Methamidophos
- CAS No.
- 10265-92-6
- Chemical Name:
- Methamidophos
- Synonyms
- Tam;METAMIDOPHOS;MONITOR;GIANT;Prodex;re9006;RE 9006;Tamanox;B-71628;ckb1220
- CBNumber:
- CB3454363
- Molecular Formula:
- C2H8NO2PS
- Molecular Weight:
- 141.13
- MOL File:
- 10265-92-6.mol
- Modify Date:
- 2024/3/14 15:18:26
| Melting point | 44.5°C |
|---|---|
| Boiling point | 208.7±23.0 °C(Predicted) |
| Density | d44.5 1.31 |
| vapor pressure | 2.3×10-3Pa (25°C) |
| refractive index | nD40 1.5092 |
| Flash point | 212 °C |
| storage temp. | 0-6°C |
| solubility | Chloroform (Slightly), Methanol (Slightly) |
| Water Solubility | >200 g l-1 (20°C) |
| pka | -0.58±0.70(Predicted) |
| form | solid |
| Stability | Stable. Incompatible with strong oxidizing agents, copper, copper alloys. |
| CAS DataBase Reference | 10265-92-6(CAS DataBase Reference) |
| NIST Chemistry Reference | Phosphoramidothioic acid, o,s-dimethyl ester(10265-92-6) |
| EPA Substance Registry System | Methamidophos (10265-92-6) |
SAFETY
Risk and Safety Statements
| Symbol(GHS) |   GHS06,GHS09 |
|---|---|
| Signal word | Danger |
| Hazard statements | H300-H311-H330-H400 |
| Precautionary statements | P264-P270-P301+P310-P321-P330-P405-P501-P280-P302+P352-P312-P322-P361-P363-P405-P501-P260-P271-P284-P304+P340-P310-P320-P403+P233-P405-P501-P273-P391-P501 |
| Hazard Codes | T+;N,N,T+,Xn,F |
| Risk Statements | 24-26/28-50-36-20/21/22-11 |
| Safety Statements | 1/2-28-36/37-45-61-26 |
| RIDADR | 2783 |
| RTECS | TB4970000 |
| HazardClass | 6.1(a) |
| PackingGroup | II |
| Toxicity | LD50 in adult male, female rats (mg/kg): 25, 27 orally (Gaines, Linder) |
Methamidophos Chemical Properties,Uses,Production
Chemical Properties
Methamidophos is a colourless crystalline solid with a pungent odour. It is readily soluble in water, alcohols, ketones, and aliphatic chlorinated hydrocarbons but sparingly soluble in ether and practically insoluble in petroleum ether. Methamidophos is also a breakdown product of another OP, namely, acephate. Methamidophos is slightly corrosive to mild steel and copper alloys.
Uses
Methamidophos is used to control a wide range of insects and mites in a very large number of crops.
General Description
Crystalline solid, technical product is off-white with a pungent odor. Used as an insecticide on a number of vegetables and on cotton.
Reactivity Profile
Organophosphates, such as Methamidophos, are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrides. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides. Avoid strong acids or alkalis. [EPA, 1998].
Health Hazard
Methamidophos is harmful or fatal if swallowed, inhaled, or absorbed through the skin.
Fire Hazard
(Non-Specific -- Organophosphorus Pesticide, n.o.s.) Container may explode in heat of fire. Fire and runoff from fire control water may produce irritating or poisonous gases. (Non-Specific -- Phosphoramidothioic Acid, O-Ethyl S-Methyl Ester) Emits very toxic fumes of nitrogen oxides, phosphorus oxides, and sulfur oxides when heated to decomposition. Stable at neutral pH. Avoid strong acids or alkalis.
