Process for the preparation of bifenthrin

Abstract

This invention relates to the field of organic synthesis and discloses a method for preparing bifenthrin. The method includes: contacting kungfu acid and 2-methyl-3-phenylbenzyl alcohol in the presence of a catalyst composition to carry out an esterification reaction; wherein the catalyst composition includes component A and component B; wherein component A is selected from oxyacid esters of group IVB elements and / or compounds formed by group IVB elements and alcohols; wherein component B is selected from at least one of inorganic salts of copper, oxides of copper, oxides of tin, and inorganic salts of tin. The bifenthrin prepared by this method has a high yield (>98%), high purity (up to 99.4%), and produces fewer bifenthrin isomers (<0.5%), meeting market requirements. The entire process is highly efficient and environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis, and specifically to a method for preparing bifenthrin. Background Technology

[0002] Bifenthrin, commonly known as bifenthrin, is a pyrethroid insecticide developed by FMC. It can be used as a highly effective insecticide and acaricide, possessing broad-spectrum insecticidal activity and high efficacy. A key characteristic of bifenthrin is its immobility in soil, making it relatively environmentally safe. Importantly, bifenthrin is rapidly metabolized in humans and other mammals, posing no risk of accumulation. In 1978, FMC disclosed the synthesis and bioactivity of bifenthrin in patent US4341796A. Subsequently, research on the applications of bifenthrin has been widely conducted worldwide. However, the synthesis process of bifenthrin technical grade still presents problems such as large amounts of waste, complex operations, and serious environmental pollution.

[0003] US4341796A discloses a method for reacting trifluorochloroquine (Z-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropionic acid, also known as trifluorochloroquine) with an aqueous potassium hydroxide solution to form a salt, followed by reaction with 2-methyl-3-chloromethylbiphenyl to produce bifenthrin. In this method, due to the use of 1.26 equivalents of 12% potassium hydroxide aqueous solution, a large amount of wastewater is generated, and the reaction yield is only 40%.

[0004] US4473709A discloses a method for preparing bifenthrin from kungfu acid and biphenyl alcohol (2-methylbiphenylbenzyl alcohol). In the process of preparing kungfu acid from kungfu acid, thionyl chloride is used, generating large amounts of hydrogen chloride and sulfuric acid dioxide gases. Furthermore, pyridine is used as an acid-binding agent in the reaction of kungfu acid and biphenyl alcohol to synthesize bifenthrin, and the presence of pyridine increases the difficulty of waste treatment.

[0005] CN103145558B and CN102827004A disclose a method for preparing kungfu acid ester by esterification with low molecular weight alcohol, and then exchanging it with biphenyl alcohol to obtain bifenthrin. This method cannot be carried out completely, is costly, and has complicated steps, making it unsuitable for industrial production.

[0006] CN109485564B discloses a method for preparing bifenthrin by condensation of trimethylsilyl magnesium chloride and kanamycin and biphenyl alcohol. The trimethylsilyl magnesium chloride used in this method is expensive and flammable, limiting its application in industrial production. Furthermore, the post-treatment process involves adding a large amount of water for two washes, resulting in a large volume of wastewater, which does not meet the requirements of green processes.

[0007] CN113788754A also reports using a single titanate ester as a catalyst for this reaction, with a preferred reaction temperature of 80-170℃ and a reaction time of 2-8 hours. However, in practical research, only titanate ester catalysis requires a higher reaction temperature. Using toluene as a solvent, the reflux reaction temperature is 112℃, and 32% of the biphenyl alcohol remains unconverted (Comparative Example 1). Using xylene as a reflux reaction temperature is 140℃, requiring 58 hours to complete the reaction. The resulting bifenthrin isomer (Formula 2) (a non-effective component, considered an impurity, and difficult to remove) is 2.8%. The effective content of the bifenthrin crude oil is 93.3%, and the yield is 93.2% (Comparative Example 2), which cannot meet market requirements. There is also no cost advantage.

