A safe treatment method for dinotefuran mother liquor

Abstract

The present invention provides a method for the safe treatment of dinotefuran mother liquor, belonging to the field of agricultural chemicals and their preparation technology. The method comprises adding a catalyst and an inorganic acid to the dinotefuran mother liquor, heating the liquor under stirring, and maintaining the temperature for a predetermined time. The catalyst is any salt or a mixture of salts formed by a metal element and an inorganic acid. The safe treatment method provided by the present invention solves the problem of gas generation during the self-decomposition of the dinotefuran mother liquor. The catalyst used in this method is inexpensive and easy to operate. After treatment, the dinotefuran mother liquor no longer releases gas, thus ensuring the safe transportation and storage of the dinotefuran mother liquor.

Description

Technical Field

[0001] The present invention relates to a method for treating a dinotefuran mother liquor, in particular to a method for safe treatment of a dinotefuran mother liquor, and belongs to the technical field of agricultural chemicals and preparation thereof. Background Art

[0002] Dinotefuran English name: Dinotefuran, chemical formula: C7H 14 N₄O₃ (CAS: 165252-70-0) is a third-generation neonicotinoid insecticide with no cross-resistance to other agents. It boasts broad-spectrum, high efficacy, and low toxicity, making it suitable for controlling a variety of pests, including cockroaches, ants, fleas, and other reptiles. The market for dinotefuran continues to expand, showing a steady growth trend.

[0003] Synthesis route of dinotefuran intermediate nitroisourea:

[0004]

[0005] The synthetic route of dinotefuran:

[0006]

[0007] The production process of dinotefuran involves the following: after dinotefuran crystallization and centrifugation, the filtrate is evaporated to dryness, methanol is added, and the dinotefuran and organic impurities in the filtrate are dissolved. The methanol is then evaporated to obtain the dinotefuran mother liquor. During production, it has been discovered that the dinotefuran mother liquor slowly releases gas, especially during the high temperatures of summer. This gas release can cause the mother liquor packaging to swell and rupture during transportation and storage, leading to liquid splashing and leakage, posing a certain risk. Experimental observations have shown that the gas release process is very slow and can last for at least 10 years. Summary of the Invention

[0008] In view of the above problems, the present invention provides a method for safely treating dinotefuran mother liquor, which solves the technical problem that dinotefuran mother liquor generates gas for a long time during transportation and storage, causing danger in the transportation and storage process.

[0009] To achieve the above-mentioned object, the technical solution of the present invention is: a method for safely treating a dinotefuran mother liquor, comprising adding a catalyst and an inorganic acid to the dinotefuran mother liquor, heating the liquor under stirring conditions, and maintaining the temperature for a predetermined time; the catalyst is any salt or a mixture of several salts formed by a metal element and an inorganic acid.

[0010] Furthermore, the metal element in the catalyst is manganese, cobalt, aluminum, or magnesium, and the inorganic acid in the catalyst is sulfuric acid, hydrochloric acid, acetic acid, 65% nitric acid, or phosphoric acid. Examples of catalyst types include manganese chloride, manganese sulfate, 65% manganese nitrate, manganese phosphate, manganese acetate, cobalt chloride, cobalt sulfate, cobalt acetate tetrahydrate, aluminum chloride, aluminum sulfate, aluminum phosphate, magnesium chloride, magnesium sulfate, magnesium phosphate, and their corresponding hydrates.

[0011] Furthermore, the added amount of the catalyst is 0.01% to 0.1% by weight of the treated dinotefuran mother solution.

[0012] Furthermore, the inorganic acid added to the dinotefuran mother liquor simultaneously with the catalyst is any one of sulfuric acid, hydrochloric acid, acetic acid, nitric acid with a volume concentration of 65%, or phosphoric acid, or a mixture thereof, and the amount of the inorganic acid is 0.1% to 1.0% by weight of the treated dinotefuran mother liquor.

