Liquid-phase phosgenation reaction equipment and application thereof
By designing liquid phase phosgeneization reaction equipment and using retrograde convection and stirring devices, the problems of large usage and low utilization in traditional methods are solved, and efficient isocyanate preparation is achieved and product yield is improved.
Patent Information
- Application Number
- CN202411526653.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2024-12-13
AI Technical Summary
The liquid phase phosgene synthesis method of traditional isocyanate has problems such as large phosgene use, low phosgene utilization rate and low product yield.
A liquid phase phosgeneization reaction device is designed, including a reactor, a first condensation device and a second condensation device. Gas is input into the reactor through the intake device, and after condensation, liquid is transported to the second condensation device through the liquid discharge device. , the liquid film is formed by using the lowering film head to perform retrograde convection, improve gas utilization, and improve reaction efficiency through the stirring device and the material separation device.
When the phosgene usage is low, a higher phosgene utilization rate and product yield are obtained, which improves the preparation efficiency of isocyanate.
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Figure CN119113994A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of phosgenation reaction equipment, and in particular to a liquid phase phosgenation reaction equipment and its application. Background Art
[0002] The current preparation process of isocyanate includes two commonly used processes: gas phase phosgene method and liquid phase phosgene method. Among them, the gas phase phosgene method requires the liquid amine to be vaporized under high temperature conditions, and then reacted with gas phase phosgene to generate isocyanate. Since the process conditions have high requirements on the purity and form of the raw material amine and equipment, the production cost is relatively high. The overall process route of the liquid phase phosgene method is relatively simple, the requirements on raw materials and equipment are not high, and it has higher economic benefits.
[0003] However, the traditional liquid-phase phosgene synthesis method of isocyanate has the problems of large phosgene usage, low phosgene utilization rate and low product yield. Summary of the invention
[0004] Based on this, it is necessary to provide a liquid phase phosgenation reaction device and its application. The liquid phase phosgenation reaction device of the present application can be applied to the liquid phase phosgenation synthesis of isocyanate, and can obtain a higher phosgene utilization rate and a higher product yield when the phosgene usage is low.
[0005] In a first aspect, the present application provides a liquid-phase phosgenation reaction device, comprising: a reactor, a first condensing device, and a second condensing device;
[0006] The reactor is provided with an air inlet device and a first air outlet device, wherein the air inlet device is used to input gas into the reactor, and the air outlet device is used to transport the gas in the reactor to the first condensing device;
[0007] The first condensing device is used to condense gas, and a second gas outlet device and a liquid outlet device are provided on the first condensing device; the liquid outlet device is used to transport the condensed liquid to the second condensing device, and the second gas outlet device is used to transport the uncondensed gas to the second condensing device;
[0008] The second condensing device is used to condense gas, a falling film head is arranged in the second condensing device, and the output end of the liquid outlet device is connected to the input end of the falling film head; the falling film head is provided with a liquid outlet facing the inner wall of the second condensing device, and the falling film head is used to form a liquid film that can slide down along the inner wall of the second condensing device; the setting height of the liquid outlet of the falling film head is higher than the setting height of the output end of the second gas outlet device;
[0009] The second condensing device is also provided with a reflux device, and the reflux device is used to reflux the liquid to the reaction kettle.
[0010] In some embodiments, the liquid-phase phosgenation reaction equipment further comprises a stirring device, and the stirring device is disposed in the reactor;
[0011] The stirring device includes a stirring shaft, and a first stirring member and a second stirring member spaced apart on the stirring shaft; the first stirring member is closer to the bottom of the reactor than the second stirring member, the first stirring member is used to generate an axial flow field, and the second stirring member is used to generate a radial flow field.
[0012] In some embodiments, the first stirring element comprises a propeller, and the second stirring element comprises a disc turbine blade.
[0013] In some embodiments, the ratio of the maximum diameter of the first stirring member to the diameter of the reactor is (5-8):10.
[0014] In some embodiments, the liquid-phase phosgenation reaction equipment further includes a defoaming member, which is disposed on the stirring shaft and is used to break bubbles; compared with the second stirring member, the defoaming member is further away from the bottom of the reactor.
