Preparation method of high-efficiency catalyst and application of high-efficiency catalyst in synthesis of L-refined glufosinate-ammonium

Abstract

The invention relates to the technical field of catalysts, in particular to a preparation method of a high-efficiency catalyst and application of the high-efficiency catalyst in synthesis of L-refined glufosinate ammonium. D-mannose and tartaric acid ester are used as main raw materials to react to prepare modified tartaric acid, then the modified tartaric acid and serine are mixed to generate Schiff base reaction to prepare a mixed catalyst, and the mixed catalyst is used for preparing the L-refined glufosinate ammonium. And introducing into an organic zinc metal framework to obtain the high-efficiency catalyst. The efficient catalyst is suitable for synthesis of L-refined glufosinate-ammonium, the chiral purity of L-refined glufosinate-ammonium is improved, and meanwhile, compared with a common hydrochloric acid solution catalyst, the condition is milder.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to a preparation method of a high-efficiency catalyst and application of the catalyst in the synthesis of L-fine glufosinate ammonium. Background Art

[0002] Glufosinate is a highly efficient, broad-spectrum, low-toxic, non-selective organophosphorus contact herbicide that is currently widely used, including L and DL glufosinate, of which L-glufosinate mainly plays a herbicidal role, so the herbicidal effect of DL-glufosinate is relatively weak. At present, researchers have developed different synthesis methods to improve the chiral purity of L-glufosinate. For example, WO2022 / 077989A1 "Preparation method of L-glufosinate" uses L-4-chloro-2-aminobutyric acid ethyl ester and chloromethylphosphite (MCP for short) to synthesize a five-membered ring structure intermediate (MPO for short), which is then hydrolyzed to obtain glufosinate. Another example is CN116789695A, "A method for preparing glufosinate ammonium" uses methyl phosphorus dichloride to first prepare an intermediate from methyl dimethylamine or methyl diethylamine, then react with L-4-chloro-2-aminobutyric acid ethyl ester to prepare a five-membered ring intermediate, and then hydrolyze to obtain refined glufosinate ammonium. However, these two methods for preparing refined glufosinate ammonium have many steps, and the consumption of organic bases is large, and there is still room for reducing production costs.

[0003] In addition, in 202410127501.X, the applicant disclosed a method for synthesizing L-fine glufosinate ammonium, which has a simple synthesis process, uses less organic base, can reduce the preparation cost, and has a high yield of L-fine glufosinate ammonium, but the compound

[0004]

[0005] Hydrochloric acid solution needs to be added for hydrolysis to obtain refined glufosinate hydrochloride. This process not only has a high reaction temperature, but also has the risk of racemization, which is not conducive to maintaining chiral stability.

[0006] Therefore, it is urgent to develop an efficient catalyst for the synthesis of L-phosphinothricin ammonium that can maintain chiral purity and has mild reaction conditions. Summary of the invention

[0007] The main purpose of the present invention is to provide a method for preparing a highly efficient catalyst and its application in the synthesis of L-glufosinate-ammonium, wherein the catalyst can maintain the chiral purity of L-glufosinate-ammonium and the reaction conditions are mild.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] In one aspect, the present invention provides a method for preparing a high-efficiency catalyst, comprising the following steps:

[0010] S1. D-mannose and tartaric acid are mixed and added to anhydrous methanol, and concentrated sulfuric acid is added thereto. The mixture is heated to 60-70° C. and stirred at a constant temperature for 12-15 hours. After the reaction is completed, the mixture is cooled to room temperature, concentrated under reduced pressure, dried, and subjected to column chromatography to obtain modified tartaric acid.

[0011] S2, adding the modified tartaric acid, serine and piperidine in step S1 to anhydrous methanol, heating to 60-70° C. and stirring for 5-6 hours, cooling to room temperature after the reaction, and filtering to obtain a mixed catalyst;

[0012] S3, adding zinc nitrate hexahydrate and benzotriazole to the first solvent, and then adding the mixed catalyst in step S2 to the system, heating to 140-150° C. and stirring at constant temperature for 24-26 hours. After the reaction is completed, cooling to room temperature, centrifugally filtering and washing with anhydrous ethanol to obtain a high-efficiency catalyst.

[0013] The applicant disclosed a method for preparing L-fine glufosinate in the patent application with publication number 202410127501.X, which improved the yield of L-fine glufosinate. With the continuous development and R&D innovation of the company, the applicant found that the intermediate compound in the previous application

[0014]

[0015] After hydrolysis with hydrochloric acid solution, L-glufosinate-ammonium may occasionally undergo racemization, resulting in the disappearance of chirality.

