Preparation method of 3-(ethyoxyl methyl phosphonyl) propionaldehyde

Abstract

The invention provides a preparation method of 3-(ethyoxyl methyl phosphonyl) propionaldehyde, which comprises the following steps: mixing acrolein and acetic acid to obtain an acid-aldehyde mixed solution; diethyl ester and ethyl alcohol are directly mixed or added into an organic solvent to be mixed, and alcohol ester mixed liquid is obtained; continuously pumping the acid-aldehyde mixed solution and the alcohol-ester mixed solution into a multi-stage microchannel loop reactor from each feeding point according to a ratio, and carrying out a condensation reaction to obtain an acetal solution; the acetal solution is pretreated, diluted hydrochloric acid is added for heat preservation hydrolysis, vacuum desolvation is conducted after heat preservation is finished, and 3-(ethyoxyl methyl phosphonyl) propionaldehyde is obtained. According to the method, the condensation reaction is carried out in the multi-stage microchannel loop reactor, so that the mixing effect is greatly improved, the reaction heat is quickly removed, and the reaction time is shortened. And meanwhile, a circulation and acid-aldehyde grading attenuation feeding mode is adopted, so that the problem of side reaction increase caused by over-high acid-aldehyde ratio in a local channel is avoided, and the reaction efficiency and the reaction yield are effectively improved.

Description

Technical Field

[0001] The invention belongs to the field of glufosinate-ammonium intermediate production, and specifically relates to a method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde. Background Art

[0002] 3-(Ethoxymethylphosphonyl) propionaldehyde (phosphonaldehyde for short) can be produced by hydrolysis of 3-(ethoxymethylphosphonyl) propionyl acetal (acetal for short), and is an important intermediate in the synthesis of glufosinate ammonium. Phosphonaldehyde can be obtained by cyanamination, hydrolysis, ammoniation and other steps to obtain glufosinate ammonium. Glufosinate ammonium is a non-selective herbicide developed by Hoechst (now BASF) in Germany in 1986. It has a good market prospect and a significant growth momentum, and has become the world's second largest herbicide. Therefore, research in this direction has produced many patent results.

[0003] Patent CN1267305A is a raw material with methylphosphite and anhydride as a condensing agent, and generates adducts (including acetals) with acrolein addition reaction in the presence of alcohol. The reaction can be carried out without solvent or in the presence of aliphatic or aromatic hydrocarbons or alcohol organic solvents, such as: methylene chloride, toluene, dimethylbenzene, chlorobenzene, ether, ethanol, n-butanol, etc. However, the yield of glufosinate-ammonium in practical applications of the scheme is low, and the effect is far below the level reported. In addition, the patent adopts a batch process in this step of strong exothermic condensation, and does not adopt a continuous method synthesis reaction, and heat cannot be removed rapidly in a large production unit, which restricts device efficiency, and the problem of excessive concentration of local acrolein will also occur in the dropwise reaction, which is unfavorable for suppressing side reactions.

[0004] Patent CN1858054A uses a weak acid as a condensing agent, adds the weak acid to acrolein, and then drops it into methyl phosphite for reaction. The weak acid includes aliphatic carboxylic acids containing C1-C18, aliphatic carboxylic acids containing aromatic groups, etc. The solvent used is water or an organic solvent such as aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, ethers or alcohols. In patent CN103396440B, methyl phosphinate reacts with acrolein under the action of a catalyst to obtain methyl propionaldehyde phosphonate, and the catalyst is an aliphatic carboxylic acid with 1-10 carbon atoms or an aliphatic carboxylic acid with 8-16 carbon atoms containing aromatic groups, and the molar ratio of the catalyst to methyl phosphinate is 0.2-3:1. The molar ratio of methyl phosphinate to acrolein is 1:1-3, the reaction temperature is -50°C-150°C, and the reaction time is 1-12 hours. Patent CN107236001A drips a mixture of anhydrous ethanol and acrolein into a mixture of anhydrous ethanol, glacial acetic acid, and diethyl methylphosphite to react, thereby suppressing the occurrence of side reactions and improving the reaction efficiency. The ratio of glacial acetic acid, anhydrous ethanol, and diethyl methylphosphite is (1-1.5): (3-40): 1, which is beneficial to improving the yield of phosphinaldehyde. These methods still use intermittent methods, the device efficiency is not high, and it is not conducive to suppressing side reactions.