[0015] In some embodiments, the liquid-phase phosgenation reaction equipment further comprises a material distribution device, which is disposed in the reactor; compared with the stirring element for generating an axial flow field, the material distribution device is closer to the bottom of the reactor;
[0016] The output end of the air intake device is connected to the input end of the material distribution device, and the material distribution device is provided with a plurality of discharge holes arranged at intervals.
[0017] In some embodiments, the output end of the reflux device is connected to the input end of the material distribution device.
[0018] In some embodiments, the material distribution device is annular, and a plurality of discharge holes are spaced apart and distributed on one side of the material distribution device facing the bottom of the reactor.
[0019] In some embodiments, the liquid outlet device has a first U-shaped bend, and the first U-shaped bend can form a liquid seal in the liquid outlet device.
[0020] In some embodiments, the reflux device has a second U-shaped bend, and the second U-shaped bend can form a liquid seal in the reflux device.
[0021] In a second aspect, the present application provides a use of the liquid-phase phosgenation reaction equipment described in any one of the above items as a reactor in a liquid-phase phosgenation reaction.
[0022] In a third aspect, the present application provides an application of the liquid-phase phosgenation reaction equipment described in any one of the above items as a reactor in the liquid-phase synthesis of isocyanate.
[0023] In the above-mentioned liquid-phase phosgenation reaction equipment, gas raw materials are introduced into the reactor through the air inlet device, and a gas-liquid two-phase reaction or a gas-liquid-solid three-phase reaction can be carried out in the reactor. The unreacted gas in the reactor, the gas generated by the reaction, and the volatilized solvent and other gases can be transported to the first condensing device through the gas outlet device and then condensed, and then the liquid condensed in the first condensing device is transported to the second condensing device through the liquid outlet device. When the condensed liquid is transported to the second condensing device, the liquid can be discharged to the inner wall of the condensing device through a plurality of liquid outlets facing the inner wall of the second condensing device through a falling film head, forming a liquid film that can slide down along the inner wall of the second condensing device. At the same time, the setting height of the liquid outlet of the falling film head is higher than the setting height of the output end of the second gas outlet device. When the uncondensed gas in the first condensing device is transported to the second condensing device through the gas outlet device, the gas will rise from bottom to top. The gas rising from the bottom will form a reverse convection with the liquid film sliding down the inner wall of the second condensing device, so that the liquid absorbs the gas. At the same time, the second condensing device will also perform secondary condensation on the unabsorbed liquid, and after forming the liquid, it will be mixed with the above-mentioned liquid film, and then refluxed to the reactor through the reflux device to continue to participate in the reaction. The above-mentioned liquid-phase phosgenation reaction equipment can improve the utilization rate of gas raw materials, thereby obtaining a higher product yield. Furthermore, the liquid-phase phosgenation reaction equipment of the present application can be applied to the liquid-phase phosgene synthesis of isocyanates, and a higher phosgene utilization rate and a higher product yield can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG1 is a schematic structural diagram of a liquid phase phosgenation reaction device provided in one embodiment of the present application;
[0025] FIG2 is a partial enlarged schematic diagram of the structure within the dotted frame in FIG1 ;
[0026] FIG3 is a schematic structural diagram of a stirring device provided in one embodiment of the present application;
[0027] FIG4 is a schematic structural diagram of a first stirring member, a second stirring member and a defoaming member on a stirring device provided in an embodiment of the present application.
[0028] Description of Reference Numerals
[0029] 1. Reactor; 2. First condensing device; 3. Second condensing device; 4. Liquid outlet device; 5. Anti-impact device; 6. Falling film head; 7. Gas outlet; 8. Material distributor; 9. Stirring device; 10. Air inlet device; 11. Reflux device; 12. First stirring element; 13. Second stirring element; 14. Defoaming element; 15. First gas outlet device; 16. Second gas outlet device; 17. First U-shaped bend; 18. Second U-shaped bend. DETAILED DESCRIPTION
[0030] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.
[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.
