Glyphosate crystallization method capable of eliminating fine grains and edges and application of glyphosate crystallization method

Abstract

The invention provides a glyphosate crystallization method capable of eliminating fine grains and edges and an application thereof, the glyphosate crystallization method comprises the following steps: (1) dropwise adding alkali liquor into a first batch of glyphosate samples to be crystallized for crystallization to obtain crystallization liquid; (2) mixing and diluting a second batch of glyphosate samples to be crystallized with alkali liquor to obtain mixed liquor; and (3) mixing the crystallization liquid with the mixed liquid to obtain the glyphosate crystal. According to the method provided by the invention, fine crystals generated in the glyphosate crystallization process can be eliminated, so that the obtained crystals are smooth in edge, good in fluidity and not easy to bond into blocks, and the whole method does not need additional equipment and is suitable for existing industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of glyphosate production, and particularly relates to a glyphosate crystallization method for eliminating fine crystals and edges and an application thereof. Background Art

[0002] Glyphosate is a highly effective, low-toxic, low-cost broad-spectrum herbicide with white crystals, no odor, and no volatility. Glyphosate is an amino acid derivative, and its solubility is closely related to pH value. The main production routes of glyphosate in the world include the glycine method and the iminodiacetic acid (IDA) method. Among them, the glycine-dimethyl phosphite method in the glycine method is the main production route in China. The production process includes depolymerization, addition, esterification, acid hydrolysis, dealcoholization and crystallization. During the crystallization process, a certain concentration of alkali solution needs to be added to the reaction solution to adjust the crystallization solution to a certain pH value, and then crystals are precipitated.

[0003] During the pH adjustment process, the crystallization solution will release heat violently due to acid-base neutralization, and the addition of concentrated alkali solution will lead to local supersaturation, resulting in a large number of fine crystals. The crystal particles formed are small in size and thin in shape with sharp edges. The crystals are easy to break and agglomerate, and have poor fluidity. Therefore, it is necessary to develop a new crystallization method to eliminate fine crystals and obtain smooth crystals with good fluidity and not easy to break.

[0004] CN103275119A discloses a crystallization process for producing glyphosate by the glycine method, and the steps include: (A) in the process of preparing glyphosate by the dimethyl phosphite method, the triethylamine salt condensation liquid of dimethyl phosphate obtained after the condensation reaction is hydrolyzed with hydrochloric acid to obtain a hydrolyzate; (B) diluting the hydrolyzate after the hydrolysis is completed with water, cooling to below 70°C under stirring, adding triethylamine to neutralize the excess hydrochloric acid, stirring evenly, and measuring the pH value; (C) continuing to cool to below 35°C, separating, washing, and drying to obtain the glyphosate original drug. However, in the above cooling and crystallization process, the problem of too small particle size of the crystal product and subsequent difficulty in filtration cannot be solved, and the problem of fine crystals cannot be solved.

[0005] CN118239977A discloses a method for continuous crystallization of glyphosate with elimination of fine crystals and its device system, the method comprising: subjecting glyphosate dealcoholation liquid to first crystallization in a first crystallization kettle to obtain a first feed liquid; continuously adding the upper layer of the first feed liquid to an alkali adjustment kettle for alkali adjustment to obtain a second feed liquid, continuously adding the lower layer of the first feed liquid to a second crystallization kettle for second crystallization to obtain a third feed liquid; continuously adding the second feed liquid and the third feed liquid to a third crystallization kettle for third crystallization to obtain a glyphosate crystal material. The method and its device system provided by the invention can obtain glyphosate solids with larger particle size and uniform particle size distribution, and can operate continuously and stably.

[0006] CN118239976A discloses a method for intermittent crystallization of glyphosate to eliminate fine crystals and its device system, the method comprising the following steps: (1) subjecting glyphosate dealcoholation liquid to a first crystallization in a crystallization kettle to obtain a crystallization liquid; (2) adding the upper layer of the crystallization liquid obtained in step (1) to an alkali adjustment kettle for alkali adjustment to obtain a first mixed liquid; (3) mixing the first mixed liquid obtained in step (2) with the remaining crystallization liquid in the crystallization kettle, and then sequentially performing a second crystallization, solid-liquid separation and washing to obtain glyphosate solid. The method and its device system provided by the invention can obtain glyphosate solid with a large particle size and uniform particle size distribution.

