Chlorpyrifos technical containing stabilizer and application of the stabilizer

Abstract

The present application relates to a kind of stable chlorpyrifos technical and the application of stabilizer, the content of chlorpyrifos in the chlorpyrifos technical is 92.0-99.5%, chlorpyrifos technical contains stabilizer, stabilizer is p-hydroxyanisole, beta-propionolactone, or the composition consisting of p-hydroxyanisole and beta-propionolactone, wherein the mass content of stabilizer in chlorpyrifos technical is 0.05 ‰-5.0 ‰.The present application uses p-hydroxyanisole, beta-propionolactone or the composition consisting of p-hydroxyanisole and beta-propionolactone as the stabilizer of chlorpyrifos technical solves the stability problem of chlorpyrifos technical, especially can effectively reduce the decomposition of active ingredient in chlorpyrifos technical.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of pesticides, and particularly relates to a technical chlorpyrifos, and especially to a chlorpyrifos technical containing a stabilizer and application of the stabilizer. BACKGROUND

[0002] Chlorpyrifos is also known as chlorpyrifos, chlorpyrifos, and its chemical name is O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl) thiophosphoric acid, and its molecular formula is C9H11Cl3NO3PS. It is a broad-spectrum organophosphorus insecticide and miticide, and its mechanism of action is to inhibit acetylcholinesterase, and it has contact, stomach and fumigation three kinds of action modes, and can effectively prevent and control more than 100 kinds of pests and mites such as aphids, borers, armyworms, leaf rollers, scales, leafhoppers and mites.

[0003] The pure chlorpyrifos is a white crystal with a slight mercaptan smell, and its melting point is 42.5-43℃, its vapor pressure is 2.46x10-3Pa / 25℃, it is hardly soluble in water, and it is soluble in acetone, benzene, chloroform and most organic solvents. It is stable in acidic medium and easily decomposed in alkaline medium, and it is stable at room temperature. The chlorpyrifos technical is unchanged when stored under normal conditions for two years, and its decomposition rate increases with the increase of temperature and pH value. It has corrosive effect on copper and brass.

[0004] The current industrial synthesis method of chlorpyrifos mainly includes double solvent method and aqueous phase method, and the main raw materials are 3,5,6-trichloropyridin-2-ol sodium and O,O-diethyl thiophosphoryl chloride. The double solvent method is to form a double solvent system with water and an organic solvent, which can effectively inhibit the hydrolysis of O,O-diethyl thiophosphoryl chloride, and the yield can reach 95%. The general aqueous phase method is to add 3,5,6-trichloropyridin-2-ol sodium into water, add a catalyst, and drop O,O-diethyl thiophosphoryl chloride and an acid-binding agent at the same time, and chlorpyrifos technical is directly obtained by crystallization under cooling. The synthesis process of chlorpyrifos also includes the reaction of sodium trichloropyridinol, ethyl chloride and a catalyst, after the reaction is completed, the lower oil phase is taken out after standing and separating, and then chlorpyrifos is washed with water and alcohol, and white chlorpyrifos technical is obtained by filtration and drying. In the synthesis process, the yield and purity of chlorpyrifos are improved, but in the process of transportation and storage, the storage time of chlorpyrifos technical is improved, the decomposition rate of chlorpyrifos is reduced, and the activity of chlorpyrifos is reduced. However, the problem of long-term stable storage of chlorpyrifos has not been solved, especially the problem of reduction of active ingredient content of chlorpyrifos caused by transportation and storage under high temperature. SUMMARY

[0005] In order to solve the problems of reduction of purity and instability of appearance of chlorpyrifos technical in long-term storage, the present application provides a chlorpyrifos technical with improved stability, a stabilizer for improving stability and application thereof.

[0006] Specifically, the application provides a stable chlorpyrifos technical composition, the content of chlorpyrifos in the chlorpyrifos technical composition is 92.0-99.5%, the chlorpyrifos technical composition contains a stabilizer, the stabilizer is p-hydroxyanisole, beta-propiolactone or a composition consisting of p-hydroxyanisole and beta-propiolactone, and the mass content of the stabilizer in the chlorpyrifos technical composition is 0.05‰-5.0‰.