[0005] Patent CN111018907B continuously feeds diethyl methylphosphite and "a mixture of acrolein and glacial acetic acid" into a continuous reactor to synthesize crude acetal, making the preparation of crude acetal more efficient. The molar ratio of diethyl methylphosphite to acrolein is 1-1.2:1, the molar ratio of acetic acid to acrolein is 1-1.2:1, the temperature in the reactor is 15-35°C, and the apparent residence time is 2.5h-24h. This patent uses both the acetic acid method and continuous reaction, but does not fully consider the problem of excessive diethyl ester and excessive acrolein in the local reaction ratio during continuous reaction. There must be too high a concentration of diethyl ester at the diethyl ester feed port, and there must be too high acrolein at the acrolein feed port, and too high acrolein concentration will lead to an increase in acrolein double addition byproducts. This patent uses multi-stage graded feeding to ensure that diethyl ester is always excessive during the main reactions of the first few stages. Moreover, the large-flow reflux speeds up the dispersion of acrolein, avoids the problem of excessive local concentration of acrolein, and inhibits the occurrence of side reactions.

[0006] Patent CN112898338A adds diethyl methylphosphite and acrolein and acetic acid mixture dropwise into the reactor simultaneously, and when studying, it is found that when diethyl methylphosphite is added dropwise to acrolein-weak acid mixture, due to the influence of excessive acid, side reactions occur in a large number, and the target acetal content is lower than 60%, which may be due to the double addition by-product caused by the local excessive amount of acrolein. It is also found that under the auxiliary effect of alcohols, the presence of ethanol reduces the content of target acetal in the reaction solution, and the more ethanol, the lower the target acetal content. This scheme still needs to use an amount of ethanol when using organic solvents such as aromatic hydrocarbons, halogenated hydrocarbons or solvent-free. This patent still cannot avoid or reduce the problem of excessive local concentration of acrolein in the reaction process.

[0007] In general, the above patent solution has the following defects:

[0008] 1) In actual production, batch reaction or continuous reaction is often used. In order to prevent the local concentration from being too high, the feed rate cannot be too fast, and a large amount of reaction heat cannot be removed quickly, resulting in low utilization of condensation reaction equipment.

[0009] 2) Although the use of microchannel reactors can effectively solve the problem of rapid heat removal, it will lead to excessive acrolein in local channels when the material is diverted, increasing the occurrence of side reactions.

[0010] 3) During the hydrolysis of acetal, the ethoxy group on phosphorus may also be hydrolyzed. Therefore, measures need to be taken and conditions need to be controlled during the hydrolysis of acetal to prevent excessive hydrolysis of acetal. Summary of the invention

[0011] In order to overcome the defects in the prior art, the present invention provides a novel method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde.

[0012] The basic concept of the technical solution of the present invention is as follows:

[0013] A method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde comprises the following steps:

[0014] (1) mixing acrolein and acetic acid to obtain an acid-aldehyde mixed solution;

[0015] (2) directly mixing diethyl ester with ethanol or adding them into an organic solvent to obtain an alcohol-ester mixed solution;

[0016] (3) continuously injecting the acid-aldehyde mixed solution and the alcohol-ester mixed solution into a multi-stage microchannel loop reactor from each feeding point according to a ratio to carry out a condensation reaction to obtain an acetal solution;

[0017] (4) pre-treating the acetal solution, then adding dilute hydrochloric acid to hydrolyze the solution by heat preservation, and vacuum desolventizing after the heat preservation to obtain 3-(ethoxymethylphosphonyl)propanal.

[0018] As an embodiment, in step (2), the organic solvent is an aromatic hydrocarbon, a halogenated hydrocarbon or an alcohol solvent.

[0019] Preferably, the molar ratio of the organic solvent to the diethyl ester is (2-10):1; preferably, the temperature of the condensation reaction in step (3) is 0-20°C, more preferably 5-10°C.

[0020] As an embodiment, when the diethyl ester in step (2) is directly mixed with ethanol, or when an aromatic hydrocarbon or halogenated hydrocarbon solvent is used, the molar ratio of acrolein, acetic acid, diethyl ester and ethanol is (1-1.2):(1-1.2):1:(0.5-1.5), preferably (1-1.05):(1-1.05):1:(0.6-1.2).

[0021] As an embodiment, when an alcohol organic solvent is used in step (2), the molar ratio of acrolein, acetic acid and diethyl ester is (1-1.2):(0.3-0.8):1, preferably (1-1.05):(0.5-0.6):1.