[0007] However, the above two methods cannot solve the problem of sharp edges of crystal particles.

[0008] CN116574129A discloses a glyphosate crystallization method for eliminating fine crystals, wherein a glyphosate synthetic liquid is obtained by the glycine-dimethyl phosphite method; then concentrated hydrochloric acid with a concentration of 30% or more and a molar ratio of 3.5-5 with glycine is added to the glyphosate synthetic liquid for acid hydrolysis; the acid hydrolysis liquid is heated to 110-120°C for dealcoholization, and the dealcoholization liquid is added to a crystallization kettle for crystallization in 2-5 sections in a slow-first-fast-later-fast manner within 4-10 hours, and liquid alkali is added during the crystallization process to adjust the pH value to 0.5-2.0, and glyphosate crystals with uniform particle size are obtained by filtration and washing. This invention solves the problems of small particle size and large loss in the washing process in the glyphosate production process. The crystallization of glyphosate by this method can increase the crystal particle size, and the crystal product is easier to wash, and the glyphosate loss in the washing process can be reduced. However, it also does not solve the problem of sharp edges of crystal particles.

[0009] Therefore, how to provide a glyphosate crystallization method that can effectively eliminate fine crystals and obtain smooth crystals with good fluidity and not easy to break has become an urgent problem to be solved. Summary of the invention

[0010] In view of the shortcomings of the prior art, the object of the present invention is to provide a glyphosate crystallization method and application thereof for eliminating fine crystals and edges. The method provided by the present invention can eliminate fine crystals and edges produced during the glyphosate crystallization process, so that the edges of the obtained crystals are smooth, the crystals have good fluidity, and are not easy to stick together. Moreover, the overall method does not require the use of additional equipment and is suitable for existing industrial production.

[0011] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0012] In one aspect, the present invention provides a method for crystallizing glyphosate by eliminating fine crystals and edges and corners, the method comprising the following steps:

[0013] (1) adding alkaline solution to the first batch of glyphosate samples to be crystallized to obtain a crystal solution;

[0014] (2) mixing and diluting the second batch of glyphosate samples to be crystallized with an alkali solution to obtain a mixed solution;

[0015] (3) mixing the crystallization liquid with the mixed liquid to obtain glyphosate crystals;

[0016] There is no order distinction between steps (1) and (2).

[0017] The above method uses a two-stage alkali addition method, which reduces the temperature rise problem of acid-base neutralization by dispersing the excessive concentration of alkali solution. The fine glyphosate crystals obtained in the crystallization process are eliminated by the secondary alkali solution mixture, and the edges of the large crystal particles obtained are also smooth. The crystals have good fluidity and are not easy to stick together.

[0018] Preferably, the glyphosate sample to be crystallized comprises a glyphosate hydrochloric acid solution or a glyphosate dealcoholate solution.

[0019] The glyphosate dealcoholation liquid is a glyphosate synthetic liquid prepared by a glycine-dimethyl phosphite method, which is obtained by sequentially adding acid and dealcoholating.

[0020] Preferably, the pH of the glyphosate hydrochloric acid solution is -1 to 0.5, for example, -1, -0.9, -0.8, -0.7, -0.6, -0.5, -0.4, -0.3, -0.2, -0.1, 0, 0.1, 0.2, 0.3, 0.4 or 0.5, but is not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable.

[0021] Preferably, the pH of the glyphosate dealcoholation solution is -1 to 0.5, for example, -1, -0.9, -0.8, -0.7, -0.6, -0.5, -0.4, -0.3, -0.2, -0.1, 0, 0.1, 0.2, 0.3, 0.4 or 0.5, but is not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable.

