A method for preparing 3-hydroxypropanal by hydrating acrolein

Abstract

The present invention discloses a method for preparing 3-hydroxypropionaldehyde by hydrating acrolein. The raw materials are pretreated, water is adsorbed by resin as a hydration raw material, and the reaction process conditions are controlled and a heating program is designed to make a certain concentration of acrolein aqueous solution at a low temperature of 20-75°C and a volume space velocity of 0.3-5h ‑1 , the reaction is carried out at a linear speed of 0.01-15m / h. Under this condition, the reaction can effectively inhibit the enrichment of metal ions, reduce side reactions, and prevent catalyst agglomeration. At the same time, by controlling the reaction process, the reaction efficiency can be guaranteed, the stability of the catalyst can be improved, and the catalyst life can be extended. It is an efficient reaction process with industrial prospects.

Description

Technical Field

[0001] The invention belongs to the field of chemical synthesis, and in particular relates to a method for preparing 3-hydroxypropanal by hydrating acrolein with high reaction efficiency and good stability. Background Art

[0002] Polytrimethylene terephthalate (PTT) fiber is an ideal clothing fabric due to its excellent tensile resilience, fluffiness, dyeability, wrinkle resistance and stain resistance. The synthesis of the polymerization monomer 1,3-propylene glycol (1,3-PDO) is a key link in the production of PTT polyester. The production process and synthesis cost of 1,3-propylene glycol are also important factors affecting the market prospects of PTT.

[0003] With the continuous development of new technologies, Degussa has achieved large-scale industrial production of 1,3-propylene glycol by acrolein hydration hydrogenation, Shell by ethylene oxide hydroformylation, DuPont by corn biofermentation, and Tsinghua Zhixing by glycerol / sugar fermentation. Due to its low technical difficulty, mild process conditions, mature process scheme, and low production cost, the acrolein hydration hydrogenation route is one of the earlier developed and currently successfully industrialized production routes. However, due to the active nature of acrolein and its easy self-polymerization, in the process of acrolein hydration to 3-hydroxypropanal, it is easy to be accompanied by side reactions such as self-polymerization and polycondensation of acrolein and 3-hydroxypropanal, and these reactions will intensify with the increase of temperature. The generated by-products are difficult to separate, which will not only reduce the catalyst activity of the hydration reaction and the subsequent hydrogenation reaction, but also reduce the reaction efficiency, and at the same time increase the consumption quota of raw materials and shorten the service life of the catalyst. There is no report of large-scale industrial production in China.

[0004] Patent CN1369471A uses polystyrene chelating resin as raw material, and by controlling the reaction process, the selectivity of 3-hydroxypropanal can be as high as 93%, and the catalyst life can reach more than 650 hours; Patent CN 110204422 B discloses a production process that is simple to operate, has high catalyst activity, long life, and is easy to achieve large-scale industrial production, and the total yield of 1,3-propylene glycol is as high as more than 75%; Patent CN114409518A uses boron-phosphorus-gallium modified alumina catalyst for the reaction of preparing 3-hydroxypropanal by hydration of acrolein, which can effectively inhibit the occurrence of self-polymerization and heteropolymerization side reactions, and improve the selectivity of 3-hydroxypropanal and the stability of the catalyst.

[0005] The above-mentioned methods for preparing 3-hydroxypropanal by hydration of acrolein all have the problems of low reaction efficiency, poor operation stability, and short catalyst service life. At present, the research on the process of preparing 1,3-propylene glycol by acrolein hydration hydrogenation is mainly concentrated in the small-scale and pilot stages, and there is little research on the scale-up process, which brings great challenges to the subsequent industrial scale-up and is not conducive to the industrial application of the method. Therefore, the acrolein hydration process is very critical in the process of preparing 1,3-PDO by hydration hydrogenation of acrolein. It is of great significance to develop a process for preparing 3-hydroxypropanal by hydration of acrolein with high reaction efficiency and good catalyst stability. Summary of the invention

[0006] The invention aims to provide a method for preparing 3-hydroxypropionaldehyde by hydrating acrolein. The method can effectively inhibit metal ion enrichment, reduce side reactions, prevent catalyst from caking, and facilitate long-term operation of the hydration reaction by pretreatment of raw materials. Meanwhile, the reaction efficiency can be guaranteed by controlling the reaction process, and the stability of the catalyst can be improved, and the life of the catalyst can be extended. The problems of low efficiency, poor catalyst stability and short life in the industrialized acrolein hydration process can be solved, and the blank of domestic industrialized acrolein hydration technology can be filled.