[0007] In the chlorpyrifos technical composition, the content of chlorpyrifos in the chlorpyrifos technical composition is 92.0-99.5%, which means that the purity of the chlorpyrifos technical composition is 92.0-99.5%, that is, the mass content of chlorpyrifos, the effective component in the chlorpyrifos technical composition, is 92.0-99.5%.

[0008] Preferably, in the chlorpyrifos technical composition, the stabilizer is p-hydroxyanisole, the mass content of p-hydroxyanisole in the chlorpyrifos technical composition is 0.1‰-1.0‰, or the stabilizer is beta-propiolactone, the mass content of beta-propiolactone in the chlorpyrifos technical composition is 0.1‰-1.0‰.

[0009] Preferably, in the chlorpyrifos technical composition, the stabilizer is a composition consisting of p-hydroxyanisole and beta-propiolactone, the mass content of p-hydroxyanisole in the chlorpyrifos technical composition is 0.1‰, and the mass content of beta-propiolactone in the chlorpyrifos technical composition is 0.1‰.

[0010] In the technical solution, the chlorpyrifos technical composition actually contains a stabilizer and chlorpyrifos; after the addition of the stabilizer, the composition still meets the quality standard of chlorpyrifos technical composition, so the composition is still chlorpyrifos technical composition. Because the content of chlorpyrifos in the composition meets the standard of the content of chlorpyrifos technical composition, the chlorpyrifos technical composition or chlorpyrifos technical composition has the same meaning. In the application, the term "chlorpyrifos technical composition" is mainly used because it involves the calculation of the content of the stabilizer in the chlorpyrifos technical composition. Actually, the chlorpyrifos technical composition is chlorpyrifos technical composition, and only the content of the stabilizer is added in the production of chlorpyrifos technical composition. Therefore, in essence, the chlorpyrifos technical composition is also a composition, and the definition of "chlorpyrifos technical composition" is also clear. When the term "chlorpyrifos technical composition" is used alone, it generally refers to the chlorpyrifos technical composition obtained by industrial production, which does not contain any component produced in the industrial production.

[0011] The calculation of the content of the stabilizer in the chlorpyrifos technical composition is explained as follows.

[0012] For example, the meaning of "the mass content of p-hydroxyanisole in chlorpyrifos technical is 0.1‰-1.0‰" in the following is "adding p-hydroxyanisole of 0.1‰-1.0‰ of the mass of chlorpyrifos technical into chlorpyrifos technical", that is, if there are 1000g of chlorpyrifos technical, then adding 1g of p-hydroxyanisole, which is 1‰ of the mass of chlorpyrifos technical, the total mass after adding is 1001g. For another example, the meaning of "the mass of p-hydroxyanisole added into chlorpyrifos technical is 0.1‰-1.0‰ of the mass of chlorpyrifos technical" is explained by example as follows: if there are 1000g of chlorpyrifos technical, adding p-hydroxyanisole of 1‰ of the mass of chlorpyrifos technical is adding 1g, and the total mass of the technical after adding is 1001g.

[0013] The present application also provides the use of a stabilizer for improving the stability of chlorpyrifos technical, wherein the stabilizer is p-hydroxyanisole, β-propiolactone, or a composition consisting of p-hydroxyanisole and β-propiolactone.

[0014] Preferably, in the above use, the stabilizer is p-hydroxyanisole, the mass content of p-hydroxyanisole in chlorpyrifos technical is 0.1‰-1.0‰, or the stabilizer is β-propiolactone, the mass content of β-propiolactone in chlorpyrifos technical is 0.1‰-1.0‰, or the stabilizer is a composition consisting of p-hydroxyanisole and β-propiolactone, the mass ratio of p-hydroxyanisole and β-propiolactone is 1:1, and the mass content of the composition consisting of p-hydroxyanisole and β-propiolactone in chlorpyrifos technical is 0.2‰.

