A method for synthesizing a standard sample of clethodim lithium salt

Abstract

The invention discloses a method for synthesizing a standard sample of clethodim lithium salt, wherein clethodim and lithium hydroxide are mixed, and then the mixture is heated under high-speed shearing to react, and filtered after the reaction to obtain a standard sample of clethodim lithium salt. The invention is simple to operate, has a short process flow, is simple to post-process the product, does not require complex equipment, and the entire reaction process can be solvent-free, thereby avoiding solvent residues, meeting green environmental protection requirements, and the obtained standard sample has high purity and high yield, thereby avoiding the influence of solvents on the quality of the standard sample.

Description

Technical Field

[0001] The invention relates to a method for synthesizing a clethodim lithium salt standard sample, and in particular to a method for synthesizing a clethodim lithium salt standard sample which is simple to operate, green and environmentally friendly, does not require complex equipment, and has high standard sample purity, and belongs to the technical field of organic synthesis. Background Art

[0002] Clethodim lithium salt is the standard sample for quantitative analysis of Clethodim technical, and its general storage period is 3-5 months. Currently, the price of Clethodim lithium salt standard sample is high and its content is low, which is not conducive to the quantitative analysis of samples by enterprises.

[0003] At present, there are few reports on the preparation method of clethodim lithium salt standard. Patent CN111423346A discloses a preparation method of clethodim lithium salt standard, using acetone as solvent, adding clethodim and anhydrous lithium hydroxide to acetone, the molar ratio of clethodim to lithium hydroxide is 1.1-1.3:1; stirring and heating to 30℃-60℃, reacting for 8-12 hours; naturally cooling to 10℃-15℃ to precipitate crystals, filtering to obtain crystals, and washing with acetone; vacuum drying the crystals, crushing and sieving to obtain the final standard. This method has two main shortcomings. First, the operation process is cumbersome, requiring filtering, evaporation, drying, crushing and other operations, high equipment requirements and great difficulty; second, there are many solvent residues, which affect the product quality. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for synthesizing a standard sample of clethodim lithium salt. The method has the advantages of simple operation, short process flow, simple product post-processing, no need for complex equipment, solvent-free participation in the entire reaction process, avoiding solvent residue, meeting green environmental protection requirements, and the obtained clethodim lithium salt standard sample has high purity and high yield, avoiding the influence of solvent on the quality of the standard sample.

[0005] The specific technical solutions of the present invention are as follows:

[0006] A method for synthesizing a standard sample of clethodim lithium salt comprises the following steps: mixing clethodim and lithium hydroxide, then heating the mixture under high-speed shearing to react, and filtering after the reaction to obtain a standard sample of clethodim lithium salt.

[0007] Furthermore, in the above synthesis method, the raw material clethodim is liquid, and the raw material lithium hydroxide is solid.

[0008] Further, the reaction of the present invention can be carried out in the presence of a solvent or in the absence of a solvent. However, considering that the presence of a solvent increases the cost, increases the difficulty of post-processing, and is prone to residual effects on product quality, it is preferably carried out in the absence of a solvent. The reason why the present invention can be carried out in the absence of an additional solvent is that the present invention utilizes the characteristics of the oil phase of clethodim, and clethodim itself can be used as both a raw material and a solvent during the reaction. Furthermore, the present invention adopts a high-speed shear stirring method, and the strong shearing effect of high-speed shearing strengthens the solid-liquid two-phase mixing of clethodim and lithium hydroxide, so that the two can also react quickly in the absence of a solvent.

[0009] Further, the molar ratio of clethodim to lithium hydroxide is 0.5-1.5:1, for example, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, preferably 0.9-1.3:1, and more preferably 1-1.2:1.

[0010] Furthermore, high-speed shearing can be achieved by using existing high-speed shearing equipment in the prior art, and the speed of high-speed shearing is 3000-20000rpm, for example, 3000rpm, 4000rpm, 5000rpm, 6000rpm, 7000rpm, 8000rpm, 9000rpm, 10000rpm, 11000rpm, 12000rpm, 13000rpm, 14000rpm, 15000rpm, preferably 8000-15000rpm.

[0011] Further, clethodim and lithium hydroxide are reacted at a reaction temperature under high-speed shearing, and the reaction temperature is 10-80°C, for example, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, preferably 20-60°C, and more preferably 40-50°C.

