A method for synthesizing o-3-chloro-2-propenyl hydroxylamine

Abstract

The application discloses a synthesis method of O-3-chloro-2-propenyl hydroxylamine, which comprises the following steps: directly reacting compound B with water under the action of a catalyst to obtain O-3-chloro-2-propenyl hydroxylamine; and the catalyst is Amberlyst-15 resin. According to the application, O-3-chloro-2-propenyl hydroxylamine can be prepared from compound B in one step by selecting a special catalyst, the operation is simple, the selectivity of the catalyst is high, the side reaction is less, the reaction process is easy to control, and the participation of hydrochloric acid and liquid alkali is not needed in the reaction process, so that waste salt and waste water such as sodium chloride and sodium acetate are not generated, the environmental protection pressure is reduced, and the application is a green route with wide prospects.

Description

Technical Field

[0001] This invention relates to a method for synthesizing O-3-chloro-2-propenylhydroxylamine, specifically a method for synthesizing O-3-chloro-2-propenylhydroxylamine that is simple in process, generates no wastewater containing waste salts, causes little environmental pollution, has high yield and purity, and is suitable for industrial production. Background Technology

[0002] O-3-chloro-2-propenylhydroxylamine is a key raw material for herbicides such as clethodim, bensulfuron-methyl, thiamethoxam, clethodim, pyranofurone, cyclobenzanil, butaniloxanil, and oxadiazon. This type of herbicide is a broad-spectrum post-emergence herbicide for controlling grassy weeds in broadleaf crops. It has a strong killing effect on annual and perennial grassy weeds and is mainly suitable for weed control in farmland of more than 40 crops including soybeans, cotton, peanuts, and watermelons. It can also control more than 30 kinds of grassy weeds such as barnyard grass.

[0003] There are currently many reported methods for synthesizing O-3-chloro-2-propenylhydroxylamine:

[0004] Wu Yingxiao (Pesticides, 2004, 43(3): 113) introduced a synthetic route (as follows): Ethyl acetate is acylated to N-acetylhydroxylamine in the presence of sodium hydroxide, and then N-acetyl-O-(3-chloro-2-propenyl)hydroxylamine is prepared by O-alkylation with trans-1,3-dichloropropene under alkaline conditions. Then, O-3-chloro-2-propenylhydroxylamine is obtained by acidification with hydrochloric acid, neutralization with sodium hydroxide, extraction, and solvent removal. The process of obtaining O-3-chloro-2-propenylhydroxylamine from N-acetyl-O-(3-chloro-2-propenyl)hydroxylamine generates a large amount of wastewater containing sodium acetate, sodium chloride, and ethanol, which causes significant environmental pollution.

[0005]

[0006] EP0121701 describes a method for obtaining O-3-chloro-2-propenylhydroxylamine by reacting benzaldehyde with hydroxylamine to generate benzaldehyde oxime, then reacting it with trans-1,3-dichloropropene to generate benzaldehyde oxime ether, then refluxing it with concentrated hydrochloric acid in the presence of butanol and neutralizing it with liquid alkali. However, the benzaldehyde used in this method is expensive, resulting in high production costs.

[0007] CN101648887 describes a method for preparing O-3-chloro-2-propenylhydroxylamine hydrochloride by reacting acetone oxime or butanone oxime with trans-1,3-dichloropropene and dimethyl sulfoxide as solvents in the presence of an alkali metal hydroxide, followed by hydrolysis with hydrochloric acid. This method uses expensive DMSO as a solvent, faces difficulties in separating the solvent from water, and requires neutralization with liquid alkali before use, generating a large amount of sodium chloride wastewater.

[0008] This shows that most current methods for synthesizing O-3-chloro-2-propenylhydroxylamine suffer from the problem of large amounts of saline wastewater. With increasing environmental awareness and stricter environmental requirements, environmental issues have become a significant obstacle to the industry's development. Therefore, upgrading products, changing the past extensive development model, improving the atom utilization rate of processes, and finding more scientific and environmentally friendly intermediate synthesis routes are urgent problems that the chemical and pesticide industries need to solve. Summary of the Invention

[0009] To address the shortcomings of existing synthesis processes for O-3-chloro-2-propenylhydroxylamine, this invention provides a method for synthesizing O-3-chloro-2-propenylhydroxylamine. This method improves the process route for synthesizing O-3-chloro-2-propenylhydroxylamine from N-acetyl-O-(3-chloro-2-propenyl)hydroxylamine. By introducing a catalyst, O-3-chloro-2-propenylhydroxylamine can be successfully obtained in one step from N-acetyl-O-(3-chloro-2-propenyl)hydroxylamine. This method is simple to operate, simplifies the process flow, reduces the difficulty of post-processing, improves production efficiency, generates no waste salt, and meets environmental protection requirements.

