Methamidophos

Structural formula
	Structural formula without specifying the stereochemistry
General
Surname	Methamidophos
other names	Thiophosphoric acid O , S dimethyl ester amide; O , S -dimethylamidothiophosphate; Tamaron;
Molecular formula	C 2 H 8 NO 2 PS
Brief description	colorless solid
External identifiers / databases
EC number	233-606-0
ECHA InfoCard	100.030.538
PubChem	4096
Wikidata	Q421055
properties
Molar mass	141.13 g mol −1
Physical state	firmly
density	1.27 g cm −3
Melting point	44.9 ° C
boiling point	decomposition
solubility	very easily soluble in water (> 2000 g l −1 at 20 ° C); soluble in alcohols and ketones; slightly soluble in ether;
safety instructions
H and P phrases	H: 300 + 310 + 330-400
	P: 260-262-280-301 + 330 + 331 + 310-302 + 352 + 310-304 + 340 + 310
Toxicological data	7.5 mg kg −1 ( LD 50 , rat , oral ) ; 118 mg kg −1 ( LD 50 , rabbit , transdermal ) ;
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Methamidophos is a chemical compound from the group of Thiophosphorsäureamide and an organophosphate - insecticide .

Stereoisomerism

As methamidophos contains a chiral center on the phosphorus atom, there are two stereoisomers that are mirror image behave, the ( R ) - enantiomer and the ( S ) enantiomer. The racemate - a 1: 1 mixture of the ( R ) -enantiomer and the ( S ) -enantiomer - is used as an insecticide .

Extraction and presentation

Methamidophos is made from dimethylphosphorodithioic acid (DMPA), which is chlorinated to O , O -dimethylchlorothiophosphate (DMPCT). This reacts with ammonia and then with either dimethyl sulfate or methyl iodide to form the end product.

properties

Methamidophos is a colorless crystalline substance. The technical product (about 73% purity) forms yellowish to colorless crystals with a melting point below 40 ° C. When heated, the compound decomposes without boiling.

use

Methamidophos is a systemic insecticide and acaricide introduced in 1969 with a broad spectrum of activity in numerous crops. It is used in large quantities in the cultivation of rice in China.

Admission

No plant protection products containing this active ingredient are permitted in the EU or Switzerland .

safety instructions

Methamidophos showed a very high acute toxicity: LD ₅₀ (rat, oral): 7.5 mg / kg body weight; LD ₅₀ (rat, dermal): 69 mg / kg body weight; LC ₅₀ (inhalation rat) 0.063 mg / l air (4h). In tests on rats, the typical clinical symptoms (salivation and tearing, dyspnoea, twitching, convulsions) of cholinesterase inhibition were observed. However, it was found to be non-irritating to the skin and eyes and non-sensitizing.

Individual evidence

↑ ^a ^b ^c Methamidophos. In: Decision Guidance Documents: Methamidophos - Methyl parathion - Monocrotophos - Parathion - Phosphamidon. Operation of the PIC procedure for pesticides included because of their acute hazard classification and concern as to their impact on human health under conditions of use in developing countries. Food and Agriculture Organization of the United Nations, 1997, accessed January 22, 2012 .
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Entry on Methamidophos in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .
↑ Health and Safety Guide (HSG) for Methamidophos , accessed December 1, 2014.
↑ Entry on Methamidophos in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ Thomas A. Unger: Pesticide Synthesis Handbook . William Andrew, 1996, ISBN 0-8155-1853-6 , pp. 380 ( limited preview in Google Book search).
↑ entry methamidophos in enius.
↑ International Development Research Center ( Memento of May 10, 2005 in the Internet Archive )
↑ Directorate-General for Health and Food Safety of the European Commission: entry on Methamidophos in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on March 26, 2016.
↑ BGVV: Brief assessment of Methamidophos (PDF; 22 kB), as of May 2002.

[fao-1] Methamidophos. In: Decision Guidance Documents: Methamidophos - Methyl parathion - Monocrotophos - Parathion - Phosphamidon. Operation of the PIC procedure for pesticides included because of their acute hazard classification and concern as to their impact on human health under conditions of use in developing countries. Food and Agriculture Organization of the United Nations, 1997, accessed January 22, 2012 .

[GESTIS-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Entry on Methamidophos in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .

[3] Health and Safety Guide (HSG) for Methamidophos , accessed December 1, 2014.

[CLP_100.030.538-4] Entry on Methamidophos in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[unger-5] Thomas A. Unger: Pesticide Synthesis Handbook . William Andrew, 1996, ISBN 0-8155-1853-6 , pp. 380 ( limited preview in Google Book search).

[6] try methamidophos in enius.

[idrc-7] International Development Research Center ( Memento of May 10, 2005 in the Internet Archive )

[8] Directorate-General for Health and Food Safety of the European Commission: entry on Methamidophos in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on March 26, 2016.

[9] BGVV: Brief assessment of Methamidophos (PDF; 22 kB), as of May 2002.