Preparation method of thiocyclam
By replacing toluene with dichloroethane and using sodium thiosulfate and formaldehyde as catalysts, the problems of electrostatic hazards and low catalyst yields during the production of insecticidal rings are solved, and the effect of improving production safety and economic benefits is achieved.
Patent Information
- Application Number
- CN202411781847.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-05
- Publication Date
- 2025-03-11
AI Technical Summary
The prior art uses toluene as a solvent when producing insecticidal rings, which poses the risk of static electricity and safety accidents. At the same time, the yield of the catalyst is limited, making it difficult to meet the requirements of safe production and economic benefits.
Dihalogenated hydrocarbon dichloroethane is used instead of toluene as a solvent, and the combination of sodium thiosulfate and formaldehyde is used as a catalyst to improve the yield of the insecticidal ring.
It effectively avoids static electricity danger, improves production safety, and reduces production costs and energy consumption, is suitable for industrial production, and significantly increases the yield of insecticidal rings.
Smart Images
Figure CN119591580A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for preparing an insecticide ring. Background Art
[0002] Another name for the insecticide ring is Yiweisha, and its chemical name is N,N-dimethyl-1,2,3-trithiacyclohexane-5-amine oxalate, with a molecular weight of 271.26 and a melting point between 125 and 128 degrees Celsius (it will decompose). The insecticide ring is a type of nereis toxin insecticide, which can kill pests by contact (contact killing effect) and can also be toxic after being eaten by pests (stomach poison effect). It also has a certain internal conduction ability and egg-killing effect. In particular, it should be pointed out that the insecticide ring has a good control effect on Lepidoptera and Coleoptera pests. This insecticide is mainly used for the control of rice pests, such as rice stem borer and yellow stem borer. When used, 50% of the soluble powder is usually applied by pouring or spraying with water. In addition, the insecticide ring can be mixed with fast-acting pesticides to improve the effect, but it needs to be used with extreme caution in silkworm breeding areas.
[0003] At present, most domestic manufacturers of insecticide rings use toluene as a solvent. Toluene is a colorless, transparent liquid with an aromatic odor similar to benzene, a flash point of 4°C, and is flammable. However, toluene is a precursor chemical, and during use, toluene is prone to generate and accumulate static electricity due to excessive flow rate, thus causing safety accidents such as flash explosions. Toluene vapor can also spread from low places to far places, and once it encounters a fire source, it may backfire, which poses a great safety risk to personnel at the work site.
[0004] At present, the domestic production process of insecticide ring mainly includes three parts: cyclization reaction, salt formation reaction and solvent recovery. The cyclization reaction includes: first dissolving the measured water and sodium sulfide in the dissolving kettle for use; then adding the measured insecticide, toluene and formaldehyde into the cyclization kettle, and dripping sodium sulfide solution at -10 to 10°C to react to generate cyclization liquid insecticide ring (N,N-dimethyl-1,2,3-dithiacyclohexane-5-amine); after the reaction, the cyclization liquid is layered and washed with water to neutrality, and then dried after water absorption for use. The salt formation reaction includes: adding methanol into the salt formation kettle, and adding oxalic acid for stirring and dissolving; then, adding the above dried cyclization liquid at -5 to 15°C to generate insecticide ring oxalate (N,N-dimethyl-1,2,3-trithiacyclohexane-5-amine oxalate). Solvent recovery includes: the centrifugal mother liquor contains solvents such as toluene and methanol, which can be recovered for reuse through extraction separation and distillation separation in a solvent recovery tower. However, in the cyclization reaction process, the yield improvement of the cyclization reaction using formaldehyde catalysis is relatively limited; in addition, in the process of washing, stratification, water absorption and drying and solvent recovery after the cyclization liquid is generated, the solution will flow, which can easily generate and accumulate static electricity, thereby causing safety accidents such as flash explosions.