[0010] The specific technical solution of this invention is as follows:

[0011] A method for synthesizing O-3-chloro-2-propenylhydroxylamine (compound D) includes the step of directly reacting compound B (N-acetyl-O-(3-chloro-2-propenyl)hydroxylamine) with water in the presence of a catalyst to obtain O-3-chloro-2-propenylhydroxylamine;

[0012] The structural formula of compound B is as follows:

[0013]

[0014] The structural formula of the O-3-chloro-2-propenylhydroxylamine is as follows:

[0015]

[0016] This invention utilizes a catalyst to directly and directly yield O-3-chloro-2-propenylhydroxylamine from compound B in one step. The reaction does not use inorganic acids or bases, thus avoiding the generation of waste salts such as sodium chloride and sodium acetate. The use of the catalyst shortens the process flow, reduces waste, lowers production costs, and increases product yield.

[0017] Furthermore, the catalyst used in this invention is Amberlyst-15 resin, which is commercially available.

[0018] Furthermore, the amount of catalyst used is 0.1-100% of the mass of compound B, preferably 0.5-20 wt%, more preferably 1-10 wt%.

[0019] Furthermore, compound B and water react in the presence of a catalyst to produce O-3-chloro-2-propenylhydroxylamine and acetic acid. The molar ratio of water to compound B is 0.8-10:1, preferably 1-7:1, and more preferably 3-5:1.

[0020] Furthermore, compound B can be obtained using methods disclosed in the prior art, for example, by acylation of methyl acetate or ethyl acetate with hydroxylamine hydrochloride or hydroxylamine sulfate, followed by etherification with trans-1,3-dichloropropene.

[0021] Furthermore, the reaction system also includes alcohols, which serve as both solvents and raw materials for the reaction with the byproduct acetic acid. The acetic acid byproduct formed in the reaction can be converted into acetate under the action of a catalyst. Acetate can be used as a starting material for the synthesis of compound B, thus achieving the purpose of resource utilization of byproducts.

[0022] Furthermore, the alcohol is methanol or ethanol. The molar ratio of compound B to the alcohol is 1:1-10, preferably 1:2-6.

[0023] When the alcohols are methanol and ethanol, the following reactions occur in the reaction system:

[0024]

[0025] Furthermore, the reaction temperature is 20-100℃, preferably 30-70℃, and more preferably 35-50℃, considering the boiling point of the by-product acetate. Samples are taken during the reaction to determine the content of the raw materials, and the reaction is terminated after all the raw materials have reacted.

[0026] Furthermore, the reaction is carried out under negative pressure. During the reaction, the volatile acetate is continuously separated out by the negative pressure, which promotes the forward reaction. Preferably, the pressure is maintained at -0.02 MPa to -0.08 MPa during the reaction, more preferably -0.04 to -0.06 MPa.

[0027] Furthermore, the order of adding raw materials in the synthesis method of the present invention is as follows: compound B, alcohol, water, and catalyst are added, and the reaction is carried out under heating and negative pressure to obtain O-3-chloro-2-propenylhydroxylamine and ester. More preferably, compound B and alcohol are mixed first, heated to the reaction temperature, and then water and catalyst are added, and the reaction is carried out under negative pressure and maintained at the temperature.

[0028] Furthermore, the reaction is carried out under negative pressure, and the by-product acetate is continuously separated out. At the same time, because alcohol is volatile, some alcohol is also lost. Therefore, alcohol needs to be added intermittently during the reaction to ensure that the molar ratio of compound B to alcohol is 1:1-10, preferably 1:2-6, throughout the entire reaction process.

[0029] The present invention has the following beneficial effects:

[0030] 1. This invention employs a catalyst-catalyzed method to prepare O-3-chloro-2-propenylhydroxylamine from compound B in one step. The catalyst exhibits high selectivity, few side reactions, and the reaction process is easy to control and operate. Simultaneously, the byproduct acetic acid reacts with the solvent alcohol to synthesize acetate under catalysis. This product can be reused as a raw material in the synthesis of compound B, thus realizing the resource utilization of the byproduct. The entire process generates minimal waste and is easy to implement.

[0031] 2. This invention yields O-3-chloro-2-propenylhydroxylamine from compound B via a one-step reaction under mild conditions. It eliminates the need for intermediate steps such as solvent removal, extraction, layering, and neutralization, simplifying the process, shortening reaction time, and improving production efficiency. Post-processing is simple, requiring no washing, layering, or dehydration, facilitating separation and purification, reducing wastewater treatment burden, minimizing waste, lowering production costs, meeting environmental requirements, and making it more suitable for industrial production.