[0015] Preferably, in the above use, the mass content of the active ingredient chlorpyrifos in chlorpyrifos technical is 92.0-99.5%.

[0016] Preferably, in the above use, the stability of chlorpyrifos technical refers to that the decomposition rate of the active ingredient chlorpyrifos is less than 5% when chlorpyrifos technical is stored at 60℃ for 9 days.

[0017] Preferably, in the above use, the stability of chlorpyrifos technical refers to that the decomposition rate of the active ingredient chlorpyrifos is less than 3% when chlorpyrifos technical is stored at 60℃ for 9 days.

[0018] Preferably, in the above use, the stability of chlorpyrifos technical refers to that the decomposition rate of the active ingredient chlorpyrifos is less than 1.2% when chlorpyrifos technical is stored at 60℃ for 9 days.

[0019] Preferably, in the above use, the stability of chlorpyrifos technical refers to that the decomposition rate of the active ingredient chlorpyrifos is less than 1.2% when chlorpyrifos technical is stored at 60℃ for 9 days, and the liquid of chlorpyrifos technical at 60℃ is clear.

[0020] Preferably, in the above use, the decomposition rate of the active ingredient chlorpyrifos refers to the percentage of the decrease in chlorpyrifos content of chlorpyrifos technical material after heat storage at 60℃ relative to the initial chlorpyrifos content in the technical material. The chlorpyrifos content is the mass percentage of chlorpyrifos calculated by measuring according to the method of GB / T 19604-2017 Chlorpyrifos Technical Material and using the external standard method, or the chlorpyrifos content is the mass percentage of chlorpyrifos calculated by measuring according to the method of GB / T 19604-2017 Chlorpyrifos Technical Material and using the area normalization method.

[0021] The appearance of chlorpyrifos technical material can be observed to be clear or have flocculent precipitates in a molten state. Generally, chlorpyrifos is in a molten state at a temperature above 43℃, that is, in a liquid state. Therefore, the appearance of chlorpyrifos can be observed under the condition of heat storage at 60℃. The stability under the condition of heat storage at 60℃ is a method for rapidly measuring the stability of chlorpyrifos under normal temperature storage conditions, and the principle is the same as that of the method for measuring the heat storage stability of chlorpyrifos formulations. Therefore, the stability of the stabilizer to chlorpyrifos technical material is measured by heat storage to determine the stability of the stabilizer to chlorpyrifos technical material under normal temperature.

[0022] In the technical solutions of the above chlorpyrifos technical material composition and use, the stabilizer p-hydroxyanisole, also known as hydroquinone monomethyl ether, p-benzene diol monomethyl ether, p-methoxyphenol, 1,4-methoxyphenol, is abbreviated as MEHQ (hereinafter also abbreviated as MEHQ), has a molecular weight of 124.14, is a white flaky crystal or waxy solid at normal temperature, has a relative density of 1.55, a melting point of 53℃, and a boiling point of 243℃. It is soluble in ethanol, acetone, ethyl acetate and toluene, and slightly soluble in water. It can absorb part of the ultraviolet rays, has stable chemical properties, is flammable, has low toxicity, is an important chemical raw material for synthesizing aryl ester liquid crystals, and can also be used as a dye intermediate.

[0023] In the technical solutions of the above chlorpyrifos technical material composition and use, the stabilizer beta-propiolactone, also known as beta-propanoyl lactone, has a chemical formula of C3H4O2 and is a colorless liquid. It is mainly used as an intermediate for modifying drugs, resins and fibers, and is also used as a bactericidal disinfectant for blood plasma and vaccines.

[0024] To solve the above technical problems of the present application, other stabilizers for chlorpyrifos technical material are also selected, such as 2,6-di-tert-butyl-4-methylphenol (hereinafter abbreviated as BHT), 1,2-butanediol, diethyl malonate, triethyl citrate, lauryl aldehyde, etc. These stabilizers have an effect on the stability of chlorpyrifos technical material, but none of them is as good as beta-propiolactone and p-hydroxyanisole in reducing the decomposition rate of chlorpyrifos technical material.