[0013] Furthermore, a catalyst and an inorganic acid are added to the dinotefuran mother solution at 0-20° C., and the temperature is raised to 115-125° C., and the temperature is kept at this temperature for 50-70 minutes.

[0014] Furthermore, a catalyst and an inorganic acid are added to the dinotefuran mother solution at 10-15° C., and the temperature is raised to 118-122° C. for 55-65 minutes.

[0015] Furthermore, a catalyst and an inorganic acid were added to the dinotefuran mother solution at 10-15° C., and the temperature was raised to 120° C. for 60 minutes.

[0016] Furthermore, the heating rate is 9-11°C / hour.

[0017] Furthermore, the safety treatment method is to remove impurities from the dinotefuran mother liquor using the above-mentioned treatment method. The impurity structure in the dinotefuran mother liquor is shown in Formula I:

[0018]

[0019] Furthermore, after treatment, the impurity content is reduced from 10-20% to below 0.1%, and the gas released by the decomposition of the impurities is nitrogen. The present invention utilizes high-performance liquid chromatography (HPLC) to detect the progress of impurity decomposition and the extent of gas release by observing changes in the impurity content in the liquid phase spectrum. Furthermore, HPLC detection shows that the dinotefuran content in the dinotefuran mother liquor does not decrease after treatment using the present invention.

[0020] The beneficial effects of the safety treatment method of the dinotefuran mother solution of the present invention are:

[0021] The present invention has analyzed the generation mechanism of impurities through theory as follows:

[0022]

[0023] The reaction equation for producing gas is as follows:

[0024]

[0025] The synthesis of dinotefuran uses nitroisoureas, a polynitrogen compound containing nitro groups, and furfural, an amino-containing raw material. During the reaction, the nitro compounds are reduced to nitroso compounds. The nitroso impurities formed by the reduction of nitroisoureas are particularly water-soluble and accumulate in the dinotefuran mother liquor during the production process, reaching a concentration of 10-20%. Nitroso compounds are unstable and decompose to release nitrogen gas, a process accelerated by heat. However, relying solely on heating, this decomposition and gas release process can take at least 10 years.

[0026] The treatment method of the present invention can completely decompose impurities in a short period of time, and the dinotefuran mother liquor no longer releases gas after treatment, thereby improving the safety of production, transportation and storage.

[0027] The treatment method of the present invention is simple to operate, safe and reliable, and the catalyst is low in cost and easily available.

[0028] The present invention can determine the content of impurities through a high-performance liquid chromatography method, and can calculate the total amount of gas released by a unit of dinotefuran mother liquor based on the molecular weight of the impurities. The calculated total amount of gas is consistent with the total amount of gas actually monitored during the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Figure 1 This is a liquid chromatogram before treatment with the dinotefuran mother solution in Example 1 of the present invention;

[0031] Figure 2 This is a liquid chromatogram of the dinotefuran mother liquor after treatment in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0033] A method for safely treating a dinotefuran mother liquor comprises adding a catalyst and an inorganic acid to the dinotefuran mother liquor, heating the liquor under stirring conditions, and maintaining the temperature for a predetermined time; the catalyst is any salt or a mixture of several salts formed by a metal element and an inorganic acid.

[0034] Preferably, the metal element in the catalyst is manganese, cobalt, aluminum, or magnesium, and the inorganic acid in the catalyst is sulfuric acid, hydrochloric acid, acetic acid, 65% nitric acid, or phosphoric acid. Examples of catalyst types include manganese chloride, manganese sulfate, 65% manganese nitrate, manganese phosphate, manganese acetate, cobalt chloride, cobalt sulfate, cobalt acetate tetrahydrate, aluminum chloride, aluminum sulfate, aluminum phosphate, magnesium chloride, magnesium sulfate, magnesium phosphate, and their corresponding hydrates. The catalyst is added in an amount of 0.01% to 0.1% by weight of the dinotefuran mother liquor being treated.

