Preparation method of thidiazuron preparation

Abstract

The invention discloses a preparation method of a thidiazuron preparation, and relates to the technical field of thidiazuron preparation. The preparation method of the thidiazuron preparation comprises the following steps: adding 5-amino-1, 2, 3-thiadiazole, ethylene glycol dimethyl ether and triethylamine into a four-neck flask, heating and uniformly stirring, dropwise adding phenyl isocyanate into the mixed solution obtained in the step 1, heating to carry out catalytic synthesis reaction, cooling to room temperature, and carrying out suction filtration to obtain yellow solid thidiazuron. And further treating to obtain the thidiazuron preparation. Sodium nitrite is selected as a solvent in the preparation process of 5-amino-1, 2, 3-thiadiazole, and the amount of substance of another initial material aminoacetonitrile hydrochloride is controlled in the preparation reaction, so that the yield of thidiazuron is ensured to be optimal, the reaction temperature range and the dropwise adding amount are determined, the optimal reaction conditions are finally perfected, and the yield of 5-amino-1, 2, 3-thiadiazole is improved. A preparation mode which is simpler to operate, higher in yield and suitable for industrial production is provided for preparation of the thidiazuron preparation.

Description

Technical Field

[0001] The invention relates to the technical field of thidiazuron preparation, in particular to a method for preparing a thidiazuron preparation. Background Art

[0002] Thidiazuron is a new type of highly effective plant growth regulator, its chemical name is 1-phenyl-3-(1,2,3-thiadiazol-5-yl)urea, its English name is Thidiazuron, abbreviated as TDZ. Its pure product is colorless and odorless crystals, with a melting point of 210.5-212.5℃ (decomposition). Thidiazuron has a strong cell division activity, which can promote plant photosynthesis, improve fruit quality, and increase fruit storage resistance. It is used as a shedding agent in cotton planting. After being absorbed by the leaves of cotton plants, it can promote the natural formation of separation tissue between the petiole and the stem and cause the leaves to fall early, which is conducive to mechanical cotton harvesting and can make cotton tillering about 10 days earlier, which helps to improve the grade of cotton.

[0003] For example, the preparation method of thidiazuron disclosed in Chinese patent publication number CN101386601B can make the yield of thidiazuron reach more than 92%, the purity reach more than 98%, and the price of the solvent butanone used is low (its market price is one-third of tetrahydrofuran and one-quarter of ethylene glycol dimethyl ether), it is easy to industrialize production, and the solvent is easy to recover.

[0004] However, the above method has harsh process conditions for the industrial synthesis of thiadiazole, and there are still certain difficulties in scale-up production. The yield of thiadiazole prepared by using solvents such as butanone and phenyl isocyanate as starting materials can still be further improved. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method for preparing a thidiazuron preparation, which solves the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention is implemented by the following technical scheme, a method for preparing a thidiazuron preparation comprises the following specific steps: Step 1: Add 60.5 g of 5-amino-1,2,3-thiadiazole, 250 mL of ethylene glycol dimethyl ether, and 8 drops of triethylamine into a 500 mL four-necked bottle, heat up, and stir evenly; Step 2: add 67.5 g of phenyl isocyanate dropwise to the mixed solution obtained in step 1, keep warm for 6 hours, raise the temperature to cause a catalytic synthesis reaction, cool to room temperature, and filter to obtain 73.4 g of yellow solid thidiazuron; Step 3, the solid thiadiazole obtained in step 2 is made into a soft material with an appropriate amount of ethanol, the pressure is reduced for 24 hours, and a filter sieve is used for double screening, and further processed to obtain thiadiazole tablets, thiadiazole capsules, thiadiazole granules, pills or sustained-release preparations.

[0007] A further improvement of the technical solution of the present invention is that the molar ratio of 5-amino-1,2,3-thiadiazole in step one to phenyl isocyanate in step two is 1:0.3 to 1:0.35.

[0008] A further improvement of the technical solution of the present invention is that the heating temperature in step one is set to 40±2°C, the insulation temperature in step two is set to 40°C, and the heating temperature in step two is set to 65°C.

[0009] A further improvement of the technical solution of the present invention is that the temperature of the ethanol used in step three is set to 60±4°C, and the decompression temperature is set to 70±2°C.

