Parathion
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| General | ||||||||||||||||
| Surname | Parathion | |||||||||||||||
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| Molecular formula | C 10 H 14 NO 5 PS | |||||||||||||||
| Brief description |
brown liquid with a garlic-like odor |
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| properties | ||||||||||||||||
| Molar mass | 291.3 g mol −1 | |||||||||||||||
| Physical state |
liquid |
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| density |
1.27 g cm −3 |
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| Melting point |
6.1 ° C |
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| boiling point |
375 ° C |
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| solubility |
practically insoluble in water (24 mg l −1 at 20 ° C) |
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| Refractive index |
1.5370 (25 ° C) |
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| safety instructions | ||||||||||||||||
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| MAK |
DFG / Switzerland: 0.1 mg m −3 (measured as inhalable dust ) |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C | ||||||||||||||||
Parathion ( synonym E 605 ), an alkyl phosphate , is an ester of thiophosphoric acid (see also phosphoric acid ester ) and is therefore also called thiophos . The term “mother-in-law poison” is also popularly used for the pesticide, as the insecticide was misused for many well-known suicides and murders.
history
The substance and its effectiveness were developed and examined by Gerhard Schrader in 1944 as part of his work on phosphoric acid esters . After the documents and patents were transferred to the Allies in 1945, Parathion was marketed by American Cyanamid and Monsanto , among others, from 1947, and by Bayer AG in Europe from 1948 .
Bayer produced Parathion under the name "E 605". This repeatedly leads to confusion with the E numbers for food additives administered by the European Union . Parathion has no connection with these, as the E numbers were introduced much later and there is no food additive with the code “E 605”. Rather, the E of "E 605" results from the fact that the laboratory journal with the experiments on newly developed chemicals with insecticidal properties was kept at that time by a chemical engineer named E. Ewe. These substances included many other phosphoric acid esters (for example Potasan , E 838). The E for food additives, on the other hand, stands for “Europe” or “European Union” and for English edible (“edible”).
Later on, based on the structure of parathion, many other compounds with similar properties such as parathion-methyl (produced from 1949) or fenitrothion were developed and marketed.
In 1949, the use of "Bayer E 605" was found to be harmful to health. Since the amount inhaled when dusting the plants outdoors is sufficient to cause severe damage to health, the authorities expressly point out that the instructions for use must be strictly followed.
The world's first documented murder with E 605 was committed by Christa Lehmann in 1952 .
Extraction and presentation
Parathion 2 can be obtained by reacting diethylphosphorothionic chloride 1 with sodium p -nitrophenolate.
properties
Parathion is a liquid that is extremely toxic to insects and warm-blooded animals . However, it is not toxic to plants. In its pure state, the liquid is colorless and almost odorless, the technical compound that is coming on the market is colored yellow-brown for safety reasons and is flavored with a pungent garlic-like odor.
Parathion dissolves at 24 mg / l in water and is only slowly hydrolyzed in the acidic to neutral pH range, but rapidly in the alkaline pH range . Parathion irreversibly blocks the enzyme acetylcholinesterase after it has been converted into its oxygen analogue Paraoxon (E 600) by oxidative desulfurization . It acts as a contact poison and must therefore not come into contact with the skin . The effect of the parathion is based on a sustained excitation of muscarinic and nicotinic acetylcholine receptors , which results from the reduced breakdown of the released acetylcholine. Vomiting, diarrhea, sweating, muscle twitching, headaches, respiratory paralysis and severe cramps occur. Parathion is related to various chemical warfare agents such as tabun , sarin and soman , but they are much more effective at blocking acetylcholinesterase.
An evaluation by the IARC from March 2015 came to the conclusion that parathion was classified in category 2B ( possibly carcinogenic to humans ) on the basis of the investigations in rats and mice .
use
Parathion is used as an insecticide and acaricide .