[0022] As an embodiment, the multi-stage microchannel circulation reactor is composed of 3 to 10 reactors composed of microchannels, circulation pipes and circulation pumps connected in series; the feeding method is: the alcohol-ester mixed liquid enters from the first reactor, and the acid-aldehyde mixed liquid enters from the first reactor in batches in a decaying manner of 40% to 60%, 20% to 40% of the total amount of the acid-aldehyde mixed liquid, and 0 to 20% of the remaining reactors.

[0023] Preferably, the reflux rate of the multi-stage microchannel loop reactor is 2 to 10 times, more preferably 3 to 6 times, the total mass flow rate of all feeds at each stage.

[0024] Preferably, the total average residence time of the acid-aldehyde mixed solution and the alcohol-ester mixed solution in the multi-stage microchannel loop reactor is 1 to 120 minutes, preferably 30 to 60 minutes.

[0025] As an embodiment, in step (4), the acetal solution is pretreated in the following manner: when aromatic hydrocarbons or halogenated hydrocarbons are used as organic solvents, pure water in an amount of 4 to 8 times the molar amount of diethyl ester is added for phase separation; when diethyl ester and ethanol are directly mixed, pure water in an amount of 4 to 8 times the molar amount of diethyl ester is added for dilution; when alcohol organic solvents are used, vacuum dealcoholization is first performed, and then pure water in an amount of 4 to 8 times the molar amount of diethyl ester is added for dilution, preferably pure water in an amount of 5 to 6 times the molar amount of diethyl ester is added.

[0026] As an embodiment, when ethanol is used as the solvent, the vacuum dealcoholization temperature of the acetal solution is 40 to 65°C, preferably 50 to 60°C.

[0027] Preferably, the temperature for adding pure water for phase separation or dilution is 10-25°C.

[0028] As an embodiment, in step (4), the mass concentration of the dilute hydrochloric acid is 0.5% to 5%, preferably 1% to 2.5%; the molar amount of HCl in the dilute hydrochloric acid is 0.02 to 0.1 times, preferably 0.03 to 0.05 times, of the molar amount of diethyl ester.

[0029] As an embodiment, in step (4), the hydrolysis insulation temperature is 10 to 25° C., and the insulation time is 1 to 5 hours.

[0030] As an embodiment, in step (4), the temperature of vacuum desolventizing is 30 to 60°C, preferably 35 to 50°C.

[0031] The present invention has the following beneficial effects:

[0032] 1. The preparation method of the present invention carries out condensation reaction in a multi-stage microchannel circulation reactor, greatly improves the mixing effect, quickly removes the reaction heat, and shortens the reaction time. At the same time, the feeding mode of circulation and acid aldehyde graded attenuation is adopted to avoid the problem of increased side reactions caused by too high acid aldehyde ratio in local channels, and effectively improves the reaction efficiency and reaction yield.

[0033] 2. The preparation method of the present invention classifies the amount of acetic acid used and the treatment method of the acetal solution when using different solvents. Manufacturers can select a production method suitable for themselves based on their own resource advantages and characteristics, effectively reduce acetic acid consumption, reduce by-product generation, and save energy consumption.

[0034] 3. The preparation method of the present invention adopts a pretreatment method of adding pure water to reduce the reaction heat released by the acidification of acetal, and uses dilute hydrochloric acid for hydrolysis to reduce the acid concentration, effectively inhibiting the excessive hydrolysis of phosphaldehyde and preventing the hydrolysis of the ethoxy group on phosphorus. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a schematic flow diagram of a method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde in a multi-stage microchannel loop reactor.

[0036] Figure 2 It is the gas chromatogram of the phosphinaldehyde prepared in Example 1 of the present invention.

[0037] Figure 3 It is the gas chromatography-mass spectrometry of the phosphinaldehyde prepared in Example 1 of the present invention.

[0038] Figure 4 It is the nuclear magnetic hydrogen spectrum of the phosphine aldehyde prepared in Example 1 of the present invention.

[0039] Figure 5 It is the nuclear magnetic hydrogen spectrum of the phosphine aldehyde prepared in Example 1 of the present invention.