[0032] 3. This invention synthesizes O-3-chloro-2-propenylhydroxylamine under negative pressure. The byproduct acetate produced in the reaction is continuously separated from the reaction system, promoting the forward reaction. At the same time, the separated acetate can be used as a starting material, avoiding product waste and environmental pollution.

[0033] 4. The reaction process of this invention does not require the participation of hydrochloric acid or liquid alkali, nor does it introduce a large amount of water. Therefore, it does not produce sodium chloride or sodium acetate waste salt and wastewater, thus reducing environmental pressure. Attached Figure Description

[0034] Figure 1 The image shows the liquid chromatography-mass spectrometry (LC-MS) diagram of O-3-chloro-2-propenylhydroxylamine obtained in Example 1. Detailed Implementation

[0035] The present invention will be further described below through specific embodiments. The following description is merely exemplary and does not limit its content.

[0036] In the following examples, the catalyst Amberlyst-15 resin (hereinafter referred to as A-15cat) was purchased from the market.

[0037] Example 1

[0038] 1. Compound B: N-acetyl-O-(3-chloro-2-propenyl)hydroxylamine with a purity of 95% was prepared according to the method in the literature: Pesticides, 2004, 43(3):113.

[0039] 2. In a 250ml three-necked flask equipped with a distillation column, thermometer, and stirrer, 78.7g of compound B and 80.1g of methanol were added. The temperature was then raised to 45℃, and 9.0g of water and 0.8g of A-15cat were added. At this temperature, the reaction was carried out under negative pressure (pressure -0.05MPa) to remove the generated methyl acetate. Simultaneously, 20g of methanol was continuously added to the reaction flask during the reaction. After the conversion of compound B was successful, a solution of compound D (i.e., O-3-chloro-2-propenylhydroxylamine) was obtained. Simultaneously, a mixed solution of methyl acetate was obtained by negative pressure separation, yielding 109.6g.

[0040] 3. After filtering the reaction solution to recover the catalyst and removing the solvent, 51.9 g of compound D (pale yellow oily liquid) was obtained. GC analysis showed a content of 92.3%, and the yield was 89.1% based on compound B.

[0041] Example 2

[0042] Compound D was synthesized according to the method of Example 1, except that different masses of catalyst were added. The amount of catalyst and the reaction results are shown in Table 1 below.

[0043]

[0044] Example 3

[0045] 1. Compound B: N-acetyl-O-(3-chloro-2-propenyl)hydroxylamine with a purity of 95% was prepared according to the method in the literature: Pesticides, 2004, 43(3):113.

[0046] 2. In a 500ml three-necked flask equipped with a distillation column, thermometer, and stirrer, 78.7g of compound B and 160.2g of methanol were added. The temperature was then raised to 40℃, and 18.0g of water and 4.0g of A-15cat were added. At this temperature, the reaction was carried out under negative pressure (pressure -0.06MPa) to remove the generated methyl acetate. After the conversion of compound B was successful, a solution of compound D (i.e., O-3-chloro-2-propenylhydroxylamine) was obtained. Simultaneously, a mixed solution of methyl acetate was separated under negative pressure, yielding 169.0g.

[0047] 3. After filtering the reaction solution to recover the catalyst and removing the solvent, 53.1 g of compound D was obtained. GC analysis showed a content of 91.2%, and the yield was 90.1% based on compound B.

[0048] Example 4

[0049] 1. Compound B: N-acetyl-O-(3-chloro-2-propenyl)hydroxylamine with a purity of 95% was prepared according to the method in the literature: Pesticides, 2004, 43(3):113.

[0050] 2. In a 500ml three-necked flask equipped with a distillation column, thermometer, and stirrer, 78.7g of compound B was added, along with methanol. The temperature was then raised to 40℃, and 18.0g of water and 4.0g of A-15cat were added. At this temperature, the reaction was carried out under negative pressure (pressure -0.06MPa) to remove the generated methyl acetate. Methanol was continuously added to maintain the molar ratio of compound B to compound B as required in Table 2. After successful conversion of compound B, a solution of compound D (i.e., O-3-chloro-2-propenylhydroxylamine) was obtained, and a mixed solution of methyl acetate was simultaneously separated under negative pressure.

[0051] 3. After filtering the reaction solution to recover the catalyst and removing the solvent, compound D was obtained, and its content was analyzed by GC.