The sale in the trade as a plant protection product "E 605 forte" took place only after presentation of an identity card, since numerous cases of poisoning and homicides with parathion have already been described in the literature. The plant protection product is denatured so that it cannot be accidentally swallowed. A pungent odor can also often be observed.
On July 9, 2001, the European Commission issued a decision banning the sale, import, use and authorization of plant protection products containing parathion. The sale for storage with subsequent export from the territory of the European Union was not prohibited . Furthermore, all approvals already issued for such plant protection products had to be withdrawn within six months. In Switzerland there is also no longer any approval as an active ingredient in plant protection . Since January 8, 2002, when the approval of pesticides containing parathion (E 605 forte, E Combi, POX) expired, there has been a general ban on the sale of "E 605 forte" in stores and its further use.
Parathion irreversibly blocks acetylcholinesterase and is therefore not suitable for medical use.
Antidotes
For a long time, high-dose atropine was used by the emergency services to prevent poisoning by parathion . Atropine binds to the same receptors as acetylcholine, but without activating them. This prevents the triggering of new nerve stimuli. Since too much atropine also has a toxic effect, so that this treatment is fraught with complications, atropine is given today in smaller, repetitive steps until the symptoms improve, depending on the patient's symptoms. Oximes ( obidoxime , pralidoxime ) are used to detach the phosphate group from acetylcholinesterase from acetylcholinesterase and make it functional again . However, this reactivation is only possible a short time after exposure to parathion and requires intensive medical care.
Web links
Individual evidence
- ↑ a b c d e f g h i Entry on parathion in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
- ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-410.
- ↑ Entry on parathion 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 .
- ↑ Swiss Accident Insurance Fund (Suva): Limits - Current MAK and BAT values (search for 56-38-2 or parathion ), accessed on November 2, 2015.
- ↑ a b c Parathion data sheet at Sigma-Aldrich , accessed on May 5, 2008 ( PDF ).
- ↑ a b H. P. Plate, E. Frömming: The animal pests of our greenhouse plants, their way of life and ... Duncker & Humblot, 1953, p. 219 ( limited preview in Google Book search).
- ↑ a b c G. Matolcsy, M. Nádasy, V. Andriska: Pesticide Chemistry . Elsevier, 1989, ISBN 0-08-087491-6 , pp. 122 ( limited preview in Google Book search).
- ↑ Jørgen Stenersen: Chemical Pesticides Mode of Action and Toxicology . CRC Press, 2004, ISBN 0-7484-0910-6 , pp. 103 ( limited preview in Google Book search).
- ^ Gerhard Schrader: Contributions to one hundred years of company history . Ed .: Farbenfabriken Bayer AG. Leverkusen 1963, p. 117 .
- ^ Message from the Ministry of the Interior in Württemberg-Baden, quoted from: Plant pest control agent Bayer E 605 from September 19, 1949 . In: The Hessian Minister of the Interior (ed.): State Gazette for the State of Hesse. 1949 no. 42 , p. 437 , item 726 ( online at the information system of the Hessian state parliament [PDF; 1,4 MB ]).
- ↑ Kracher, R. et al. (2007): Lexicon of Chemistry . 2nd volume (Gest to Pere), Jokers edition. Heidelberg: Spektrum Verlag S. 460. ISBN 978-3-8274-1909-5 .
- ^ IARC press release of March 20, 2015 IARC Monographs Volume 112: evaluation of five organophosphate inscecticides and herbicides , accessed on March 23, 2015.
- ↑ Decision 2001/520 / EC of the Commission of 9 July 2001 on the non-inclusion of parathion in Annex I of Council Directive 91/414 / EEC and the revocation of the authorizations for plant protection products with this active substance .
- ↑ Directive 91/414 / EEC (PDF) of the Council of July 15, 1991 on the placing of plant protection products on the market.
- ↑ General Directorate Health and Food Safety of the European Commission: Entry on parathion in the EU pesticide database; Entry in the national directory of plant protection products in Switzerland ; accessed on February 14, 2016.