Triclopyr butoxyethyl ester synthesis method

Abstract

The invention discloses a triclopyr butoxyethyl ester synthesis method which comprises the following steps: triclopyr alkane ester and ethylene glycol monobutyl ether are taken as raw materials, ionic liquid is taken as a catalyst, reaction is carried out at 70-100 DEG C for not less than 2 hours, triclopyr butoxyethyl ester is obtained, and the ionic liquid is at least one of [MIM-PS] [HSO4], [MIM-PS] [Cl], [MIM-PS] [CF3COO] and [MIM-PS] [TsO]. According to the method, the triclopyr butoxyethyl ester is prepared through a solvent-free ester exchange method, the byproduct alcohol is easy to remove, the used catalyst can be recycled after being washed with water, few three wastes are generated, and industrialization is facilitated.

Description

Technical Field

[0001] The invention relates to a method for synthesizing organic matter, in particular to a method for synthesizing butoxyethyl triclopyr Background Art

[0002] Butoxyethyl triclopyr (also known as triclopyr butoxyethyl), [(3,5,6-trichloro-2-pyridyl)oxy]acetic acid, is a pyridyloxycarboxylic acid herbicide. Its main methods can be divided into three types: dehydration esterification of triclopyr and ethylene glycol monobutyl ether, ester exchange of triclopyr methyl and ethylene glycol monobutyl ether, and etherification of triclopyridinol sodium and 2-butoxyethyl chloroacetate. However, the dehydration esterification method is prone to produce high-salt wastewater, and the etherification reaction yield is low (Wang Jun et al. "Study on the synthesis of butoxyethyl triclopyr." Modern Pesticides 16.4 (2017): 3), and the ester exchange method requires heating to reflux temperature, which is a harsh condition. The invention patent application with publication number CN 109180570 A discloses a method for preparing butoxyethyl triclopyr, wherein ethyl triclopyr and ethylene glycol monobutyl ether are used as raw materials, and tetrabutyl titanate, methanesulfonic acid or toluenesulfonic acid are used as catalysts to synthesize butoxyethyl triclopyr by an ester exchange method, but the post-processing is complicated. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a method for synthesizing butoxyethyl triclopyr with convenient post-processing.

[0004] Technical solution: The synthesis method of triclopyr acetic acid butoxyethyl ester of the present invention comprises the following steps: using triclopyr acetic acid alkane ester and ethylene glycol monobutyl ether as raw materials, using ionic liquid as catalyst, reacting at 70-100°C for not less than 2 hours to obtain triclopyr acetic acid butoxyethyl ester, wherein the ionic liquid is [MIM-PS][HSO 4 ], [MIM-PS][Cl], [MIM-PS][CF 3 At least one of [COO], [MIM-PS], [TsO].

[0005] Preferably, the triclopyr alkyl ester is triclopyr methyl ester or triclopyr ethyl ester.

[0006] Preferably, the catalyst is added in an amount of 5 to 50% by weight of the triclopyr alkyl ester.

[0007] Preferably, the catalyst is added in an amount of 5-20% by weight of the triclopyr alkane ester. 5% of the catalyst can make the reaction yield reach more than 95%. Increasing the catalyst addition ratio is conducive to the separation of the catalyst and the reaction raw materials, and is conducive to the recovery and application of the catalyst.

[0008] Preferably, the molar ratio of triclopyr alkane ester to ethylene glycol monobutyl ether is 1:1 to 1:2, more preferably 1:1 to 1:1.2.

[0009] Preferably, the reaction temperature is 70-90°C.

[0010] Preferably, the reaction time is 2 to 5 hours.

[0011] Preferably, the preparation method of the ionic liquid is:

[0012] (1) At room temperature, 1,3-propane sultone is dissolved in 1,2-dichloroethane, and an equimolar amount of N-methylimidazole is added dropwise. After the addition is complete, the reaction is carried out for no less than 2 hours to obtain 1-sulfonic acid propyl-3-methylimidazole inner salt [MIM-PS].

[0013] (2) At room temperature, 1-sulfonic acid propyl-3-methylimidazolium salt [MIM-PS] is dissolved in water, an equimolar amount of acid is added, and the temperature is raised to 90-100° C. for reaction for at least 1 hour to obtain an ionic liquid.

[0014] Preferably, in step (2), the acid used is at least one of concentrated hydrochloric acid, trifluoroformic acid, p-toluenesulfonic acid and concentrated sulfuric acid.