[0022] Preferably, the time for adding the alkali solution in step (1) is 0.5-1.5h, for example 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1h, 1.1h, 1.2h, 1.3h, 1.4h or 1.5h, but is not limited to the above-listed values, and other values ​​not listed within the above numerical range are also applicable.

[0023] Preferably, the pH of the crystallization solution in step (1) is 0.9-1.4, such as 0.9, 1, 1.1, 1.2, 1.3 or 1.4, but is not limited to the above-listed values. Other values ​​not listed in the above numerical range are also applicable.

[0024] Preferably, the pH of the mixed solution in step (2) is 8-13, for example 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5 or 13, but is not limited to the values ​​listed above. Other values ​​not listed within the above numerical range are also applicable.

[0025] The above-mentioned specific pH range can effectively crystallize the product and can control the pH range of the solution after the subsequent crystallization liquid and the mixed liquid are mixed to be reasonable, which can not only effectively meet the crystallization requirements, but also effectively remove fine crystals to obtain smooth crystals.

[0026] Preferably, the solute of the alkali solution is any one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate or potassium bicarbonate, or a combination of at least two of them.

[0027] Preferably, the mass fraction of the alkali solution is 20-40%, such as 20%, 25%, 30%, 35% or 40%, etc., but is not limited to the above-listed values, and other values ​​not listed within the above numerical range are also applicable.

[0028] Preferably, the mass ratio of the first batch of glyphosate samples to be crystallized to the second batch of glyphosate samples to be crystallized is 1:(1-5), for example 1:1, 1:2, 1:3, 1:4 or 1:5, etc., but is not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable.

[0029] The above-mentioned specific mass ratio combined with pH limitation can effectively control the pH range of the solution after the crystallization solution and the mixed solution are mixed, so that the method can not only effectively meet the crystallization requirements, but also effectively remove fine crystals to obtain smooth crystals.

[0030] On the other hand, the present invention also provides the use of the glyphosate crystallization method as described above in glyphosate production.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The invention provides a glyphosate crystallization method for eliminating fine crystals and edges and corners. The two-stage alkali addition method is used to reduce the temperature rise problem of acid-base neutralization by dispersing the excessively high concentration of alkali solution. The glyphosate fine crystals obtained in the crystallization process are eliminated by the secondary alkali solution mixture, and the edges of the obtained large crystal particles become smooth. The crystals have good fluidity and are not easy to stick together. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is an optical microscope image of the glyphosate crystals obtained in step (3) of Example 1;

[0034] Figure 2is an optical microscope image of glyphosate crystals of the final product of Example 1;

[0035] Figure 3 is an optical microscope image of glyphosate crystals of the final product of Example 2;

[0036] Figure 4 is an optical microscope image of glyphosate crystals of the final product of Example 3;

[0037] Figure 5 is an optical microscope image of glyphosate crystals of the final product of Example 4;

[0038] Figure 6 is an optical microscope image of glyphosate crystals of the final product of Example 5;

[0039] Figure 7 is an optical microscope image of glyphosate crystals of the final product of Example 6;

[0040] Figure 8 is an optical microscope image of glyphosate crystals of the final product of Example 7;

[0041] Fig. 9 is an optical microscope image of glyphosate crystals of the final product of Example 8;

[0042] Fig.10 is an optical microscope image of glyphosate crystals of the final product of Example 9;

[0043] Fig.11 This is an optical microscope image of glyphosate crystals of the final product of Comparative Example 1;

[0044] Fig.12 This is an optical microscope image of glyphosate crystals of the final product of Comparative Example 2. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0046] Example 1

[0047] This embodiment provides a glyphosate crystallization method for eliminating fine crystals and edges and corners, and the specific steps are as follows:

[0048] (1) preparing a hydrochloric acid aqueous solution with a pH value of -0.3, adding glyphosate solid thereto, and preparing a saturated glyphosate hydrochloric acid aqueous solution;

[0049] (2) Add 1 / 3 of the glyphosate hydrochloric acid aqueous solution into the crystallizer and start stirring at a stirring speed of 300 rpm;

[0050] (3) 40% NaOH solution was added dropwise to the crystallizer (1 h), and the pH was adjusted to 1.2 to obtain a crystal solution (the optical microscope image of glyphosate crystals after the pH reached 1.2 is shown in FIG. Figure 1 shown);

[0051] (4) The remaining 2 / 3 of the glyphosate hydrochloric acid aqueous solution was added to the 40% NaOH solution and mixed until the pH value of the solution after mixing was 12, thereby obtaining a mixed solution.