[0032] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0034] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0035] 1 and 2, an embodiment of the present application provides a liquid-phase phosgenation reaction device, comprising: a reactor 1, a first condensing device 2 and a second condensing device 3; the reactor 1 is provided with an air inlet device 10 and a first air outlet device 15, the air inlet device 10 is used to input gas into the reactor 1, and the air outlet device is used to transport the gas in the reactor 1 to the first condensing device 2; the first condensing device 2 is used to condense the gas, and the first condensing device 2 is provided with a second air outlet device 16 and a liquid outlet device 4; the liquid outlet device 4 is used to transport the condensed liquid to the second condensing device 3, and the second air outlet device 16 is used to transport the condensed liquid to the second condensing device 3. The device 16 is used to transport the uncondensed gas to the second condensing device 3; the second condensing device 3 is used to condense the gas, and a falling film head 6 is arranged inside the second condensing device 3, and the output end of the liquid outlet device 4 is connected to the input end of the falling film head 6; the falling film head 6 is provided with a liquid outlet facing the inner wall of the second condensing device 3, and the falling film head 6 is used to form a liquid film that can slide down along the inner wall of the second condensing device 3; the setting height of the liquid outlet of the falling film head 6 is higher than the setting height of the output end of the second gas outlet device 16; the second condensing device 3 is also provided with a reflux device 11, and the reflux device 11 is used to reflux the liquid to the reactor 1.
[0036] In the above-mentioned liquid-phase phosgenation reaction equipment, gas raw materials are introduced into the reactor 1 through the gas inlet device 10, and a gas-liquid two-phase reaction or a gas-liquid-solid three-phase reaction can be carried out in the reactor 1. The unreacted gas, the gas generated by the reaction, and the volatilized solvent and other gases in the reactor 1 can be transported to the first condensing device 2 through the gas outlet device and can be condensed, and then the liquid condensed in the first condensing device 2 is transported to the second condensing device 3 through the liquid outlet device 4. When the condensed liquid is transported to the second condensing device 3, the liquid can be discharged to the inner wall of the condensing device through a plurality of liquid outlets facing the inner wall of the second condensing device 3 through the falling film head 6, forming a liquid film that can slide down along the inner wall of the second condensing device 3. At the same time, the setting height of the liquid outlet of the falling film head 6 is higher than the setting height of the output end of the second gas outlet device 16. When the uncondensed gas in the first condensing device 2 is transported to the second condensing device 3 through the gas outlet device, the gas will rise from the bottom to the top. The gas rising from the bottom will form a reverse convection with the liquid film sliding down the inner wall of the second condensing device 3, so that the liquid absorbs the gas. At the same time, the second condensing device 3 will also perform secondary condensation on the unabsorbed liquid, and the liquid will be mixed with the above-mentioned liquid film after forming the liquid, and then refluxed to the reactor 1 through the reflux device 11 to continue to participate in the reaction. The above-mentioned liquid phase phosgenation reaction equipment can improve the utilization rate of gas raw materials, thereby obtaining a higher product yield.
[0037] It is understandable that phosgene is also called carbonyl chloride, and its chemical formula is COCl2. The liquid phase phosgenation reaction equipment of the present application can be applied to liquid phase phosgenation reaction. Exemplarily, the liquid phase phosgenation reaction equipment of the present application can be applied to the liquid phase phosgene synthesis of isocyanate: after the addition is completed, phosgene is slowly introduced into the kettle. The hydrogen chloride and other gases produced by the reaction and the escaped phosgene will carry a small amount of solvent into the first condenser, and after being cooled down, they will be divided into a liquid phase (mainly a solvent) and a gas phase (mainly phosgene and hydrogen chloride) in the first condenser. The liquid phase enters the second condenser, and the solvent will continue to absorb the phosgene in the gas phase in the reverse direction after film formation. The unabsorbed phosgene is continued to be condensed into liquid light and flows back to the reactor with the absorption saturated solvent to continue to participate in the reaction, and the cycle is repeated until the reaction is completed. By using the liquid phase phosgenation reaction equipment, a higher phosgene utilization rate and a higher isocyanate product yield can be obtained.