[0007] In order to achieve the above invention objectives and the above technical effects, the technical solution of the present invention is as follows:

[0008] A method for preparing 3-hydroxypropanal by hydrating acrolein comprises the following steps:

[0009] a) Raw material pretreatment: deionized water is adsorbed by a chelating resin and then mixed with an acrolein raw material containing an inhibitor through a static mixer to prepare an acrolein aqueous solution of a certain concentration;

[0010] b) Acrolein hydration reaction: Acrolein aqueous solution is subjected to a solid acid catalyst and a temperature program method is adopted: Ti = 1.10^(1-vi / 0.5)*5.41*lnti+20(vi<0.5m / h), Ti = 1.05^[(vi-0.5) / vi]*5.41*lnti+20(vi≥0.5m / h), wherein Ti in the formula represents the instantaneous reaction hot spot temperature / °C, ti represents the operation time / h, and vi represents the operation linear velocity m / h. When Ti = 20-75°C and the volume space velocity is 0.3-5h -1 , under the condition of vi = 0.01-15m / h, a hydration reaction occurs to obtain a hydration reaction liquid;

[0011] c) Separation of hydration liquid: The hydration reaction liquid is subjected to low temperature molecular distillation or vacuum distillation to obtain a 3-hydroxypropanal aqueous solution.

[0012] The 3-hydroxypropionaldehyde (3-HPA) aqueous solution obtained in step c) of the present invention is used as a raw material for 1,3-PDO hydrogenation, and acrolein is recycled.

[0013] In the present invention, the chelating resin is selected from one or more of thiourea resin, aminoacetic acid resin, aminophosphoric acid resin, amidoxime resin, polyvinylpyridine resin, hydroxyquinoline resin and mixed bed resin, preferably aminoacetic acid and aminophosphoric acid resin.

[0014] In the present invention, the adsorption rate of the chelating resin in step a) is 2-6 BV / h, preferably 3-5 BV / h, wherein BV represents the resin bed volume.

[0015] In the present invention, the internal structure of the static mixer in step a) is selected from SV type, SK type, and SX type, preferably SV type and SK type mixers.

[0016] In the present invention, the concentration of acrolein in the acrolein aqueous solution in step a) is 10-25wt.%, preferably 12%-17wt.%, for example 12wt.%, 14wt.%, 15wt.%, 17wt.%.

[0017] The polymerization inhibitor of the present invention is selected from one or more of phenolic polymerization inhibitors, quinone polymerization inhibitors and nitroxide free radical polymerization inhibitors, preferably one or more of hydroquinone, tert-butylhydroquinone, p-benzoquinone and methylhydroquinone, more preferably hydroquinone.

[0018] In the method of the present invention, based on the sum of the weight of acrolein and water, the added amount of the polymerization inhibitor is 0.01wt.%-0.1wt.%, preferably 0.015wt.%-0.03wt.%, for example 0.015wt.%, 0.020wt.%, 0.025wt.%, 0.030wt.%.

[0019] In the present invention, the solid acid catalyst described in step b) is selected from one or more of a cation exchange resin catalyst, a molecular sieve catalyst, and a metal oxide supported solid acid catalyst, preferably one or more of an aminoacetic acid type cation exchange resin, an aminophosphoric acid type resin, and an H-USY molecular sieve catalyst.

[0020] In the present invention, the programmed temperature method described in step b) has an initial temperature of 20° C. and a maximum termination temperature of 75° C., taking into account both reaction activity and selectivity, and a reaction pressure of 0.05-0.5 MPaG, preferably 0.1-0.2 MPaG.

[0021] In the present invention, the reaction in step b) is carried out in a reactor such as an adiabatic fixed bed, a moving bed, a fluidized bed, a tubular fixed bed reactor, a reactive distillation tower, etc., preferably an adiabatic or tubular fixed bed reactor.

[0022] In the present invention, the conditions for separating acrolein from the hydration liquid in step c) are a pressure of 15-21 kPaA and a bottom temperature of 50-65° C., which ensures both a lower distillation temperature and a shorter residence time of the acrolein hydration liquid in the bottom of the tower, and a high acrolein yield at the top of the tower and low condensation energy consumption.