[0052] (5) Add the mixed solution dropwise to the crystallization solution, filter, wash and dry to obtain glyphosate crystals (optical microscope image as shown in FIG. Figure 2 shown).

[0053] Example 2

[0054] This embodiment provides a glyphosate crystallization method for eliminating fine crystals and edges and corners, and the specific steps are as follows:

[0055] (1) preparing a hydrochloric acid aqueous solution with a pH value of 0.5, adding solid glyphosate thereto, and preparing a saturated glyphosate hydrochloric acid aqueous solution;

[0056] (2) Add 1 / 2 of the glyphosate hydrochloric acid aqueous solution into the crystallizer and start stirring at a stirring speed of 300 rpm;

[0057] (3) adding 30% NaOH solution (0.5 h) to the crystallizer and adjusting the pH to 0.9 to obtain a crystal solution;

[0058] (4) The remaining 1 / 2 of the glyphosate hydrochloric acid aqueous solution was added to the 30% NaOH solution and mixed until the pH value of the solution after mixing was 13, thereby obtaining a mixed solution.

[0059] (5) Add the mixed solution dropwise to the crystallization solution, filter, wash and dry to obtain glyphosate crystals (optical microscope image as shown in FIG. Figure 3 shown).

[0060] Example 3

[0061] This embodiment provides a glyphosate crystallization method for eliminating fine crystals and edges and corners, and the specific steps are as follows:

[0062] (1) taking a glyphosate dealcoholization liquid (pH=0.5, obtained by sequentially adding acid and dealcoholizing a glyphosate synthetic liquid prepared by a glycine-dimethyl phosphite method);

[0063] (2) Add 1 / 4 of the glyphosate dealcoholation solution into the crystallizer and start stirring at a stirring speed of 300 rpm;

[0064] (3) adding 20% ​​sodium carbonate solution (1.5 h) to the crystallizer and adjusting the pH to 1.4 to obtain a crystal solution;

[0065] (4) The remaining 3 / 4 of the glyphosate dealcoholation solution was added to a 20% sodium carbonate solution and mixed. The pH value of the solution after mixing was 8, thereby obtaining a mixed solution.

[0066] (5) Add the mixed solution dropwise to the crystallization solution, filter, wash and dry to obtain glyphosate crystals (optical microscope image as shown in FIG. Figure 4 shown).

[0067] Example 4

[0068] This embodiment provides a method for crystallizing glyphosate to eliminate fine crystals and sharp edges. The specific steps are the same as those in Example 1 except that the pH is adjusted to 0.5 by controlling the dripping time in step (3).

[0069] Optical microscope picture of the product Figure 5 shown.

[0070] Example 5

[0071] This embodiment provides a method for crystallizing glyphosate by eliminating fine crystals and sharp edges. The specific steps are the same as those in Example 1 except that the dropping time is controlled in step (3) to adjust the pH to 2.

[0072] Optical microscope picture of the product Figure 6 As shown in the figure, it can be seen that due to the high pH, ​​a large amount of crystals are dissolved after the final crystallization liquid is mixed with the mixed liquid, and the remaining crystals are smaller in size.

[0073] Example 6

[0074] This embodiment provides a method for crystallizing glyphosate to eliminate fine crystals and sharp edges. The specific steps are the same as those in Example 1 except for adjusting the pH to 7.5 in step (4).

[0075] Optical microscope picture of the product Figure 7 shown.

[0076] Example 7

[0077] This embodiment provides a method for crystallizing glyphosate to eliminate fine crystals and sharp edges. The specific steps are the same as those in Example 1 except for adjusting the pH to 14 in step (4).