[0010] A further improvement of the technical solution of the present invention is that the 5-amino-1,2,3-thiadiazole in step 1 includes the following specific production steps: S1: Add aminoacetonitrile hydrochloride into a flask, add water while stirring until it is dissolved, add dichloromethane, control the reaction temperature at -2.5±2.5℃, add sodium nitrite aqueous solution dropwise, let it stand and keep warm for 0.5h until the mixed solution is separated into layers; S2: The oil layer in the layered solution obtained in S1 is added into a four-necked flask by a pipette gun, and the flask is placed in a -2.5±2.5℃ environment and stored in a freezing pump. Dichloromethane is added into the water layer in the layered solution, and the solution is cooled to 0℃. 10% hydrochloric acid is added dropwise, and the solution is kept at 0℃ until the water layer is separated. The water layer in the flask is discarded, and the oil layer is retained. S3: Combine the oil layer in the flask with the oil layer in the four-necked flask, add 30% calcium carbonate aqueous solution to the mixed oil layer and stir evenly. After standing and stratifying, add triethylamine to the oil layer. After the addition is complete, lower the temperature to -8°C, introduce hydrogen sulfide gas, and then filter to obtain the desired 5-amino-1,2,3-thiadiazole.

[0011] A further improvement of the technical solution of the present invention is that the molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride in S1 is 1:0.65 to 1:0.50, and the total amount of the sodium nitrite aqueous solution is added for 20 minutes, and the molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride is 1.3:1.0.

[0012] A further improvement of the technical solution of the present invention is that the molar ratio of the 30% calcium carbonate aqueous solution to triethylamine in S3 is 1:0.23 to 1:0.40, and the total amount of triethylamine is added dropwise for 10 minutes.

[0013] A further improvement of the technical solution of the present invention is that the purity of aminoacetonitrile hydrochloride is 98.8%, the purity of hydrogen sulfide is 99.99%, the purity of dichloromethane is greater than 99.9%, the purity of triethylamine is greater than 99.5%, and the purity of ethylene glycol dimethyl ether is greater than 99.5%.

[0014] Compared with the prior art, the invention has the beneficial effects of selecting sodium nitrite as a solvent in the preparation process of 5-amino-1,2,3-thiadiazole and controlling the amount of another starting material, aminoacetonitrile hydrochloride, in the preparation reaction, ensuring that the yield of thidiazuron is optimal, determining the temperature range of the reaction and the amount of dripping, and finally perfecting the optimal reaction conditions, thereby providing a preparation method suitable for industrial production with simpler operation and higher yield for the preparation of thidiazuron preparations. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The figure is a schematic diagram of the process for preparing a thidiazuron preparation; Figure 2 The schematic diagram of the preparation of 5-amino-1,2,3-thiadiazole in the preparation method of thiadiazole preparation is shown in FIG. DETAILED DESCRIPTION

[0016] Various exemplary embodiments, features and aspects of the present application will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0017] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0018] In addition, in order to better illustrate the present application, numerous specific details are provided in the specific embodiments below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In some examples, methods, means, and elements well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

[0019] The present invention provides a method for preparing a thidiazuron preparation, comprising the following specific steps: Step 1: Add 60.5 g of 5-amino-1,2,3-thiadiazole, 250 mL of ethylene glycol dimethyl ether, and 8 drops of triethylamine into a 500 mL four-necked bottle, heat up, and stir evenly; Step 2: add 67.5 g of phenyl isocyanate dropwise to the mixed solution obtained in step 1, keep warm for 6 hours, raise the temperature to cause a catalytic synthesis reaction, cool to room temperature, and filter to obtain 73.4 g of yellow solid thidiazuron; Step 3, the solid thiadiazole obtained in step 2 is made into a soft material with an appropriate amount of ethanol, the pressure is reduced for 24 hours, and a filter sieve is used for double screening, and further processed to obtain thiadiazole tablets, thiadiazole capsules, thiadiazole granules, pills or sustained-release preparations.

[0020] The molar ratio of 5-amino-1,2,3-thiadiazole in step one to phenyl isocyanate in step two is 1:0.3 to 1:0.35.

[0021] The heating temperature in step 1 is set to 40±2°C, the insulation temperature in step 2 is set to 40°C, and the heating temperature in step 3 is set to 65°C.