[0023] The reduction in reaction activity and stability during the hydration of acrolein is mainly affected by the following factors: polymer covering active sites resulting in a reduction in active sites, loss or shedding of active groups during operation, reduction in catalyst active sites resulting from metal ion adsorption, and changes in the acidic environment, etc., which can be controlled by the following means. By controlling the reaction process: adding inhibitors to slow down the self-polymerization of acrolein, by controlling the reaction temperature, space velocity, and linear velocity within a suitable range, reducing the production of polymers and their residence on the catalyst surface, thereby reducing the coverage of active sites, while preventing the loss of active groups due to excessive temperature or excessive flow of raw materials; the relationship between reaction temperature and reaction time at different linear velocities and different reaction stages is obtained through experiments, and controlled by programmed temperature rise, which is not only easy to scale up industrial operations, but also ensures stable catalyst activity and high reaction selectivity, and prevents polymer accumulation from covering active sites; during the scale-up process, the linear velocity is too small, the external diffusion is slow, the mass transfer is hindered, and the reaction efficiency is reduced , the linear velocity is too large, the active groups on the catalyst surface adsorb the raw materials, the balance of desorption intermediates is broken, the catalyst is over-washed, and the reaction performance and catalyst stability are affected; in the process of acrolein hydration process scale-up and long-term operation, metal ions will inevitably be enriched with long-term operation, resulting in a decrease in reaction activity and even bed compaction; by pretreating the raw materials, the enrichment of metal ions can be prevented, the acidic environment at the inlet end and the reduction of active sites can be avoided, and the polymerization of acrolein caused by excessive accumulation of adsorbed metal ions can be prevented, thereby causing catalyst pulverization and catalyst bed compaction; therefore, raw material pretreatment and reaction process control are particularly important for the acrolein hydration reaction process.

[0024] The positive effects of the present invention are:

[0025] (1) The chelated ion exchange resin of the present invention can form a multi-coordinated complex with metal ions, effectively inhibiting the enrichment of metal ions, avoiding the reduction of catalyst active sites and the change of acidic environment during long-term operation, resulting in the intensification of side reactions such as polymerization reactions, thereby causing catalyst agglomeration.

[0026] (2) The linear velocity in the present invention can not only ensure a high mass transfer efficiency, but also control a suitable adsorption and desorption rate, and can take into account both the efficiency and selectivity of the reaction. The reaction yield is greater than 88%, and the selectivity of 3-hydroxypropanal is greater than 93%.

[0027] (3) The temperature raising method of the present invention adopts a programmed temperature raising method, which makes the reaction process more gentle and easy to control and industrially scale up, can reduce the loss of catalyst active sites, and compensate for the reduction of catalyst activity.

[0028] (4) The problem of instability and easy deactivation of solid catalysts during the hydration process is effectively solved, and the catalyst life can reach more than 6000 hours, which is conducive to industrial application. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with embodiments, but the scope of the present invention is not limited to these embodiments.

[0030] Gas phase analysis conditions: Shimadzu gas chromatograph, RTX-WAX column, 50 °C for 5 min; 10 °C / min to 80 °C, hold for 5 min; 10 °C / min to 100 °C, hold for 5 min; 10 °C / min to 220 °C, hold for 15 min.

[0031] Analysis of metal ion types and contents: The metal content was analyzed using Varian's 710ES inductively coupled plasma emission spectrometer with a plasma gas flow rate of 15 ml / min and an atomizing gas pressure of 200 kPa.

[0032] The main sources of raw materials are as follows:

[0033] Reagent name purity factory Acrolein Analytical grade Shandong Xinglu Biological Hydroquinone Analytical grade Sinopharm Chemical Reagent Co., Ltd. D403 Industrial pure Dandong Pearl D860 Analytical grade Dandong Pearl S910 Analytical grade Purolite TP207 Analytical grade LANXESS IRC747 Analytical grade Rohm and Haas H-USY Analytical grade Shandong Hefa Environmental Protection Technology Co., Ltd.

[0034] The composition of deionized water is as follows:

[0035]

[0036] In the following examples and comparative examples, the adsorption bed was filled with 200 ml of resin and 20 cm of quartz sand was placed above and below. In the hydration reaction, 100 ml of solid acid catalyst was placed in the middle bed layer of the fixed bed, 20 cm of quartz sand was placed above and below, and a 100-mesh 316L metal screen was installed.