[0008] Therefore, in order to overcome the above-mentioned defects, a method for preparing bifenthrin is needed. Summary of the Invention

[0009] The purpose of this invention is to overcome the problem that high yield, low by-products, low energy consumption and environmental friendliness are mutually exclusive in the existing technology, and to provide a method for preparing bifenthrin.

[0010] To achieve the above objectives, the present invention provides a method for preparing bifenthrin, characterized in that the method comprises: contacting kungfu acid and 2-methyl-3-phenylbenzyl alcohol in the presence of a catalyst composition to carry out an esterification reaction;

[0011] The catalyst composition comprises component A and component B;

[0012] Component A is selected from oxyacid esters of group IVB elements and / or compounds formed by group IVB elements and alcohols;

[0013] Component B is selected from at least one of inorganic salts of copper, oxides of copper, oxides of tin, and inorganic salts of tin.

[0014] Through the above technical solution, the present invention provides a method for preparing bifenthrin. The use of a low-cost catalyst composition can result in a high yield (>98%) and high purity (up to 99.4%) of bifenthrin product, with fewer bifenthrin isomers (<0.5%), which can meet market requirements. The entire process is efficient and environmentally friendly. Detailed Implementation

[0015] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0016] As mentioned above, one aspect of the present invention provides a method for preparing bifenthrin, characterized in that the method includes: esterification reaction of kungfu acid and 2-methyl-3-phenylbenzyl alcohol in the presence of a catalyst composition;

[0017] The catalyst composition comprises component A and component B;

[0018] Component A is selected from oxyacid esters of group IVB elements and / or compounds formed by group IVB elements and alcohols;

[0019] Component B is selected from at least one of inorganic salts of copper, oxides of copper, oxides of tin, and inorganic salts of tin.

[0020] In some embodiments of the present invention, preferably, component A is selected from at least one of titanate, zirconate and fatty zirconium alcohol.

[0021] In some embodiments of the present invention, preferably, component B is selected from at least one of cuprous oxide, copper hydroxide, copper oxide, cuprous chloride, basic copper chloride, copper chloride, stannous oxide, tin hydroxide, tin oxide, and stannous chloride and tin chloride.

[0022] In some embodiments of the present invention, preferably, component A is selected from at least one of isopropyl titanate, propyl titanate, butyl titanate, isopropyl zirconate, butyl zirconate, and zirconium isopropoxide.

[0023] In some embodiments of the present invention, preferably, component B is selected from copper hydroxide and / or tin hydroxide.

[0024] In some embodiments of the present invention, preferably, component A is isopropyl titanate and component B is copper hydroxide.

[0025] In some embodiments of the present invention, preferably, the esterification reaction is carried out in the presence of a solvent.

[0026] In some embodiments of the present invention, preferably, the solvent is selected from at least one of aromatic hydrocarbons, halogenated aromatic hydrocarbons and alkanes, and more preferably from at least one of toluene, xylene and trimethylbenzene.

[0027] In this invention, the xylene and trimethylbenzene each comprise at least one of their respective isomers.

[0028] In some embodiments of the present invention, preferably, the mass ratio of component A to component B is 0.1-10:1, more preferably 0.1-0.5:1, and more preferably 0.2-0.4:1.

[0029] In some embodiments of the present invention, preferably, the mass ratio of the catalyst composition, kung fu acid and 2-methyl-3-phenylbenzyl alcohol is 0.01-1:1-2:1, and more preferably 0.01-0.1:1-1.1:1.

[0030] In some embodiments of the present invention, preferably, the esterification reaction is carried out at a temperature of 80-175°C for a time of 10-30 hours.

[0031] In some embodiments of the present invention, preferably, the esterification reaction is carried out at a temperature of 80-145°C for a time of 15-18 hours.

[0032] In some embodiments of the present invention, preferably, the temperature of the esterification reaction is 80-115°C.

[0033] In some embodiments of the present invention, preferably, the esterification reaction is carried out under dehydration conditions.

[0034] In this invention, the dehydration conditions are obtained by reflux with water.

[0035] In this invention, the reflux water removal refers to using the principle of azeotropic reaction of toluene and water to distill the vaporized toluene and water components out of the system. The distilled material then separates into layers, with the lower layer being the water layer, which is separated from the system. The upper layer of toluene is returned to the reactor to continue to be used as a solvent, thereby removing water from the reaction system produced by mixing.