[0005] In order to improve the yield of the cyclization reaction, the catalyst can be further screened. At the same time, in order to reduce the above-mentioned accidents, in addition to increasing the static cross-connection on the equipment and facilities, the solvent can also be replaced to completely eliminate the generation and accumulation of static electricity. Therefore, in order to achieve both safe production and economic benefits, it is urgent to find alternative solvents that are more stable, safer, and more economical than toluene, as well as catalysts that can significantly increase the yield of the cyclization reaction, for the preparation of insecticide rings. Summary of the invention
[0006] In order to overcome the deficiencies of the prior art, one of the purposes of the present invention is to provide a method for preparing an insecticidal ring, which can ensure safe production while taking into account economic benefits.
[0007] One of the purposes of the present invention is achieved by the following technical solution:
[0008] A method for preparing an insecticide ring, the specific process comprises the following steps:
[0009] (1) adding water, sodium chloride, formaldehyde, ethylene dichloride and sodium thiosulfate to a single insecticide, and then adding a sodium sulfide solution at -5 to 2°C, stirring for reaction; allowing the reaction solution to stand for stratification, taking out the lower organic phase, washing with water, and drying to obtain an insecticide solution;
[0010] (2) adding the insecticide solution obtained in step (1) to the oxalic acid solution, stirring for reaction, and centrifuging to recover the solvent to obtain the insecticide ring.
[0011] Furthermore, the usage ratio of the insecticide, sodium chloride, formaldehyde, ethylene dichloride, sodium thiosulfate and sodium sulfide in step (1) is (23-27) g: (50-70) g: (14-18) g: (160-220) mL: (4-8) g: (11-13) g.
[0012] Furthermore, the mass of the oxalic acid in step (2) is 34% to 41% of the mass of the raw insecticide.
[0013] Furthermore, the stirring reaction in step (1) is carried out at a temperature of -10 to 10°C and for a time of 0.5 to 1.0 h.
[0014] Furthermore, the stirring reaction in step (2) is carried out at a temperature of -5 to 10°C and for a time of 0.5 to 1.0 h.
[0015] Furthermore, in step (2), the temperature of the insecticide solution obtained in step (1) added to the oxalic acid solution is -3 to 2°C.
[0016] Furthermore, the oxalic acid solution in step (2) is a methanol solution of oxalic acid.
[0017] Compared with the prior art, the present invention has the following beneficial effects:
[0018] The present invention uses dihalogenated hydrocarbon dichloroethane instead of toluene in the prior art as a solvent, thereby avoiding the danger of static electricity generation and accumulation during washing, drying of the cyclization liquid and recovery of the solvent, improving the safety of on-site workers, and reducing production costs and energy consumption, and is suitable for industrial production. In addition, the present invention uses sodium thiosulfate and formaldehyde as a catalyst, thereby increasing the yield of the insecticide ring without affecting the quality of the original drug. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is a schematic diagram of the liquid chromatography purity of the insecticide ring in Example 1 of the present invention;
[0020] Figure 2 Schematic diagram of the standard liquid chromatography purity of the insecticide ring of the present invention. DETAILED DESCRIPTION
[0021] Below, in conjunction with the accompanying drawings and specific embodiments, the present invention is further described. It should be noted that, under the premise of no conflict, the embodiments described below or the technical features can be arbitrarily combined to form new embodiments. The specific conditions not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, unless otherwise specified, are conventional products obtained through commercial channels.
[0022] Example 1
[0023] A method for preparing an insecticide ring, the specific process comprises the following steps:
[0024] (1) Weigh 58 g of sodium sulfide and 380 g of water into a 500 mL beaker, stir and dissolve, and set aside; weigh 120 g of insecticide monochloride, 580 g of water, 20 g of sodium thiosulfate, 280 g of sodium chloride, 98 g of formaldehyde, and 900 mL of dichloroethane into a 2000 mL four-necked bottle and stir; then cool the 2000 mL four-necked bottle to -5°C, and dropwise add the dissolved sodium sulfide aqueous solution; the dropwise addition is terminated and the mixture is reacted at -5°C for 0.5 h; the reaction solution is allowed to stand and separate, and the lower organic phase is washed with water until neutral, and then dried over anhydrous sodium sulfate to obtain an insecticide solution;
[0025] (2) Weigh 48 g of oxalic acid and 118 g of methanol into a 1000 mL four-necked bottle and stir; cool the 1000 mL four-necked bottle to 0° C. and begin to dropwise add the insecticide solution obtained in step (1); react at 2° C. for 0.5 h after the dropwise addition is completed; centrifuge to recover the solvent to obtain the insecticide. The purity of the liquid chromatography instrument is 88.53%, the yield is 94.91%, and the purity of the liquid chromatography instrument is as follows: Figure 1 As shown, the standard spectrum of insecticide ring is as follows Figure 2 shown.