[0037] Example 1

[0038] Deionized water was passed through an adsorption bed filled with resin D403 at an adsorption rate of 4 BV / h, and then mixed with acrolein raw material containing 0.02 wt.% of inhibitor hydroquinone through an SV type static mixer to prepare an acrolein aqueous solution with an acrolein concentration of 12 wt.%; 100 ml of TP207 hydrogen type resin was used as a hydrated solid acid catalyst at a pressure of 0.05 MPaG and a volume space velocity of 0.3 h -1At a linear speed of 0.5 m / h, the reaction temperature was controlled by a temperature program method, a hydration reaction occurred, and a hydration reaction liquid was obtained, with a 3-hydroxypropanal yield of 88.5% and a selectivity of 94.2%. The reaction temperature was adjusted in real time by a temperature program method, and the hot spot temperature Ti of the fixed bed reaction section was controlled to be 5.41*lnti+20. After the operating time ti reached 26400h, the hot spot temperature Ti reached 75°C, reaching the maximum operating temperature set for the resin, and the catalyst was considered to be deactivated, and the catalyst life was 26400h.

[0039] The comparison of catalyst metal ions before and after the reaction is shown in the following table:

[0040]

[0041]

[0042] Example 2

[0043] Deionized water was passed through an adsorption bed filled with resin D860 at an adsorption rate of 2 BV / h, and then mixed with acrolein raw material containing 0.01 wt.% of inhibitor hydroquinone through an SV type static mixer to prepare an acrolein aqueous solution with an acrolein concentration of 15 wt.%; 100 ml of TP207 hydrogen type resin was used as a hydrated solid acid catalyst at a pressure of 0.1 MPaG and a volume space velocity of 0.6 h -1 At a linear speed of 10 m / h, the reaction temperature was controlled by a temperature program method, a hydration reaction occurred, and a hydration reaction liquid was obtained, with a 3-hydroxypropanal yield of 88.7% and a selectivity of 93.6%. The reaction temperature was adjusted in real time by a temperature program method, and the hot spot temperature Ti of the fixed bed reaction section was controlled to be Ti=1.05^0.95*5.41*lnti+20(vi≥0.5m / h). After the operating time ti reached 10800h, the hot spot temperature Ti reached 72.6°C, and the reaction selectivity was significantly reduced, below 90%, which was considered as catalyst deactivation, and the catalyst life was 10800h.

[0044] The comparison of catalyst metal ions before and after the reaction is shown in the following table:

[0045]

[0046] Example 3

[0047] Deionized water was passed through an adsorption bed filled with resin S910 at an adsorption rate of 4 BV / h, and then mixed with acrolein raw material containing 0.015 wt.% of inhibitor hydroquinone through an SK type static mixer to prepare an acrolein aqueous solution with an acrolein concentration of 10 wt.%; 100 ml of IRC747 hydrogen resin was used as a hydrated solid acid catalyst at a pressure of 0.1 MPaG and a volume space velocity of 0.5 h -1At a linear speed of 15 m / h, the reaction temperature was controlled by a temperature program method, a hydration reaction occurred, and a hydration reaction liquid was obtained, with a 3-hydroxypropanal yield of 88.2% and a selectivity of 93.4%. The reaction temperature was adjusted in real time by a temperature program method, and the hot spot temperature Ti of the fixed bed reaction section was controlled to be Ti=1.05^0.97*5.41*lnti+20(vi≥0.5m / h). After the operating time Ti reached 18000h, the hot spot temperature Ti reached 75°C, reaching the maximum operating temperature set for the resin, and the catalyst life was 18000h.

[0048] Comparison of catalyst metal ion indicators before and after the reaction:

[0049]

[0050] Example 4

[0051] Deionized water was passed through an adsorption bed filled with resin S910 at an adsorption rate of 6 BV / h, and then mixed with acrolein raw material containing 0.1 wt.% of inhibitor hydroquinone through an SV type static mixer to prepare an acrolein aqueous solution with an acrolein concentration of 25 wt.%; 100 ml of IRC747 hydrogen resin was used as a hydrated solid acid catalyst at a pressure of 0.5 MPaG and a volume space velocity of 5 h -1 At a linear velocity of 0.01 m / h, the reaction temperature was controlled by a temperature program method, a hydration reaction occurred, and a hydration reaction liquid was obtained, with a 3-hydroxypropanal yield of 88.1% and a selectivity of 94.7%. The reaction temperature was adjusted in real time by a temperature program method, and the hot spot temperature Ti of the fixed bed reaction section was controlled to be Ti=1.10^0.98*5.41*lnti+20(vi<0.5m / h). After the operating time ti reached 6600, the hot spot temperature Ti reached 72.2°C, and the reaction selectivity was significantly reduced, below 90%, which was considered as catalyst deactivation, and the catalyst life was 6600h.