[0038] As shown in Figure 3, in some embodiments, the liquid-phase phosgenation reaction equipment also includes a stirring device 9, which is arranged in the reactor 1; the stirring device 9 includes a stirring shaft, and a first stirring member 12 and a second stirring member 13 arranged at intervals on the stirring shaft; the first stirring member 12 is closer to the bottom of the reactor 1 than the second stirring member 13, the first stirring member 12 is used to generate an axial flow field, and the second stirring member 13 is used to generate a radial flow field.
[0039] The first stirring member 12 near the bottom of the reactor 1 is used to generate an axial flow field, which can push the reaction liquid in the reactor 1 to the bottom of the reactor 1, and then turn back and move upward along the inner wall of the reactor 1, so as to realize the circulation of the reaction liquid from bottom to top. The second stirring member 13 is used to generate a radial flow field, which can push the reaction raw materials near the stirring device 9 radially toward the side wall of the reactor 1, so that it can be better mixed with the reaction liquid that moves upward along the inner wall of the reactor 1, so as to achieve uniform mixing of gas-liquid two-phase or gas-liquid-solid three-phase. Furthermore, the contact between phosgene and other raw materials can be improved, and the utilization rate of phosgene can be improved.
[0040] 4 , in some embodiments, the first stirring member 12 includes a screw propeller, and the second stirring member 13 includes a disc turbine blade.
[0041] In some embodiments, the ratio of the maximum diameter of the first stirring member 12 to the diameter of the reactor 1 is (5-8):10.
[0042] The ratio of the maximum diameter of the first stirring member 12 to the diameter of the reactor 1 within the above range can make the liquid level rise within a suitable range to achieve a higher reaction yield. Optionally, the ratio of the maximum diameter of the first stirring member 12 to the diameter of the reactor 1 is 5:10, 5.5:10, 6:10, 6.5:10, 7:10, 7.5:10 or 8:10, or the ratio of the maximum diameter of the stirring member 12 to the diameter of the reactor 1 can also be within the range between any two of the above ratios.
[0043] In some embodiments, the liquid-phase phosgenation reaction equipment further includes a defoaming member 14 , which is disposed on the stirring shaft and is used to break bubbles; compared with the second stirring member 13 , the defoaming member 14 is further away from the bottom of the reactor 1 .
[0044] In the photochemical reaction, a large amount of insoluble gas hydrogen chloride is produced, accompanied by the escape of phosgene, and these gases will form dense small bubbles. Due to the existence of surface tension, these bubbles will not break immediately, and they will carry liquid and solid upwards. In severe cases, they will overflow from the kettle and even cause material impact. These small bubbles can be broken by the defoaming element 14.
[0045] In some embodiments, the defoaming member 14 includes a radial straight blade.
[0046] It can be understood that the number of the second stirring member 13 can be one or more, and the number of the defoaming member 14 can be one or more.
[0047] In some of the embodiments, the liquid-phase phosgenation reaction equipment further includes a material distribution device 8, which is disposed in the reactor 1; compared with the stirring element used to generate an axial flow field, the material distribution device 8 is closer to the bottom of the reactor 1; the output end of the air intake device 10 is connected to the input end of the material distribution device 8, and a plurality of discharge holes arranged at intervals are provided on the material distribution device 8.
[0048] The output end of the gas inlet device 10 is connected to the input end of the material distribution device 8. Through the multiple discharge holes of the material distribution device 8 arranged at intervals, the gas raw material introduced into the reactor 1 can be distributed more evenly in the reactor 1. At the same time, compared with the stirring member used to generate the axial flow field, the material distribution device 8 is closer to the bottom of the reactor 1, and it can also increase the contact between the gas raw material and the liquid raw material in the reactor 1 after the gas is introduced into the reactor 1. When the liquid-phase phosgenation reaction equipment of the present application is applied to the liquid-phase phosgenation reaction, the contact area and residence time between phosgene and other materials can be increased, and the utilization rate of phosgene can be improved.
[0049] Optionally, the number of the discharge holes is more than 5. Further optionally, the number of the discharge holes is 5 to 15. Further optionally, the number of the discharge holes is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15.
[0050] In some embodiments, the output end of the reflux device 11 is connected to the input end of the material distribution device 8 .