[0026] Example 2
[0027] A method for preparing an insecticide ring, the specific process comprises the following steps:
[0028] (1) Weigh 55 g of sodium sulfide and 340 g of water into a 500 mL beaker, stir and dissolve, and set aside; weigh 115 g of insecticide monochloride, 500 g of water, 20 g of sodium thiosulfate, 250 g of sodium chloride, 90 g of formaldehyde, and 800 mL of dichloroethane into a 2000 mL four-necked bottle and stir; stir the 2000 mL four-necked bottle and cool it to -3°C, and dropwise add the dissolved sodium sulfide aqueous solution; after the dropwise addition is completed, react at 0°C for 0.5 h; the reaction solution is allowed to stand and separate, and the lower organic phase is washed with water until neutral, and dried over anhydrous sodium sulfate to obtain an insecticide solution;
[0029] (2) Weigh 40 g of oxalic acid and 110 g of methanol into a 1000 mL four-necked bottle and stir; cool the 1000 mL four-necked bottle to -3°C with stirring and begin to dropwise add the cyclization liquid; after the dropwise addition is completed, react at -5°C for 0.5 h; recover the solvent by centrifugation to obtain the insecticide ring (purity of 89.82%, yield of 95.35%).
[0030] Example 3
[0031] A method for preparing an insecticide ring, the specific process comprises the following steps:
[0032] (1) Weigh 65 g of sodium sulfide and 450 g of water into a 500 mL beaker, stir and dissolve, and set aside; weigh 135 g of insecticide monochloride, 650 g of water, 40 g of sodium thiosulfate, 350 g of sodium chloride, 70 g of formaldehyde, and 1100 mL of dichloroethane into a 2000 mL four-necked bottle and stir; stir the 2000 mL four-necked bottle and cool it to 2° C., and dropwise add the dissolved sodium sulfide aqueous solution; after the dropwise addition is completed, react at -10° C. for 1 hour; the reaction solution is allowed to stand and separate, and the lower organic phase is washed with water until neutral, and dried over anhydrous sodium sulfate to obtain an insecticide solution;
[0033] (2) Weigh 55 g of oxalic acid and 135 g of methanol into a 1000 mL four-necked bottle and stir; cool the 1000 mL four-necked bottle to 2° C. and begin to dropwise add the cyclization liquid; after the dropwise addition is completed, react at 5° C. for 1 h; recover the solvent by centrifugation to obtain the insecticide ring (purity of 87.98%, yield of 91.63%).
[0034] Example 4
[0035] A method for preparing an insecticide ring, the specific process comprises the following steps:
[0036] (1) Weigh 58 g of sodium sulfide and 380 g of water into a 500 mL beaker, stir and dissolve, and set aside; weigh 120 g of insecticide monochloride, 580 g of water, 20 g of sodium thiosulfate, 280 g of sodium chloride, 98 g of formaldehyde, and 950 mL of dichloroethane into a 2000 mL four-necked bottle and stir; stir the 2000 mL four-necked bottle and cool it to -5°C, and dropwise add the dissolved sodium sulfide aqueous solution; after the dropwise addition is completed, react at 10°C for 0.5 h; the reaction solution is allowed to stand and separate, and the lower organic phase is washed with water until neutral, and dried over anhydrous sodium sulfate to obtain an insecticide solution;
[0037] (2) Weigh 48 g of oxalic acid and 118 g of methanol into a 1000 mL four-necked bottle and stir; cool the 1000 mL four-necked bottle to 0° C. and begin to dropwise add the cyclization liquid; react at 10° C. for 0.5 h after the dropwise addition is completed; recover the solvent by centrifugation to obtain the insecticide ring (purity of 85.25%, yield of 91.52%).
