Glufosinate
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| ( S ) -glufosinate (left) and ( R ) -glufosinate (right) | |||||||||||||||||||
| General | |||||||||||||||||||
| Surname | Glufosinate | ||||||||||||||||||
| other names |
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| Molecular formula |
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| properties | |||||||||||||||||||
| Molar mass | 181.13 g · mol -1 | ||||||||||||||||||
| Physical state |
firmly |
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| density |
1.4 g cm −3 (20 ° C) |
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| Melting point |
215 ° C |
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| solubility |
very light in water (1370 g l −1 at 20 ° C) |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | |||||||||||||||||||
Glufosinate , also known as phosphinothricin , is a herbicide and the first peptidically bound, naturally occurring amino acid with a phosphinic acid group to be described in the literature .
The glufosinate residue was discovered in 1971 as a component of the tripeptide bialaphos in streptomycetes . A special feature is the rarity of the carbon-phosphorus-carbon bond and the biosynthesis of this chemically stable group, which has not yet been fully clarified. Glufosinate is classified as toxic to reproduction by the BMELV .
Isomers and salts
Glufosinate has a stereocenter, so there are two enantiomers of the compound, ( S ) -glufosinate and ( R ) -glufosinate. The 1: 1 mixture is called a racemate .
| Enantiomers of glufosinate | ||
| Surname | ( S ) -glufosinate | ( R ) -glufosinate |
| other names |
L -glufosinate (-) - glufosinate glufosinate-P |
D -glufosinate (+) - glufosinate D -phosphinothricin |
| Structural formula |
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| CAS number | 35597-44-5 | 73679-07-9 |
| 51276-47-2 (racemate) | ||
| EC number | 690-077-2 | |
| 257-102-5 (racemate) | ||
| ECHA info card | 100.217.200 | |
| 100.051.893 (racemate) | ||
| PubChem | 91619 | 6971307 |
| 4794 (racemate) | ||
| Wikidata | Q27266088 | Q27093615 |
| Q302204 (racemate) | ||
The ammonium salt of the racemic acid, "glufosinate ammonium", is often used in commercial products .
Manufacturing
Various methods for the synthesis of racemic glufosinate [1: 1 mixture of ( S ) -glufosinate and ( R ) -glufosinate] are described in the literature.
The industrial synthesis is mainly based on acrolein cyanohydrin acetate (ACA). Glufosinate is produced from it by adding a methylphosphinic acid ester, subsequent reaction with ammonia and hydrolysis of the ester formed.
use
herbicide
The racemic ammonium salt of phosphinothricin is contained as a component in various commercial herbicides and is used under several trade names as a (total) herbicide with contact and partially systemic effects. The best known of these trade names is Basta ® . Glufosinate is effective against both monocotyledons and dicotyledonous plants. It is not absorbed through the roots, but mainly through the green parts of the plant, where it inhibits glutamine synthetase . This leads to the accumulation of ammonium in the leaf tissue of the plant and furthermore to a lack of glutamine and other amino acids . This leads to the inhibition of photosynthesis , chlorosis and ultimately the death of the leaf tissue and ultimately the entire plant. Glufosinate is therefore also included in the group of amino acid antagonistic herbicides.
Genetic Resistance
It was possible to genetically engineer resistance to the herbicide in crops such as maize, rice, rapeseed or lettuce. For this purpose, the gene for the enzyme phosphinothricin acetyl transferase (PAT enzyme) was isolated from the bacterium Streptomyces viridochromogenes . The bacterium that produces phosphinothricin itself protects itself from its own poison by transferring an acetyl group to phosphinothricin and thereby inactivating it.
One example is the rice LL62 . LL62 is resistant to the Bayer broad-spectrum herbicide Liberty (with the active ingredient glufosinate ammonium). Bayer submitted its application for approval to import LL62 into the EU in 2004. The application relates to use as food, feed and processing. In the USA there is already a permit for cultivation.
regulation
Europe
In the European Union, glufosinate had been approved for plant protection products since 2007, which expired on September 30, 2017. At national level, glufosinate is approved in five EU countries. In Germany, the marketing authorization for the formerly only glufosinate-containing product "Basta" expired on December 31, 2015; an extension of the marketing authorization was not applied for. Stocks were allowed to be used up until June 30, 2017. However, the active ingredient manufactured by BASF is still being exported to Brazil. In Switzerland, there is a use-by period until January 6, 2022.
The permitted daily dose and the acute reference dose are each 21 µg per kilogram of body weight and day, the acceptable user exposure is 2.1 µg per kilogram of body weight and day.
Due to the assumed risks for mammals and non-target arthropods , the Implementing Regulation (EU) No. 365/2013 of April 22, 2013 stipulated that only strip-wise or selective herbicide applications with glufosinate were permitted, in doses of a maximum of 750 g active ingredient / ha (treated surface) per application and with a maximum of two applications per year. In order to implement the implementing regulation, the BVL prohibited or restricted the use of the glufosinate-containing product "Basta" on November 13, 2013 for certain crops.
Web links
Individual evidence
- ↑ a b c d e entry on glufosinate. In: Römpp Online . Georg Thieme Verlag, accessed on May 7, 2014.
- ↑ a b c Entry on ammonium 2-amino-4- (hydroxymethylphosphinyl) butyrate in the GESTIS substance database of the IFA , accessed on July 23, 2016(JavaScript required) .
- ↑ Entry on 2-amino-4- (hydroxymethylphosphinyl) butyric acid 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 .
- ↑ Federal Ministry of Food, Agriculture and Consumer Protection: New legal regulations for plant protection products at EU level (PDF; 75 kB) BMELV homepage, Jan. 2009; accessed March 22, 2013.
- ↑ External identifiers or database links for ammonium glufosinate : CAS number: 77182-82-2, EC number: 278-636-5, ECHA InfoCard: 100.071.466 , GESTIS substance database : 530263 , PubChem : 53597 , Wikidata : Q3011371 .
- ↑ Bernd Schäfer: Natural substances of the chemical industry , Elsevier, 2007, pp. 471–475, ISBN 978-3-8274-1614-8 .
- ↑ Evonik Degussa .
- ↑ Marcus Diemer: Immunanalytical methods with chemical and enzymatic derivatization for the determination of glufosinate . 2002, production / synthesis ( PDF ).
- ↑ a b c Directorate-General for Health and Food Safety of the European Commission: Entry on Glufosinate in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on April 25, 2020.
- ↑ Bayer AG: Plant protection product "Basta"
- ^ Benjamin Luig, Fran Paula de Castro, Alan Tygel, Lena Luig, Simphiwe Dada, Sarah Schneider, Jan Urhahn: Hazardous pesticides. (PDF; 2.4 MB) from Bayer and BASF - a global business with double standards. Rosa Luxemburg Foundation , INKOTA network , Bischöfliches Hilfswerk Misereor , Campanha Permanente Contra os Agrotóxicos e Pela Vida, Khanyisa, April 2020, accessed on April 25, 2020 .
- ↑ Implementing Regulation (EU) No. 365/2013 of the Commission of April 22, 2013 (PDF) amending Implementing Regulation (EU) No. 540/2011 with regard to the conditions for the approval of the active substance glufosinate.
- ↑ BVL: Change in the authorization of the plant protection product Basta . November 8, 2013. Accessed March 9, 2016.