[0016] The high-efficiency catalyst of the present application can not only improve the chiral purity of L-aminobutyric acid, but also has milder reaction conditions than conventional hydrochloric acid solution as a catalyst. The reason may be that the hydroxyl group in serine can form a hydrogen bond with the nitrogen on benzotriazole, and the active group in serine attacks the carbonyl group of the amide bond, breaking the amide bond. However, the applicant's research found that although the addition of serine can increase the decomposition rate of the intermediate compound, its chirality still has the problem of racemization.

[0017] The present application can improve the chiral induction efficiency in the decomposition process of the intermediate by introducing modified tartaric acid, and can also further provide protons to promote the decomposition of the intermediate compound. In the past, researchers usually used sodium tartrate or potassium tartrate as a regulator to anchor in the metal organic framework, but it lost the ability to provide protons. The present application uses a specific modified tartaric acid to not only improve the chiral induction efficiency but also provide protons in the organic zinc metal framework, further promoting the decomposition of the intermediate compound. The reason may be that the modified tartaric acid contains an aldehyde group, which can form a Schiff base with the amino group in serine, and then the modified tartaric acid is anchored in the organic zinc metal framework through the complexing ability of serine and zinc ions.

[0018] In some embodiments, in step S1, the molar ratio of D-mannose to tartaric acid is 1:(0.8-1).

[0019] Preferably, in step S1, the molar ratio of D-mannose to tartaric acid is 1:0.9.

[0020] In some embodiments, in step S2, the molar ratio of the modified tartaric acid, serine and piperidine is 1:(1-1.2):(1-1.2).

[0021] Preferably, in step S2, the molar ratio of the modified tartaric acid, serine and piperidine is 1:1.1:1.1.

[0022] In some embodiments, in step S2, the volume of the anhydrous methanol is 4 to 6 times the total mass of the modified tartaric acid, serine and piperidine.

[0023] Preferably, in step S2, the volume of the anhydrous methanol is 5 times the total mass of the modified tartaric acid, serine and piperidine.

[0024] In some embodiments, in step S3, the first solvent is a mixture of ethanol and N,N-dimethylformamide, and the volume ratio of the two is 1:(0.8-1.1).

[0025] Preferably, in step S3, the first solvent is a mixture of ethanol and N,N-dimethylformamide, and the volume ratio of the two is 1:0.9.

[0026] In some embodiments, in step S3, the volume of the first solvent is 12 to 15 times the total mass of zinc nitrate hexahydrate and benzotriazole.

[0027] Preferably, in step S3, the volume of the first solvent is 13 times the total mass of zinc nitrate hexahydrate and benzotriazole.

[0028] In some embodiments, in step S3, the mass ratio of the mixed catalyst to zinc nitrate hexahydrate is 1:(0.2-0.4).

[0029] Preferably, in step S3, the mass ratio of the mixed catalyst to zinc nitrate hexahydrate is 1:0.3.

[0030] During the decomposition process of the intermediate compound, the amide therein can form ion coordination with zinc and then decompose. The applicant can prevent the mixed catalyst from competing for the active sites of zinc, resulting in a weakening of the synergistic catalytic effect, by regulating the mass ratio of the mixed catalyst to zinc nitrate hexahydrate.

[0031] In some embodiments, in step S3, the molar ratio of zinc nitrate hexahydrate to benzotriazole is 1:(2.5-3).

[0032] Preferably, in step S3, the molar ratio of zinc nitrate hexahydrate to benzotriazole is 1:2.7.

[0033] Another aspect of the present invention provides an application of a high-efficiency catalyst obtained by any of the above preparation methods in the synthesis of L-glufosinate-ammonium.

