MCPA is a strong, selective and widely used herbicide . MCPA - an abbreviation of the English full name of the substance - English. 2-methyl-4-chlorophenoxyacetic acid .
| ICCA | |
|---|---|
| Are common | |
| Systematic name | 4-chloro-2-methylphenoxyacetic acid |
| Abbreviations | MHVU, UT-10, 2M-4X, MHV, MSR |
| Chem. formula | C 9 H 9 ClO 3 |
| Physical properties | |
| condition | yellowish crystalline powder with a phenol odor |
| Molar mass | 200.62 g / mol |
| Density | 1.18-1.21 g / cm³ |
| Thermal properties | |
| T. melt. | 114-118 ° C |
| Chemical properties | |
| Water solubility | 825 mg / L (23 ° C) [1] ammonium salt: 866 g / L esters: 5 mg / l |
| Classification | |
| Reg. CAS number | |
| Pubchem | |
| Reg. EINECS number | |
| Smiles | |
| Inchi | |
| Chebi | |
| Chemspider | |
| Security | |
| LD 50 | 700 mg · kg −1 (rat, oral) [2]
|
| R-phrases | R22 R38 R41 R50 / 53 |
| S-phrases | (S2) S26 S37 S39 S60 S61 |
| H-phrases | H302 , H315 , H318 , H410 |
| P-phrases | P273 , P280 , P305 + 351 + 338 , P501 |
| GHS pictograms |    |
Content
History
In 1936, at the experimental station in the English village of Jellotts Hill , ICIs began to study the effect of auxins on plant growth and to find selective ways to destroy weeds without damaging crops such as corn [3] .
Sinerholm and Zimmermann in 1945 and Templeman and Foster in 1946 were the first to report the synthesis of MCPA [4] . Templeman and Foster were looking for compounds with similar or better selectivity than 1-naphthalene acetic acid , which would inhibit weed growth and not have a negative effect on cereal growth. They synthesized MCPA from the corresponding phenol via a simple substitution reaction, mixing it with monochloracetic acid and diluted base [5] .
The synthesis of MCPA is carried out by a substitution reaction between chloroacetic acid and 4-chloro-2-methylphenol under alkaline conditions.
William and his colleagues could not share the discovery and publish the results with the world scientific community, since the British government immediately classified all materials and the patent. It is worth noting that later, in recognition of the work, Temleman was awarded and promoted to officers of the British Empire. [6]
Use
Since MCPA is a relatively inexpensive substance, it is used as a complexing agent or as a building block for more complex substances [7] .
Typically, this herbicide is used as a salt or as esters. It is used mainly against broadleaf weeds, such as thistles or sorrel on cereal crops and pastures. It is selective for broadleaf weeds, including deciduous trees. Clovers are resistant to its action in moderate concentrations. Although MCPA is not very toxic [8] , it turned out to increase the bioavailability of metal ions due to complexation [9] , and now work is underway to rid it of this undesirable ability [10] .
Statement
In a number of EU states, in particular Germany and Austria, as well as in Switzerland, the ICCA is allowed for use [11] .
Effect
In terms of its chemical structure, MCPA resembles auxin , which accelerates weed growth so much that the plant dies due to overspending.
Note
- ↑ Gimeno Olga; Plucinski Pawel; Kolaczkowski Stan T .; Rivas Francisco J .; Alvarez Pedro M. Removal of the Herbicide MCPA by Commercial Activated Carbons: Equilibrium, Kinetics, and Reversibility // Industrial & Engineering Chemistry Research : journal. - 2003. - Vol. 42 , no. 5 . - P. 1076-1086 . - DOI : 10.1021 / ie020424x .
- ↑ 1 2 Record of (4-Chlor-2-methylphenoxy) essigsäure in the GESTIS Substance Database of the IFA
- ↑ The Times , 2 July 1954; Imperial Chemical Industries Limited: Display Advertising
- ↑ S. Budaver, ed. The Merck Index (11th ed.). - Merck & Co, Inc., 1989.
- ↑ WG Templeman; WA Sexton. The Differential Effect of Synthetic Plant Growth Substances upon Plant Species. I. Seed Germination and Early Growth Responses to α-Naphthylacetic Acid and Compounds of General Formula aryl OCHCOO (English) // Proceedings of the Royal Society of London : journal. - 1946. - Vol. 133 , no. 872 . - P. 300-313 . - DOI : 10.1098 / rspb.1946.0014 .
- ↑ Roman Potapov. Chemistry that changed the world. - Selfpab. - S. 5.
- ↑ AR Prasad, T. Ramalingam, AB Rao, PV Diwan, PB Sattur: Synthesis and biological evaluation of 3-aryloxyalkyl-6-aryl-7H-s-triazolo [3,4-b] [1,3,4] thiadiazines .
- ↑ MCPA . Extrnsion Toxicology Network . Cornell.
- ↑ J. Kobylecka; B. Ptaszynski; R. Rogaczewski; A. Turek. Phenoxyalkanoic acid complexes. Part I. Complexes of lead (II), cadmium (II) and copper (II) with 4-chloro-2-methylphenoxyacetic acid (MCPA) (Eng.) // Thermochimica Acta: journal. - 2003. - Vol. 407 , no. 1-2 . - P. 25-31 . - DOI : 10.1016 / S0040-6031 (03) 00287-9 .
- ↑ R. Kruszynski, TJ Bartczak, B. Ptaszynski and A. Turek. A Novel Leadbis (4-Chloro-2-Methylphenoxy) - Acetate Polymeric Complex (Eng.) // Journal of Coordination Chemistry: journal. - 2002. - Vol. 55 , no. 9 . - P. 1079-1089 . - DOI : 10.1080 / 0095897021000010035 .
- ↑ Generaldirektion Gesundheit und Lebensmittelsicherheit der Europäischen Kommission: Eintrag zu MCPA in der EU-Pestiziddatenbank ; Eintrag in den nationalen Pflanzenschutzmittelverzeichnissen der Schweiz Archived March 26, 2016 at Wayback Machine , Österreichs Archived March 26, 2016 at Wayback Machine und Deutschlands (link not available) (link not available) ; abgerufen am 25.