Reaction method for catalyzing aldehyde condensation by liquid base

Abstract

The reaction method comprises the following steps: mixing a raw material aldehyde and a liquid alkali catalyst, feeding the mixture into a condensation reaction coupling device to carry out an aldehyde condensation reaction, and under the action of negative pressure of a steam ejector and tower bottom heating, steaming out a gas-phase component generated by the aldehyde condensation reaction to an extraction separation condenser, after condensation, entering an extraction separator; one part of a mixture of a product and a liquid alkali catalyst after the aldehyde condensation reaction is heated and then returns to a condensation reaction tower coupling device, one part of the mixture is cooled by an oil-alkali separation cooler and then enters an oil-alkali separator, the separated liquid alkali catalyst is led out, one part of the product is led into an extraction separator, and the other part of the product is led out; the raw material aldehyde is extracted in the extraction separator, the extracted oil phase is conveyed back to the distillation section of the condensation reaction tower coupling device, and the water phase is discharged. The condensation reactor and the condensation circulating tower are coupled and transformed, reaction heat and product reflux are fully utilized, the technological process can be simplified, the operation flexibility can be improved, and energy consumption can be reduced.

Description

Technical Field

[0001] This invention relates to the technical field of liquid base-catalyzed aldehyde condensation, and more specifically, to a reaction method for liquid base-catalyzed aldehyde condensation. Background Technology

[0002] Aldol condensation refers to the nucleophilic addition of compounds containing active α-hydrogen atoms, such as aldehydes, ketones, carboxylic acids, and esters, to carbonyl compounds under the action of a catalyst to obtain β-hydroxy aldehydes or acids, or further dehydration to obtain α, β-unsaturated aldehydes, ketones, or esters.

[0003] In the aldol condensation reaction described above, the condensation between aldehydes is a crucial step in many production processes. Taking actual production as an example, liquid alkali (NaOH solution) is mixed with the raw aldehyde and then fed into the condensation reactor. After the reaction in the condensation reactor, the product is introduced into a condensation circulation tower. While the reboiler at the bottom of the condensation circulation tower heats the product, a cooling water heat exchanger at the top condenses the water vapor carrying a small amount of the raw aldehyde. A steam ejector then provides negative pressure to pump the condensate to a flash tank for further processing. The oil phase in the flash tank is returned to the condensation tower as reflux, while the aqueous phase is collected for the next stage of processing.

[0004] There are two key points to consider in actual production. First, the water produced in the condensation reaction rapidly dilutes the liquid alkaline solution used as a catalyst. Changes in the concentration of the liquid alkaline solution significantly affect the conversion rate and selectivity of the reaction, not only reducing the yield of the target product but also causing more severe catalyst contamination from the generated acids. Although the process design incorporates a method to maintain the concentration of the liquid alkaline solution in the condensation reactor by replenishing a higher concentration of catalyst, some aldehyde residue remains when the material is withdrawn from the bottom of the reactor. This means that the diluted liquid alkaline solution can still act as a catalyst in the condensation circulation tower, allowing the condensation reaction to continue, leading to an increase in by-products. This should be avoided. Second, the process still consumes a significant amount of cooling and heating energy. Heat consumption mainly includes steam consumption in the reboiler at the bottom of the tower and the steam ejector at the top. Cooling consumption mainly includes cooling water consumed by the condensation tower condenser, condensation wastewater condenser, and condensation tower cooler. Optimization of energy consumption should be sought. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, and taking advantage of the exothermic nature of aldehyde condensation and the different solubilities of aldehydes in water and organic matter, this invention improves upon existing technologies by providing a liquid alkali-catalyzed aldehyde condensation reaction method. This aims to ultimately reduce energy consumption and achieve better process performance. By coupling and modifying the condensation reactor and condensation circulation tower, this invention fully utilizes the heat of reaction and product reflux, thereby simplifying the process flow, increasing operational flexibility, and reducing energy consumption.

[0006] The objective of this invention is achieved through the following technical solutions.

[0007] A method for liquid base-catalyzed aldehyde condensation reaction includes the following steps:

[0008] After the raw material aldehyde and liquid alkaline catalyst are mixed, they enter the condensation reaction coupling device to carry out the aldehyde condensation reaction. Under the negative pressure provided by the steam ejector and the heating at the bottom of the tower, the gaseous components generated by the aldehyde condensation reaction are distilled out to the extraction separation condenser and then enter the extraction separator after condensation.