[0040] Marking Description:

[0041] ① microchannel reactor; ② circulation pump; ③ alcohol-ester mixed liquid feed inlet; ④ primary acid-aldehyde mixed liquid feed inlet; ⑤ secondary acid-aldehyde mixed liquid feed inlet; ⑥ tertiary acid-aldehyde mixed liquid feed inlet; ⑦ discharge port. DETAILED DESCRIPTION

[0042] The embodiments of the present invention are carried out in a multi-stage microchannel loop reactor. The multi-stage microchannel loop reactor can be provided with three, four, five or six microchannel reactors ①, etc. Figure 1 As shown, when three microchannel reactors ① are provided, the multi-stage microchannel loop reactor includes three microchannel reactors ① connected in series through three loop pumps ② and pipelines to form a loop. The three-stage microchannel reactor ① is Figure 1 In the figure, it is briefly represented as a primary reactor, a secondary reactor and a tertiary reactor. The primary reactor is provided with an alcohol-ester mixed liquid feed port ③ and a primary acid-aldehyde mixed liquid feed port ④, the secondary reactor is provided with a secondary acid-aldehyde mixed liquid feed port ⑤, and the tertiary reactor is provided with a tertiary acid-aldehyde mixed liquid feed port ⑥ and a discharge port ⑦. The setting methods of other multi-stage microchannel loop reactors are referred to this setting method and so on.

[0043] Examples 1-4

[0044] (1) mixing acrolein and acetic acid in a molar ratio of 1.05:0.5 to prepare an acid-aldehyde mixed solution for standby use;

[0045] (2) mixing diethyl ester, ethanol and toluene in a molar ratio of 1:0.7:2.6 to prepare a toluene solution of a mixture of alcohol and ester;

[0046] (3) continuously injecting the alcohol-ester mixed toluene solution into the alcohol-ester mixed solution feed port ③ of the primary reactor at a diethyl ester flow rate of 0.02 mol / min, and simultaneously continuously injecting the acid-aldehyde mixed solution into the acid-aldehyde mixed solution feed ports of each level in the multi-stage microchannel loop reactor according to different schemes in Table 1 to carry out condensation reaction to obtain acetal solution;

[0047] (4) The obtained acetal solution was respectively hydrolyzed according to the different hydrolysis schemes in Table 1, and water and acid were added in sequence to complete the hydrolysis reaction. Finally, the acid water was removed by vacuum desolvation. The vacuum degree was -0.098 MPa and the desolvation end temperature was 40°C to obtain 3-(ethoxymethylphosphonyl)propanal.

[0048] The corresponding phosphine aldehyde product yields obtained in Examples 1-4 (corresponding to Schemes 1-4 in the table) are shown in Table 1 below.

[0049] Table 1

[0050]

[0051] The phosphinaldehyde prepared in Example 1 was subjected to gas chromatography, gas chromatography-mass spectrometry and nuclear magnetic resonance detection, and the results obtained are as follows: Figure 2-5 shown.

[0052] Figure 2 The peak at 2-3 min is ethanol, the peak at 3-4 min is tetrahydrofuran, the peak at 13-14 min is phosphine aldehyde.

[0053] Phosphaldehyde 1 H NMR (DMSO-d6, 500MHz) δ: 9.7 (s, 1H), 3.8-4.0 (quint, J = 7.1Hz, 2H), 2.5-2.7 (m, 2H), 1.8-2.0 (m, 2H), 1.4 (d, J = 14.0Hz, 3H), 1.2 (t, J = 7.1Hz, 3H); 13 C NMR (DMSO-d6, 125MHz) δ: 201.9, 59.9, 36.2, 21.6 (d, J = 94.4Hz), 16.8, 13.6 (d, J = 91.6Hz). GC-MS (70eV) m / z (%): 164 (M+, 1), 136 (26), 119 (35), 108 (89), 80 (76), 79 (100).

[0054] Example 5

[0055] (1) mixing acrolein and acetic acid in a molar ratio of 1.05:0.55 to prepare an acid-aldehyde mixed solution;

[0056] (2) mixing diethyl ester and ethanol in a molar ratio of 1:8 to prepare an alcohol-ester mixed solution;

[0057] (3) continuously injecting the alcohol ester mixed liquid into the alcohol ester mixed liquid feed port ③ of the first reactor of the three-stage microchannel circulation reactor at a diethyl ester molar flow rate of 0.02 mol / min, and simultaneously continuously injecting the acid aldehyde mixed liquid into the first acid aldehyde mixed liquid feed port ④, the second acid aldehyde mixed liquid feed port ⑤, and the third acid aldehyde mixed liquid feed port ⑥ at acrolein molar flow rates of 0.0105 mol / min, 0.0063 mol / min, and 0.0042 mol / min, respectively, for reaction, the reaction temperature is controlled at 5° C., the circulation ratio of each stage is controlled at about 3 times the total feed flow rate, the total average residence time of the materials in the three-stage microchannel circulation reactor is 30 minutes, and the acetal solution is obtained by continuous reaction;