[0025] The present application also provides a method for improving the stability of chlorpyrifos technical by adding a stabilizer into chlorpyrifos technical, wherein the effective component chlorpyrifos in the chlorpyrifos technical has a mass content of 92.0-99.5%.

[0026] Preferably, the method is to add the stabilizer into the solid chlorpyrifos technical, then to melt the chlorpyrifos technical by heating to above 43℃, and then to mix thoroughly, and then to cool the liquid chlorpyrifos technical to solid state to obtain the chlorpyrifos technical with improved stability.

[0027] Preferably, the method is to add the stabilizer into the liquid chlorpyrifos technical and mix thoroughly, and then to cool the liquid chlorpyrifos technical to solid state to obtain the chlorpyrifos technical with improved stability.

[0028] Preferably, in the above method, the stabilizer is p-hydroxyanisole, β-propiolactone, or a composition consisting of p-hydroxyanisole and β-propiolactone, wherein the mass of the stabilizer added into the chlorpyrifos technical is 0.05‰-5.0‰ of the mass of the chlorpyrifos technical.

[0029] Preferably, in the above method, the stabilizer is p-hydroxyanisole, and the mass of the p-hydroxyanisole added into the chlorpyrifos technical is 0.1‰-1.0‰ of the mass of the chlorpyrifos technical, or the stabilizer is β-propiolactone, and the mass of the β-propiolactone added into the chlorpyrifos technical is 0.1‰-1.0‰ of the mass of the chlorpyrifos technical.

[0030] Preferably, in the above method, the stabilizer is a composition consisting of p-hydroxyanisole and β-propiolactone, the mass of the p-hydroxyanisole added into the chlorpyrifos technical is 0.1‰ of the mass of the chlorpyrifos technical, and the mass of the β-propiolactone added into the chlorpyrifos technical is 0.1‰ of the mass of the chlorpyrifos technical.

[0031] Advantages of the present application

[0032] The present application uses p-hydroxyanisole, β-propiolactone, or a composition consisting of p-hydroxyanisole and β-propiolactone as the stabilizer for chlorpyrifos technical to solve the stability problem of chlorpyrifos technical, and effectively reduce the decomposition of chlorpyrifos technical.

[0033] The present application uses a composition consisting of p-hydroxyanisole and β-propiolactone as the stabilizer to reduce the decomposition rate of chlorpyrifos technical to below 1.2% under the condition of 9 days of hot storage at 60℃, and effectively ensure the appearance of the molten chlorpyrifos technical to be clear and shape. DETAILED DESCRIPTION

[0034] The chlorpyrifos technical material used in the following examples is produced by Zhejiang Xin Nong Chemical Co., Ltd., and the stabilizer used is an analytical pure product purchased on the market. The chemical name of BHT is 2, 6-di-tert-butyl-4-methylphenol, and the chemical name of MEHQ is p-hydroxyanisole.

[0035] In the following examples, the method of adding stabilizers to chlorpyrifos technical material is to mix the stabilizer and chlorpyrifos technical material thoroughly to obtain a mixture, then melt the mixture by heating to 60°C, and then stir thoroughly. The calculation method of the addition amount of the stabilizer is: according to the mass of the chlorpyrifos technical material sample as the base, the content of the stabilizer is added, for example, 1‰ of stabilizer is added to 200g of chlorpyrifos technical material, which is 0.2g. After adding the stabilizer, the total mass is 200.2g. Because the amount of stabilizer added is very low, the content of stabilizer in the total mass of chlorpyrifos technical material after adding the stabilizer is also infinitely close to 1‰, which is equivalent to adding 1‰ of stabilizer to the chlorpyrifos technical material. Therefore, in the experiment, in order to take the sample relatively accurately, the mass of the stabilizer is taken according to 1‰, 0.2‰, 0.1‰ of the mass of the chlorpyrifos technical material sample, that is, in the case of 200g of chlorpyrifos technical material, the sampling is 0.2g, 0.04g and 0.02g respectively.