[0009] The product of the aldehyde condensation reaction and the liquid alkaline catalyst mixture are partially heated and returned to the coupling device of the condensation reaction tower, and partially cooled by the oil-alkali separator and then enter the oil-alkali separator. The oil-alkali separator separates the aldehyde condensation product from the liquid alkaline catalyst by static overflow. The liquid alkaline catalyst is then discharged, and part of the aldehyde condensation product is introduced into the extraction separator, while the other part of the aldehyde condensation product is directly discharged.

[0010] The aldehyde in the raw material is extracted in the extraction separator. The extracted oil phase is fed back to the distillation section of the condensation reaction tower coupling device, and the extracted aqueous phase is discharged.

[0011] Furthermore, the condensation reaction tower coupling device is divided into an upper distillation section and a lower reaction section. The distillation section is equipped with several whole tower plates, which are filled with packing material. The reaction section is equipped with a stirring paddle.

[0012] Furthermore, the radius of the distillation section of the condensation reaction tower coupling device is smaller than the radius of its reaction section, and the distillation section and the reaction section are directly connected. In the cross-section of the condensation reaction tower coupling device, the column heights of the reaction section and the distillation section are parallel, and the line connecting the column heights forms an obtuse angle with the column heights.

[0013] Furthermore, the condensation reaction tower coupling device is formed by coupling a condensation circulation tower and a condensation reactor. The condensation circulation tower is used as a distillation section after removing the lower end cap, and the condensation reactor is used as a reaction section after removing the upper end cap.

[0014] Furthermore, the top temperature of the condensation reaction tower coupling device 1 is 40-80℃, the bottom temperature is 100-140℃, and the internal pressure of the condensation reaction tower coupling device 1 is 0.001-0.005Mpa.

[0015] Furthermore, the distillation section tray of the condensation reaction tower coupling device 1 is loaded with packing material, which is Sulzer Mellapak 350Y structured 304 stainless steel packing.

[0016] Furthermore, the liquid alkaline catalyst is a liquid alkaline aqueous solution, including but not limited to weak bases and strong bases.

[0017] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0018] This invention couples the condensation reactor and condensation circulation tower in the original process. By modifying the coupling of the aldehyde condensation unit, the process flow is shortened, thereby reducing pipeline heat loss and fully utilizing the exothermic reaction to distill off the generated water. The distilled water maintains the catalyst concentration immediately, reducing side reactions. Simultaneously, the generated product is used to extract and recover the distilled raw material, which is then refluxed back into the tower as cooling energy. This complements the heat provided by the reboiler at the bottom of the tower, increasing operational flexibility and saving energy.

[0019] Compared with the original process and equipment, the present invention shortens the process flow, makes full use of reaction heat and product reflux, improves the operational flexibility of the device, and more stably controls the concentration of liquid alkaline catalyst while saving energy. Attached Figure Description

[0020] Figure 1 This is a schematic flowchart of the reaction method for liquid base-catalyzed aldehyde condensation according to the present invention.

[0021] Figure reference numerals: 1-Condensation reaction tower coupling device, 2-Agitator, 3-Tower plate, 4-Reboiler, 5-Reaction tower bottom pump, 6-Oil-alkali separator, 7-Oil-alkali separation cooler, 8-Extraction separator, 9-Extraction separation condenser, 10-Steam ejector, 11-Aldehyde-alkali feed pipe, 12-Aldehyde-alkali discharge pipe, 13-Reboiler reflux pipe, 14-Aldehyde-alkali separation pipe, 15-Alkali pipe, 16-Product reflux pipe, 17-Steam pipe, 18-Negative pressure pipe, 19-Oil phase reflux pipe, 20-Aqueous phase collection pipe, 21-Product outlet pipe. Detailed Implementation

[0022] The present invention will now be further described with reference to the accompanying drawings.

[0023] This invention proposes a reaction method for liquid alkali-catalyzed aldehyde condensation. By coupling and modifying the condensation reactor and condensation circulation tower, the reaction heat and product reflux are fully utilized, which simplifies the process flow, improves operational flexibility, and reduces energy consumption.

[0024] like Figure 1As shown, the condensation reaction tower coupling device 1 is divided into an upper distillation section and a lower reaction section. Both the distillation section and the reaction section can be cylindrical. The radius of the distillation section of the condensation reaction tower coupling device 1 is smaller than the radius of its reaction section. The distillation section and the reaction section are directly connected. In the cross-section of the condensation reaction tower coupling device 1, the column heights of the reaction section and the distillation section are parallel, and the line connecting the column heights forms an obtuse angle with the column heights. The distillation section contains several whole tower plates 3, each of which is loaded with packing material. Sulzer Mellapak 350Y structured 304 stainless steel packing material can be used, and the packing material can have a specific surface area of ​​300-400 m². 3 / m 2 The packing material, with a porosity of 90-98%, can be either bulk or structured to achieve ideal mass and heat transfer effects. The reaction section is equipped with a stirring paddle 2, such as a mechanical stirring paddle. The condensation reaction tower coupling device 1 consists of a condensation circulation tower and a condensation reactor coupled together. The condensation reactor has a typical reactor structure, with a cylindrical body and arc-shaped end caps at both ends. The cylindrical wall is equipped with manholes, material flow holes, and instrumentation ports. The condensation circulation tower has a typical distillation tower structure, also with a cylindrical body and arc-shaped end caps at both ends. The column includes manholes, material inlets and outlets, packing material, and other auxiliary instruments and equipment. The condensation circulation tower, with its lower end cap removed, serves as the distillation section, and the condensation reactor, with its upper end cap removed, serves as the reaction section; the two circular sections are connected.

[0025] The lower part of the condensation reaction tower coupling device 1 is connected to an aldehyde-alkali feed pipe 11. The steam outlet at the top of the condensation reaction tower coupling device 1 is sequentially connected to a steam ejector 10, an extraction separation condenser 9, and an extraction separator 8 via a negative pressure pipe 18. The oil phase outlet of the extraction separator 8 is connected to the reflux port of the upper distillation section of the condensation reaction tower coupling device 1 via an oil phase reflux pipe 19. The bottom outlet of the condensation reaction tower coupling device 1 is connected to the inlet of the bottom pump 5 of the reaction tower via an aldehyde-alkali discharge pipe 12. The outlet of the bottom pump 5 of the reaction tower is divided into two paths: one path is connected to the reflux port of the lower reaction section of the condensation reaction tower coupling device 1 via a reboiler reflux pipe 13, and a reboiler 4 is installed on the reboiler reflux pipe 13; the other path is connected to the inlet of the oil-alkali separator 6 via an aldehyde-alkali separation pipe 14, and an oil-alkali separation cooler 7 is installed on the aldehyde-alkali separation pipe 14. One outlet of the oil-alkali separator 6 is connected to an alkali solution pipe 15, and the other outlet is connected to a product reflux pipe 16 and a product outlet pipe 21, respectively. The product reflux pipe 16 connects this outlet to the inlet of the extraction separator 8. The steam ejector 10 is also connected to a steam pipe 17, which provides power to the steam ejector 10 to create a vacuum. The aqueous phase outlet of the extraction separator 8 is connected to an aqueous phase collection pipe 20.

[0026] The specific implementation process of the liquid base-catalyzed aldehyde condensation reaction method of the present invention is as follows:

[0027] After the raw material aldehyde and liquid alkaline catalyst are mixed, they enter the condensation reaction coupling device 1 through the aldehyde-alkali feed pipe 11. Heating occurs through a loop formed by the aldehyde-alkali discharge pipe 12, the bottom pump 5 of the reaction tower, the reboiler reflux pipe 13, and the reboiler 4, and the aldehyde condensation reaction takes place under the action of the stirring paddle 2. As a violently exothermic reaction, the released heat maintains the reaction temperature while saving the medium-pressure steam consumed by the reboiler 4. The bottom temperature of the condensation reaction coupling device 1 is essentially equal to the reaction temperature, between 100℃ and 140℃. Simultaneously, a steam ejector 10 provides negative pressure to the condensation reaction coupling device 1, with the negative pressure between 0.001-0.005 MPa, appropriately distilling off the water generated in the aldehyde condensation reaction to maintain the concentration of the liquid alkaline catalyst. The top temperature of the tower is maintained at 40-80℃. The liquid alkaline catalyst is a liquid alkaline aqueous solution, including but not limited to weak bases (such as sodium carbonate, sodium bicarbonate, and sodium acetate) and strong bases (such as sodium hydroxide, calcium hydroxide, sodium hydride, and sodium alkoxide).

[0028] The gaseous component generated by the aldehyde condensation reaction, which consists of water and a small amount of raw material aldehyde, is distilled off under the negative pressure provided by the steam ejector 10 and the heating at the bottom of the tower. After passing through the negative pressure pipe 18, it is condensed by the extraction separation condenser 9 and enters the extraction separator 8.

[0029] The product from the aldehyde condensation reaction and the liquid alkaline catalyst mixture are propelled by the bottom pump 5 of the reaction tower. After passing through the aldehyde-alkali discharge pipe 12, a portion of the mixture is returned to the condensation reaction tower coupling device 1 after being heated by the reboiler 4 via the reboiler reflux pipe 13. The other portion passes through the aldehyde-alkali separation pipe 14 and the oil-alkali separator 7 before entering the oil-alkali separator 6. The oil-alkali separator 6 separates the aldehyde condensation product from the liquid alkaline catalyst through a static overflow. The liquid alkaline catalyst is then discharged through the alkali pipe 15 for further processing. A small portion of the aldehyde condensation product is introduced into the extraction separator 8 via the product reflux pipe 16, while the other portion is directly discharged via the product discharge pipe 21.

[0030] Inside the extraction separator 8, the water condensed from the extraction separator condenser 9 and the aldehyde condensation product, two immiscible media, are used to extract the evaporated aldehyde by utilizing their different solubilities. The extracted oil phase (containing both the aldehyde condensation product and the aldehyde) is returned to the distillation section of the condensation reaction tower coupling device 1 via the oil phase reflux pipe 19, while the extracted aqueous phase is discharged through the aqueous phase collection pipe 20 for further processing.

[0031] Example 1

[0032] After butyraldehyde and sodium hydroxide aqueous solution are mixed, they enter the condensation reaction coupling device 1 through the aldehyde-alkali feed pipe 11. Heating occurs through a loop formed by the aldehyde-alkali discharge pipe 12, the bottom pump 5 of the reaction tower, the reboiler reflux pipe 13, and the reboiler 4, and the aldehyde condensation reaction takes place under the action of the stirring paddle 2. As a violently exothermic reaction, the heat released maintains the reaction temperature while saving the medium-pressure steam consumed by the reboiler 4. The bottom temperature of the condensation reaction coupling device 1 is 110℃. Simultaneously, a negative pressure is provided to the condensation reaction coupling device 1 by the steam ejector 10, resulting in an internal pressure of 0.005 MPa. Appropriate amounts of water generated during the aldehyde condensation reaction are evaporated to maintain the concentration of the sodium hydroxide aqueous solution, and the top temperature of the condensation reaction coupling device 1 is 50℃.

[0033] The gaseous component generated by the aldehyde condensation reaction, which consists of water and a small amount of butyraldehyde, is distilled off under the negative pressure provided by the steam ejector 10 and the heating at the bottom of the tower. After passing through the negative pressure pipe 18, it is condensed by the extraction separation condenser 9 and enters the extraction separator 8.

[0034] The product of the aldehyde condensation reaction, a mixture of 2-ethyl-3-propyl acrolein and an aqueous sodium hydroxide solution, is propelled by the bottom pump 5 of the reaction tower. After passing through the aldehyde-alkali discharge pipe 12, a portion of it returns to the condensation reaction tower coupling device 1 after being heated by the reboiler 4 via the reboiler reflux pipe 13. The other portion enters the oil-alkali separator 6 after passing through the aldehyde-alkali separation pipe 14 and the oil-alkali separator cooler 7. The oil-alkali separator 6 separates the aldehyde condensation product 2-ethyl-3-propyl acrolein and the aqueous sodium hydroxide solution through static overflow. The aqueous sodium hydroxide solution is discharged through the alkali pipe 15 for further processing. A small portion of the aldehyde condensation product 2-ethyl-3-propyl acrolein is introduced into the extraction separator 8 via the product reflux pipe 16, while the other portion is directly discharged via the product discharge pipe 21.

[0035] Inside the extraction separator 8, the water condensed from the extraction separator condenser 9 and the aldehyde condensation product 2-ethyl-3-propylacrolein, two immiscible media, are used to extract the evaporated butyraldehyde due to their different solubilities. The extracted oil phase (containing 2-ethyl-3-propylacrolein and butyraldehyde) is returned to the distillation section of the condensation reaction tower coupling device 1 via the oil phase reflux pipe 19 for temperature regulation and butyraldehyde reuse. The extracted aqueous phase is discharged via the aqueous phase collection pipe 20 for further processing.

[0036] Example 2

[0037] After pentaldehyde and sodium hydroxide aqueous solution are mixed, they enter the condensation reaction coupling device 1 through the aldehyde-alkali feed pipe 11. Heating occurs through a loop formed by the aldehyde-alkali discharge pipe 12, the bottom pump 5 of the reaction tower, the reboiler reflux pipe 13, and the reboiler 4, and the aldehyde condensation reaction takes place under the action of the stirring paddle 2. As a violently exothermic reaction, the aldehyde condensation reaction releases heat to maintain its own reaction temperature while saving the medium-pressure steam consumed by the reboiler 4. The bottom temperature of the condensation reaction coupling device 1 is 140℃. Simultaneously, a steam ejector 10 provides negative pressure to the condensation reaction coupling device 1, resulting in an internal pressure of 0.003 MPa. Appropriate amounts of water generated during the aldehyde condensation reaction are evaporated to maintain the concentration of the sodium hydroxide aqueous solution, and the top temperature of the condensation reaction coupling device 1 is 80℃.

[0038] The gaseous component generated by the aldehyde condensation reaction, which consists of water and a small amount of pentanal, is distilled off under the negative pressure provided by the steam ejector 10 and the heating at the bottom of the tower. After passing through the negative pressure pipe 18, it is condensed by the extraction separation condenser 9 and enters the extraction separator 8.

[0039] The product of the aldehyde condensation reaction, 2-propyl-2-heptenal, and the sodium hydroxide aqueous solution are mixed and propelled by the bottom pump 5 of the reaction tower. After passing through the aldehyde-alkali discharge pipe 12, a portion of the mixture is returned to the condensation reaction tower coupling device 1 after being heated by the reboiler 4 via the reboiler reflux pipe 13. The other portion passes through the aldehyde-alkali separation pipe 14 and the oil-alkali separation cooler 7 before entering the oil-alkali separator 6. The oil-alkali separator 6 separates the aldehyde condensation product 2-propyl-2-heptenal and the sodium hydroxide aqueous solution through static overflow. The sodium hydroxide aqueous solution is discharged through the alkali pipe 15 for further processing. A small portion of the aldehyde condensation product 2-propyl-2-heptenal is introduced into the extraction separator 8 through the product reflux pipe 16, while the other portion is directly discharged through the product discharge pipe 21.

[0040] Inside the extraction separator 8, the water condensed from the extraction separator condenser 9 and the aldehyde condensation product 2-propyl-2-heptenal, two immiscible media, are used to extract the evaporated pentanal by utilizing their different solubilities for butyraldehyde. The extracted oil phase (containing 2-propyl-2-heptenal and pentanal) is returned to the distillation section of the condensation reaction tower coupling device 1 through the oil phase reflux pipe 19 for temperature regulation of the condensation reaction tower coupling device 1 and for the reuse of pentanal. The extracted aqueous phase is discharged through the aqueous phase collection pipe 20 for further processing.

[0041] Example 3

[0042] After the mixture of butyraldehyde and pentanaldehyde and the sodium hydroxide aqueous solution are mixed, they enter the condensation reaction coupling device 1 through the aldehyde-alkali feed pipe 11. Heating occurs through a loop formed by the aldehyde-alkali discharge pipe 12, the bottom pump 5 of the reaction tower, the reboiler reflux pipe 13, and the reboiler 4, and the aldehyde condensation reaction takes place under the action of the stirring paddle 2. As a violently exothermic reaction, the aldehyde condensation reaction releases heat to maintain its own reaction temperature while saving the medium-pressure steam consumed by the reboiler 4. The bottom temperature of the condensation reaction coupling device 1 is 100℃. Simultaneously, a negative pressure is provided to the condensation reaction coupling device 1 by the steam ejector 10, and the internal pressure of the condensation reaction coupling device 1 is 0.001 MPa. Appropriate amounts of water generated during the aldehyde condensation reaction are evaporated to maintain the concentration of the sodium hydroxide aqueous solution, and the top temperature of the condensation reaction coupling device 1 is 40℃.

[0043] The gaseous component generated by the aldehyde condensation reaction, which consists of water and a small amount of butyraldehyde and pentanaldehyde, is distilled off under the negative pressure provided by the steam ejector 10 and the heating at the bottom of the tower. After passing through the negative pressure pipe 18, it is condensed by the extraction separation condenser 9 and enters the extraction separator 8.

[0044] The mixture of 2-propyl-2-hexenal and 2-ethyl-2-heptenal after the aldehyde condensation reaction, along with the sodium hydroxide aqueous solution, is propelled by the bottom pump 5 of the reaction tower. After passing through the aldehyde-alkali discharge pipe 12, a portion of it returns to the condensation reaction tower coupling device 1 after being heated by the reboiler 4 via the reboiler reflux pipe 13. The other portion enters the oil-alkali separator 6 after passing through the aldehyde-alkali separation pipe 14 and the oil-alkali separator cooler 7. The oil-alkali separator 6 separates the 2-propyl-2-hexenal and 2-ethyl-2-heptenal mixture from the sodium hydroxide aqueous solution through static overflow. The sodium hydroxide aqueous solution is then discharged through the alkali pipe 15 for further processing. A small portion of the 2-propyl-2-hexenal and 2-ethyl-2-heptenal mixture is introduced into the extraction separator 8 via the product reflux pipe 16, while the other portion is directly discharged via the product discharge pipe 21.

[0045] Inside the extraction separator 8, the water condensed from the extraction separator condenser 9 and the mixed product of 2-propyl-2-hexenal and 2-ethyl-2-heptenal, two immiscible media, are used to extract the evaporated butyraldehyde and pentanal by utilizing their different solubilities. The extracted oil phase (containing the mixed product of 2-propyl-2-hexenal, 2-ethyl-2-heptenal, butyraldehyde, and pentanal) is returned to the distillation section of the condensation reaction tower coupling device 1 through the oil phase reflux pipe 19 for temperature regulation of the condensation reaction tower coupling device 1 and for the reuse of butyraldehyde and pentanal. The extracted aqueous phase is discharged through the aqueous phase collection pipe 20 for further processing.

[0046] Although the functions and working processes of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific functions and working processes described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these are within the protection scope of the present invention.

Claims

1. A method for liquid base-catalyzed aldehyde condensation reaction, characterized in that, The process includes the following: After the raw material aldehyde and liquid alkaline catalyst are mixed, they enter the condensation reaction coupling device (1) to carry out the aldehyde condensation reaction. Under the negative pressure provided by the steam ejector (10) and the heating at the bottom of the tower, the gas phase component generated by the aldehyde condensation reaction is distilled out to the extraction separation condenser (9) and then enters the extraction separator (8) after condensation. The product of the aldehyde condensation reaction and the liquid alkaline catalyst mixture are partially heated and returned to the condensation reaction tower coupling device (1), and partially cooled by the oil-alkali separator cooler (7) and then enter the oil-alkali separator (6). The oil-alkali separator (6) separates the aldehyde condensation product from the liquid alkaline catalyst by static overflow. The liquid alkaline catalyst is then discharged, and part of the aldehyde condensation product is introduced into the extraction separator (8), while the other part of the aldehyde condensation product is directly discharged. The raw material aldehyde is extracted in the extraction separator (8), and the extracted oil phase is fed back to the distillation section of the condensation reaction tower coupling device (1), while the extracted aqueous phase is discharged.

2. The reaction method for liquid base-catalyzed aldehyde condensation according to claim 1, characterized in that, The condensation reaction tower coupling device (1) is divided into an upper distillation section and a lower reaction section. The distillation section is filled with several whole tower plates, and the tower plates are loaded with packing. The reaction section is filled with a stirring paddle (2).

3. The reaction method for liquid base-catalyzed aldehyde condensation according to claim 2, characterized in that, The radius of the distillation section of the condensation reaction tower coupling device (1) is smaller than the radius of its reaction section. The distillation section and the reaction section are directly connected. In the cross-section of the condensation reaction tower coupling device (1), the column heights of the reaction section and the distillation section are parallel, and the line connecting the column heights forms an obtuse angle with the column heights.

4. The reaction method for liquid base-catalyzed aldehyde condensation according to claim 2, characterized in that, The condensation reaction tower coupling device (1) is formed by coupling a condensation circulation tower and a condensation reactor. The condensation circulation tower is used as a distillation section after removing the lower end cap, and the condensation reactor is used as a reaction section after removing the upper end cap.

5. The reaction method for liquid base-catalyzed aldehyde condensation according to claim 2, characterized in that, The temperature at the top of the condensation reaction tower coupling device (1) is 40-80℃, the temperature at the bottom is 100-140℃, and the internal pressure of the condensation reaction tower coupling device (1) is 0.001-0.005Mpa.

6. The reaction method for liquid base-catalyzed aldehyde condensation according to claim 2, characterized in that, The distillation section tray of the condensation reaction tower coupling device (1) is loaded with packing material, which is Sulzer Mellapak 350Y structured 304 stainless steel packing.

7. The reaction method for liquid base-catalyzed aldehyde condensation according to claim 1, characterized in that, The liquid alkaline catalyst is a liquid alkaline aqueous solution, including but not limited to weak bases and strong bases.

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