[0058] (4) The acetal solution obtained continuously is subjected to vacuum dealcoholization, the vacuum degree is -0.098MPa, the desolventizing end temperature is 60°C, and the solvent ethanol is removed; then it is cooled to 20°C, 5.5 molar equivalents of pure water are added while stirring, and the temperature is maintained at 20°C. After stirring evenly, 0.033 molar equivalents of 1.5wt% hydrochloric acid are added, and the temperature is kept at 20°C for 3h; finally, the acid water is removed by vacuum desolventizing, the vacuum degree is -0.098MPa, and the desolventizing end temperature is 40°C, and the product phosphaldehyde is obtained with a yield of 97.8%.

[0059] Example 6

[0060] (1) mixing acrolein and acetic acid in a molar ratio of 1.05:0.8 to prepare an acid-aldehyde mixed solution;

[0061] (2) mixing diethyl ester and ethanol in a molar ratio of 1:8 to prepare an alcohol-ester mixed solution;

[0062] (3) continuously injecting the alcohol ester mixed liquid into the alcohol ester mixed liquid feed port ③ of the first reactor of the three-stage microchannel circulation reactor at a diethyl ester molar flow rate of 0.02 mol / min, and simultaneously continuously injecting the acid aldehyde mixed liquid into the first acid aldehyde mixed liquid feed port ④, the second acid aldehyde mixed liquid feed port ⑤, and the third acid aldehyde mixed liquid feed port ⑥ at acrolein molar flow rates of 0.0105 mol / min, 0.0063 mol / min, and 0.0042 mol / min, respectively, for reaction; the reaction temperature is controlled at 5° C., the circulation ratio of each stage is controlled at about 3 times the total feed flow rate, the total average residence time of the material in the three-stage microchannel circulation reactor is 30 minutes, and the acetal solution is obtained by continuous reaction;

[0063] (4) The acetal solution obtained continuously is subjected to vacuum dealcoholization with a vacuum degree of -0.098 MPa and a desolventizing end temperature of 60°C to remove ethanol; it is then cooled to 20°C, and 5.5 molar equivalents of pure water are added while stirring, and the temperature is maintained at 20°C. After stirring evenly, 0.033 molar equivalents of 1.5wt% hydrochloric acid are added, and the temperature is maintained at 20°C for 3 hours; finally, the acid water is removed by vacuum desolventizing with a vacuum degree of -0.098 MPa and a desolventizing end temperature of 40°C to obtain the product phosphaldehyde with a yield of 96.6%.

[0064] Example 7

[0065] (1) mixing acrolein and acetic acid in a molar ratio of 1.05:1.0 to prepare an acid-aldehyde mixed solution;

[0066] (2) mixing diethyl ester and ethanol in a molar ratio of 1:1.14 to prepare an alcohol-ester mixed solution;

[0067] (3) continuously injecting the alcohol ester mixed liquid into the alcohol ester mixed liquid feed port of the first reactor of the three-stage microchannel circulation reactor at a diethyl ester molar flow rate of 0.02 mol / min, and simultaneously continuously injecting the acid aldehyde mixed liquid into the first acid aldehyde mixed liquid feed port ④, the second acid aldehyde mixed liquid feed port ⑤, and the third acid aldehyde mixed liquid feed port ⑥ at acrolein molar flow rates of 0.0105 mol / min, 0.0063 mol / min, and 0.0042 mol / min, respectively, for reaction; the reaction temperature is controlled at 5° C., the circulation ratio of each stage is controlled at about 3 times the total feed flow rate, the total average residence time of the material in the three-stage microchannel circulation reactor is 30 minutes, and the acetal solution is obtained by continuous reaction;

[0068] (4) Add 5.5 molar equivalents of pure water to the obtained acetal solution at 10-20° C. with stirring, and keep the temperature at 20° C. After stirring evenly, continue to add 0.033 molar equivalents of 1.5wt% hydrochloric acid, and keep the temperature at 20° C. for 3 hours; finally, remove the acid water by vacuum desolventizing, the vacuum degree is -0.098MPa, and the desolventizing end temperature is 40° C. to obtain the product phosphaldehyde with a yield of 96.3%.