[0052] The methanol dosage and reaction results are shown in Table 2 below:

[0053]

[0054] Example 5

[0055] 1. Compound B: N-acetyl-O-(3-chloro-2-propenyl)hydroxylamine with a purity of 95% was prepared according to the method in the literature: Pesticides, 2004, 43(3):113.

[0056] 2. In a 500ml three-necked flask equipped with a distillation column, thermometer, and stirrer, 78.7g of compound B and 48.0g of methanol were added. The temperature was then raised to 40℃, and 45.0g of water and 8.0g of A-15cat were added. At this temperature, the reaction was carried out under negative pressure (pressure -0.05MPa) to remove the generated methyl acetate. Simultaneously, 50g of methanol was continuously added to the reaction flask during the reaction. After the conversion of compound B was successful, a solution of compound D (i.e., O-3-chloro-2-propenylhydroxylamine) was obtained. Simultaneously, a mixed solution of methyl acetate was obtained by negative pressure separation, yielding 137.6g.

[0057] 3. After filtration and recovery of cat, and removal of solvent and water, 53.4 g of compound D was obtained. GC analysis showed a purity of 91%, and the yield was 90.4% based on compound B.

[0058] Example 6

[0059] Compound D was synthesized according to the method in Example 5, except that different masses of water were added. The amount of water used and the reaction results are shown in Table 3 below.

[0060]

[0061] Example 7

[0062] 1. Compound B: N-acetyl-O-(3-chloro-2-propenyl)hydroxylamine with a purity of 95% was prepared according to the method in the literature: Pesticides, 2004, 43(3):113.

[0063] 2. In a 500ml three-necked flask equipped with a distillation column, thermometer, and stirrer, 78.7g of compound B and 92.1g of ethanol were added. The temperature was then raised to 45℃, and 45.0g of water and 8.0g of A-15cat were added. At this temperature, the reaction was carried out under negative pressure (pressure -0.07MPa) to remove the generated ethyl acetate. Simultaneously, 40g of ethanol was continuously added to the reaction flask to maintain the molar ratio of compound B to ethanol within the range of 1:3. After the conversion of compound B was successful, a solution of compound D (i.e., O-3-chloro-2-propenylhydroxylamine) was obtained, and 141.0g of a mixed solution of ethyl acetate was obtained by separation under negative pressure.

[0064] 3. After filtration and recovery of cat, and removal of solvent and water, 51.4 g of compound D was obtained. GC analysis showed a purity of 91.3%, and the yield was 87.3% based on compound B.

[0065] Comparative Example 1

[0066] Compound D was prepared according to the method of Example 1, except that the catalyst A-15cat was replaced with 3.7g of Amberlyst-21cat, and 26.8g of compound D was obtained with a purity of 54.5% and a yield of 27.2%.

[0067] Comparative Example 2

[0068] Compound D was prepared according to the method of Example 1, except that 5 g of water was used. 58.9 g of compound D was obtained, with a purity of 28.5% and a yield of 31.2%.

Claims

1. A method for synthesizing O-3-chloro-2-propenylhydroxylamine, characterized in that: The reaction includes the step of directly reacting compound B with water in the presence of a catalyst to obtain O-3-chloro-2-propenylhydroxylamine; the reaction is carried out under reduced pressure, and the generated ester is continuously separated during the reaction. The structural formula of compound B is as follows: The catalyst is Amberlyst-15 resin; The molar ratio of water to compound B is 1:3~10; The amount of catalyst used is 1-10 wt% of the mass of compound B; The reaction system also contains an alcohol, which reacts with the byproduct acetic acid to form an ester. The molar ratio of compound B to the alcohol is 1:1-10.

2. The synthesis method according to claim 1, characterized in that: The reaction temperature is 20-100℃.

3. The synthesis method according to claim 2, characterized in that: The reaction temperature is 30-70℃.

4. The synthesis method according to claim 3, characterized in that: The reaction temperature is 35-50℃.

5. The synthesis method according to claim 1, characterized in that: The alcohol is methanol or ethanol.

6. The synthesis method according to claim 1, characterized in that: The molar ratio of compound B to alcohol is 1:2-6.

7. The synthesis method according to claim 1, characterized in that: Compound B, alcohol, water, and catalyst were mixed and heated to produce O-3-chloro-2-propenylhydroxylamine and its ester.

8. The synthesis method according to claim 1 or 7, characterized in that: If necessary, alcohol is continuously added during the reaction to ensure that the molar ratio of compound B to alcohol is 1:1-10 throughout the entire reaction.

9. The synthesis method according to claim 8, characterized in that: If necessary, alcohol is continuously added during the reaction to ensure that the molar ratio of compound B to alcohol is 1:2-6 throughout the entire reaction.

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