[0034] In some embodiments, the method for synthesizing L-fine glufosinate-ammonium comprises the following steps:

[0035] (1) Under a protective gas atmosphere, the compound represented by formula I

[0036]

[0037] and the solvent, stirring evenly, while dropping the catalyst and diethyl methyl phosphite into the system, heating and stirring under a slightly negative pressure, after the reaction is completed, vacuum distillation is performed to obtain a mixed product of the compound represented by formula II-1 and the compound represented by formula II-2

[0038]

[0039] (2) Add anhydrous hydrogen chloride ethanol solution dropwise to the mixed product in step (1), heat and stir, and evaporate to dryness under reduced pressure after the reaction is completed to obtain the compound represented by formula III

[0040]

[0041] (3) Adding a high-efficiency catalyst to the compound system represented by formula III in step (2), heating and stirring, evaporating the solvent under reduced pressure after the reaction is completed, adding an alcohol solution and heating and stirring, cooling to 0-10°C for crystallization, thereby obtaining L-fine glufosinate hydrochloride, then mixing L-fine glufosinate hydrochloride with aqueous ammonia until the pH of the mixed system is 5-6, and freeze-drying to obtain crude L-fine glufosinate, then mixing the crude L-fine glufosinate with 800 mL of methanol and stirring for 20-30 minutes, centrifuging and filtering, and then adjusting the pH of the filtrate to 7-8 with aqueous ammonia, and freeze-drying to obtain L-fine glufosinate;

[0042] Wherein, X is one of Cl, Br or I; R1 is one of methyl, ethyl, propyl or tert-butyl.

[0043] In some embodiments, the mass ratio of the compound represented by Formula III to the high-efficiency catalyst is 1:(0.2-0.3).

[0044] Preferably, the mass ratio of the compound represented by formula III to the high-efficiency catalyst is 1:0.25.

[0045] In some embodiments, in step (3), after adding the high-efficiency catalyst, the temperature of the temperature-raising reaction is 50 to 60° C., and the reaction time is 20 to 22 hours.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) The reaction conditions of the high-efficiency catalyst of the present invention are milder than those of conventional hydrochloric acid solution as a catalyst. The introduction of modified tartaric acid can improve the chiral induction efficiency in the decomposition process of the intermediate. In addition, the modified tartaric acid contains an aldehyde group, which can form a Schiff base with the amino group in serine. The modified tartaric acid is then anchored in the organic zinc metal skeleton through the complexing ability of serine and zinc ions, providing protons for the organic zinc metal skeleton, thereby further promoting the decomposition of the intermediate compound.

[0048] (2) The high-efficiency catalyst of the present invention is more suitable for the synthesis of L-glufosinate-ammonium, can improve the chiral purity of L-glufosinate-ammonium, and the synthesis conditions are milder. DETAILED DESCRIPTION

[0049] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Example 1

[0051] A method for preparing a high-efficiency catalyst comprises the following steps:

[0052] S1. 0.5 mol of D-mannose and 0.45 mol of tartaric acid were mixed and added into 1 L of anhydrous methanol, into which 54 g of concentrated sulfuric acid with a mass concentration of 98% was added, the temperature was raised to 65° C. and stirred at a constant temperature for 13 h. After the reaction was completed, the mixture was cooled to 27° C., concentrated and dried under reduced pressure, and subjected to column chromatography to obtain modified tartaric acid;

[0053] S2, adding 0.5 mol of modified tartaric acid, 0.55 mol of serine and 0.55 mol of piperidine in step S1 to 1.3 L of anhydrous methanol, heating to 65 ° C and stirring for 5.5 h, cooling to 27 ° C after the reaction is completed, and filtering to obtain a mixed catalyst;

[0054] S3, add 0.2 mol zinc nitrate hexahydrate and 0.54 mol benzotriazole to a mixture of 800 mL anhydrous ethanol and 750 mL N, N-dimethylformamide, then add 200 g of the mixed catalyst in step S2 to the system, heat to 145°C and stir at a constant temperature for 25 hours. After the reaction is completed, cool to 27°C, centrifuge and filter, and rinse with anhydrous ethanol to obtain a high-efficiency catalyst.

[0055] Example 2

[0056] A method for preparing a high-efficiency catalyst comprises the following steps:

[0057] S1. 0.5 mol of D-mannose and 0.4 mol of tartaric acid were mixed and added into 1 L of anhydrous methanol, into which 54 g of concentrated sulfuric acid with a mass concentration of 98% was added, the temperature was raised to 60° C. and stirred at a constant temperature for 15 h. After the reaction was completed, the mixture was cooled to 27° C., concentrated and dried under reduced pressure, and subjected to column chromatography to obtain modified tartaric acid;

[0058] S2, adding 0.5 mol of modified tartaric acid, 0.5 mol of serine and 0.5 mol of piperidine in step S1 to 1 L of anhydrous methanol, heating to 60° C. and stirring for 6 h, cooling to 27° C. after the reaction is completed, and filtering to obtain a mixed catalyst;

[0059] S3, add 0.13 mol zinc nitrate hexahydrate and 0.36 mol benzotriazole to a mixture of 550 mL anhydrous ethanol and 440 mL N, N-dimethylformamide, then add 200 g of the mixed catalyst in step S2 to the system, heat to 140°C and stir at a constant temperature for 26 hours. After the reaction is completed, cool to 27°C, centrifuge and filter, and rinse with anhydrous ethanol to obtain a high-efficiency catalyst.

