Paraquat, respirable
Paraquat aqueous
CAS: 4685-14-7
Molecular Formula: C12H14N2+2
Paraquat, respirable - Names and Identifiers
| Name | Paraquat aqueous |
| Synonyms | Pectone Paraquat Pillarzone Paraquat ion Paraquat aqueous Paraquat, inhalable Paraquat, respirable Paraquat aqueous solution |
| CAS | 4685-14-7 |
| EINECS | 225-141-7 |
| InChI | InChI=1/C12H14N2/c1-13-7-3-11(4-8-13)12-5-9-14(2)10-6-12/h3-10H,1-2H3/q+2 |
Paraquat, respirable - Physico-chemical Properties
| Molecular Formula | C12H14N2+2 |
| Molar Mass | 186.25 |
| Density | 0.9748 (rough estimate) |
| Melting Point | 300 °C (decomp) |
| Boling Point | 310.75°C (rough estimate) |
| Appearance | Yellow solid |
| Color | Off-white Powder |
| Refractive Index | 1.5600 (estimate) |
| Physical and Chemical Properties | This product is solid, insoluble in water. |
| Use | It is a kind of quick-acting killer herbicide, which is widely used in rubber, banana, sugarcane, Orchard, farmland and other places |
Paraquat, respirable - Risk and Safety
| Hazard Symbols | T - Toxic |
| Risk Codes | 26/27/28 - Very toxic by inhalation, in contact with skin and if swallowed. |
| Safety Description | S1 - Keep locked up. S13 - Keep away from food, drink and animal foodstuffs. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) |
| UN IDs | 2781 |
| Hazard Class | 6.1(a) |
| Packing Group | II |
| Toxicity | LD50 orl-rat: 150 mg/kg FMCHA2 -,C118,83 |
Paraquat, respirable - Reference Information
| EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
| original drug | paraquat is a white crystal, which was first developed by the British plant protection company in 1958 and is not volatile. Decomposition above 300 ℃, vapor pressure the original drug is moderately toxic. Acute oral LD50 in rats is 112~150 mg/kg. Acute percutaneous LD50240 mg/kg in rabbits. It has a moderate irritation effect on the eyes and skin of rabbits. TLm(48 h) for carp was 48 mg/L. The LD50 for chickens and birds is 300~380 and 950~100000 mg/kg respectively. No teratogenic, mutagenic and carcinogenic effects were found under the test conditions. Paraquat is a fast-acting contact-killing quaternary ammonium herbicide. The active ingredient paraquat bipyridine cation can be quickly absorbed by the green part of the plant, and it is reduced to bipyridine free radicals through photosynthesis and respiration, and then self-oxidation The water and oxygen in the leaf tissue form hydrogen peroxide and peroxygen free radicals. This kind of substance is extremely destructive to the chloroplast layer membrane, so that photosynthesis and chlorophyll synthesis quickly stop. Regardless of single dicotyledonous plants, the green part will be damaged and discolored 2~3 hours after being treated. Rain after several hours of application does not affect the efficacy. Once paraquat is in contact with the soil, it is adsorbed and passivated. It has no killing effect on underground rhizome tissues and hidden seeds. It can only kill annual weeds and control the overground part of perennial weeds, but it cannot kill perennial weeds. The underground rhizomes of the weeds cannot be eradicated. The residual period is 10~15 days, and the weeding effect is not affected by temperature. |
| paraquat poisoning | moderate toxicity. But it is extremely toxic to humans and mammals, and there is no specific antidote, and the mortality rate of oral poisoning is very high. At present, it has been banned or strictly restricted by more than 20 countries. Acute oral LD50 was 150 mg/kg in rats and 204 mg/kg in rabbits, which was low toxicity to poultry, fish and bees. It has a stimulating effect on the eyes and can cause nails, skin ulcers, etc.; oral administration of 3 grams can cause systemic poisoning, and cause multiple organ failure such as liver and kidney, pulmonary fibrosis (irreversible) and respiratory failure. Because the symptoms are not obvious in the golden period of pre-poisoning treatment, it is easy to misdiagnose or ignore the disease. |