[0036] Example 1: Screening of stabilizers for improving the stability of chlorpyrifos technical material

[0037] Samples were taken from the same batch of chlorpyrifos technical material, each sample being 200g, and then the corresponding proportion of stabilizers recorded in Table 1 was added according to the mass percentage of the sample to carry out stability experiments. The sample of chlorpyrifos technical material without adding stabilizer (referred to as "original sample" in Table 1 below) and the sample of chlorpyrifos technical material with added stabilizer were placed in a 60°C oven at the same time for heat storage, and test samples were taken from each sample every 24 hours, while the appearance of the chlorpyrifos sample in liquid state was observed. The test sample was taken for the last time after 120 hours of heat storage, and the sampling amount of the test sample should meet the requirements of mass content detection, which is generally 0.1g. The test was measured according to the method in "GB / T 19604-2017 Chlorpyrifos Technical Material", and the content of chlorpyrifos was calculated by external standard method, and the mass content of chlorpyrifos, trichloropyridol and chlorpyrifos isomers was calculated by area normalization method. The specific results are shown in Table 1 below.

[0038] Table 1: Results of stabilizer screening experiment for stability of chlorpyrifos technical material

[0039]

[0040] The time in Table 1 above is the length of time for heat storage at 60°C, which is 0 hours, 24 hours, 48 hours, 72 hours, 96 hours and 120 hours respectively.

[0041] From the above Table 1, it can be seen that the chlorpyrifos technical and the chlorpyrifos technical with the addition of stabilizers, after 60°C heat storage for 120 hours, among them, the sample of chlorpyrifos technical with the addition of 1‰ MEHQ is still clear at 60°C, but the external standard method decomposition rate is 0.91%, which is higher than the decomposition rate of chlorpyrifos containing 1‰ β-propiolactone and higher than the decomposition rate of chlorpyrifos containing 1‰ BHT. From the external standard method decomposition rate, its effect of reducing the decomposition of chlorpyrifos is not obvious, but MEHQ as the effect of maintaining the appearance stability of chlorpyrifos technical is the best among these stabilizers.

[0042] The effect of β-propiolactone on reducing the decomposition rate of chlorpyrifos technical is better than other stabilizers, and the external standard method decomposition rate of chlorpyrifos technical containing β-propiolactone after 120 hours of heat storage is only 0.27%, which is far lower than 1.4% of chlorpyrifos technical without adding any stabilizer, and also lower than the decomposition rates of other stabilizers such as pine rosin alcohol, BHT, MEHQ, 1,2-butanediol, diethyl malonate, triethyl citrate, lauryl aldehyde. According to the area normalization method decomposition rate, the decomposition rate of chlorpyrifos technical containing β-propiolactone is the lowest, and the proportion of by-products trichloropyridol and chlorpyrifos isomers is also the lowest.

[0043] From Table 1, it can be seen that β-propiolactone is the most suitable stabilizer for reducing the decomposition rate of chlorpyrifos technical, and MEHQ is the most suitable stabilizer for stabilizing the appearance of chlorpyrifos.

[0044] Therefore, β-propiolactone and MEHQ are selected to further verify their effects on the stability of chlorpyrifos technical, mainly by changing the content of β-propiolactone and MEHQ, extending the heat storage time and mixing β-propiolactone and MEHQ to verify the stability of chlorpyrifos technical.