[0036] In this invention, the temperature of the reflux water is 80-175℃, preferably 80-115℃; the time is 10-30h, preferably 15-18h.

[0037] The present invention will be described in detail below through examples. In the following examples, the gas phase internal standard content parameter was measured by the gas phase internal standard method; the HPLC normalized detection parameter was measured by the liquid phase normalization method; the kung fu acid raw material was a commercially available product of Fuxin Dadeli Chemical Co., Ltd.; 2-methyl-3-phenylbenzyl alcohol was a commercially available product of Fuxin Dadeli Chemical Co., Ltd.; isopropyl titanate was a commercially available product of McLean Chemical Co., Ltd.; and copper hydroxide was a commercially available product of McLean Chemical Co., Ltd.

[0038] The equation for the esterification reaction is as follows:

[0039]

[0040] Example 1

[0041] 110 g of toluene was added to a 500 mL reaction flask. Stirring was then started, and 40 g (0.162 mol) of kungfu acid, 31.7 g (0.158 mol) of 2-methyl-3-phenylbenzyl alcohol, and a catalyst composition (0.3 g of isopropyl titanate and 1 g of copper hydroxide) were added sequentially. The mixture was heated to reflux and water was removed for 16 hours. GC analysis showed that 0.2% of 2-methyl-3-phenylbenzyl alcohol remained. The mixture was then cooled to 30 °C. 10 g of water and 2 g of NaOH were added with stirring. After stirring for 30 min, the catalyst was removed by filtration. The filtrate was separated into layers to obtain an oil layer. After concentrating the oil layer and recovering toluene, 66.8 g of crude oil was obtained. The gas chromatography internal standard content was 98.3%, and the yield was 98.3%. HPLC normalization analysis showed 99.4% purity and 0.12% bifenthrin isomers.

[0042] Example 2

[0043] 110 g of xylene was added to a 500 mL reaction flask. Stirring was then started, and 40 g (0.162 mol) of kungfu acid, 31.7 g (0.158 mol) of 2-methyl-3-phenylbenzyl alcohol, and a catalyst composition (0.3 g of isopropyl titanate and 1 g of copper hydroxide) were added sequentially. The mixture was heated to reflux and water was removed for 16 hours. GC analysis showed that 0.1% of 2-methyl-3-phenylbenzyl alcohol remained. The mixture was then cooled to 30 °C. 10 g of water and 2 g of NaOH were added with stirring. After stirring for 30 min, the catalyst was removed by filtration. The filtrate was separated into layers to obtain an oil layer. After concentrating the oil layer and recovering xylene, 66.8 g of crude oil was obtained. The gas chromatography internal standard content was 98.3%, and the yield was 98.3%. HPLC normalization analysis showed 99.4% purity and 0.25% bifenthrin isomers.

[0044] Example 3

[0045] 110 g of toluene was added to a 500 mL reaction flask. Stirring was then started, and 40 g (0.162 mol) of kungfu acid, 31.7 g (0.158 mol) of 2-methyl-3-phenylbenzyl alcohol, and a catalyst composition (0.5 g of 87% zirconium isopropoxide and 1 g of copper hydroxide) were added sequentially. The mixture was heated to reflux for 16 hours to remove water. GC analysis showed that 0.5% of 2-methyl-3-phenylbenzyl alcohol remained. The mixture was then cooled to 30 °C. 10 g of water and 2 g of NaOH were added with stirring. After stirring for 30 min, the mixture was filtered to remove insoluble matter. The filtrate was separated into layers to obtain an oil layer. After concentrating the oil layer and recovering toluene, 65.2 g of crude oil was obtained. The gas chromatography internal standard content was 98.0%, and the yield was 95.7%. HPLC normalization analysis showed 99.0% purity and 0.18% bifenthrin isomers.