| precautions | (1) this product is a moderately toxic and corrosive liquid, which must be contained in a metal container during transportation, and the bottle cap must be tightly stored in a safe place. (2) Light can accelerate the efficacy of paraquat; although it delays the effective speed of the agent in shade or cloudy days, it does not reduce the weeding effect in the end. The efficacy can be basically guaranteed when it rains 30 minutes after application. (3) safety measures and first aid for poisoning: when using, pesticides must be used according to the general rules for safe use. When handling the concentrated liquid, you must wear rubber gloves and masks to avoid contact between the liquid medicine and the skin. When the liquid medicine splashes on the skin or eyes, it should be rinsed immediately. Do not let livestock enter the spraying area within 24 hours after spraying. If the liquid medicine is taken by mistake, it will immediately induce vomiting and be sent to the hospital. 15% bleaching soil suspension or 7% soaponite or activated carbon suspension should also be given suitable laxatives. If necessary, hemodialysis and blood perfusion treatment should be carried out. (4) do not use mist or micro sprayer to apply, and avoid spraying on the green part of plants when applying between rows. (5) paraquat is an killing herbicide, which is used in gardens and crop growth period. Do not pollute crops to avoid phytotoxicity. (6) protective measures should be taken when dispensing and spraying. rubber gloves, masks and overalls should be worn. If the liquid is splashed into the eyes or skin, rinse immediately. |
| toxicity | acute oral LD50 in rats is 205 mg/kg(112~150 mg/kg) and 143 mg/kg(104 mg/kg) in mice. Acute percutaneous LD50500mg/kg in rats and 235 mg/kg in rabbits. The 2-year feeding test for rats was 170mg/kg, and the dog was 34mg/kg. No teratogenic, carcinogenic and mutagenic effects were found in animal experiments. LC50 was 40mg/L (48h) for carp and 68mg/L (48h) for trout. It has moderate irritation to rabbit eyes and skin, and inhalation may cause epistaxis. |
| Uses | N, N'-dimethyl -4, 4-coupled pyridine is an intermediate of the herbicide paraquat. It is a fast-acting divisiveness contact-killing herbicide, which is widely used for weeding in rubber, banana, sugarcane, orchard, farmland and other places Quick-acting, broad-spectrum, contact-killing, and divisiveness herbicide. After the bipyridine cation is quickly absorbed by the plant leaves, it is reduced to bipyridine free radicals through photosynthesis and respiration in the green tissue, and through autoxidation, the water and oxygen in the leaf tissue form hydrogen peroxide and peroxygen free radicals, Destroy the chloroplast layer membrane, stop photosynthesis and chlorophyll synthesis, and promote dryness. The agent was used before seedlings and lost its activity in contact with soil, and had no effect on crop seedlings unearthed after spraying. It has no effect on brown bark, and woody plant trunks are safe. Light will increase the efficacy of the drug. The overcast delay agent is effective. After wheat and rape were harvested, the previous crop stalks and field weeds were treated directly with 20% water agent 30~45mL/100 m2 and 3~4.5kg of water were treated on the leaves without ploughing. This method can also be used after rice is harvested. It can also be used in orchards, mulberry fields, rubber fields, tea gardens, paddy fields and weeds in wheat fields (cow felt, Cyperaceae, Meiniang, pig disaster, strands, Setaria, crickets, bamboo leaf grass, etc.). Generally, it uses 20% water agent 30~45mL/100 m2 and sprays 3.75kg of water. Paraquat is a large variety of non-selective herbicide. It can kill ground weeds and dry them up before crop emergence. It is used in orchards, mulberry fields, rubber plantations, rice fields, dry land and no-tillage planting land. Weeding. |
| production method | the first method: after dimer is formed from pyridine and magnesium powder, it is oxidized with nitromethane and then separated and crystallized to obtain γ,γ-bipyridine. Then γ,γ-bipyridine and chloroacetic acid are catalyzed to obtain paraquat chloride. The second method: dissolve metal sodium in liquid ammonia to obtain a sodium ion ammonia solution with free electrons, and then dimerze with pyridine and solvent at -20 ~-30 ℃ to prepare ionic 4,4 '-tetrahydrobipyridine disodium, and then oxidize with air at -20 ~-30 ℃ to prepare bipyridine. Finally, bipyridine is diluted with water and reacted with methyl chloride under pressure to make paraquat chloride. This method has high yield, few by-products, and can be operated continuously, but it needs to consume metal sodium and operate at a low temperature of -30°C. The third method: first quaternize pyridine into N-methylpyridine hydrochloride, and then dimerize in the presence of a catalyst to obtain 1,1'-dimethyl-4, 4'-dihydrobipyridine, and then oxidize to obtain paraquat. Raw material consumption quota: pyridine 350kg/t, dimethyl sulfate 580kg/t, chlorine 280kg/t, sodium hydroxide 880kg/t. preparation method 1 uses pyridine and magnesium powder as raw materials to generate dimer initiated by sodium sand, and then oxidizes with nitromethane to obtain 4,4 '-bipyridine after separation and crystallization with 53% yield. 