[0060] Example 3

[0061] A method for preparing a high-efficiency catalyst comprises the following steps:

[0062] S1. 0.5 mol of D-mannose and 0.5 mol of tartaric acid were mixed and added into 1 L of anhydrous methanol, 54 g of concentrated sulfuric acid with a mass concentration of 98% was added thereto, the temperature was raised to 70°C and stirred at a constant temperature for 12 h, after the reaction was completed, the mixture was cooled to 27°C, concentrated under reduced pressure and dried, and subjected to column chromatography to obtain modified tartaric acid;

[0063] S2, adding 0.5 mol of modified tartaric acid, 0.6 mol of serine and 0.6 mol of piperidine in step S1 to 1.6 L of anhydrous methanol, heating to 70° C. and stirring for 5 h, cooling to 27° C. after the reaction is completed, and filtering to obtain a mixed catalyst;

[0064] S3, add 0.26 mol zinc nitrate hexahydrate and 0.72 mol benzotriazole to a mixture of 1.2 L anhydrous ethanol and 1.3 L N, N-dimethylformamide, then add 200 g of the mixed catalyst in step S2 to the system, heat to 150 ° C and stir at a constant temperature for 24 hours, cool to 27 ° C after the reaction, centrifuge and filter, and rinse with anhydrous ethanol to obtain a high-efficiency catalyst.

[0065] Example 4

[0066] A method for preparing a high-efficiency catalyst, the specific implementation method is the same as Example 1, except that the D-mannose is 0.7 mol.

[0067] Example 5

[0068] A method for preparing a high-efficiency catalyst, the specific implementation method is the same as Example 1, except that the mass of the mixed catalyst is 400g.

[0069] Comparative Example 1

[0070] A method for preparing a catalyst comprises the following steps:

[0071] S1. 0.5 mol of D-mannose and 0.45 mol of tartaric acid were mixed and added into 1 L of anhydrous methanol, into which 54 g of concentrated sulfuric acid with a mass concentration of 98% was added, the temperature was raised to 65° C. and stirred at a constant temperature for 13 h. After the reaction was completed, the mixture was cooled to 27° C., concentrated and dried under reduced pressure, and subjected to column chromatography to obtain modified tartaric acid;

[0072] S2. Mix 0.5 mol of modified tartaric acid, 0.55 mol of serine and 0.55 mol of piperidine in step S1 and add into 1.3 L of anhydrous methanol. Heat to 65° C. and stir for 5.5 h. After the reaction is completed, cool to 27° C. and filter to obtain the catalyst.

[0073] Comparative Example 2

[0074] A method for preparing a catalyst comprises the following steps:

[0075] 0.2 mol of zinc nitrate hexahydrate and 0.54 mol of benzotriazole are added to a mixture of 800 mL of anhydrous ethanol and 750 mL of N,N-dimethylformamide. Then, 200 g of serine in step (1) is added to the system and the temperature is raised to 145°C and stirred at this temperature for 25 hours. After the reaction is completed, the temperature is lowered to 27°C, and the mixture is centrifuged and washed with anhydrous ethanol to obtain the catalyst.

[0076] Example 6

[0077] A method for synthesizing L-glufosinate-ammonium comprises the following steps:

[0078] (1) Under N2 atmosphere, 0.60 mol of the compound represented by formula I

[0079]

[0080] and 200mL chlorobenzene, stirred evenly, and at the same time, 0.03mol 2,4,6-trimethylpyridine and 0.66mol diethyl methylphosphite were added dropwise to the system, and the temperature was raised to 90°C and stirred for 18h under a slight negative pressure of 0.06MPa. After the reaction was completed, the mixture was distilled under reduced pressure at a pressure of 0.11MPa and a distillation temperature of 50°C to obtain a mixed product of the compound represented by formula II-1 and the compound represented by formula II-2.