[0035] The inorganic acid added to the dinotefuran mother liquor simultaneously with the catalyst is any one of sulfuric acid, hydrochloric acid, acetic acid, nitric acid with a volume concentration of 65%, or phosphoric acid, or a mixture thereof. The amount of the inorganic acid is 0.1% to 1.0% by weight of the treated dinotefuran mother liquor.

[0036] Preferably, the catalyst and inorganic acid are added to the dinotefuran mother liquor at 0-20°C, the temperature is raised to 115-125°C, and the temperature is kept at this temperature for 50-70 minutes. More preferably, the catalyst and inorganic acid are added to the dinotefuran mother liquor at 10-15°C, the temperature is raised to 118-122°C, and the temperature is kept at this temperature for 55-65 minutes. Even more preferably, the catalyst and inorganic acid are added to the dinotefuran mother liquor at 10-15°C, the temperature is raised to 120°C, and the temperature is kept at this temperature for 60 minutes.

[0037] The heating rate is 9-11°C / hour, preferably 10°C / hour.

[0038] The above-mentioned safety treatment method is to remove impurities from the dinotefuran mother liquor using the above-mentioned treatment method. The impurity structure in the dinotefuran mother liquor is shown in Formula I:

[0039]

[0040] After treatment, the impurity content is reduced from 10-20% to below 0.1%, and the gas released by the decomposition of the impurities is nitrogen. The present invention utilizes high-performance liquid chromatography (HPLC) to detect the progress of impurity decomposition and the extent of gas release by observing changes in the impurity content in the liquid phase spectrum. HPLC detection also shows that the dinotefuran content in the dinotefuran mother liquor does not decrease after treatment using the present invention.

[0041] The chromatographic conditions for HPLC detection are:

[0042] HPLC: mobile phase is methanol + water = 30 + 70, detection wavelength is 269 nm, flow rate is 1.0 ml / min, elution mode is isocratic;

[0043] Chromatographic column specifications: 250*4.6mm 5um C18

[0044] Example 1

[0045] 240 kg of dinotefuran mother liquor was added to a 500L reactor equipped with a gas flowmeter. After liquid phase detection, the normalized value of the impurity area of ​​the generated gas was 13.3%. The temperature was controlled to below 20°C (the temperature was controlled at 15°C in this embodiment) and 24 g of manganese chloride and 24 g of 65% nitric acid were added. After stirring evenly, the temperature was started to rise, and the heating rate was controlled to be 10°C / h. The gas release rate was fastest when the reaction temperature was 60-100°C. When the temperature was raised to 120°C, the gas release rate gradually slowed down. After keeping warm for 1 hour, the gas release was completed and cooled to room temperature. The sample was taken and tested by high performance liquid phase, and the impurities in the released gas were reduced to 0.06%. The dinotefuran content in the mother liquor before treatment was determined to be 24.8%, and the dinotefuran content in the mother liquor after treatment was 25.7%. The chromatograms of the dinotefuran mother liquor raw material before treatment and the mother liquor raw material after treatment are shown as follows: Figure 1 and Figure 2 As shown, the box in the figure shows the changes in the chromatogram before and after the treatment of gas impurities.

[0046] Example 2

[0047] 500kg of dinotefuran mother liquor was added to a 1000L reactor equipped with a gas flowmeter. Liquid phase analysis revealed an 11.5% gaseous impurity area. The mixture was then cooled to below 20°C (10°C in this embodiment) and 200g of manganese phosphate, 200g of cobalt acetate tetrahydrate, and 100g of aluminum chloride were added. After stirring, 312g of 32% hydrochloric acid, 200g of acetic acid, and 200g of phosphoric acid were added. After stirring, the mixture began to heat up, controlling the heating rate to 10°C / h. The gas release rate was fastest when the reaction temperature was between 60 and 100°C. After heating to 120°C, the gas release rate gradually slowed. After incubation for 1 hour, the gas release was complete and the mixture was cooled to room temperature. High-performance liquid chromatography (HPLC) analysis revealed that the gaseous impurity area was reduced to 0. The dinotefuran content in the mother liquor before treatment was 25.4%, while the dinotefuran content in the mother liquor after treatment was 26.6%.