[0051] In some embodiments, the material distribution device 8 is annular, and a plurality of discharge holes are spaced apart and distributed on one side of the material distribution device 8 facing the bottom of the reactor 1 .
[0052] The discharge holes are spaced apart on one side of the distributing device 8 facing the bottom of the reactor 1, which can prevent the holes from being blocked when solid materials are added on the top; at the same time, when the reaction liquid is discharged, there is no liquid accumulation in the distributing device 8; at the same time, the phosgene can flow to the bottom, increasing the contact area and residence time between the phosgene and the material, and improving the utilization rate of the phosgene.
[0053] In some embodiments, the material distribution device 8 is a tubular material distribution device 8 .
[0054] In some embodiments, the diameter of the dividing device 8 is greater than 20 mm.
[0055] Optionally, the diameter of the material distribution device 8 is 20 mm to 200 mm. Further optionally, the diameter of the material distribution device 8 is 20 mm, 40 mm, 60 mm, 80 mm, 100 mm, 120 mm, 140 mm, 160 mm, 180 mm or 200 mm, or the diameter of the material distribution device 8 can also be within the range between any two of the above diameters.
[0056] In some embodiments, the diameter of the discharge hole is greater than 1 mm.
[0057] Optionally, the aperture of the discharge hole is 1 mm to 10 mm. Further optionally, the aperture of the discharge hole is 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm, or the aperture of the discharge hole can also be within the range between any two of the above apertures.
[0058] In some embodiments, the second condensing device 3 further has an air outlet 7 , and the air outlet 7 is used to discharge the uncondensed gas in the second condensing device 3 .
[0059] In some embodiments, the second condensing device 3 further includes an anti-shock device 5 , and the anti-shock device 5 is disposed around the periphery of the falling film head 6 .
[0060] In some embodiments, the liquid outlet device 4 has a first U-shaped bend 17 , and the first U-shaped bend 17 can form a liquid seal in the liquid outlet device 4 .
[0061] In some embodiments, the reflux device 11 has a second U-shaped bend 18 , and the second U-shaped bend 18 can form a liquid seal in the reflux device 11 .
[0062] Yet another embodiment of the present application provides a use of any of the above-mentioned liquid-phase phosgenation reaction equipment as a reactor in a liquid-phase phosgenation reaction.
[0063] Yet another embodiment of the present application provides a use of any of the above-mentioned liquid-phase phosgenation reaction equipment as a reactor in the liquid-phase synthesis of isocyanate.
[0064] Another embodiment of the present application provides a method for preparing isocyanate, using the above-mentioned liquid phase phosgenation reaction equipment, comprising the following steps:
[0065] Adding an organic solvent into the reaction kettle 1, and controlling the liquid level of the organic solvent to be between the defoaming element 14 and the second stirring element 13;
[0066] With stirring turned on, add the amine raw material into the reaction kettle 1;
[0067] Slowly introduce phosgene into reactor 1;
[0068] The phosgene and solvent escaped from the reaction are refluxed into the reactor 1 through the first condensation device 2 and the second condensation device 3 for recycling until the reaction is completed.
[0069] In some embodiments, the organic solvent includes at least one of toluene, chlorobenzene, o-dichlorobenzene, dimethyl carbonate and diethyl carbonate.
[0070] In some embodiments, the amine raw material includes an amine or at least one of an amine hydrochloride, an amine sulfate, an amine carbonate, and an amine nitrate.
[0071] In some embodiments, the amine raw material includes at least one of hexamethylenediamine or a salt thereof, isophoronediamine or a salt thereof, diphenylmethanediamine or a salt thereof, pentamethylenediamine or a salt thereof, toluenediamine or a salt thereof, and meta-xylylenediamine or a salt thereof.