[0052] Example 5

[0053] Deionized water was passed through an adsorption bed filled with resin D403 at an adsorption rate of 4 BV / h, and then mixed with acrolein raw material containing 0.022 wt.% of inhibitor ZJ-701 through an SV type static mixer to prepare an acrolein aqueous solution with an acrolein concentration of 17 wt.%; 100 ml of H-USY hydrogen molecular sieve was used as a hydrated solid acid catalyst at a pressure of 0.25 MPaG and a volume space velocity of 0.5 h -1At a linear speed of 1 m / h, the reaction temperature was controlled by a temperature program method, a hydration reaction occurred, and a hydration reaction liquid was obtained, with a 3-hydroxypropanal yield of 89.3% and a selectivity of 93.1%. The reaction temperature was adjusted in real time by a temperature program method, and the hot spot temperature Ti of the fixed bed reaction section was controlled to be Ti=1.05^0.5*5.41*lnti+20(vi≥0.5m / h). After the operating time Ti reached 20300h, the hot spot temperature Ti reached 75°C, reaching the maximum operating temperature set for the resin, and the catalyst life was 20300h.

[0054] Comparative Example 1

[0055] Deionized water without resin adsorption and acrolein raw material containing 0.02wt.% of inhibitor hydroquinone were mixed in an SV type static mixer to prepare a 12wt.% acrolein aqueous solution; 100ml TP207 hydrogen resin was used as a hydration solid acid catalyst at a pressure of 0.05MPaG and a volume space velocity of 0.3h -1 The reaction temperature was controlled by a temperature program method at a linear speed of 0.5 m / h, and a hydration reaction occurred to obtain a hydration reaction liquid with a 3-hydroxypropanal yield of 72.5% and a selectivity of 92.7%. The reaction temperature was adjusted in real time by a temperature program method to control the hot spot temperature Ti of the fixed bed reaction section to 5.41*lnti+20. After the operation time ti reached 5000h, the hot spot temperature Ti reached 66°C, the reaction selectivity was significantly reduced, below 90%, and the pressure drop of the fixed bed layer was significantly increased. After the catalyst was removed, the catalyst morphology changed significantly, and there was an obvious phenomenon of agglomeration and powdering. ICP analysis showed that the divalent metal ions Ca, Fe, Mg, etc. were significantly enriched.

[0056] Comparison of catalyst metal ion indicators before and after the reaction:

[0057]

[0058] Comparative Example 2

[0059] Deionized water was passed through an adsorption bed filled with resin D403 at an adsorption rate of 4 BV / h, and then mixed with acrolein raw material containing 0.02 wt.% of inhibitor hydroquinone through an SV type static mixer to prepare a 12 wt.% acrolein aqueous solution; 100 ml of TP207 hydrogen type resin was used as a hydrated solid acid catalyst, the reaction temperature was 50°C, the pressure was 0.1 MPaG, the volume space velocity was 0.3 h -1 At a linear velocity of 0.5 m / h, hydration reaction occurred to obtain a hydration reaction liquid with a 3-hydroxypropanal yield of 75.2%, a selectivity of 91.5%, and a catalyst life of 2000 h. Both the catalyst activity and selectivity decreased significantly and could not be restored by raising the temperature.

[0060] Comparative Example 3

[0061] Deionized water was passed through an adsorption bed filled with resin D860 at an adsorption rate of 2 BV / h, and then mixed with acrolein raw material containing 0.01 wt.% of inhibitor hydroquinone through an SV type static mixer to prepare an acrolein aqueous solution with an acrolein concentration of 15 wt.%; 100 ml of TP207 hydrogen type resin was used as a hydrated solid acid catalyst at a pressure of 0.1 MPaG and a volume space velocity of 0.6 h -1 The reaction temperature was controlled by a temperature program method at a linear velocity of 20 m / h, and a hydration reaction occurred to obtain a hydration reaction liquid with a 3-hydroxypropanal yield of 70.2% and a selectivity of 93.2%. The reaction temperature was adjusted in real time by a temperature program method to control the hot spot temperature Ti of the fixed bed reaction section to be 1.05^0.975*5.41*lnti+20(vi≥0.5m / h). After the operating time Ti reached 5600h, the hot spot temperature Ti reached 69.0°C. At this time, due to the excessive space velocity, the reaction was difficult to stably control, and the reaction activity was significantly reduced to less than 40%.

