Carbaryl Carbaryl

Structural formula

• Numbering system
• Physical property data
• Toxicological data
• Ecological data
• Molecular structure data
• Computing chemical data
• More
  • Properties and Stability
  • Storage method
  • Synthesis method
  • Purpose

Numbering system

CAS number:63-25-2

MDL number:MFCD00021467

EINECS number:200-555-0

RTECS number:FC5950000

BRN number:1875862

PubChem number:24879646

Physical property data

1. Properties: Pure product is white crystal, industrial product is slightly gray or pink

2. Density (g/mL, 20/20℃): 1.232

3. Relative vapor density (g/mL, air=1): Uncertain

4. Melting point (ºC): 142

5. Boiling point (ºC, normal pressure): 315

6. Boiling point (ºC, 5.2kPa): Uncertain

7. Refractive index: Uncertain

8. Flash point (ºC): 202.7

9. Specific rotation (º): Uncertain

10. Autoignition point or ignition temperature (ºC): Uncertain

11. Vapor pressure ( Pa, 25ºC): 0.666

12. Saturated vapor pressure (kPa, 60ºC): Uncertain

13. Heat of combustion (KJ/mol): Uncertain

14. Critical temperature (ºC): Uncertain

15. Critical pressure (KPa): Uncertain

16. Log value of oil-water (octanol/water) partition coefficient : Uncertain

17. Explosion upper limit (%, V/V): Uncertain

18. Explosion lower limit (%, V/V): Uncertain

19. Solubility: dimethylformamide>45%, acetone>20%, cyclohexanone>20%, methyl ethyl ketone>15%, chloroform>10%, ethanol>5%, toluene>1%, water 40mg /L(30℃)

Toxicological data

Male rats acute oral LD50 It is 800 mg/kg, and the female is 500 mg/kg. The acute transdermal LD50> is 4000mg/kg in male rats and greater than 2000mg/kg in rabbits. Rats were fed feed containing 200mg/kg for 2 years without any adverse reactions. For carp LC50 > 10mg/L (48h), cicada LC50 is 1.95mg (96h). For acute menstruation of wild ducks LD50> 2000mg/kg. Very toxic to bees.

Ecological data

None yet

Molecular structure data

1. Molar refractive index: 59.03

2. Molar volume (cm³/mol): 169.9

3. Isotonic specific volume (90.2K ): 440.5

4. Surface tension (dyne/cm): 45.1

5. Polarizability (10^-24cm³): 23.40

Compute chemical data

1. Reference value for hydrophobic parameter calculation (XlogP): None

2. Number of hydrogen bond donors: 1

3. Number of hydrogen bond acceptors: 2

4. Number of rotatable chemical bonds: 2

5. Number of tautomers: 2

6. Topological molecule polar surface area 38.3

7. Number of heavy atoms: 15

8. Surface charge: 0

9. Complexity: 230

10. Number of isotope atoms: 0

11. Determine the number of atomic stereocenters: 0

12. Uncertain number of atomic stereocenters: 0

13. Determine the number of chemical bond stereocenters: 0

14. Number of uncertain chemical bond stereocenters: 0

15. Number of covalent bond units: 1

Properties and stability

1. It is relatively stable to light, heat and acidic substances, and is easily decomposed when encountering alkaline substances. Easily degraded in soil microbial environment, producing -naphthol, -naphthyl-carboxy-methylcarbamate, -4-hydroxy-1-naphthyl-methylcarbamate and 5-carboxy-1-naphthalene Among them, 1-naphthyl-carboxy-methylcarbamate may be harmful or mutagenic.

2. Exist in tobacco leaves and smoke.

3. Less toxic to humans and animals.

Storage method

This product should be sealed and stored in a cool, dry place. Contact with alkaline substances should be avoided during storage and transportation.

Synthesis method

(1) Thermal method: Preheat phosgene to about 90°C, preheat methylamine to 220°C, adjust the flow rate at a molar ratio of 1:3:1 to carry out the acyl chloride synthesis reaction, and the temperature of the upper part of the synthesizer is controlled at 340~360℃, the lower temperature is controlled at 240~280℃. The reaction gas buffer outlet pressure should be controlled below 0.1 MPa, and the water temperature of the acid chloride receiver and condenser jacket should be strictly controlled. The average content of methylcarbamoyl chloride obtained is more than 90%, and the yield is more than 83%. Put carnaphthol and carbamoyl chloride into the condensation kettle at a molar ratio of 1:1.2, and stir the reaction. The process can be done by first dissolving methylcarbamyl chloride in carbon tetrachloride, chlorobenzene, toluene or other solvents, and then reacting with carnaphthol; it can also be prepared by mixing it with 5% carnaphthol sodium aqueous solution and 3% hydrogen The sodium oxide solution and the methylcarbamyl chloride solution are put into the condensation kettle, and the temperature is controlled at 10 to 15°C and the pH is 8 to 11 for continuous reaction. The overflowing reactant is centrifuged, washed with water, and dried to obtain carbaryl.

