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Preparation methods of 3,4-dimethyl pyrazole and 3,4-dimethyl pyrazole phosphate

A technology of dimethylpyrazole phosphate and dimethylpyrazole, which is applied in the field of preparation of 3,4-dimethylpyrazole, can solve the problem of high price of 3-methyl-2-butanone and a large amount of strong acidity Waste water, high anti-corrosion requirements, etc., to achieve the effect of simple operation, reduction of three wastes, and high product purity

Active Publication Date: 2013-02-06
ZHEJIANG UNIV OF TECH +1
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AI Technical Summary

Problems solved by technology

This route is simple to operate, but the price of starting material 3-methyl-2-butanone is higher
[0007] In addition, in all the above-mentioned methods, a large amount of concentrated sulfuric acid is used as the oxidizing agent for dehydrogenating pyrazoline to pyrazole, which not only requires high anti-corrosion equipment, but also produces a large amount of strong acid waste water in the post-treatment process, and produces a large amount of suffocation in the reaction process. Toxic sulfur dioxide gas (one of the six indicators strictly controlled by the national environmental protection on the atmosphere), the three wastes are difficult to deal with and the cost is high

Method used

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  • Preparation methods of 3,4-dimethyl pyrazole and 3,4-dimethyl pyrazole phosphate
  • Preparation methods of 3,4-dimethyl pyrazole and 3,4-dimethyl pyrazole phosphate

Examples

Experimental program
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Effect test

Embodiment 1

[0036] The synthesis of embodiment 1 3-methyl-3-buten-2-one

[0037] The ratio of the amount of feed material 2-butanone: paraformaldehyde (M=30): protonic acid is 1.0:0.9:0.1, and the protonic acid is sulfuric acid.

[0038]In a 500mL three-necked flask equipped with a thermometer, reflux condenser and mechanical stirring, add 144g (2mol) of 2-butanone, 54g (1.8mol) of paraformaldehyde, and 182mL of methanol. Sulfuric acid solution (concentrated sulfuric acid 20g (0.2mol) diluted with 15mL of methanol), dropwise addition, 30-35 ℃ heat preservation reaction for 20h, after the reaction is completed, adjust the pH to 7-8, and collect 96-98 ℃ fractions by atmospheric distillation to obtain 3- Methyl-3-buten-2-one 136.0g (1.62mol) product yield 81%, content 99.4% (GC). 1 H NMR (400 MHz, CDCl 3 ): δ= 5.96 (s, 1H), 5.80 (s, 1H), 2.37 (s, 3H), 1.90 (s, 3H). MS (EI): m / z= 84 (M + , 100).

Embodiment 2

[0039] Example 2 Synthesis of 3,4-dimethylpyrazole

[0040] The molar ratio of 3-methyl-3-buten-2-one:hydrazine hydrate:hydrogen peroxide:basic compound is 1.0:0.8:1.3:0.1, and the basic compound is triethylamine.

[0041] In a 1000mL three-neck flask equipped with a thermometer, reflux condenser and mechanical stirring, 136g (1.62mol) of 3-methyl-3-buten-2-one prepared in Example 1 was added, and 85% hydrated Hydrazine solution 70.1g (1.3mol), control the reaction temperature not higher than 50°C, keep the reaction at 40-50°C for 2 hours after the dropwise addition, and add 16.3g (0.16mol) of triethylamine when the reaction solution drops to 25-30°C , and slowly add 238.6g (2.1mol) of 30% aqueous hydrogen peroxide solution dropwise. After the dropwise addition, keep the temperature at 30-35°C for 10h, cool to room temperature, add 200mL of toluene, stand and separate to obtain the toluene layer, and first recover under reduced pressure The crude product 3,4-dimethylpyrazole ...

Embodiment 3

[0043] Example 3 Synthesis of 3,4-dimethylpyrazole phosphate

[0044] Dissolve 143g of 3,4-dimethylpyrazole obtained in Example 2 in 100mL of ethanol, add phosphoric acid at room temperature to adjust the pH to 1-3, continue stirring at room temperature for 5h, filter, and dry to obtain 3,4 -Dimethylpyrazole phosphate 277.4g, product yield 96%, content 99.1% (HPLC).

[0045] M.p.168.7~169.6 o C. IR (KBr), ν / cm -1 = 2721, 2375, 1074, 977. 1 H-NMR (400 MHz, D 2 O): δ= 7.67 (s, 1H), 2.24 (s, 3H), 1.96 (s, 3H). 13 C-NMR (100MHz, D 2 O): δ= 143.4, 132.5, 116.0, 8.7, 7.0. MS (ESI): m / z = 217.8 (M + +Na).

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Abstract

The invention discloses preparation methods of 3,4-dimethyl pyrazole and 3,4-dimethyl pyrazole phosphate. The preparation method of the 3,4-dimethyl pyrazole comprises the following steps of: (1) reacting 2-butanone and paraformaldehyde at the temperature of 30-60 DEG C under the action of protonic acid for 4-20 hours in an organic solvent A, adjusting pH (Potential of Hydrogen) to be 7-8 after the reaction is finished, and performing atmospheric distillation to obtain 3-methyl-3-butylene-2-ketone; and (2) thermally reacting the 3-methyl-3-butylene-2-ketone prepared by the step (1) with hydrazine hydrate at the temperature of 40-50 DEG C for 2-8 hours, cooling reaction solution to 25-30 DEG C, adding an alkaline compound and hydrogen peroxide aqueous solution, and performing thermal reaction at the temperature of 30-60 DEG C for 3-10 hours after the addition is finished, wherein the obtained reaction solution is post-treated to obtain the 3,4-dimethyl pyrazole. The 3,4-dimethyl pyrazole is then reacted with phosphoric acid to form a salt so as to obtain the 3,4-dimethyl pyrazole phosphate. The method has the advantages of cheap and readily available raw materials, easiness in operation, high reaction yield, high product purity, capabilities of removing a large amount of concentrated sulfuric acid in a technological process and thus reducing the production of three wastes and high suitability for industrial large-scale production.

Description

(1) Technical field [0001] The invention relates to a preparation method of 3,4-dimethylpyrazole, and also relates to a preparation method of 3,4-dimethylpyrazole phosphate. (2) Background technology [0002] 3,4-Dimethylpyrazole Phosphate (DMPP), a highly efficient, safe, non-toxic and cheap nitrogen fertilizer nitrification inhibitor developed by German BASF company. Approved by the German government in 1999, a large number of field application tests were carried out in Germany and Europe, and successful commercial production and large-scale application in agricultural production. It is known as the most promising new generation of slow-release fertilizer in the 21st century. . Therefore, 3,4-dimethylpyrazole phosphate (DMPP) has very broad application and development prospects. [0003] 3,4-Dimethylpyrazole (DMPZ) is an important intermediate in the synthesis of DMPP. After the DMPP is applied to the soil with urea, it can be hydrolyzed into DMPZ under the action of the...

Claims

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Application Information

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IPC IPC(8): C07D231/12
Inventor 陈志卫苏为科毕建豪张春雷徐灿闯黄生建
Owner ZHEJIANG UNIV OF TECH
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