioxide and epoxide, the probability of fluid backflow in the reaction channel 9 is low, but for the sake of safety and stability of the production process, the present application still recommends setting a baffle 12 on the inner wall of the reaction channel 9; and, in actual use, the present application recommends setting the baffle 12 in the feeding direction of the reaction channel 9 to better prevent the fluid backflow in the reaction channel 9 during the preparation process.

[0037] In summary, the synthesis system of cyclic carbonate provided in the present application forms a containing chamber with the jacket and the reaction unit through a reaction channel arranged in the reaction unit and a jacket arranged on the outer surface of the reaction unit, and the reaction unit is evenly heated by the hot oil in the containing chamber, thereby improving the stability of the cyclic carbonate preparation process.

Claims

1. A synthesis system for cyclic carbonate, characterized in that: The invention comprises a reaction unit, wherein the reaction unit is provided with a first feed port, a second feed port, and a first discharge port, wherein the first feed port is connected to a carbon dioxide supply unit, the second feed port is connected to an epoxide supply unit, and the first discharge port is connected to a condensation unit. The reaction unit comprises a first continuous reactor, wherein the first continuous reactor is provided with a reaction channel, and the outer surface of the first continuous reactor is provided with a jacket, wherein the first feed port, the second feed port, and the first discharge port are connected to the reaction channel, wherein a containing cavity is formed between the jacket and the first continuous reactor, and wherein a heat transfer fluid is provided in the containing cavity.

2. The synthesis system of cyclic carbonate according to claim 1, characterized in that: The reaction unit further comprises a second continuous reactor, one end of the second continuous reactor is connected to the first discharge port, and the other end of the second continuous reactor is connected to the condensation unit.

3. The synthesis system of cyclic carbonate according to claim 1, characterized in that: The diameter of the reaction channel increases and decreases alternately along its length.

4. The synthesis system of cyclic carbonate according to claim 1, characterized in that: The diameter of the reaction channel changes periodically along its length direction.

5. The synthesis system of cyclic carbonate according to claim 1, characterized in that: The inner wall of the reaction channel is provided with a baffle, and the baffle is used to prevent the fluid in the reaction channel from flowing back.

6. The synthesis system of cyclic carbonate according to claim 2, characterized in that: The carbon dioxide supply unit is connected to the first feed port through a first delivery pipe, and the first delivery pipe is provided with a first pump; The epoxide supply unit is connected to the second feed port via a second delivery pipe, and the second delivery pipe is provided with a second pump; The second continuous reactor is connected to the condensing unit via a third delivery pipe, and the third delivery pipe is provided with a first valve.

7. The synthesis system of cyclic carbonate according to claim 6, characterized in that: It also includes a fourth delivery pipe, one end of which is connected to the epoxide supply unit, and the other end is connected to the second feed port. The fourth delivery pipe is provided with a third pump, and the second feed port is provided with a second valve, which is a three-way valve, and the three-way valve is used to switch the connection relationship among the second delivery pipe, the fourth delivery pipe and the second feed port.

8. The synthesis system of cyclic carbonate according to claim 1, characterized in that: The condensing unit is provided with an air outlet and a second material outlet, the air outlet is communicated with an external waste gas treatment device, and the second material outlet is communicated with an external product collection device.

9. The synthesis system of cyclic carbonate according to claim 1, characterized in that: The heat transfer fluid is selected from any one of thermal oil, steam and ethylene glycol.

10. The synthesis system of cyclic carbonate according to claim 1, characterized in that: The heat transfer fluid is heat transfer oil, which is selected from any one of benzene ring type heat transfer oil, alkyl naphthalene type heat transfer oil, alkyl biphenyl type heat transfer oil, biphenyl and biphenyl ether low melting mixture type heat transfer oil, alkyl biphenyl ether type heat transfer oil, and mineral type heat transfer oil.

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