[0078] Optical microscope picture of the product Figure 8 shown.

[0079] Example 8

[0080] This embodiment provides a glyphosate crystallization method for eliminating fine crystals and edges. The specific steps are consistent with those of Example 1 except that the ratio of glyphosate hydrochloric acid aqueous solution in steps (2) and (4) is 1:0.5.

[0081] Optical microscope picture of the product Fig. 9 shown.

[0082] Example 9

[0083] This embodiment provides a glyphosate crystallization method for eliminating fine crystals and edges. The specific steps are consistent with those of Example 1 except that the ratio of glyphosate hydrochloric acid aqueous solution in steps (2) and (4) is 1:4.

[0084] Optical microscope picture of the product Fig.10 shown.

[0085] Comparative Example 1

[0086] This comparative example provides a glyphosate crystallization method for eliminating fine crystals and edges and corners. For specific steps, refer to Example 1 of CN116574129A.

[0087] Optical microscope picture of the product Fig.11 shown.

[0088] Comparative Example 2

[0089] This comparative example provides a glyphosate crystallization method for eliminating fine crystals and edges and corners. The specific steps refer to Example 1 of CN118239976A.

[0090] Optical microscope picture of the product Fig.12 shown.

[0091] from Figure 1-12 It can be found that the method provided by the present invention can eliminate fine crystals produced during the crystallization of glyphosate, and the obtained crystals have smooth edges, good crystal fluidity, and are not easy to stick together; by comparing Examples 1-9, it can be found that the present invention can effectively eliminate the sharp edges and corners of the crystals by controlling relevant parameters, making the edges smoother, improving the crystal fluidity, and preventing breakage; by comparing Example 1 and Comparative Examples 1-2, it can be found that the present invention significantly eliminates the sharp edges of glyphosate crystals compared to the prior art by adopting a specific two-stage alkali addition method, and does not require the use of special equipment, which is beneficial to existing industrial production.

[0092] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the glyphosate crystallization method and application of the present invention to eliminate fine crystals and edges, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0093] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0094] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for crystallizing glyphosate to eliminate fine crystals and edges, characterized in that: The glyphosate crystallization method comprises the following steps: (1) adding alkaline solution to the first batch of glyphosate samples to be crystallized to obtain a crystal solution; (2) mixing and diluting the second batch of glyphosate samples to be crystallized with an alkali solution to obtain a mixed solution; (3) mixing the crystallization liquid with the mixed liquid to obtain glyphosate crystals; There is no order distinction between steps (1) and (2).

2. The glyphosate crystallization method according to claim 1, characterized in that: The glyphosate sample to be crystallized includes a glyphosate hydrochloric acid solution or a glyphosate dealcoholate solution.

3. The glyphosate crystallization method according to claim 2, characterized in that: The pH of the glyphosate hydrochloric acid solution is -1 to 0.

5.

4. The glyphosate crystallization method according to claim 2 or 3, characterized in that: The pH of the glyphosate dealcoholation solution is -1 to 0.

5.

5. The glyphosate crystallization method according to any one of claims 1 to 4, characterized in that: The time for adding the alkali solution in step (1) is 0.5-1.5h.

6. The glyphosate crystallization method according to any one of claims 1 to 5, characterized in that: The pH of the crystallization solution in step (1) is 0.9-1.

4.

7. The glyphosate crystallization method according to any one of claims 1 to 6, characterized in that: The pH of the mixed solution in step (2) is 8-13.

8. The glyphosate crystallization method according to any one of claims 1 to 7, characterized in that: The solute of the alkali solution is any one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate or potassium bicarbonate, or a combination of at least two thereof; Preferably, the mass fraction of the alkali solution is 20-40%.

9. The glyphosate crystallization method according to any one of claims 1 to 8, characterized in that: The mass ratio of the first batch of glyphosate samples to be crystallized to the second batch of glyphosate samples to be crystallized is 1:(1-5).

10. Use of the glyphosate crystallization method according to any one of claims 1 to 9 in glyphosate production.

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