[0015] Preferably, in step (1), the N-methylimidazole is added dropwise for no less than 30 minutes.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: 1. Simple post-treatment: the butoxyethyl triclopyr acetic acid ester prepared by the solvent-free, ester exchange method can easily remove the by-product alcohol, and the used catalyst can be recovered by washing with water, which produces less three wastes and is conducive to industrialization; 2. Mild reaction conditions and high yield: the reaction temperature is reduced to below 100°C, and the reaction can be completed at 70-90°C, and the yield of the target product can reach more than 95%; 3. High catalytic efficiency: the catalyst can be recycled and the catalytic activity is not reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flow chart of a method for preparing a catalyst according to a first embodiment of the present invention;

[0018] Figure 2 It is a flow chart of the preparation method of butoxyethyl triclopyr of the present invention;

[0019] Figure 3 It is a liquid chromatogram of a sample of butoxyethyl triclopyrazone prepared by the method of the second embodiment of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0021] Example 1: Preparation of Catalyst

[0022] (1) Weigh 24.42 g (0.2 mol) of 1,3-propane sultone and dissolve it in 100 mL of 1,2-dichloroethane. Transfer the mixture to a 250 mL three-necked flask. Add 16.4 g (0.2 mol) of N-methylimidazole dropwise under strong stirring. The addition time is controlled to be more than 30 min. After the addition is completed, allow the mixture to naturally warm to room temperature. Continue to stir vigorously for 2 h. The generated white precipitate is filtered and washed with ether (30 mL × 3). Then, the ether is removed under reduced pressure to obtain the product, 1-propylsulfonic-3-methylimidazolium (MIM-PS) 40.10 g, with a yield of 98.2%. The mixture is sealed and stored for later use.

[0023] (2) Weigh 10.21 g (0.05 mol) of MIM-PS and dissolve it in 10 mL of water. Transfer it to a 100 mL three-necked flask, then add 5.0 g (0.05 mol) of concentrated sulfuric acid dropwise under ice bath and strong stirring for 30 min. After the addition is complete, the temperature is naturally raised to room temperature and stirred for 15 min. Then, the temperature is heated to 100 °C and reacted for 1 h. After the reaction is completed, the water is removed under reduced pressure, and then washed with anhydrous ether several times (10 mL × 3), and vacuum dried at 100 °C for 6 h to obtain a light yellow viscous liquid [MIM-PS][HSO 4 ](MW302.31)14.5g, yield is 95.9%.

[0024] According to the same synthesis method, the acid used in step (2) was replaced with concentrated HCl, CF 3 COOH, p-CH 3 C 6 H 4 SO 3 H, the corresponding catalysts were prepared and recorded as [MIM-PS][Cl], [MIM-PS][CF 3 COO], [MIM-PS][TsO].

[0025] Example 2: [MIM-PS] [HSO 4 ] Catalytic synthesis of butoxyethyl triclopyr

[0026] (1) Add ethyl triclopyr acetate 28.5 g (MW 284.52), ethylene glycol monobutyl ether 14.2 g (MW 118.174) and the newly prepared catalyst [MIM-PS] [HSO 4] (liquid) 5g, control the temperature at 90℃ for esterification under stirring, react for 2h, and track the reaction by liquid chromatography. The liquid chromatography conditions are:

[0027]

[0028] (2) Post-treatment: After the reaction is completed, continue to heat under reduced pressure to ensure that ethanol is removed. The vacuum degree of reduced pressure is 0.01-0.05 MPa. Add a small amount of water to wash the ethanol-removed product. Let it stand for stratification. The upper layer is the water layer, which contains the catalyst and the raw material ethylene glycol monobutyl ether. Remove water under reduced pressure to recover the catalyst and ethylene glycol monobutyl ether in the water layer; the lower layer is the ester layer, which is a light yellow liquid, mainly a crude product of triclopyr butoxyethyl ester (MW356.63). The product content is 99.3% by liquid chromatography, and the yield is 95.3%.

[0029] Example 3: Recovered [MIM-PS] [HSO 4 ] Catalytic synthesis of butoxyethyl triclopyr

[0030] In a 500 mL single-mouth bottle, 28.5 g of ethyl triclopyr, 14.2 g of ethylene glycol monobutyl ether and the catalyst [MIM-PS] [HSO 4 ](liquid) and a small amount of ethylene glycol monobutyl ether, control the temperature to 90°C for esterification under stirring, react for 2 hours, and then post-treat as in Example 1 to obtain a pale yellow crude product of butoxyethyl trichloroacetate. The product content was detected by liquid chromatography, and the content was 98.7% with a yield of 96.5%.

[0031] Example 4: Recovered [MIM-PS] [HSO 4 ] Catalytic synthesis of butoxyethyl triclopyr

[0032] In a 500 mL single-mouth bottle, ethyl triclopyr acetic acid 28.5 g, ethylene glycol monobutyl ether 23.6 g and the catalyst [MIM-PS] [HSO 4 ](liquid), control the temperature to 90°C for esterification under stirring, react for 2 hours, and then post-treat as in Example 1 to obtain a pale yellow crude product of butoxyethyl trichloroacetate. The product content was detected by liquid chromatography, and the content was 98.15%, with a yield of 97.4%.

[0033] Example 5: Synthesis of Butoxyethyl Triclopyr

[0034] In a 500 mL single-mouth bottle, ethyl triclopyr ethyl 28.5 g, ethylene glycol monobutyl ether 14.2 g and catalyst [MIM-PS][Cl] (liquid) 10 g were added, and the temperature was controlled to 90° C. for esterification under stirring. After the reaction was carried out for 2 h, the mixture was post-treated as in Example 1 to obtain a pale yellow crude product of butoxyethyl trichloroacetate. The product content was detected by liquid chromatography, and the content was 98.95%, with a yield of 96.5%.