[0022] The temperature of the ethanol used in the step 3 is set to 60±4°C, and the reduced pressure temperature is set to 70±2°C.

[0023] The 5-amino-1,2,3-thiadiazole in step 1 includes the following specific production steps: S1: Add aminoacetonitrile hydrochloride into a flask, add water while stirring until it is dissolved, add dichloromethane, control the reaction temperature at -2.5±2.5℃, add sodium nitrite aqueous solution dropwise, let it stand and keep warm for 0.5h until the mixed solution is separated into layers; S2: The oil layer in the layered solution obtained in S1 is added into a four-necked flask by a pipette gun, and the flask is placed in a -2.5±2.5℃ environment and stored in a freezing pump. Dichloromethane is added into the water layer in the layered solution, and the solution is cooled to 0℃. 10% hydrochloric acid is added dropwise, and the solution is kept at 0℃ until the water layer is separated. The water layer in the flask is discarded, and the oil layer is retained. S3: Combine the oil layer in the flask with the oil layer in the four-necked flask, add 30% calcium carbonate aqueous solution to the mixed oil layer and stir evenly. After standing and stratifying, add triethylamine to the oil layer. After the addition is complete, lower the temperature to -8°C, introduce hydrogen sulfide gas, and then filter to obtain the desired 5-amino-1,2,3-thiadiazole.

[0024] The molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride in S1 is 1:0.65-1:0.50, and the total amount of the sodium nitrite aqueous solution is added over a time period of 20 min. The molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride is 1.3:1.0.

[0025] The molar ratio of the 30% calcium carbonate aqueous solution to triethylamine in S3 is 1:0.23-1:0.40, and the total amount of triethylamine is added over a time period of 10 minutes.

[0026] The purity of aminoacetonitrile hydrochloride is 98.8%, the purity of hydrogen sulfide is 99.99%, the purity of dichloromethane is greater than 99.9%, the purity of triethylamine is greater than 99.5%, and the purity of ethylene glycol dimethyl ether is greater than 99.5%.

[0027] Example 1: For the preparation of the above-mentioned thidiazuron preparation, a comparison of multiple experimental groups was performed, wherein experimental group 1: S1: Add aminoacetonitrile hydrochloride into a flask, add water while stirring until it is dissolved, add dichloromethane, control the reaction temperature at -2.5±2.5℃, add sodium nitrite aqueous solution dropwise, let it stand and keep warm for 0.5h until the mixed solution is separated into layers; S2: The oil layer in the layered solution obtained in S1 is added into a four-necked flask by a pipette gun, and the flask is placed in a -2.5±2.5℃ environment and stored in a freezing pump. Dichloromethane is added into the water layer in the layered solution, and the solution is cooled to 0℃. 10% hydrochloric acid is added dropwise, and the solution is kept at 0℃ until the water layer is separated. The water layer in the flask is discarded, and the oil layer is retained. S3: Combine the oil layer in the flask with the oil layer in the four-necked flask, add 30% calcium carbonate aqueous solution to the mixed oil layer and stir evenly. After standing and stratifying, add triethylamine to the oil layer. After the addition is complete, lower the temperature to -8°C, introduce hydrogen sulfide gas, and then filter to obtain the desired 5-amino-1,2,3-thiadiazole.

[0028] The molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride in S1 is 1:0.65-1:0.50, and the total amount of the sodium nitrite aqueous solution is added for 5 minutes, and the molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride is 1.0:1.0; The total amount of triethylamine was added for 20 minutes, and the temperature was 10° C. when the sodium nitrite aqueous solution was added, thereby preparing 5-amino-1,2,3-thiadiazole; Following step 1, add 60.5 g of 5-amino-1,2,3-thiadiazole, 250 mL of ethylene glycol dimethyl ether, and 8 drops of triethylamine into a 500 mL four-necked bottle, heat up, and stir evenly; Step 2: add 67.5 g of phenyl isocyanate dropwise to the mixed solution obtained in step 1, keep warm for 6 hours, raise the temperature to cause a catalytic synthesis reaction, cool to room temperature, and filter to obtain 73.4 g of yellow solid thidiazuron; Step 3, the solid thiadiazole obtained in step 2 is made into a soft material with an appropriate amount of ethanol, the pressure is reduced for 24 hours, and a filter sieve is used for double screening, and further processed to obtain thiadiazole tablets, thiadiazole capsules, thiadiazole granules, pills or sustained-release preparations.