[0012] Furthermore, the reaction time of clethodim and lithium hydroxide is 2-4 hours.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The present invention realizes the solvent-free synthesis of clethodim lithium salt by using clethodim itself as a solvent and high-speed shearing, replacing the solvent method, completely solving the inconvenience and complicated process problems caused by the use of solvents, and meeting the requirements of green environmental protection.

[0015] 2. The solvent-free method of the present invention replaces the solvent method of the prior art. After the reaction, the unreacted raw materials can be directly filtered to obtain the product. The post-processing is simple, the product is easy to separate, the product purity is high, the use of solvents and the generation of three wastes are avoided, and the reaction process is easy to control.

[0016] 3. The present invention is simple to operate, safe and clean. The target product can be obtained by reacting clethodim and lithium hydroxide under high-speed shear stirring. The reaction conditions are mild, the process is simple, no special equipment is required, the post-treatment is simple and easy to operate, and the manufacturing cost is low. Through the optimization of process conditions, the prepared standard sample has high purity and high yield. DETAILED DESCRIPTION

[0017] The present invention is further explained and illustrated below in conjunction with specific embodiments. The following description is only exemplary and does not limit the scope of protection thereof.

[0018] In the following examples, unless otherwise specified, the concentrations are all mass percentage concentrations.

[0019] Example 1

[0020] In a 500ml four-necked flask equipped with a thermometer and a high-speed shear stirrer, 421.17g of 94% clethodim technical and 24.19g of lithium hydroxide were added, the temperature was raised to 40°C, and the high-speed shear stirrer was turned on with a shear rate of 12000rpm. After 3 hours of high-speed shear reaction, the reaction solution was filtered, washed with a small amount of petroleum ether, and dried to obtain a lithium salt product of clethodim with a mass of 364.00g. The content was 99.4% after quantitative analysis, and the yield was 98.9% (calculated as lithium hydroxide).

[0021] After calibration with standard samples, it can be used as the standard sample of sethoxydim technical.

[0022] Example 2

[0023] The lithium salt of clethodim was synthesized according to the method of Example 1, except that the mass of 94% of the clethodim technical was changed. The final product is shown in Table 1 below.

[0024]

[0025] Example 3

[0026] The lithium salt of clethodim was synthesized according to the method of Example 1, except that different high-speed shearing speeds were used. The final products are shown in Table 2 below.

[0027]

[0028] Example 4

[0029] The lithium salt of clethodim was synthesized according to the method of Example 1, except that different reaction temperatures and reaction times were used. The final products are shown in Table 3 below.

[0030]

[0031] Comparative Example 1

[0032] The lithium salt of clethodim was synthesized according to the method of CN111423346A. In a 500ml dry four-necked flask, 50.80g of 92% clethodim technical, 300ml of 99% analytically pure acetone and 2.41g of anhydrous lithium hydroxide were added, stirred, heated to 60°C, stirred for 8 hours, cooled naturally to 10°C, crystals precipitated, filtered, the filter cake was washed 3 times with 30ml acetone, dried in a vacuum oven at 50°C, weighed 36.17g, content 99.0%, yield 98%.

[0033] Comparative Example 2

[0034] Clethodim lithium salt was synthesized according to the method of Example 1, except that the stirring speed was 1000 rpm. The content of the obtained Clethodim lithium salt was 73.2% by quantitative analysis, and the yield was 52.1% (calculated as lithium hydroxide).

Claims

1. A method for synthesizing a standard sample of clethodim lithium salt, characterized in that The following steps are involved: Clethodim and lithium hydroxide are mixed, and then the mixture is heated under high-speed shearing to react, and filtered after the reaction to obtain a standard sample of clethodim lithium salt; the reaction is carried out in the absence of solvent.

2. The synthesis method according to claim 1, characterized in that: The molar ratio of clethodim to lithium hydroxide is 0.5-1.5:

1.

3. The synthesis method according to claim 2, characterized in that: The molar ratio of clethodim to lithium hydroxide is 0.9-1.3:

1.

4. The synthesis method according to claim 3, characterized in that: The molar ratio of clethodim to lithium hydroxide is 1-1.2:

1.

5. The synthesis method according to claim 1 or 2, characterized in that: The high-speed shearing speed is 3000-20000rpm.

6. The synthesis method according to claim 5, characterized in that: The high-speed shearing speed is 8000-15000rpm.

7. The synthesis method according to claim 1 or 2, characterized in that: The reaction temperature is 10-80°C.

8. The synthesis method according to claim 7, characterized in that: The reaction temperature is 20-60°C.

9. The synthesis method according to claim 8, characterized in that: The reaction temperature is 40-50°C.

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