[0072] The following are specific embodiments
[0073] Example 1
[0074] This embodiment uses a liquid-phase phosgenation reaction device as shown in FIG1 to prepare pentamethylene diisocyanate through a liquid-phase phosgenation reaction. Among them, the ratio of the diameter of the first stirring member to the diameter of the reactor is (5~8):10, and a defoaming member is provided. A certain amount of solvent and pentamethylene diamine sulfate are added to the reactor through the feed port. To avoid agglomeration, the maximum concentration of pentamethylene diamine sulfate is 40wt%. Subsequently, 1.2 times the theoretical required amount of phosgene is introduced at 65°C. It is observed that the liquid level rises by up to 20%, and the liquid reflux temperature of the first condensing device and the second condensing device is set to -10°C~10°C, and then the temperature in the kettle is raised to 180°C, and the reaction is terminated after 6h of reaction. The reaction solution is subjected to subsequent rectification treatment, and the reaction yield of pentamethylene diisocyanate is 95% after calculation.
[0075] Example 2
[0076] The difference between Example 2 and Example 1 is that 1.5 times the theoretical required amount of phosgene is introduced. The reaction yield of pentamethylene diisocyanate after calculation is 95.3%.
[0077] Example 3
[0078] The only difference between Example 3 and Example 1 is that the liquid reflux temperature of the first condensing device and the second condensing device is set to 15° C. to 25° C. The reaction was terminated after 8.6 hours of reaction, and the reaction yield of pentamethylene diisocyanate was calculated to be 87.2%.
[0079] Example 4
[0080] The only difference between Example 4 and Example 1 is that the liquid reflux temperature of the first condensing device and the second condensing device is set to 15°C to 25°C, and 2.5 times the theoretical required amount of phosgene is introduced. The reaction is terminated after 7.2 hours of reaction, and the reaction yield of pentamethylene diisocyanate is calculated to be 91.5%.
[0081] Example 5
[0082] The only difference between Example 5 and Example 1 is that the ratio of the diameter of the first stirring member to the diameter of the reactor is 1:3, and to avoid agglomeration, the maximum concentration of pentamethylenediamine sulfate is 20wt%, and phosgene 3 times the theoretical required amount is introduced, and it is observed that the liquid level rises by up to 50%. The reaction is terminated after 9 hours of reaction, and the reaction yield of pentamethylene diisocyanate is 88.4% after calculation.
[0083] Example 6
[0084] The only difference between Example 6 and Example 1 is that there is no defoaming part, and 2.5 times the theoretical required amount of phosgene is introduced, and the liquid level is observed to rise by up to 80%. The reaction is terminated after 7 hours of reaction, and the reaction yield of pentamethylene diisocyanate is calculated to be 89.5%.
[0085] Comparative Example 1
[0086] The only difference between Comparative Example 1 and Example 1 is that there is no second condensing device. The reaction was terminated after 6 hours of reaction, and the reaction yield of pentamethylene diisocyanate was calculated to be 45%.
[0087] Comparative Example 2
[0088] The difference between Comparative Example 2 and Example 1 is that a conventional stirring paddle is used, the ratio of the diameter of the first stirring member to the diameter of the reactor is 1:3, there is no second condensing device, and to avoid agglomeration, the maximum concentration of pentamethylenediamine sulfate is 20wt%, and 12 times the theoretical required amount of phosgene is introduced, and the maximum liquid level rise is observed to be 95%. The reaction is terminated after 12 hours of reaction, and the reaction yield of pentamethylenediisocyanate is 75% after calculation.
[0089] The results of each embodiment and comparative example are shown in the following table:
[0090]
[0091] By comparing the results of Example 1 and Example 2, it can be seen that the phosgene reflux effect of the liquid phase phosgenation reaction equipment is very good, and increasing the amount of phosgene used does not significantly reduce the reaction time and improve the reaction yield.
[0092] By comparing the results of Example 1 to Example 4, it can be seen that the lower the reflux temperature, the smaller the phosgene demand, the shorter the reaction time, and the higher the reaction yield.
[0093] By comparing the results of Example 1, Example 2 and Example 5, it can be seen that the larger the diameter of the first stirring member, the smaller the liquid level rise, the smaller the phosgene demand, the shorter the reaction time, the greater the material concentration, and the higher the reaction yield.
[0094] By comparing the results of Example 1, Example 2 and Example 6, it can be seen that the presence of the defoaming element can reduce the liquid level rise, reduce the amount of phosgene used, shorten the reaction time, and improve the reaction yield.