[0029] Experimental Group 2: S1: Add aminoacetonitrile hydrochloride into a flask, add water while stirring until it is dissolved, add dichloromethane, control the reaction temperature at -2.5±2.5℃, add sodium nitrite aqueous solution dropwise, let it stand and keep warm for 0.5h until the mixed solution is separated into layers; S2: The oil layer in the layered solution obtained in S1 is added into a four-necked flask by a pipette gun, and the flask is placed in a -2.5±2.5℃ environment and stored in a freezing pump. Dichloromethane is added into the water layer in the layered solution, and the solution is cooled to 0℃. 10% hydrochloric acid is added dropwise, and the solution is kept at 0℃ until the water layer is separated. The water layer in the flask is discarded, and the oil layer is retained. S3: Combine the oil layer in the flask with the oil layer in the four-necked flask, add 30% calcium carbonate aqueous solution to the mixed oil layer and stir evenly. After standing and stratifying, add triethylamine to the oil layer. After the addition is complete, lower the temperature to -8°C, introduce hydrogen sulfide gas, and then filter to obtain the desired 5-amino-1,2,3-thiadiazole.

[0030] The molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride in S1 is 1:0.65-1:0.50, and the total amount of the sodium nitrite aqueous solution is added for 20 minutes, and the molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride is 1.2:1.0; The total amount of triethylamine was added for 10 minutes, and the temperature was 5° C. when the sodium nitrite aqueous solution was added, thereby preparing 5-amino-1,2,3-thiadiazole; Following step 1, add 60.5 g of 5-amino-1,2,3-thiadiazole, 250 mL of ethylene glycol dimethyl ether, and 8 drops of triethylamine into a 500 mL four-necked bottle, heat up, and stir evenly; Step 2: add 67.5 g of phenyl isocyanate dropwise to the mixed solution obtained in step 1, keep warm for 6 hours, raise the temperature to cause a catalytic synthesis reaction, cool to room temperature, and filter to obtain 73.4 g of yellow solid thidiazuron; Step 3, the solid thiadiazole obtained in step 2 is made into a soft material with an appropriate amount of ethanol, the pressure is reduced for 24 hours, and a filter sieve is used for double screening, and further processed to obtain thiadiazole tablets, thiadiazole capsules, thiadiazole granules, pills or sustained-release preparations.

[0031] Experimental Group 3: S1: Add aminoacetonitrile hydrochloride into a flask, add water while stirring until it is dissolved, add dichloromethane, control the reaction temperature at -2.5±2.5℃, add sodium nitrite aqueous solution dropwise, let it stand and keep warm for 0.5h until the mixed solution is separated into layers; S2: The oil layer in the layered solution obtained in S1 is added into a four-necked flask by a pipette gun, and the flask is placed in a -2.5±2.5℃ environment and stored in a freezing pump. Dichloromethane is added into the water layer in the layered solution, and the solution is cooled to 0℃. 10% hydrochloric acid is added dropwise, and the solution is kept at 0℃ until the water layer is separated. The water layer in the flask is discarded, and the oil layer is retained. S3: Combine the oil layer in the flask with the oil layer in the four-necked flask, add 30% calcium carbonate aqueous solution to the mixed oil layer and stir evenly. After standing and stratifying, add triethylamine to the oil layer. After the addition is complete, lower the temperature to -8°C, introduce hydrogen sulfide gas, and then filter to obtain the desired 5-amino-1,2,3-thiadiazole.

[0032] The molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride in S1 is 1:0.65-1:0.50, and the total amount of the sodium nitrite aqueous solution is added for 20 minutes, and the molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride is 1.3:1.0; The total amount of triethylamine was added for 15 minutes, and the temperature was 0° C. when the sodium nitrite aqueous solution was added, thereby preparing 5-amino-1,2,3-thiadiazole; Following step 1, add 60.5 g of 5-amino-1,2,3-thiadiazole, 250 mL of ethylene glycol dimethyl ether, and 8 drops of triethylamine into a 500 mL four-necked bottle, heat up, and stir evenly; Step 2: add 67.5 g of phenyl isocyanate dropwise to the mixed solution obtained in step 1, keep warm for 6 hours, raise the temperature to cause a catalytic synthesis reaction, cool to room temperature, and filter to obtain 73.4 g of yellow solid thidiazuron; Step 3, the solid thiadiazole obtained in step 2 is made into a soft material with an appropriate amount of ethanol, the pressure is reduced for 24 hours, and a filter sieve is used for double screening, and further processed to obtain thiadiazole tablets, thiadiazole capsules, thiadiazole granules, pills or sustained-release preparations.