4,4 '-bipyridine reacts with chloroacetic acid to synthesize paraquat under the catalysis of NaH2PO4 and EDTA disodium salt with 97.7% yield. Or use a low-temperature sodium process: dissolve metal sodium in liquid ammonia to obtain a sodium ion ammonia solution with free electrons. Then it reacts with pyridine in the presence of a solvent and dimerges at -30 ~-20 ℃ to obtain disodium (ionic state) of 4,4 '-tetrahydrobipyridine. It is oxidized with air at -20 ~-0 ℃ to obtain 4,4 '-bipyridine, and finally diluted with water, and reacted with methyl chloride under pressure to synthesize paraquat. Preparation method Dipyridine is firstly alkalized into N-methylpyridine hydrochloride, and then dimerized in the presence of a catalyst to obtain 1,1 '-dimethyl -4,4'-dihydrobipyridine, and then oxidized to obtain paraquat. The method has high yield and simple process. The key technology is dimerization reaction and product post-treatment. The catalyst used in the dimerization reaction is sodium cyanide, and the solvent is dimethyl sulfoxide or alcohol-water (the water content in the alcohol is 10% ~ 25%, not more than 40%). The reaction temperature is 40~90 ℃, and the medium is alkaline; the common oxidants in the oxidation process are sulfur dioxide, chlorine, etc. The yield varies greatly due to different reaction conditions. Example 1: Dissolve 3.1g of N-methylpyridine chloride in 10mL of water, quickly add mixed solution of 2.5g of sodium cyanide, 1g of sodium hydroxide and 40mL of ethanol under room temperature nitrogen, heat and reflux for 1.5h after adding, cool, add 10mL of liquid sulfur dioxide into purple reaction mixture, the reaction mixture turns orange, and the yield is 94% based on N-methylpyridine salt. Example 2: Dissolve N-methylpyridine chloride in 10mL of water, add 2.5g of sodium cyanide, 1g of sodium hydroxide and 40mL of ethanol under room temperature nitrogen, stir for 30min at room temperature, add heat and reflux for 30min, cool, bubble through chlorine until the blue color of the reaction mixture disappears, and then neutralize the reaction liquid with sodium carbonate to a pH value of 9.2. The yield was 95% based on N-methylpyridine chloride. Product post-treatment methods include extraction method, complexation method, etc. Such as extraction method: 400 parts of paraquat cation and 166 parts of N-methylpyridine cation are dissolved in 10000 parts of water and concentrated in vacuum. The residue is extracted 3 times with 20000 parts of chloroform, and the remaining residue contains 398 parts of paraquat cation and 1 part of N-methylpyridine chloride. Chloroform extract is repeatedly extracted with water. the preparation method is to add N-methylpyridine sulfate monomethyl ester salt, industrial ethanol, sodium cyanide, catalyst and water into the reaction kettle, drop 28% industrial lye into the reaction kettle at 5 ℃ under stirring within about 1h, gradually raise the temperature for 1.5h after adding alkali, and the temperature does not exceed 80 ℃ at the end of the reaction. at this time, it can be regarded as the completion of dimerization reaction and cooling of the product. |
| category | pesticide |
| toxicity classification | highly toxic |
| acute toxicity | oral-rat LD50: 100 mg/kg; Oral-mouse LD50: 120 mg/kg |
| flammability hazard characteristics | combustion produces toxic nitrogen oxide gas |
| storage and transportation characteristics | warehouse ventilation and low temperature drying; separate from food raw materials storage and transportation |
| fire extinguishing agent | dry powder, foam, sand |
| occupational standard | TLV-TWA 0.1 mg/m3; STEL 0.3 mg/m3 |
| toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
Last Update：2024-04-09 19:05:09
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