[0081]

[0082] (2) Add 1.21 mol of hydrogen chloride to the mixed product in step (1) to form an anhydrous hydrogen chloride ethanol solution with a mass fraction of 30%, heat to 43° C. and stir for 7 hours. After the reaction is completed, evaporate to dryness at 50° C. and 0.11 MPa vacuum pressure to obtain the compound represented by formula III

[0083]

[0084] (3) To the compound system represented by formula III in step (2), 57.5 g of a high-efficiency catalyst was added, the temperature was raised to 55° C. and stirred for 21 h. After the reaction was completed, the solvent was evaporated under reduced pressure at 50° C. and 0.11 MPa vacuum pressure, and then 976.9 mL of a 95% ethanol solution was added and the temperature was raised to 65° C. and stirred for 2 h. After cooling to 5° C., L-fine glufosinate hydrochloride was obtained after crystallization. The L-fine glufosinate hydrochloride was then mixed with aqueous ammonia until the pH of the mixed system was 5.5, and the mixture was freeze-dried to obtain a crude L-fine glufosinate. The crude L-fine glufosinate was then mixed with 800 mL of methanol and stirred for 25 min, centrifuged, and the filtrate was adjusted to pH 7.5 with aqueous ammonia, and freeze-dried to obtain L-fine glufosinate. The chiral compounds were separated by two-dimensional liquid chromatography according to the formula: ee = (LD) / (L+D)×100%, where L and D are the relative concentrations of L-configuration and D-configuration glufosinate-ammonium, and the calculated ee value of L-glufosinate-ammonium is 97.5%.

[0085] Wherein, the high-efficiency catalyst is prepared by Example 1.

[0086] Example 7

[0087] A synthesis of L-fine glufosinate ammonium, the specific implementation method is the same as that of Example 4, except that the high-efficiency catalyst is prepared from Example 2. The ee value of L-fine glufosinate ammonium is calculated to be 96.8%.

[0088] Example 8

[0089] A synthesis of L-fine glufosinate ammonium, the specific implementation method is the same as that of Example 4, except that the high-efficiency catalyst is prepared from Example 3. The ee value of L-fine glufosinate ammonium is calculated to be 97.2%.

[0090] Example 9

[0091] A synthesis of L-fine glufosinate ammonium, the specific implementation method is the same as that of Example 4, except that the high-efficiency catalyst is prepared from Example 4. The ee value of L-fine glufosinate ammonium is calculated to be 93.6%.

[0092] Example 10

[0093] A synthesis of L-fine glufosinate ammonium, the specific implementation method is the same as that of Example 4, except that the high-efficiency catalyst is prepared from Example 5. The ee value of L-fine glufosinate ammonium is calculated to be 94.2%.

[0094] Embodiment 11

[0095] A synthesis of L-fine glufosinate ammonium, the specific implementation method is the same as that of Example 4, except that the high-efficiency catalyst is prepared from Comparative Example 1. The ee value of L-fine glufosinate ammonium is calculated to be 90.1%.

[0096] Example 12

[0097] A synthesis of L-fine glufosinate ammonium, the specific implementation method is the same as Example 4, except that the high-efficiency catalyst is prepared from Comparative Example 2. The ee value of L-fine glufosinate ammonium is calculated to be 85.9%.

[0098] Calculation of chiral purity of L-glufosinate ammonium:

[0099] By calculating the yield of L-fine glufosinate, it can be seen that the L-fine glufosinate in Examples 6 to 8 is prepared by the high-efficiency catalysts of Examples 1 to 3, and the ee value is relatively high; Example 9 uses the high-efficiency catalyst prepared in Example 4, in which the molar ratio of D-mannose to tartaric acid is changed, resulting in a reduction in the amount of proton acid provided by the high-efficiency catalyst, resulting in a weakened catalytic effect, and an incomplete reaction under the same experimental conditions, thereby reducing the yield of L-fine glufosinate and thus reducing the ee value; Example 10 uses the high-efficiency catalyst prepared in Example 5, and changes the mass ratio of the mixed catalyst to zinc nitrate hexahydrate. , resulting in the mixed catalyst competing with the compound represented by Formula III for the active site of zinc, resulting in a decrease in catalytic performance. Under the same experimental conditions, the reaction is incomplete, thereby reducing the yield of L-fine glufosinate ammonium and thus reducing the ee value; Example 11 uses the catalyst prepared in Comparative Example 1, and due to the lack of the addition of an organic zinc metal skeleton, the catalytic performance is reduced. Under the same experimental conditions, the reaction is incomplete, thereby reducing the yield of L-fine glufosinate ammonium and thus reducing the ee value; Example 12 uses the catalyst prepared in Comparative Example 2, and due to the lack of the addition of modified tartaric acid, the ee value of L-fine glufosinate ammonium is reduced.