[0033] Experimental Group 4: S1: Add aminoacetonitrile hydrochloride into a flask, add water while stirring until it is dissolved, add dichloromethane, control the reaction temperature at -2.5±2.5℃, add sodium nitrite aqueous solution dropwise, let it stand and keep warm for 0.5h until the mixed solution is separated into layers; S2: The oil layer in the layered solution obtained in S1 is added into a four-necked flask by a pipette gun, and the flask is placed in a -2.5±2.5℃ environment and stored in a freezing pump. Dichloromethane is added into the water layer in the layered solution, and the solution is cooled to 0℃. 10% hydrochloric acid is added dropwise, and the solution is kept at 0℃ until the water layer is separated. The water layer in the flask is discarded, and the oil layer is retained. S3: Combine the oil layer in the flask with the oil layer in the four-necked flask, add 30% calcium carbonate aqueous solution to the mixed oil layer and stir evenly. After standing and stratifying, add triethylamine to the oil layer. After the addition is complete, lower the temperature to -8°C, introduce hydrogen sulfide gas, and then filter to obtain the desired 5-amino-1,2,3-thiadiazole.

[0034] The molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride in S1 is 1:0.65-1:0.50, and the total amount of the sodium nitrite aqueous solution is added for 5 minutes, and the molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride is 1.4:1.0; The total amount of triethylamine was added for 20 minutes, and the temperature was -5°C when the sodium nitrite aqueous solution was added, thereby preparing 5-amino-1,2,3-thiadiazole; Following step 1, add 60.5 g of 5-amino-1,2,3-thiadiazole, 250 mL of ethylene glycol dimethyl ether, and 8 drops of triethylamine into a 500 mL four-necked bottle, heat up, and stir evenly; Step 2: add 67.5 g of phenyl isocyanate dropwise to the mixed solution obtained in step 1, keep warm for 6 hours, raise the temperature to cause a catalytic synthesis reaction, cool to room temperature, and filter to obtain 73.4 g of yellow solid thidiazuron; Step 3, the solid thiadiazole obtained in step 2 is made into a soft material with an appropriate amount of ethanol, the pressure is reduced for 24 hours, and a filter sieve is used for double screening, and further processed to obtain thiadiazole tablets, thiadiazole capsules, thiadiazole granules, pills or sustained-release preparations.

[0035] Example 2, for the above four test groups, after elemental analysis, the measured results / calculated results of test group 3 are, C 49.02 / 49.08, H 3.67 / 3.66, N 25.31 / 25.44, O 7.26 / 7.26, S 17.18 / 17.18, it can be seen that the elemental analysis results are consistent with the calculated results, which is the best embodiment. Then, according to the difference in each variable, it can be known that the ratio of the amount of sodium nitrite and aminoacetonitrile hydrochloride has a certain effect on the yield of 5-amino-1,2,3-thiadiazole. In addition to the above 1.3:1.0, the ratio of sodium nitrite aqueous solution: aminoacetonitrile hydrochloride also exists in 1.0:1.0; 1.1:1.0; 1.2:1.0; 1.4:1.0; Correspondingly, in the actual preparation test, it was found that the yields of 5-amino-1,2,3-thiadiazole corresponding to the molar ratios of 1.0:1.0; 1.1:1.0; 1.2:1.0; 1.3:1.0; 1.4:1.0 were 51.8%, 53.6%, 57.2%, and 62.3%, and when the sodium nitrite aqueous solution: aminoacetonitrile hydrochloride = 1.3:1.0, the yield of 5-amino-1,2,3-thiadiazole was 68.8. Therefore, the molar ratio of sodium nitrite aqueous solution to aminoacetonitrile hydrochloride in the above-mentioned method is 1.3:1.0, which is the best embodiment. In addition, since the reaction temperature is controlled at -2.5±2.5°C when the sodium nitrite aqueous solution is added dropwise, the temperature of the sodium nitrite aqueous solution is 10°C, 5°C, 0°C, -5°C, and -10°C. Correspondingly, when the temperature of the sodium nitrite aqueous solution is 10°C, 5°C, 0°C, -5°C, and -10°C, the yield of 5-amino-1,2,3-thiadiazole is 31.7%, 44.8%, 67.4%, 68.3%, and 68.7%, respectively. It can be seen that the most appropriate temperature for dropping the sodium nitrite aqueous solution is between -5 and 0°C.