Agricultural Uses
Insecticide, Miticide: Methamidophos is a highly active, systemic, resid-ual organophosphate insecticide/acaricide/avicide with contact and stomach action. Its mode of action in insects and mammals is by decreasing the activity of an enzyme important for nervous system function called acetylcholinesterase. This enzyme is essential in the normal transmission of nerve impulses. Methamidophos is a potent acetylcholinesterase inhibitor. It is effective against chewing and sucking insects and is used to control aphids, flea beetles, worms, whiteflies, thrips, cabbage loopers, Colorado potato beetles, potato tubeworms, armyworms, mites, leafhoppers, and many others. Crop uses include broccoli, Brussels sprouts, cauliflower, grapes, celery, sugar beets, cotton, tobacco, and potatoes. It is used abroad for many vegetables, hops, corn, peaches, and other crops. Generally, methamidophos is not considered phytotoxic if used as directed, but defoliation has occurred when applied as foliar spray to deciduous fruit. It is compatible with many other pesticides, but do not use with alkaline materials. Methamidophos is slightly corrosive to mild steel and copper alloys. This compound is highly toxic to mammals, birds, and bees. Do not graze treated areas, and be sure to wear protective clothing including respirator, chemical goggles, rubber gloves, and impervious protective clothing. A U.S. EPA restricted Use Pesticide (RUP). Not approved for use in EU countries .
Trade name
ACEPHATE-MET®; BAY 71625®; BAYER 71628®; CHEVRON 9006®; CHEVRON ORTHO 9006®; FILITOX®; GS-13005®; HAMIDOP®; METAFOS®; MONITOR®; MTD®; NITOFOL®; NURATRON®; ORTHO 9006®; PATROLE®; PILLARON®; SRA 5172®; SUPRACIDE®; SWIPE®; TAHMABON®; TAMARON®; VITARON®
Safety Profile
Poison by ingestion, inhalation, sh contact, subcutaneous, and intraperitoneal routes. Human systemic effects by ingestion: fasciculations, pupdlary constriction, and sweating. A cholinesterase inhbitor type of insecticide. When heated to decomposition it emits very toxic fumes of NOx, POx, and SOx. See also PARATHION.
Potential Exposure
A potential danger to those involved in the manufacture, formulation, and application of this insecticide on vegetables and cotton
Environmental Fate
Chemical/Physical. Emits toxic fumes of phosphorus, nitrogen and sulfur oxides when heated to decomposition (Sax and Lewis, 1987).
Metabolic pathway
Methamidophos is a contact insecticide which is particularly effective against caterpillars and aphids. It also has some systemic action although much less than acephate. There is some uncertainty concerning the nature of the leaving group when the compound inhibits acetylcholinesterase although most evidence suggests that it is methanethiolate. There are claims that it requires metabolic activation to a more active inhibitor (Eto et al., 1977) and yet other evidence that it does not (Khasawinah et al., 1978). Most studies which have examined the biotransformation of acephate have identified methamidophos as one of its metabolites and the latter is considered to be the active metabolite. The main route of biotransformation in soil is through deamination. In mammals, metabolism involves de-O-methylation, de-S-methylation and deamination, with de- O-methylation in the liver probably being the most important route. There is no evidence as to whether demethylation is hydrolytic or oxidative. Methamidophos and its metabolites are highly polar and no conjugates have been identified. There is some evidence that the compound can lead to delayed neurological degeneration in mammals through inhibition of 'neuropathy target esterase'.
Metabolism
Acute oral LD50 for rats is about 20 mg/kg. Inhalation LC50 (4 h) for rats is 0.2 mg/L air. NOEL (2 yr) for rats is 2 mg/kg diet (0.1 mg/kg/d). ADI is 4 μg/kg b.w. Methamidophos itself shows only a poor anti-AChE activity, oxidative activation being suggested. It appears to cause delayed neuropathy. The major part of administered methamidophos in animals is rapidly eliminated from the body through urine and respiration. The major metabolic routes are O-demethylation, S-demethylation, and deamination. In plants, deaminated methamidophos is a major metabolite. Methamidophos is degraded rapidly in soil by deamination and demethylation, to eventually form carbon dioxide and phosphoric acid.
Shipping
UN2783 Organophosphorus pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials
Incompatibilities
Incompatible with strong acids or alkali. Attacks mild steel and copper-containing alloys (technical grade)
Waste Disposal
In accordance with 40CFR 165 recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.
Methamidophos Preparation Products And Raw materials
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