MCPA

Structural formula
General
Surname	MCPA
other names	4-chloro- o- tolyloxyacetic acid; 2-methyl-4-chlorophenoxyacetic acid; MCPA;
Molecular formula	C 9 H 9 ClO 3
Brief description	yellowish crystalline powder with a phenolic odor
External identifiers / databases
EC number	202-360-6
ECHA InfoCard	100.002.146
PubChem	7204
ChemSpider	6935
Wikidata	Q149413
properties
Molar mass	200.62 g mol −1
Physical state	firmly
density	1.56 g cm −3
Melting point	118-119 ° C ; in technical quality 115-117 ° C;
solubility	very heavy in water (300 mg l −1 at 25 ° C)
safety instructions
H and P phrases	H: 302-315-318-410
	P: 273-280-305 + 351 + 338-501
Toxicological data	700 mg kg −1 ( LD 50 , rat , oral ) ; > 2000 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 .

MCPA, or 2-methyl-4-chlorophenoxyacetic acid, is a powerful, selective, and widely used herbicide .

history

The synthesis of MCPA was published by Synerholme and Zimmerman in 1945 and by Templeman and Foster in 1946 and was the result of finding a more selective substitute for the synthetic auxin 1-naphthylacetic acid .

MCPA is synthesized by a substitution reaction between chloroacetic acid and 4-chloro-2-methylphenol .

use

Since MCPA is an inexpensive substance, it is used as a complex ligand or as a building block for more complex active ingredients.

MCPA is generally used as a salt or as an ester as a herbicide. It is mainly used against broad-leaved weeds such as thistles or dock in agriculture. Although MCPA is not toxic, it has been found to increase the bioavailability of metal ions by forming complexes.

Admission

In a number of EU countries, including Germany and Austria, as well as Switzerland, plant protection products containing this active ingredient are approved.

effect

MCPA is similar to auxin and is a growth substance herbicide that accelerates the growth of weeds so much that the plant dies due to the resulting nutrient deficiency.

Brands

MCPA-containing products are sold under the following brand names:

Agritox
Agroxones
Banvel M
Chiptox
Chwastox
Cornox
Methoxone
Rhonox
Tigrex
Verdone Extra (GB)
Weed Rhap
Weed'n'Feed
Weed-B-Gone
Zero Bindii & Clover Weeder (Australia)
U 46 M fluid

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g Entry on (4-chloro-2-methylphenoxy) acetic acid in the GESTIS substance database of the IFA , accessed on February 14, 2017(JavaScript required) .
↑ ^a ^b Entry on MCPA. In: Römpp Online . Georg Thieme Verlag, accessed on February 22, 2014.
↑ Entry on (4-chloro-2-methylphenoxy) acetic 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 .
^ WG Templeman, WA Sexton: The Differential Effect of Synthetic Plant Growth Substances and other Compounds upon Plant Species. I. Seed Germination and Early Growth Responses to Formula-Naphthylacetic Acid and Compounds of the General Formula arylOCH ₂ COOR . In: Proceedings of the Royal Society B: Biological Sciences . tape 133 , no. 872 , August 7, 1946, p. 300-313 , doi : 10.1098 / rspb.1946.0014 .
↑ 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 . In: European Journal of Medicinal Chemistry . 25 1989, pp. 199-201. doi: 10.1016 / 0223-5234 (89) 90116-5 .
↑ 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) . In: Thermochimica Acta . tape 407 , no. 1-2 , December 2003, pp. 25–31 , doi : 10.1016 / s0040-6031 (03) 00287-9 ( PDF ).
↑ General Directorate Health and Food Safety of the European Commission: Entry on MCPA in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on March 25, 2016.

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g Entry on (4-chloro-2-methylphenoxy) acetic acid in the GESTIS substance database of the IFA , accessed on February 14, 2017(JavaScript required) .

[roempp-2] