CN115850064B

CN115850064B - Preparation process of butyl methacrylate

Info

Publication number: CN115850064B
Application number: CN202111114717.5A
Authority: CN
Inventors: 康学青; 胡展; 乔小飞; 刘盼盼; 郑京涛; 郭华; 鞠昌迅; 杨国忠
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2021-09-23
Filing date: 2021-09-23
Publication date: 2024-12-03
Anticipated expiration: 2041-09-23
Also published as: CN115850064A

Abstract

The invention discloses a preparation process of butyl methacrylate, comprising the following steps: (1) adding methyl methacrylate, n-butanol and a catalyst into a reaction distillation tower respectively to carry out an ester exchange reaction, wherein methyl methacrylate and product methanol form an azeotrope and are discharged from the top of the tower, and the tower bottom is provided with a two-stage reboiler; (2) the mixture in the tower bottom of the reaction distillation tower enters a light component removal tower to remove light components; (3) the product in the tower bottom of the light component removal tower enters a product tower, the product is separated and purified, and butyl methacrylate is obtained at the top of the tower. The process flow is simple, can be operated continuously and stably, has low production cost, saves energy consumption, and has high reaction efficiency.

Description

Preparation process of butyl methacrylate

Technical Field

The invention relates to the field of chemical engineering process design, in particular to a preparation process of butyl methacrylate.

Background

Butyl Methacrylate (BMA) is an important organic chemical intermediate. Is widely used for producing acrylic coating, adhesive, finishing agent for paper, leather and textile, emulsifying agent, polishing agent, deodorant, etc. At present, the main production process of BMA is the transesterification of n-butyl alcohol (BUOH) and Methyl Methacrylate (MMA), the reaction is an equilibrium reaction, and the main process at present is a kettle reactor technology or a kettle-first-tower-last technology, so that the reaction efficiency is low, the side reaction is more, the post-treatment process is complex, and the operation is complex.

Patent CN105481688a discloses a production process of high-efficiency and environment-friendly butyl methacrylate, n-butyl alcohol and methyl methacrylate are adopted as raw materials, an esterification product is formed through steam heating reaction, materials of an esterification kettle enter the esterification tower in the form of azeotrope, unreacted methyl methacrylate and methanol generated by reaction are distilled out from the top of the esterification tower, the method has the characteristics that the energy-saving effect is not obvious due to the fact that all materials are mixed and fed, the reaction rectification principle is not fully utilized to remove the product in situ to enhance the reaction effect, and a single-stage reboiler and a common reaction kettle are difficult to provide sufficient gas-liquid separation space to cause lower reaction efficiency, so that a great space for improvement exists.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides a preparation process of butyl methacrylate, wherein qualified BMA products can be obtained through a reaction rectifying tower, a light component removing tower and a product tower, the whole process is continuously operated, the reaction rectifying tower couples the reaction and the rectification together, the product methanol is removed through a rectifying technology, the reaction effect is enhanced, the yield of the separated product is higher by adopting reduced pressure rectification, and the production cost is greatly reduced.

In order to achieve the purpose of the invention, the invention provides the following technical scheme:

a preparation process of butyl methacrylate comprises the following steps:

(1) Methyl methacrylate, n-butanol and a catalyst are respectively added into a reaction rectifying tower to carry out transesterification, wherein the methyl methacrylate and the product methanol form an azeotrope, the azeotrope is discharged from the top of the tower, and a two-stage reboiler is arranged at the bottom of the tower;

(2) The mixture at the bottom of the reaction rectifying tower enters a light component removing tower to remove light components;

(3) And (3) the tower bottom product of the light component removal tower enters a product tower, and butyl methacrylate is obtained at the tower top by adopting the separation and purification of the product.

In some preferred embodiments of the present invention, in the step (1), the molar ratio of methyl methacrylate to n-butanol is 1.1-1.5:1, and by controlling the excessive amount of methyl methacrylate, the minimum azeotrope with Methanol (MEOH) can be formed, so that MEOH is timely removed from the reaction system to improve the reaction efficiency.

In some preferred embodiments of the invention, n-butanol and a catalyst have higher boiling points, methyl Methacrylate (MMA) enters a reaction rectifying tower from the middle part of the tower, methyl Methacrylate (MMA) has lower boiling points, butanol (BUOH) and Methyl Methacrylate (MMA) enter the reaction rectifying tower from the tower bottom, countercurrent contact can be carried out in a filler at the lower section of the reaction rectifying tower, the reaction of butanol and methyl methacrylate is mainly carried out in the tower bottom, and because of excessive MMA, the excessive MMA and methanol generated by the reaction can form an azeotrope in the range of MMA proportion controlled by the invention, the MMA-methanol azeotrope is discharged from the tower top at the reaction temperature, and the MMA-methanol azeotrope can be sent to a four-carbon MMA device esterification reactor for utilization.

In some preferred embodiments of the present invention, in the step (1), the tower bottom is provided with a two-stage reboiler, the one-stage reboiler adopts a horizontal multi-tube side forced circulation type reboiler, and the two-stage reboiler is one of a wiped evaporator, a rising film reboiler and a falling film reboiler, preferably a wiped evaporator.

Preferably, the residence time of the feed in the secondary reboiler is no more than 10 seconds;

The primary reboiler and the secondary reboiler of the tower kettle are operated in parallel; the application discloses a method for preparing a high-efficiency Methanol (MEOH) from a high-efficiency methanol-free reactive distillation column, which comprises the steps of forming a first-stage reboiler which is a horizontal multi-tube Cheng Jiangzhi circulation type reboiler, forming back pressure through a flow limiting element (a flow limiting orifice plate or a regulating valve and the like) at a process side outlet to ensure that the inside of a heat exchanger is full liquid phase, relieving material polymerization, enabling the flow limiting element to be close to a column, enabling the material at the outlet of the first-stage reboiler to be fully returned to the column kettle, providing rising steam for a reactive distillation column, enabling liquid phase to be extracted into a light component removing column, arranging a baffle plate for gas-liquid separation in the reactive distillation column, ensuring the gas-liquid separation effect of the material returned by the reboiler, and enabling the traditional reboiler to generally select a single horizontal multi-tube Cheng Jiangzhi circulation type reboiler, wherein the gas-liquid separation baffle plate is not arranged in the column.

In some preferred embodiments of the invention, a baffle is arranged on the bottom of the reaction rectifying tower.

The baffle comprises a horizontal section and a downward inclined section, the diameter of the tower kettle is set to be D, and the length d1 of the horizontal section is not smaller than 200mm and the higher value in 0.3D, namely d1 is larger than or equal to 200mm and larger than or equal to 0.3D. The angle X between the horizontal section and the downward sloping section is 90゜-150゜ which can be adjusted according to the equipment size and reboiler return port size, generally 120゜ is recommended.

Preferably, in order to provide sufficient gas residence time and reduce entrainment of liquid, the distance D2 of the lower edge of the baffle from the liquid surface is not less than 400mm and a higher value of 0.5D, i.e., D2 is not less than 400mm and not less than 0.5D.

Further, the distance D3 of the reboiler return port from the packing is not less than 400mm and a higher value of 0.5D, i.e., D2 is 400mm or more and 0.5D or more.

The distance d6 between the lower edge of the baffle and the tower wall is preferably 0.4D-0.6D, so that the flow of liquid and gas can be more smooth.

In order to evaporate MEOH to a gas phase to the greatest extent, the return ports N3 and N4 of the secondary reboiler are arranged above the baffle plate (the directions of the pipe orifices of the N3 and the N4 are not particularly required), so that gas and liquid are fully separated, MEOH carried by the liquid phase is as little as possible, a horizontal section of the baffle plate needs to be provided with a tear hole to prevent liquid collection when the vehicle stops, the diameter of the tear hole is generally 6-10 mm, the baffle plate is provided with an air purging port N6 for purging polymerization inhibition air, on one hand, liquid polymerization on the baffle plate is reduced, on the other hand, tear hole liquid leakage under normal working conditions is reduced, and the purging flow is generally 1-10 Nm ³/hr.

Preferably, the height H of the tower bottom of the reactive rectifying tower is more than or equal to twice the diameter of the tower bottom, so that sufficient gas-liquid separation space and liquid buffering time are provided.

In some preferred embodiments of the invention, the operation pressure of the reactive rectifying tower is 60 kPaA-120 kPaA, the temperature of the bottom of the tower is 90 ℃ to 120 ℃, the temperature of the top of the tower is 50 ℃ to 100 ℃, and the residence time of the tower bottom is 1-4 hr;

Because of the heat sensitivity of MMA and BMA, the heating medium used by the reboiler can be hot water, steam or hot oil, the temperature is generally controlled at 100-140 ℃, and the material is prevented from heat-sensitive polymerization caused by overhigh temperature;

preferably, the operation temperature of a primary reboiler of the reactive distillation column is 95-115 ℃ and the operation pressure is 60-120 kPaA;

preferably, the operation temperature of a secondary reboiler of the reactive distillation column is 100-120 ℃ and the operation pressure is 60-120 kPaA;

preferably, the primary reboiler and the secondary reboiler of the reactive distillation column are operated at the same pressure as the reactive distillation column.

Preferably, the primary reboiler of the reactive distillation column is operated at a temperature less than the secondary reboiler.

In some preferred embodiments of the present invention, the catalyst is selected from one of p-toluenesulfonic acid, methanesulfonic acid, ion exchange resin, p-toluenesulfonic acid.

In some preferred embodiments of the present invention, in the step (2), a continuous vacuum rectification technology is adopted to remove substances with boiling point lower than that of BMA (mainly BUOH, MMA, etc.), the light components at the top of the tower can be returned to the reactive rectification tower for recycling, the substances at the bottom of the tower are mainly BMA and heavy components, and the products are further processed by the product tower;

the light component removing tower is characterized in that the tower bottom of the light component removing tower is connected with a reboiler, the operation temperature of the reboiler is 100-140 ℃, preferably 100-120 ℃, and the reboiler is preferably a horizontal multitube Cheng Jiangzhi circulation type reboiler.

Preferably, the operating pressure of the light component removal tower is 5 kPaA-20 kPaA, the temperature of the tower bottom is 90-110 ℃, and the temperature of the tower top is 40-80 ℃.

In the step (3), the product tower also adopts a continuous vacuum rectification technology to separate the product, qualified BMA products are extracted from the tower top, and the tower bottom is a heavy component and has strong heat sensitivity.

Preferably, the tower bottom of the product tower is provided with a two-stage reboiler, the one-stage reboiler is a horizontal multitube Cheng Jiangzhi circulation type reboiler, the two-stage reboiler is selected from a scraper type evaporator, and the two-stage reboiler is adopted in the tower, so that the scraper type evaporator can treat materials with high viscosity and polymers, and the concentration degree is high, and further the product at the outlet of the one-stage reboiler can be recovered.

Preferably, the residence time of the material in the secondary reboiler is not more than 10s, so that BMA products can be fully recovered, and BMA loss is reduced.

Further, the reboiler heating medium can be in various forms of steam, hot oil, hot water and the like, and the temperature cannot be excessively high (generally not more than 150 ℃) so as to prevent substances from polymerizing and coking on a heating surface;

because of the thermosensitive property of BMA, the heating medium used by the reboiler can be selected from hot water, steam or hot oil, the temperature is generally controlled at 100-140 ℃, and the thermosensitive polymerization of materials caused by overhigh temperature is prevented;

the operating pressure of the product tower is 5 kPaA-20 kPaA, the temperature of the tower bottom is 90-115 ℃, and the temperature of the tower top is 40-80 ℃;

the operation temperature of a primary reboiler of the product tower is 95-115 ℃ and the operation pressure is 5-20 kPaA;

the operation temperature of a secondary reboiler of the product tower is 100-120 ℃ and the operation pressure is 5-20 kPaA;

preferably, the operating pressures of the primary reboiler and the secondary reboiler of the product column are the same as the operating pressure of the product column.

Preferably, the primary reboiler operating temperature is less than the secondary reboiler operating temperature.

In order to prevent the materials from polymerizing, polymerization inhibitors can be added to the reaction rectifying tower, the light component removing tower, the reflux pipeline at the top of the product tower and the spray pipeline of the condenser at the top of the tower, wherein the addition amount of the polymerization inhibitor is 0.01% -0.1% of the total feeding amount by mass.

The polymerization inhibitor is one or more selected from methyl hydroquinone THQ, p-benzoquinone PBQ, p-hydroxyanisole HQME, 2-tertiary butyl hydroquinone MTBHQ and 2, 5-di-tertiary butyl hydroquinone 2, 5-DTBHQ.

Compared with the prior art, the application has the main beneficial effects that:

(1) The reaction of methyl methacrylate and n-butanol is a liquid phase equilibrium reaction, and the existence of the product methanol MEOH has an inhibition effect on the reaction, and the continuous reaction rectification technology is used for removing the product MEOH, so that the reaction equilibrium can be broken, the forward reaction is promoted, the methanol can be removed, the inhibition effect of the methanol on the reaction is reduced, and the reaction efficiency is improved. The invention enables excessive MMA and MEOH to produce azeotrope by controlling the adding proportion of methyl methacrylate, removes the azeotrope from the top of the tower, removes the residual methanol in the tower bottom liquid by adopting a two-stage reboiler, improves the reaction driving force, and improves the reaction efficiency.

(2) The process has the advantages of simple design and operation, mild reaction conditions, continuous and airtight whole process, environment friendliness, cleanness and low production cost, and only 3 rectifying towers are needed in the whole process.

Drawings

FIG. 1 is a schematic illustration of the reaction process of an embodiment of the present invention.

FIG. 2 is a schematic diagram of the structure of the reactive distillation column of the present invention.

Wherein, C01 is the reaction rectifying column, C02 is the light component removal column, C03 is the product column, E01 is the reaction rectifying column condenser, E02 is the reaction rectifying column primary reboiler, E03 is the reaction rectifying column secondary reboiler, E04 is the light component removal column condenser, E05 is the light component removal column reboiler, E06 is the product column condenser, E07 is the product column primary reboiler, E08 is the product column secondary reboiler, and A is the baffle.

Detailed Description

The embodiment of the invention adopts a synthesis process shown in fig. 1, and comprises a reaction rectifying tower C01, a light component removal tower C02 and a product tower C03, wherein a primary reboiler E02 and a secondary reboiler E03 are arranged at the tower bottom of the reaction rectifying tower C01.

N-butanol and catalyst enter a reactive rectifying tower from the middle part of the tower, and methyl methacrylate enters the reactive rectifying tower from the tower bottom.

The first-stage reboiler E02 of the reaction rectifying tower is a horizontal multitube Cheng Jiangzhi circulation type reboiler, and the second-stage reboiler E03 of the reaction rectifying tower is a scraper evaporator.

The light component removal tower reboiler E05 is a horizontal multitube Cheng Jiangzhi circulation type reboiler, the product tower primary reboiler E07 is a horizontal multitube Cheng Jiangzhi circulation type reboiler, and the product tower secondary reboiler E08 is a scraper type evaporator.

Polymerization inhibitor is added to the reaction rectifying tower, the light component removing tower, the tower top reflux pipeline of the product tower and the tower top condenser spray pipeline, the adding amount of the polymerization inhibitor is 0.05% of the total feeding amount mass, and the polymerization inhibitor is polymerization inhibitor 701 (cas 2226-96-2).

The reaction rectifying tower is provided with two-stage reboiler return ports N3 and N4, a fresh material inlet N1, a recovered material inlet N5, a discharge port N2 and an air purging port N6, and the air purging flow is 5Nm ³/hr. A baffle A is arranged in the reaction rectifying tower, and an included angle X between the horizontal section of the baffle and the downward inclined section is 120゜.

As shown in fig. 2, the specific structural parameters of the reactive distillation column of the present invention are as follows:

Sign symbol	Comparative example 1 size	Examples 1,2,3 dimensions
			D	1.2m	1.2m
H	3m	3m
			d1	Without any means for	0.4m
X	Without any means for	120゜
			d2	Without any means for	0.6m
d3	0.6m	0.6m
			d4	0.2m	0.2m
d5	0.2m	0.2m
			d6	0.6m	0.6m

Where d4 is the distance from the baffle to the secondary reboiler return port and d5 is the distance from the baffle to the air purge port N6.

Example 1

By adopting the synthesis process shown in FIG. 1 and the reaction rectifying tower shown in FIG. 2, MMA is fed at the bottom of the reaction rectifying tower, the feed flow rate is 775kg/hr, the feed flow rate of BUOH at the middle section of the tower is about 510kg/hr, the pressure at the top of the reaction rectifying tower is 1.1barA, the reflux ratio at the top of the tower is controlled to be 15, the reaction temperature is 112 ℃, the temperature at the top of the tower is 67 ℃, the residence time of the tower bottom is 2h, the steam addition amount of the primary reboiler of the reaction rectifying tower is adjusted, so that the primary reboiler power of the reaction rectifying tower is about 540kW, the secondary reboiler power of the reaction rectifying tower is about 60kW, the outlet temperature of the primary reboiler of the reaction rectifying tower is 113 ℃, the outlet temperature of the secondary reboiler of the reaction rectifying tower is 116 ℃, the residence time in the secondary reboiler is 5 seconds, the BMA and the BUOH content of the tower are lower than 10ppm, the outlet MEOH content of the primary reboiler of the reaction rectifying tower is about 0.6wt%, the BMA content is about 41wt%, and the BMA flow rate is about 465kg/hr, and the reaction rectifying tower and the yield is increased by about 20% under the premise that the test energy consumption is unchanged.

The mixture at the bottom of the reaction rectifying tower enters a light component removing tower, the top pressure of the light component removing tower is 11kPaA, the top temperature of the tower is 57 ℃, and the bottom temperature of the tower is 99 ℃.

And (3) the tower bottom product of the light component removal tower enters a product tower, and butyl methacrylate is obtained at the tower top by adopting the separation and purification of the product.

The operating pressure of the product tower is 5 kPaA-20 kPaA, the temperature of the bottom of the tower is 90-115 ℃, and the temperature of the top of the tower is 40-80 ℃.

Example 2

The difference between the embodiment and the embodiment 1 is that the second reboiler of the reaction rectifying tower is changed from a scrapping mode to a falling film mode, other conditions are unchanged, experiments show that the temperature of the top of the tower is 67 ℃, the outlet temperature of the first reboiler of the reaction rectifying tower is 112 ℃, the outlet temperature of the second reboiler of the reaction rectifying tower is 116 ℃, the BMA and BUOH contents of the top of the tower are lower than 10ppm, the MEOH content of the outlet of the first reboiler of the reaction rectifying tower is about 0.7wt%, the outlet of the second reboiler of the reaction rectifying tower is 0.33wt%, the BMA content is about 40wt% and the BMA flow is about 453kg/hr, and experiments show that the BMA yield is increased by about 18% by setting the second reboiler to the falling film mode on the premise of unchanged energy consumption.

Example 3

This example 3 uses the same reactive distillation column and scheme as example 1, with varying feed conditions, MMA feeding at the bottom of the reactive distillation column, MMA feeding flow 787kg/hr, BUOU feeding at the middle of the column, feeding flow about 485kg/hr, rectifying column top pressure 1.13barA, column top temperature 67 ℃, secondary reboiler outlet temperature 120 ℃, column top BMA and BUOH content less than 10ppm, column bottom liquid phase outlet MEOH content about 0.4wt%, secondary scraper reboiler liquid phase outlet MEOH content about 0.1wt%, further BMA content about 60wt%, flow 611kg/hr, the column energy consumption about 670kW (wherein first stage reboiler 600kW, secondary reboiler 70 kW), light ends column top pressure 12kPaA, column top temperature 60 ℃, column bottom temperature 100 ℃ mainly MMA and BUOH, column bottom mainly BMA content <1wt%, column bottom mainly BMA content about 98wt%, product column top pressure 12kPaA, temperature 67 ℃, column top temperature 100 ℃ mainly BMA content about 99 wt%, and BMA content about 50wt%, wherein the column bottom weight content is about 50%.

Comparative example 1

The synthesis process of comparative example 1 is shown with reference to fig. 1, and the main difference from the process of example 1 is that the reaction rectifying column in comparative example 1 is provided with only a primary reboiler, no secondary reboiler, and no baffle inside the reaction rectifying column. MMA was fed at the bottom of the reactive distillation column, the feed flow rate 775kg/hr, BUOU at the middle stage of the column was about 510kg/hr, the pressure at the top of the reactive distillation column was 1.1barA, the reflux ratio at the top of the column was controlled to 15, the temperature at the top of the column was 67 ℃ and the outlet temperature at the primary reboiler of the reactive distillation column was 112 ℃, the BMA and BUOH contents at the top of the column were less than 10ppm, the MEOH content at the outlet of the primary reboiler at the bottom of the column was about 0.8% by weight, the BMA content was about 34% by weight, the BMA flow rate was about 388kg/hr, and the energy consumption of the column (primary reboiler) was about 600kW (steam consumption about 1 t/hr). The BMA yield of example 1 was higher than that of example 1 at the same energy consumption.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the technical solution of the present invention in any way. Any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. The preparation process of butyl methacrylate is characterized by comprising the following steps of:

(3) The product at the bottom of the light component removal tower enters a product tower, and butyl methacrylate is obtained at the top of the tower by adopting separation and purification of the product;

The reaction rectifying tower is provided with a baffle, the baffle comprises a horizontal section and a downward inclined section, the diameter of the tower kettle is set to be D, the length D1 of the horizontal section is not smaller than 200mm and a higher value in 0.3D, and the angle X between the horizontal section and the downward inclined section is 90゜-150゜.

2. The process according to claim 1, wherein in step (1), the molar ratio of methyl methacrylate to n-butanol is 1.1-1.5:1.

3. The process of claim 1, wherein in step (1), the tower bottom is provided with a two-stage reboiler, the one-stage reboiler is a horizontal multi-tube side forced circulation type reboiler, and the two-stage reboiler is one of a scraper evaporator, a rising film reboiler and a falling film reboiler.

4. A process according to claim 3, wherein the secondary reboiler is a wiped film evaporator.

5. A process according to claim 3, wherein the residence time of the material in the secondary reboiler is not more than 10 seconds.

6. The process according to claim 1, wherein the distance D2 of the lower edge of the baffle from the liquid surface is not less than the higher value of 400mm and 0.5D.

7. The process according to claim 1, wherein the distance D3 of the reboiler return port from the packing is not less than the higher value of 400mm and 0.5D.

8. The process of claim 1, wherein the distance d6 from the lower edge of the baffle to the tower wall is 0.4d to 0.6d.

9. The process according to claim 1, wherein the reactive rectifying column has an operating pressure of 60kpaa to 120kpaa, a column bottom temperature of 90 ℃ to 120 ℃, a column top temperature of 50 ℃ to 100 ℃, and a column bottom residence time of 1 to 4hr.

10. The process of claim 1, wherein the primary reboiler of the reactive distillation column is operated at a temperature of 95 ℃ to 115 ℃ and at a pressure of 60kpaa to 120kpaa.

11. The process of claim 1, wherein the secondary reboiler of the reactive distillation column is operated at a temperature of from 100 ℃ to 120 ℃ and at a pressure of from 60kpaa to 120kpaa.

12. The process of claim 1, wherein the primary reboiler and the secondary reboiler of the reactive distillation column are operated at the same pressure as the reactive distillation column.

13. The process of claim 1 wherein the primary reboiler of the reactive distillation column operates at a temperature less than the secondary reboiler operating temperature.

14. The process of claim 1 wherein the catalyst is selected from the group consisting of p-toluenesulfonic acid, methanesulfonic acid, ion exchange resins, and p-toluenesulfonic acid.

15. The process according to claim 1, wherein the light ends removal column bottoms are connected with a reboiler, and the reboiler is operated at a temperature of 100-140 ℃.

16. The process of claim 15, wherein the light ends removal column bottoms are connected to a reboiler having an operating temperature of 100 to 120 ℃.

17. The process of claim 15 wherein the reboiler of the bottom of the light ends column is a horizontal multitube Cheng Jiangzhi cycle type reboiler.

18. The process of claim 1, wherein the light ends column is operated at a pressure of 5kpaa to 20kpaa, a column bottom temperature of 90 ℃ to 110 ℃, and a column top temperature of 40 ℃ to 80 ℃.

19. The process of claim 1 wherein the product bottoms are provided with two stage reboilers, the one stage reboiler being a horizontal multitube Cheng Jiangzhi cycle type reboiler and the two stage reboiler being selected from the group consisting of wiped film evaporators.

20. The process of claim 19 wherein the residence time of the material in the secondary reboiler is no more than 10s.

21. The process of claim 19, wherein the heating medium used in the reboiler of the product column is hot water, steam or hot oil at a temperature of 100-140 ℃.

22. The process of claim 1, wherein the product column operates at a pressure of 5kpaa to 20kpaa, a column bottom temperature of 90 ℃ to 115 ℃, and a column top temperature of 40 ℃ to 80 ℃.

23. The process of claim 19, wherein the primary reboiler of the product column is operated at a temperature of 95 ℃ to 115 ℃ and at a pressure of 5kpaa to 20kpaa;

the operation temperature of the secondary reboiler of the product tower is 100-120 ℃ and the operation pressure is 5-20 kPaA.

24. The process of claim 19 wherein the product column primary reboiler and secondary reboiler are operated at the same pressure as the product column operating pressure.

25. The process of claim 19 wherein the primary reboiler of the product column has an operating temperature that is less than the operating temperature of the secondary reboiler.

26. The process according to claim 1, wherein polymerization inhibitors are added to the reactive rectifying column, the light component removal column, the reflux pipeline at the top of the product column and the spray pipeline of the condenser at the top of the column, and the addition amount of the polymerization inhibitors is 0.01% -0.1% of the total feeding amount by mass.

27. The process of claim 26 wherein the polymerization inhibitor is selected from one or more of methyl hydroquinone THQ, p-benzoquinone PBQ, p-hydroxyanisole HQMME, 2-tert-butyl hydroquinone MTBHQ, 2, 5-di-tert-butyl hydroquinone 2, 5-DTBHQ.