[0048] Examples 3-12

[0049] The processing steps of Examples 3-12 are basically the same as those of Examples 1 and 2, except that the types of substances added and the parameter conditions are different. The specific conditions and processing results are shown in the following table:

[0050] Table 1

[0051]

[0052]

[0053]

[0054] Experimental Example 1

[0055] The treated dinotefuran mother solutions of Examples 1-12 were subjected to an accelerated stability test of the dinotefuran mother solution. The test process and results are shown in the following table:

[0056] Table 2

[0057]

[0058] Table 3 Test results

[0059]

[0060] In Table 2 and Table 3, the storage environment is hot storage at 54℃±2, which is indicated by “hot” in the table.

[0061] In summary, the safe treatment method provided by the present invention solves the problem of gas generation during the self-decomposition of dinotefuran mother liquor; the catalyst of this method is inexpensive and easy to operate; after treatment by this method, the dinotefuran mother liquor no longer releases gas, thereby ensuring the safe transportation and storage of the dinotefuran mother liquor.

[0062] Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

Claims

1. A method for safe treatment of dinotefuran mother liquor, characterized in that: Add a catalyst and an inorganic acid or acetic acid to the dinotefuran mother solution, heat it up under stirring and keep it warm for a predetermined time; the catalyst is any salt or a mixture of several salts formed by a metal element and an inorganic acid or acetic acid; The metal element in the catalyst is manganese, cobalt, aluminum or magnesium, and the inorganic acid in the catalyst is sulfuric acid, hydrochloric acid, nitric acid with a volume concentration of 65% or phosphoric acid.

2. The method for safe treatment of dinotefuran mother liquor according to claim 1, characterized in that: The added amount of the catalyst is 0.01% to 0.1% of the weight of the treated dinotefuran mother liquor.

3. The method for safe treatment of dinotefuran mother liquor according to claim 1, characterized in that: The inorganic acid added to the dinotefuran mother liquor simultaneously with the catalyst is any one of sulfuric acid, hydrochloric acid, nitric acid with a volume concentration of 65% or phosphoric acid, or a mixture thereof. The amount of the inorganic acid or acetic acid is 0.1% to 1.0% by weight of the treated dinotefuran mother liquor.

4. The method for safe treatment of dinotefuran mother liquor according to claim 1, characterized in that: Add catalyst and inorganic acid or acetic acid to the dinotefuran mother liquor at 0-20°C, raise the temperature to 115-125°C, and keep warm for 50-70 minutes.

5. The method for safe treatment of dinotefuran mother liquor according to claim 4, characterized in that: Add catalyst and inorganic acid or acetic acid to the dinotefuran mother liquor at 10-15°C, raise the temperature to 118-122°C, and keep warm for 55-65 minutes.

6. The method for safe treatment of dinotefuran mother liquor according to claim 5, characterized in that: Add the catalyst and inorganic acid or acetic acid to the dinotefuran mother liquor at 10-15°C, raise the temperature to 120°C, and keep the temperature for 60 minutes.

7. The method for safe treatment of dinotefuran mother liquor according to any one of claims 1 to 6, characterized in that: The heating rate was 9-11°C / hour.

8. The method for safe treatment of dinotefuran mother liquor according to any one of claims 1 to 6, characterized in that: The safety treatment method is to remove impurities from the mother liquor of dinotefuran. The impurity structure in the mother liquor of dinotefuran is shown in Formula I:

9. The method for safe treatment of dinotefuran mother solution according to claim 8, characterized in that: After treatment, the content of impurities is reduced from 10-20% to below 0.1%, and the gas released by the decomposition of the impurities is nitrogen.

Images