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Parathion-methyl

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Parathion-methyl Basic information

Product Name:
Parathion-methyl
Synonyms:
  • NITROX 80(R)
  • NITRAN
  • O,O-DIMETHYL O-(4-NITROPHENYL)-PHOSPHOROTHIOATE
  • O,O-DIMETHYL-O-P-NITROPHENYL PHOSPHOROTHIOATE(R)
  • O,O-Dimethyl O-(p-nitrophenyl) thionophosphate
  • PARASHOOT(R)
  • PARATHION-METHYL
  • PARTON(R)
CAS:
298-00-0
MF:
C8H10NO5PS
MW:
263.21
EINECS:
206-050-1
Product Categories:
  • Agro-Chemicals
  • INSECTICIDE
  • META - METHEnvironmental Standards
  • 2000/60/ECMore...Close...
  • AcaricidesMethod Specific
  • Alpha sort
  • Endocrine Disruptors (Draft)Pesticides&Metabolites
  • EPA
  • European Community: ISO and DIN
  • H-MAlphabetic
  • Insecticides
  • M
  • MetabolitesPesticides
  • Oeko-Tex Standard 100
  • OrganophorousMethod Specific
  • Pesticides
  • Pesticides&Metabolites
  • PesticidesMethod Specific
  • Endocrine Disruptors (Draft)Alphabetic
Mol File:
298-00-0.mol
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Parathion-methyl Chemical Properties

Melting point:
36°C
Boiling point:
143°C (1.0 mmHg)
Density 
1.36
vapor pressure 
4.1×10-4 Pa (20 °C)
refractive index 
nD25 1.5367
Flash point:
46.1°C
storage temp. 
APPROX 4°C
form 
solid
Water Solubility 
0.005 g/100 mL
BRN 
8905814
Stability:
Stable. Flammable.
CAS DataBase Reference
298-00-0(CAS DataBase Reference)
NIST Chemistry Reference
Phosphorothioic acid, o,o-dimethyl-o-p-nitrophenyl ester(298-00-0)
EPA Substance Registry System
Phosphorothioic acid, O,O-dimethyl O-(4-nitrophenyl) ester(298-00-0)
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Safety Information

Hazard Codes 
T+;N,N,T+,Xn,F
Risk Statements 
5-24-26/28-48/22-50/53-10-67-66-51/53-36-20/22-11-65-38
Safety Statements 
28-36/37-45-60-61-26-62-16
RIDADR 
UN 2052/2783/2811
WGK Germany 
3
RTECS 
TG0175000
HazardClass 
6.1(a)
PackingGroup 
II
HS Code 
29201100
Hazardous Substances Data
298-00-0(Hazardous Substances Data)
Toxicity
LD50 in male, female rats (mg/kg): 14, 24 orally; 67, 67 dermally (Gaines)
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Parathion-methyl Usage And Synthesis

Chemical Properties

white crystalline powder

Chemical Properties

Methyl parathion is a white to yellow-brown, crystalline solid with a garlic odor.

Uses

Parathion-methyl is an derivative of Parathion (P192220), an organophosphate insecticide used on cotton, rice and fruit trees.

Uses

Insecticide, especially for cotton.

Uses

Parathion-methyl is used to control chewing and sucking pests in a wide range of crops.

Definition

ChEBI: A C-nitro compound that is 4-nitrophenol substituted by a (dimethoxyphosphorothioyl)oxy group at position 4.

General Description

Methyl parathion is a white crystalline solid dissolved in a liquid solvent carrier. The commercial product is a tan liquid (xylene solution) with a pungent odor. Parathion-methyl is slightly soluble to insoluble in water. Usually with the liquid solvent Parathion-methyl is a combustible liquid. Parathion-methyl is toxic by inhalation, ingestion and skin absorption. Parathion-methyl is used as an insecticide.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

METHYL PARATHION is half decomposed in 8 days at 40°C. When a sample was heated in a small test tube Parathion-methyl decomposed in a few minutes, the residue exploded (Food Chem. 4(1):42. 1956).

Hazard

Explosion risk when heated. Toxicby skin absorption, inhalation, and ingestion;cholinesterase inhibitor. Use has been restricted.Questionable carcinogen.

Health Hazard

Parathion-methyl is extremely toxic; the probable oral lethal dose is 5-50 mg/kg, or between 7 drops and 1 teaspoonful for a 150-lb. person. Chronic toxicity does not appear to be a major consideration.

Fire Hazard

Poisonous gases are produced in fire and when heated. Decomposition may lead to sufficient internal pressure to cause the container to rupture violently. Avoid oxidizing materials. Unstable. High temperatures (120F) cause decomposition.