[0035] Example 6: Synthesis of Butoxyethyl Triclopyr

[0036] In a 500 mL single-mouth bottle, 28.5 g of ethyl triclopyr, 14.2 g of ethylene glycol monobutyl ether and [MIM-PS] [CF 3 COO] catalyst 10g, controlled temperature at 90°C under stirring for esterification, reacted for 2h, washed with water and the solvent layer was decompressed to remove ethanol, to obtain a pale yellow crude product of butoxyethyl triclopyr. The product content was detected by liquid chromatography, and the content was 99.15%, with a yield of 95.8%.

[0037] Example 7: Synthesis of Butoxyethyl Triclopyr

[0038] In a 500 mL single-mouth bottle, 27.0 g of methyl triclopyr, 14.2 g of ethylene glycol monobutyl ether and 10 g of [MIM-PS][TsO] (liquid) were added, and the temperature was controlled at 90° C. for esterification under stirring. After reacting for 2 h, the solvent layer was washed with water and ethanol was removed under reduced pressure to obtain a pale yellow crude product of butoxyethyl trichloroacetate. The product content was detected by liquid chromatography, and the content was 99.05%, with a yield of 96.2%.

[0039] Example 8: 27.0 g of methyl triclopyr, 14.2 g of ethylene glycol monobutyl ether and 10 g of the catalyst [MIM-PS][TsO] (liquid) recovered in Example 7 were added to a 500 mL single-mouth bottle, and the temperature was controlled to 80° C. for esterification under stirring. After reacting for 2 h, the solvent layer was washed with water and ethanol was removed under reduced pressure to obtain a pale yellow crude product of butoxyethyl trichloroacetate. The product content was detected by liquid chromatography, and the content was 99.18%, with a yield of 95.9%.

[0040] The esterification reaction adopted in the embodiment of the present invention adopts an ionic liquid catalyst (liquid) as a catalyst, which can be recycled multiple times, reducing the generation of waste water, and the product yield is high and the impurity butyl ether content is low, which greatly improves its economy and environmental protection, and can be widely used in industrial production.

Claims

1. A method for synthesizing butoxyethyl triclopyr, characterized in that: The synthesis method comprises: using triclopyr alkane ester and ethylene glycol monobutyl ether as raw materials, using ionic liquid as catalyst, reacting at 70-100° C. for not less than 2 hours to obtain triclopyr butoxyethyl ester, wherein the ionic liquid is at least one of [MIM-PS][HSO4], [MIM-PS][Cl], [MIM-PS][CF3COO], and [MIM-PS][TsO].

2. The method for synthesizing butoxyethyl triclopyr according to claim 1, wherein: The triclopyr alkyl ester is triclopyr methyl ester or triclopyr ethyl ester.

3. The method for synthesizing butoxyethyl triclopyraclostrobin according to claim 1, characterized in that: The catalyst is added in an amount of 5 to 50% by weight of the triclopyr alkyl ester.

4. The method for synthesizing butoxyethyl triclopyraclostrobin according to claim 1, characterized in that: The catalyst is added in an amount of 5-20% by weight of the triclopyr alkane ester.

5. The method for synthesizing butoxyethyl triclopyr according to claim 1, characterized in that: The molar ratio of the triclopyr oxyacetic acid alkane ester to ethylene glycol monobutyl ether is 1:1 to 1:

2.

6. The method for synthesizing butoxyethyl triclopyraclostrobin according to claim 1, characterized in that: The reaction temperature is 70-90°C.

7. The method for synthesizing butoxyethyl triclopyr according to claim 1, characterized in that: The reaction time is 2 to 5 hours.

8. The method for synthesizing butoxyethyl triclopyraclostrobin according to claim 1, characterized in that: The preparation method of the ionic liquid is: (1) At room temperature, 1,3-propane sultone is dissolved in 1,2-dichloroethane, and an equimolar amount of N-methylimidazole is added dropwise. After the addition is complete, the reaction is carried out for not less than 2 hours to obtain 1-sulfonic acid propyl-3-methylimidazole inner salt [MIM-PS]; (2) At room temperature, 1-sulfonic acid propyl-3-methylimidazolium salt [MIM-PS] is dissolved in water, an equimolar amount of acid is added, and the temperature is raised to 90-100° C. for reaction for at least 1 hour to obtain an ionic liquid.

9. The method for synthesizing butoxyethyl triclopyraclostrobin according to claim 8, characterized in that: In step (2), the acid used is at least one of concentrated hydrochloric acid, trifluoromethane, p-toluenesulfonic acid and concentrated sulfuric acid.

10. The method for synthesizing butoxyethyl triclopyraclostrobin according to claim 8, characterized in that: In step (1), the N-methylimidazole is added dropwise for no less than 30 minutes.

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