Claims

1. A method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde, comprising the following steps: (1) mixing acrolein and acetic acid to obtain an acid-aldehyde mixed solution; (2) directly mixing diethyl ester with ethanol or adding them into an organic solvent to obtain an alcohol-ester mixed solution; (3) continuously injecting the acid-aldehyde mixed solution and the alcohol-ester mixed solution into a multi-stage microchannel loop reactor from each feeding point according to a ratio to carry out a condensation reaction to obtain an acetal solution; (4) pre-treating the acetal solution, then adding dilute hydrochloric acid to hydrolyze the solution by heat preservation, and vacuum desolventizing after the heat preservation to obtain 3-(ethoxymethylphosphonyl)propanal.

2. The method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde according to claim 1, characterized in that: In step (2), the organic solvent is an aromatic hydrocarbon, a halogenated hydrocarbon or an alcohol solvent; preferably, the molar ratio of the organic solvent to diethyl ester is (2-10):1; preferably, the temperature of the condensation reaction in step (3) is 0-20°C, more preferably 5-10°C.

3. The method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde according to claim 2, characterized in that: When the diethyl ester in step (2) is directly mixed with ethanol, or when an aromatic hydrocarbon or halogenated hydrocarbon solvent is used, the molar ratio of acrolein, acetic acid, diethyl ester and ethanol is (1-1.2):(1-1.2):1:(0.5-1.5), preferably (1-1.05):(1-1.05):1:(0.6-1.2).

4. The method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde according to claim 2, characterized in that: When an alcohol organic solvent is used in step (2), the molar ratio of acrolein, acetic acid and diethyl ester is (1-1.2):(0.3-0.8):1, preferably (1-1.05):(0.5-0.6):

1.

5. The method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde according to claim 1, characterized in that: The multi-stage microchannel circulation reactor is composed of 3 to 10 reactors connected in series, which are composed of microchannels, circulation pipelines and circulation pumps; the feeding method is: the alcohol ester mixture enters from the first reactor, and the acid aldehyde mixture enters from the first reactor in a decaying manner, with 40% to 60% and 20% to 40% of the total amount of the acid aldehyde mixture respectively, and the remaining reactors are 0 to 20%; Preferably, the reflux rate of the multi-stage microchannel loop reactor is 2 to 10 times, more preferably 3 to 6 times, the total mass flow rate of all feeds at each stage; Preferably, the total average residence time of the acid-aldehyde mixed solution and the alcohol-ester mixed solution in the multi-stage microchannel loop reactor is 1 to 120 minutes, preferably 30 to 60 minutes.

6. The method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde according to claim 1, characterized in that: In step (4), the acetal solution is pretreated in the following manner: when aromatic hydrocarbons or halogenated hydrocarbons are used as organic solvents, pure water in an amount of 4 to 8 times the molar amount of diethyl ester is added for phase separation; when diethyl ester and ethanol are directly mixed, pure water in an amount of 4 to 8 times the molar amount of diethyl ester is added for dilution; when alcohol organic solvents are used, vacuum dealcoholization is first performed, and then pure water in an amount of 4 to 8 times the molar amount of diethyl ester is added for dilution, preferably pure water in an amount of 5 to 6 times the molar amount of diethyl ester is added.

7. The method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde according to claim 6, characterized in that: When ethanol is used as the solvent, the vacuum dealcoholization temperature of the acetal solution is 40 to 65°C, preferably 50 to 60°C; Preferably, the temperature for adding pure water for phase separation or dilution is 10-25°C.

8. The method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde according to claim 6, characterized in that: In step (4), the mass concentration of the dilute hydrochloric acid is 0.5% to 5%, preferably 1% to 2.5%; the molar amount of HCl in the dilute hydrochloric acid is 0.02 to 0.1 times, preferably 0.03 to 0.05 times, of the molar amount of diethyl ester.

9. The method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde according to claim 1, characterized in that: In step (4), the hydrolysis insulation temperature is 10 to 25° C., and the insulation time is 1 to 5 hours.

10. The method for preparing 3-(ethoxymethylphosphonyl)propionaldehyde according to claim 1, characterized in that: In step (4), the temperature of vacuum desolventizing is 30 to 60°C, preferably 35 to 50°C.

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