Agricultural Uses

Insecticide, Nematicide: A U.S. EPA restricted Use Pesticide (RUP). Severely Restricted for use in EU, as parathion-methyl. This material is used as an insecticide on over 50 crops, primarily cotton, but also on walnuts, corn, dried beans and almonds and on several ornamentals. It is no longer allowed to be used on crops consumed by children.

Trade name

A-GRO®[C]; AI3-17292®; ATOMIC®[C]; AZOFOS®; AZOPHOS; BAMA BRAND®[C]; BAY 11405®; BAY E-601®; BLADAN M®; CEKUMETHION®; CLEAN CROP®[C]; COTTON TOX DUST®[C]; DALF®; DECLARE®; DEVITHION®; DREXEL METHYL PARATHION 4E®[C]; DURHAM[C]; E 601®; EMMY®[C]; E-Z-FLO®[C]; FALL OUT®[C]; FMC NYNAMITE®[C]; FOLIDOC®; FOLIDOL-80®; FOLIDOL M®; FOLIDOL M-40®; FOSFERNO M 50®; GEARPHOS®; 8056HC®; KILEX PARATHION®; ME-PARATHION®; MEPTOX®; METACID 50®; METACIDE®; METAFOS®; METAPHOS®; METRON®; METHYL-E 605®; METRON®; NITROX®; NITROX® 80; OLEOVOFOTOX®; PARAPEST M-50®; PENNCAP M®; PENNCAP MLS®; QUINOPHOS®; SEIS-TRES 6-3®; SINAFID M-48®; SIXTY-THREE SPECIAL E. C. INSECTICIDE®; TEKWAISA®; THIOPHENIT®; THYLPAR M-50®; TOLL®; VERTAC METHYL PARATHION TECHNISCH 80%®; WOFATOX 50 EC®

Contact allergens

A case of sensitization to methyl-parathion was described in a female agricultural worker with multiple sensitization.

Safety Profile

Poison by inhalation, ingestion, skin contact, subcutaneous, intravenous, and intraperitoneal routes. Fatal poisoning can result from skin or eye contact after very brief exposure to concentrated solution. Experimental teratogenic and reproductive effects. Questionable carcinogen. Human mutation data reported. A cholinesterase inhibitor type of insecticide. When heated to decomposition it emits very toxic fumes of NOx, POx, and SOx.

Potential Exposure

A severely hazardous pesticide formulation. Alert: This material is used as an insecticide on over 50 crops, primarily cotton, and on several ornamentals

Metabolic pathway

Parathion-methyl is a non-systemic insecticide and, where studied, metabolism parallels that of parathion and f enitrothion. The major routes of biotransformation involve desulfuration to the oxon analogue (paraoxon-methyl) and hydrolysis to give dimethyl phosphate, dimethyl phosphorothionate and 4-nitrophenol. Demethylation to give desmethylparathion- methyl and reduction of the nitro group also occurs. As with organophosphates, demethylation via glutathione-S-methyl transferases in the liver and some other tissues is an important mechanism in mammals. The major route of phase II metabolism involves conjugation of 4-nitrophenol followed by excretion.

Shipping

UN3017 Organophosphorus pesticides, liquid, toxic, flammable, flash point not ,23C, Hazard class: 6.1; Labels: 6.1-Poisonous materials, 3.-Flammable liquid. UN2783 Organophosphorus pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous material. UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1- Poisonous materials, Technical Name Required

Degradation

Parathion-methyl (1) is hydrolysed under acidic and alkaline conditions. The rate is five times faster than for parathion. Upon heating it isomerises via a thonwthiolo rearrangement to yield S-methylparahon-methyl (2) (PM). The hydrolysis of the active anticholinesterase oxon analogue (paraoxon-methyl) (3) is much faster than that of parathion-methyl. The products of parathion-methyl hydrolysis were 4-nitrophenol (4) and dimethyl phosphorothioate (5) (Thuma et al., 1983). Hydrolysis is much more rapid in alkaline than in acidic or neutral media. Photodegradation in natural sunlight led to the formation of O,O,S-trimethyl phosphorothioate (6) and trimethyl phosphate (7) (Chukwudebe et al., 1989). Zweiner et al. (1994) examined the photolysis of parathion-methyl in aqueous solution after irradiation by unfiltered UV light. The major metabolites, which were detected by GC-MS, were paraoxon-methyl (3) and 4-nitrophenol (4). These conversions are shown in Scheme 1.

Incompatibilities

Incompatible with oxidizers, strong bases; heat. Mixtures with magnesium, or endrin may be violent or explosive. Slightly decomposed by acid solutions. Rapidly decomposed by alkalies. Explosive risk when heated above 50C. The liquid xylene solution decomposes violently @ 120C

Waste Disposal

Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal. Incineration (816C, 0.5 second minimum for primary combustion; 1204C, 1.0 second for secondary combustion) with adequate scrubbing and ash disposal facilities. In accordance with 40CFR165, follow 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

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