[0046] Example 4

[0047] 110 g of toluene was added to a 500 mL reaction flask. Stirring was then started, and 40 g (0.162 mol) of kungfu acid, 31.7 g (0.158 mol) of 2-methyl-3-phenylbenzyl alcohol, and a catalyst composition (0.3 g of tetrabutyl titanate and 1 g of copper hydroxide) were added sequentially. The mixture was heated to reflux and water was removed for 16 hours. GC analysis showed that 0.5% of 2-methyl-3-phenylbenzyl alcohol remained. The mixture was then cooled to 30 °C. 10 g of water and 2 g of NaOH were added with stirring. After stirring for 30 min, the mixture was filtered to remove insoluble matter. The filtrate was separated into layers to obtain an oil layer. After concentrating the oil layer and recovering toluene, 66.5 g of crude oil was obtained. The gas chromatography internal standard content was 98.5%, and the yield was 98.1%. HPLC normalization analysis showed 99.2% purity and 0.15% bifenthrin isomers.

[0048] Example 5

[0049] 110 g of xylene was added to a 500 mL reaction flask. Stirring was then started, and 40 g (0.162 mol) of kungfu acid, 31.7 g (0.158 mol) of 2-methyl-3-phenylbenzyl alcohol, and a catalyst composition (0.3 g of isopropyl titanate and 1 g of stannous chloride) were added sequentially. The mixture was heated to reflux for 16 hours to remove water. GC analysis showed that 0.5% of 2-methyl-3-phenylbenzyl alcohol remained. The mixture was then cooled to 30 °C. 10 g of water and 2 g of NaOH were added with stirring. After stirring for 30 min, the mixture was filtered to remove insoluble matter. The filtrate was separated into layers to obtain an oil layer. After concentrating the oil layer and recovering toluene, 66.3 g of crude oil was obtained. The gas chromatography internal standard content was 98.0%, and the yield was 97.3%. HPLC normalization analysis showed 98.8% purity and 0.25% bifenthrin isomers.

[0050] Example 6

[0051] The method was carried out according to Example 1, except that reflux was not performed to remove water, and the mixture was directly refluxed for 16 hours to obtain 66.3 g of crude oil. The gas phase internal standard content was 94.3%, and the yield was 93.8%. The normalized HPLC detection showed 93.5% purity and 0.25% bifenthrin isomers.

[0052] Example 7

[0053] The method was carried out according to Example 1, except that the catalyst composition contained 1g of isopropyl titanate and 1g of copper hydroxide, yielding 66.6g of crude oil with a gas phase internal standard content of 95.9% and a yield of 95.9%; HPLC normalization detection showed 96.9% and 0.25% of bifenthrin isomers.

[0054] Comparative Example 1

[0055] 110 g of toluene was added to a 500 mL reaction flask. After stirring, 40 g (0.162 mol) of kungfu acid, 31.7 g (0.158 mol) of 2-methyl-3-phenylbenzyl alcohol, and 1.5 g of isopropyl titanate were added sequentially. The mixture was heated to reflux and water was removed for 16 hours. GC analysis showed that 61% of 2-methyl-3-phenylbenzyl alcohol remained. The mixture was then refluxed to remove water for another 58 hours, and 32% of biphenyl alcohol remained. Further reaction analysis showed that the conversion was essentially complete.

[0056] Comparative Example 2

[0057] 110 g of xylene was added to a 500 mL reaction flask. With stirring, 40 g (0.162 mol) of kungfu acid, 31.7 g (0.158 mol) of 2-methyl-3-phenylbenzyl alcohol, and 1.5 g of isopropyl titanate catalyst were added sequentially. The mixture was refluxed for 16 hours to remove water. GC analysis showed that 16.3% of 2-methyl-3-phenylbenzyl alcohol remained. The reaction was continued under reflux for 58 hours, after which 1.6% of 2-methyl-3-phenylbenzyl alcohol remained. The mixture was cooled to 30 °C. 10 g of water and 2 g of NaOH were added with stirring. After stirring for 30 min, the catalyst was removed by filtration. The filtrate was separated into layers to obtain an oil layer. After concentrating the oil layer and recovering xylene, 65.3 g of crude oil was obtained. The gas chromatography internal standard content was 93.3%, and the yield was 93.2%. HPLC normalization analysis showed 93.4% purity and 2.8% bifenthrin isomers.