[0100] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a high-efficiency catalyst, characterized in that: The steps include: S1. D-mannose and tartaric acid are mixed and added to anhydrous methanol, and concentrated sulfuric acid is added thereto. The mixture is heated to 60-70° C. and stirred at a constant temperature for 12-15 hours. After the reaction is completed, the mixture is cooled to room temperature, concentrated under reduced pressure, dried, and subjected to column chromatography to obtain modified tartaric acid. S2, adding the modified tartaric acid, serine and piperidine in step S1 to anhydrous methanol, heating to 60-70° C. and stirring for 5-6 hours, cooling to room temperature after the reaction, and filtering to obtain a mixed catalyst; S3, adding zinc nitrate hexahydrate and benzotriazole to the first solvent, and then adding the mixed catalyst in step S2 to the system, heating to 140-150° C. and stirring at constant temperature for 24-26 hours. After the reaction is completed, cooling to room temperature, centrifugally filtering and washing with anhydrous ethanol to obtain a high-efficiency catalyst.

2. The method for preparing a high-efficiency catalyst according to claim 1, characterized in that: In step S1, the molar ratio of D-mannose to tartaric acid is 1:(0.8-1).

3. The method for preparing a high-efficiency catalyst according to claim 1, characterized in that: In step S2, the molar ratio of the modified tartaric acid, serine and piperidine is 1:(1-1.2):(1-1.2).

4. The method for preparing a high-efficiency catalyst according to claim 1, characterized in that: In step S3, the first solvent is a mixture of ethanol and N,N-dimethylformamide, and the volume ratio of the two is 1:(0.8-1.1).

5. The method for preparing a high-efficiency catalyst according to claim 1, characterized in that: In step S3, the mass ratio of the mixed catalyst to zinc nitrate hexahydrate is 1:(0.2-0.4).

6. The method for preparing a high-efficiency catalyst according to claim 1, characterized in that: In step S3, the molar ratio of zinc nitrate hexahydrate to benzotriazole is 1:(2.5-3).

7. Use of a high-efficiency catalyst obtained by the preparation method according to any one of claims 1 to 6 in the synthesis of L-glufosinate-ammonium.

8. Use of the high-efficiency catalyst according to claim 7 in the synthesis of L-fine glufosinate-ammonium, characterized in that: The synthesis method of L-fine glufosinate-ammonium comprises the following steps: (1) Under a protective gas atmosphere, the compound represented by formula I and the solvent, stirring evenly, while dropping the catalyst and diethyl methyl phosphite into the system, heating and stirring under a slightly negative pressure, after the reaction is completed, vacuum distillation is performed to obtain a mixed product of the compound represented by formula II-1 and the compound represented by formula II-2 (2) Add anhydrous hydrogen chloride ethanol solution dropwise to the mixed product in step (1), heat and stir, and evaporate to dryness under reduced pressure after the reaction is completed to obtain the compound represented by formula III (3) Adding a high-efficiency catalyst to the compound system represented by formula III in step (2), heating and stirring, evaporating the solvent under reduced pressure after the reaction is completed, adding an alcohol solution and heating and stirring, cooling to 0-10°C for crystallization, thereby obtaining L-fine glufosinate hydrochloride, then mixing L-fine glufosinate hydrochloride with aqueous ammonia until the pH of the mixed system is 5-6, and freeze-drying to obtain crude L-fine glufosinate, then mixing the crude L-fine glufosinate with 800 mL of methanol and stirring for 20-30 minutes, centrifuging and filtering, and then adjusting the pH of the filtrate to 7-8 with aqueous ammonia, and freeze-drying to obtain L-fine glufosinate; Wherein, X is one of Cl, Br or I; R1 is one of methyl, ethyl, propyl or tert-butyl.

9. Use of a high-efficiency catalyst according to claim 8 in the synthesis of L-fine glufosinate-ammonium, characterized in that: The mass ratio of the compound represented by formula III to the high-efficiency catalyst is 1:(0.2-0.3).

10. Use of a high-efficiency catalyst according to claim 8 in the synthesis of L-fine glufosinate-ammonium, characterized in that: In step (3), after adding the high-efficiency catalyst, the temperature of the temperature-raising reaction is 50-60° C., and the reaction time is 20-22 h.

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