[0045] Example 2: Further verification of the stability effect of stabilizers

[0046] The stability of chlorpyrifos technical material was further verified under the conditions of prolonging the heat storage time, changing the amount of stabilizer, etc. The samples required for the experiment were still taken from the same batch of chlorpyrifos technical material in Example 1, each sample was 200 g, and the stabilizer was added according to the amount shown in Table 2 to carry out the stability experiment. The sample of chlorpyrifos technical material without adding stabilizer (referred to as "as is" in Table 2 below) was placed in a 60°C oven at the same time as the chlorpyrifos technical material sample with added stabilizer. The experiment was to take samples from each sample every 72 hours (3 days), and at the same time, the appearance of the chlorpyrifos technical material sample in liquid state was observed. The last sample was taken after 9 days of heat storage. The amount of sample taken was enough for quality content detection, generally 0.1 g. The test was measured according to the method in "GB / T 19604-2017 Chlorpyrifos Technical Material", the content of chlorpyrifos was calculated by external standard method, and the contents of chlorpyrifos, trichloropyridol and chlorpyrifos isomers were calculated by area normalization method. The specific results are shown in Table 2 below.

[0047] Table 2: Prolonged heat storage time to verify the stability of chlorpyrifos technical material and mixed stabilizer experiment

[0048]

[0049] In the above Table 2, the time is the length of time for heat storage at 60°C, which is 0 days, 3 days, 6 days and 9 days, respectively.

[0050] As can be seen from Table 2, the chlorpyrifos technical material containing 1‰ β-propiolactone had a decomposition rate of 0.69% calculated by external standard method after 9 days of heat storage, which was still at a relatively low level, but its appearance stability was very poor, and flocculent precipitate appeared. The decomposition rate reached 1.28% when the amount of β-propiolactone was reduced to 0.2‰, and the decomposition rate increased. The chlorpyrifos technical material added with 1‰ MEHQ had the best appearance stability. After 9 days of heat storage, the chlorpyrifos technical material only appeared turbidity, and no flocculent precipitate appeared. However, flocculent precipitate appeared when the amount was reduced to 0.2‰.

[0051] In the case of applying a mixture of β-propiolactone and MEHQ, the decomposition rate of chlorpyrifos technical material was only 0.37% when 0.1% of the additive was added to the chlorpyrifos technical material, and the appearance of the chlorpyrifos technical material in liquid state was still clear.

[0052] From the above results, it can be seen that the best mass concentration of β-propiolactone as a single stabilizer of chlorpyrifos technical to reduce its decomposition rate is 1 ‰, and the best mass concentration of MEHQ as a single stabilizer of chlorpyrifos technical to stabilize the appearance of liquid chlorpyrifos technical is also 1 ‰. In order to stabilize the active ingredient content and appearance of chlorpyrifos technical, the stabilizer is a combination of β-propiolactone and MEHQ, and the amount is also greatly reduced. Only 0.1 ‰ of β-propiolactone and 0.1 ‰ of MEHQ combined as stabilizers can ensure that the decomposition rate of the active ingredient in chlorpyrifos technical is low and the appearance of liquid chlorpyrifos technical is clear.

Claims

1. A stable chlorpyrifos technical composition, the content of chlorpyrifos in the chlorpyrifos technical composition being 92.0-99.5%, the chlorpyrifos technical composition containing a stabilizer, the stabilizer being a composition consisting of p-hydroxyanisole and β-propiolactone, wherein the mass content of p-hydroxyanisole in the chlorpyrifos technical composition is 0.1 ‰, and the mass content of β-propiolactone in the chlorpyrifos technical composition is 0.1 ‰.

2. Use of a stabilizer for improving the stability of chlorpyrifos technical, the stabilizer being a composition consisting of p-hydroxyanisole and β-propiolactone, the mass ratio of p-hydroxyanisole to β-propiolactone being 1:1, the mass content of the composition consisting of p-hydroxyanisole and β-propiolactone in the chlorpyrifos technical being 0.2 ‰, the mass content of the active ingredient chlorpyrifos in the chlorpyrifos technical being 92.0-99.5%, and the stability of the chlorpyrifos technical referring to the decomposition rate of the active ingredient chlorpyrifos being less than 1.2% when the chlorpyrifos technical is stored at 60℃ for 9 days, and the liquid of the chlorpyrifos technical being clear at 60℃.

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