[0036] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a thidiazuron preparation, characterized in that: The specific steps include: Step 1: Add 60.5 g of 5-amino-1,2,3-thiadiazole, 250 mL of ethylene glycol dimethyl ether, and 8 drops of triethylamine into a 500 mL four-necked bottle, heat up, and stir evenly; Step 2: add 67.5 g of phenyl isocyanate dropwise to the mixed solution obtained in step 1, keep warm for 6 hours, raise the temperature to cause a catalytic synthesis reaction, cool to room temperature, and filter to obtain 73.4 g of yellow solid thidiazuron; Step 3, the solid thiadiazole obtained in step 2 is made into a soft material with an appropriate amount of ethanol, the pressure is reduced for 24 hours, and a filter sieve is used for double screening, and further processed to obtain thiadiazole tablets, thiadiazole capsules, thiadiazole granules, pills or sustained-release preparations.

2. The method for preparing a thidiazuron preparation according to claim 1, characterized in that: The molar ratio of 5-amino-1,2,3-thiadiazole in step one to phenyl isocyanate in step two is 1:0.3 to 1:0.

35.

3. The method for preparing a thidiazuron preparation according to claim 1, characterized in that: The heating temperature in step 1 is set to 40±2°C, the insulation temperature in step 2 is set to 40°C, and the heating temperature in step 3 is set to 65°C.

4. The method for preparing a thidiazuron preparation according to claim 1, characterized in that: The temperature of the ethanol used in step 3 is set to 60±4°C, and the decompression temperature is set to 70±2°C.

5. The method for preparing a thidiazuron preparation according to claim 1, characterized in that: The 5-amino-1,2,3-thiadiazole in step 1 includes the following specific production steps: S1: Add aminoacetonitrile hydrochloride into a flask, add water while stirring until it is dissolved, add dichloromethane, control the reaction temperature at -2.5±2.5℃, add sodium nitrite aqueous solution dropwise, let it stand and keep warm for 0.5h until the mixed solution is separated into layers; S2: The oil layer in the layered solution obtained in S1 is added into a four-necked flask by a pipette gun, and the flask is placed in a -2.5±2.5℃ environment and stored in a freezing pump. Dichloromethane is added into the water layer in the layered solution, and the solution is cooled to 0℃. 10% hydrochloric acid is added dropwise, and the solution is kept at 0℃ until the water layer is separated. The water layer in the flask is discarded, and the oil layer is retained. S3: Combine the oil layer in the flask with the oil layer in the four-necked flask, add 30% calcium carbonate aqueous solution to the mixed oil layer and stir evenly. After standing and stratifying, add triethylamine to the oil layer. After the addition is complete, lower the temperature to -8°C, introduce hydrogen sulfide gas, and then filter to obtain the desired 5-amino-1,2,3-thiadiazole.

6. The method for preparing a thidiazuron preparation according to claim 5, characterized in that: The molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride in S1 is 1:0.65-1:0.50, and the total amount of the sodium nitrite aqueous solution is added over a time period of 20 min. The molar ratio of the sodium nitrite aqueous solution to aminoacetonitrile hydrochloride is 1.3:1.

0.

7. The method for preparing a thidiazuron preparation according to claim 5, characterized in that: The molar ratio of the 30% calcium carbonate aqueous solution to triethylamine in S3 is 1:0.23-1:0.40, and the total amount of triethylamine is added over a time period of 10 minutes.

8. The method for preparing a thidiazuron preparation according to claim 5, characterized in that: The purity of aminoacetonitrile hydrochloride is 98.8%, the purity of hydrogen sulfide is 99.99%, the purity of dichloromethane is greater than 99.9%, the purity of triethylamine is greater than 99.5%, and the purity of ethylene glycol dimethyl ether is greater than 99.5%.

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