(2) Cold method: Put toluene into the glass-lined reactor, then add molten carnaphthol, stir and cool to below -5°C, introduce phosgene, and add 20% sodium hydroxide dropwise solution, the reaction is maintained at pH 6 to 7. After the photochemical reaction is completed, monomethylamine and sodium hydroxide solution are still added dropwise at -5°C. After the addition is completed, the solution is stirred and kept warm for 2 hours. The reaction liquid is filtered, and the toluene in the filtrate is recovered for recycling. The filter cake is washed with dilute hydrochloric acid and water and dried to obtain carbaryl, with a content of about 95% and a yield of about 90%.
Remarks: Stable to water, sunlight or heat, it decomposes into 1-naphthol when exposed to strong alkali. Less toxic to humans and animals. Non-corrosive to metals, packaging materials and application equipment. The maximum allowable residue level in apples, pears, cabbage, and tomatoes is 5 mg/kg, and in sorghum, peaches, apricots, and vegetables, it is 10 mg/kg. ADI is 0.01mg/kg. The safety interval is 10 days. Do not apply pesticides in beekeeping areas to avoid bee poisoning. It is harmful to melons. The antidote is atropine, but do not use oxime drugs such as pralidoxime. Treatment should be symptomatic and pulmonary edema should be controlled in a timely manner.

3.Preparation of methyl isocyanate methylamine and phosgene at high temperature The gas phase reaction is carried out directly, and the reactor is a pipeline. The reaction temperature is greater than 400°C, and the reactor material is steel-lined graphite. Preventing the formation of by-products and eliminating reactor clogging are key in production. The main equipment of the methyl isocyanate separation and refining system is the dephosphorization tower, and the refining methyl isocyanate tower is a 90-tray float valve tower, both of which use high-nickel Made of alloy steel material.
4.The synthesis reaction of carbaryl is carried out in the presence of solvent at a temperature of 60~80℃, slightly There is negative pressure. The resulting mixed solution is distilled, and the excess methyl isocyanate is evaporated from the top of the distillation tower together with part of the solvent, and then reused. Carbaryl is refined in solution to obtain pure product.

Purpose

1. This product is a carbamate insecticide with contact and gastric poisoning effects and slight systemic properties. It can control more than 100 pests in more than 150 crops. It can be processed into wettable powder or gel suspension and used to control rice planthoppers, rice leafhoppers, cotton pink bollworms, soybean heartworms and fruit tree pests. It has better control effect on insects that are resistant to organochlorines and organophosphorus. The dosage is generally 375-750g of active ingredient per hectare. This product cannot be mixed with alkaline pesticides. It is highly toxic to bees and should not be used in beekeeping areas during the flowering season.

2. A broad-spectrum amino acid with high efficiency, low toxicity, low residue and long residual effect Formate ester pesticides. It has a strong contact killing effect on pests, has a stomach poisoning effect, and has a slight systemic effect. Used to control cotton bollworms, leaf rollers, cotton aphids, bridge-building insects, thrips, rice leafhoppers, rice leaf rollers, rice bracts, rice thrips and fruit tree pests. It can also control soft insects such as vegetable garden snails and slugs. animal. The commonly used dosage is 2.6～20/100m².

Insects resistant to chlorine and organophosphorus have better control effects. The dosage is generally 375-750g of active ingredient per hectare. This product cannot be mixed with alkaline pesticides. It is highly toxic to bees and should not be used in beekeeping areas during the flowering season.

2. A broad-spectrum amino acid with high efficiency, low toxicity, low residue and long residual effect Formate ester pesticides. It has a strong contact killing effect on pests, has a stomach poisoning effect, and has a slight systemic effect. Used to control cotton bollworms, leaf rollers, cotton aphids, bridge-building insects, thrips, rice leafhoppers, rice leaf rollers, rice bracts, rice thrips and fruit tree pests. It can also control soft insects such as vegetable garden snails and slugs. animal. The commonly used dosage is 2.6～20/100m².