[0095] The results of Example 1 and Comparative Example 1 show that, under the same conditions, the reaction yield of the liquid-phase phosgenation reaction equipment with the second condensing device, i.e., with a falling film head, is much greater than the reaction yield of the reaction equipment without a falling film head.
[0096] Through the results of Examples 1 to 4 and Comparative Example 2, it is found that the liquid phase phosgenation reaction equipment has greater advantages than the traditional kettle reactor in terms of kettle filling amount, phosgene demand, reaction time, reaction yield, etc.
[0097] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0098] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims, and the description and drawings may be used to interpret the contents of the claims.
Claims
1. A liquid phase phosgenation reaction equipment, characterized in that: include: A reaction kettle, a first condensing device, and a second condensing device; The reactor is provided with an air inlet device and a first air outlet device, wherein the air inlet device is used to input gas into the reactor, and the air outlet device is used to transport the gas in the reactor to the first condensing device; The first condensing device is used to condense gas, and a second gas outlet device and a liquid outlet device are provided on the first condensing device; the liquid outlet device is used to transport the condensed liquid to the second condensing device, and the second gas outlet device is used to transport the uncondensed gas to the second condensing device; The second condensing device is used to condense gas, a falling film head is arranged in the second condensing device, and the output end of the liquid outlet device is connected to the input end of the falling film head; the falling film head is provided with a liquid outlet facing the inner wall of the second condensing device, and the falling film head is used to form a liquid film that can slide down along the inner wall of the second condensing device; the setting height of the liquid outlet of the falling film head is higher than the setting height of the output end of the second gas outlet device; The second condensing device is also provided with a reflux device, and the reflux device is used to reflux the liquid to the reaction kettle.
2. The liquid phase phosgenation reaction equipment according to claim 1, characterized in that: The liquid-phase phosgenation reaction equipment further comprises a stirring device, and the stirring device is arranged in the reaction kettle; The stirring device includes a stirring shaft, and a first stirring member and a second stirring member spaced apart on the stirring shaft; the first stirring member is closer to the bottom of the reactor than the second stirring member, the first stirring member is used to generate an axial flow field, and the second stirring member is used to generate a radial flow field.
3. The liquid phase phosgenation reaction equipment according to claim 2, characterized in that: The first stirring member includes a screw propeller, and the second stirring member includes a disc turbine blade.
4. The liquid phase phosgenation reaction equipment according to claim 2, characterized in that: The ratio of the maximum diameter of the first stirring member to the diameter of the reactor is (5-8):
10.
5. The liquid phase phosgenation reaction equipment according to claim 2, characterized in that: The liquid-phase phosgenation reaction equipment further comprises a defoaming member, which is arranged on the stirring shaft and is used to break bubbles; compared with the second stirring member, the defoaming member is further away from the bottom of the reactor.
6. The liquid phase phosgenation reaction equipment according to claim 2, characterized in that: The liquid-phase phosgenation reaction equipment further includes a material distribution device, which is disposed in the reactor; compared with the first stirring member, the material distribution device is closer to the bottom of the reactor; The output end of the air intake device is connected to the input end of the material distribution device, and the material distribution device is provided with a plurality of discharge holes arranged at intervals.
7. The liquid phase phosgenation reaction equipment according to claim 6, characterized in that: The output end of the reflux device is connected to the input end of the material distribution device; and / or, The material distribution device is annular, and a plurality of discharge holes are distributed at intervals on one side of the material distribution device facing the bottom of the reactor.
8. The liquid phase phosgenation reaction equipment according to any one of claims 1 to 7, characterized in that: The liquid outlet device has a first U-shaped bend, and the first U-shaped bend can form a liquid seal in the liquid outlet device; and / or, The reflux device has a second U-shaped bend, and the second U-shaped bend can form a liquid seal in the reflux device.
9. Use of the liquid phase phosgenation reaction equipment according to any one of claims 1 to 8 as a reactor in a liquid phase phosgenation reaction.
10. Use of the liquid phase phosgenation reaction equipment according to any one of claims 1 to 8 as a reactor in the liquid phase synthesis of isocyanate.