[0062] Example 6

[0063] The acrolein aqueous solution obtained in Example 1 was distilled in a distillation tower with 10 plates, a top pressure of 15 kPaA, a bottom temperature of 50°C, a residence time of 0.5 h, and the purity of the acrolein obtained at the top of the tower was 98.5 wt.%, and the acrolein content in the bottom was 0.18 wt.%.

[0064] Example 7

[0065] The acrolein aqueous solution obtained in Example 1 was distilled in a distillation tower with 15 plates, a top pressure of 21 kPaA, a bottom temperature of 65°C, a residence time of 0.5 h, and the purity of the acrolein obtained at the top of the tower was 97.5 wt.%, and the acrolein content in the bottom of the tower was 0.09 wt.%.

Claims

1. A method for preparing 3-hydroxypropionaldehyde by hydrating acrolein, comprising the following steps: a) Raw material pretreatment: deionized water is adsorbed by a chelating resin and then mixed with an acrolein raw material containing an inhibitor through a static mixer to prepare an acrolein aqueous solution of a certain concentration; b) Acrolein hydration reaction: Acrolein aqueous solution is subjected to a solid acid catalyst and the temperature is programmed using the following equation: when vi is less than 0.5 m / h, Ti = 1.10^(1-vi / 0.5)*5.41*lnti+20; when vi is greater than or equal to 0.5 m / h, Ti = 1.05^[(vi-0.5) / vi]*5.41*lnti+20, wherein Ti represents the instantaneous reaction hot spot temperature / °C, ti represents the operating time / h, and vi represents the operating linear velocity m / h. When Ti = 20-75°C, the volume space velocity is 0.3-5h -1 , under the condition of vi = 0.01-15m / h, a hydration reaction occurs to obtain a hydration reaction liquid; c) separation of hydration liquid: the hydration reaction liquid is subjected to low temperature molecular distillation or vacuum distillation to obtain a 3-hydroxypropanal aqueous solution; The concentration of acrolein in the acrolein aqueous solution in step a) is 10-25 wt.%; The solid acid catalyst in step b) is selected from one or more of TP207, IRC747 and H-USY.

2. The method according to claim 1, characterized in that The chelating resin is selected from one or more of thiourea resin, aminoacetic acid resin, aminophosphoric acid resin, amidoxime resin, polyvinylpyridine resin, hydroxyquinoline resin and mixed bed resin.

3. The method according to claim 1, characterized in that The adsorption rate of the chelating resin described in step a) is 2-6BV / h, wherein BV represents the resin bed volume.

4. The method according to claim 1, characterized in that The adsorption rate of the chelating resin described in step a) is 3-5BV / h, wherein BV represents the resin bed volume.

5. The method according to claim 1, characterized in that The concentration of acrolein in the acrolein aqueous solution in step a) is 12%-17wt.%.

6. The method according to claim 1, characterized in that In step a), the polymerization inhibitor is selected from one or more of phenolic polymerization inhibitors, quinone polymerization inhibitors and nitroxide free radical polymerization inhibitors.

7. The method according to claim 1, characterized in that In step a), the polymerization inhibitor is selected from one or more of hydroquinone, tert-butylhydroquinone, p-benzoquinone, and methylhydroquinone.

8. The method according to claim 1, characterized in that In step a), the amount of the polymerization inhibitor added is 0.01 wt.%-0.1 wt.% based on the sum of the weight of acrolein and water.

9. The method according to claim 1, characterized in that: In step a), the amount of the polymerization inhibitor added is 0.015 wt.%-0.03 wt.% based on the sum of the weight of acrolein and water.

10. The method according to claim 1, characterized in that In step b), the programmed temperature method described in step b) has an initial temperature of 20° C., a maximum termination temperature of 75° C., and a reaction pressure of 0.05-0.5 MPaG.

11. The method according to claim 10, characterized in that The reaction pressure of step b) is 0.1-0.2 MPaG.

12. The method according to claim 1, characterized in that In step c), the conditions for separating acrolein from the hydrated liquid are a pressure of 15-21 kPaA and a bottom temperature of 50-65°C.

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