[0038] Comparative Example 1
[0039] A method for preparing an insecticide ring, the specific process comprises the following steps:
[0040] (1) Weigh 58 g of sodium sulfide and 380 g of water into a 500 mL beaker, stir and dissolve, and set aside; weigh 120 g of insecticide monochloride, 580 g of water, 280 g of sodium chloride, 98 g of formaldehyde, and 900 mL of dichloroethane into a 2000 mL four-necked bottle and stir; then stir and cool the 2000 mL four-necked bottle to -5°C, and dropwise add the dissolved sodium sulfide aqueous solution; after the dropwise addition is completed, react at -5°C for 0.5 h; the reaction solution is allowed to stand and separate, and the lower organic phase is washed with water until neutral, and dried over anhydrous sodium sulfate to obtain an insecticide solution;
[0041] (2) Weigh 48 g of oxalic acid and 118 g of methanol into a 1000 mL four-necked bottle and stir; cool the 1000 mL four-necked bottle to 0° C. and begin to dropwise add the cyclization liquid; react at 2° C. for 0.5 h after the dropwise addition ends; recover the solvent by centrifugation to obtain the insecticide ring (purity of 88.63%, yield of 75.93%).
[0042] Comparative Example 2
[0043] A method for preparing an insecticide ring, the specific process comprises the following steps:
[0044] (1) Weigh 58 g of sodium sulfide and 380 g of water into a 500 mL beaker, stir and dissolve, and set aside; weigh 120 g of insecticide monochloride, 580 g of water, 280 g of sodium chloride, 98 g of sodium thiosulfate, and 900 mL of dichloroethane into a 2000 mL four-necked bottle and stir; then stir and cool the 2000 mL four-necked bottle to -5°C, and dropwise add the dissolved sodium sulfide aqueous solution; after the dropwise addition is completed, react at -5°C for 0.5 h; the reaction solution is allowed to stand and separate, and the lower organic phase is washed with water until neutral, and dried over anhydrous sodium sulfate to obtain an insecticide solution;
[0045] (2) Weigh 48 g of oxalic acid and 118 g of methanol into a 1000 mL four-necked bottle and stir; cool the 1000 mL four-necked bottle to 0° C. and begin to dropwise add the cyclization liquid; react at 2° C. for 0.5 h after the dropwise addition ends; recover the solvent by centrifugation to obtain the insecticide ring (purity of 88.57%, yield of 73.92%).
[0046] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.
Claims
1. A method for preparing an insecticide ring, characterized in that: The specific process includes the following steps: (1) adding water, sodium chloride, formaldehyde, ethylene dichloride and sodium thiosulfate to a single insecticide, and then adding a sodium sulfide solution at -5 to 2°C, stirring for reaction; allowing the reaction solution to stand for stratification, taking out the lower organic phase, washing with water, and drying to obtain an insecticide solution; (2) adding the insecticide solution obtained in step (1) to the oxalic acid solution, stirring for reaction, and centrifuging to recover the solvent to obtain the insecticide ring.
2. The method for preparing the insecticide ring according to claim 1, characterized in that: The dosage ratio of the insecticide, sodium chloride, formaldehyde, ethylene dichloride, sodium thiosulfate and sodium sulfide in step (1) is (23-27) g: (50-70) g: (14-18) g: (160-220) mL: (4-8) g: (11-13) g.
3. The method for preparing the insecticide ring according to claim 1, characterized in that: The mass of the oxalic acid in step (2) is 34% to 41% of the mass of the raw insecticide.
4. The method for preparing the insecticide ring according to claim 1, characterized in that: The stirring reaction in step (1) is carried out at a temperature of -10 to 10°C and for a time of 0.5 to 1.0 h.
5. The method for preparing the insecticide ring according to claim 1, characterized in that: The stirring reaction in step (2) is carried out at a temperature of -5 to 10°C and for a time of 0.5 to 1.0 h.
6. The method for preparing the insecticide ring according to claim 1, characterized in that: The temperature of the insecticide solution obtained in step (1) added to the oxalic acid solution in step (2) is -3 to 2°C.
7. The method for preparing the insecticide ring according to claim 1, characterized in that: The oxalic acid solution in step (2) is a methanol solution of oxalic acid.