[0058] Comparative Example 3 (Trimethylsilane Magnesium Chloride)

[0059] 242 g of toluene was added to a 1 L reaction flask. While stirring, 123.8 g (0.5 mol) of kungfu acid, 101.1 g (0.5 mol) of 2-methyl-3-phenylbenzyl alcohol, and 2.2 g (0.015 mol) of trimethylsilane magnesium chloride were added sequentially. The mixture was heated to 60 °C and maintained at this temperature for 10 hours. The reaction was stopped after HPLC monitoring showed no change in 2-methyl-3-phenylbenzyl alcohol. After the reaction was complete, the mixture was filtered while hot, and the filtrate was collected. The filtrate was desolventized under reduced pressure to remove 121 g of toluene, and then slowly cooled to 0-5 °C and maintained at this temperature for 0.5 hours. The filtrate was then filtered, and the filter cake was washed with 20 g of toluene. The solid was collected, dried, and 199.1 g of product was obtained, with a yield of 90.5%. The normalized purity of the product, as determined by HPLC, was 96.1%, and the bifenthrin isomer was 2.5%.

[0060] Comparative Example 4

[0061] The method was carried out in Comparative Example 3, except that the catalyst composition contained 2.2 g of trimethylsilane magnesium chloride and 1.5 g of isopropyl titanate, yielding 66.8 g of product. The gas phase internal standard content was 93.7%, the yield was 93.8%, and the normalized HPLC detection showed 92.7% and 2.6% of bifenthrin isomers.

[0062] Comparative Example 5

[0063] The method was carried out in Comparative Example 3, except that the catalyst composition contained 2.2 g of copper hydroxide and 1.5 g of trimethylsilane magnesium chloride, yielding 66.7 g of product. The gas phase internal standard content was 91.7%, and the yield was 91.7%. The normalized HPLC detection showed 90.3% and 1.2% of bifenthrin isomers.

[0064] The experimental results from the above examples and comparative examples show that the examples using the technical solution of the present invention have significantly better results in terms of yield, purity, and bifenthrin isomers.

[0065] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing bifenthrin, characterized in that, The method includes: contacting kung fu acid and 2-methyl-3-phenylbenzyl alcohol in the presence of a catalyst composition and a solvent to carry out an esterification reaction; The esterification reaction is carried out under dehydration conditions, which are obtained by reflux to remove water. The catalyst composition comprises component A and component B, wherein the mass ratio of component A to component B is 0.1-0.5:

1. Component A is selected from at least one of isopropyl titanate, propyl titanate, butyl titanate, isopropyl zirconate, butyl zirconate, and zirconium isopropoxide; Component B is selected from copper hydroxide and / or stannous chloride. When component B is stannous chloride, component A is not zirconium isopropoxide. The mass ratio of the catalyst composition, kung fu acid, and 2-methyl-3-phenylbenzyl alcohol is 0.01-1:1-2:

1.

2. The method according to claim 1, wherein, Component A is isopropyl titanate, and component B is copper hydroxide.

3. The method according to claim 1, wherein, The solvent is selected from at least one of aromatic hydrocarbons, halogenated aromatic hydrocarbons, and alkanes.

4. The method according to claim 3, wherein, The solvent is at least one of toluene, xylene, and trimethylbenzene.

5. The method according to claim 1, wherein, The mass ratio of component A to component B is 0.2-0.4:

1.

6. The method according to claim 1, wherein, The mass ratio of the catalyst composition, kung fu acid, and 2-methyl-3-phenylbenzyl alcohol is 0.01-0.1:1-1.1:

1.

7. The method according to claim 1, wherein, The esterification reaction is carried out at a temperature of 80-175℃ for a time of 10-30 hours.

8. The method according to claim 7, wherein, The esterification reaction is carried out at a temperature of 80-145℃ for 15-18 hours.

9. The method according to claim 8, wherein, The esterification reaction is carried out at a temperature of 80-135℃.

Images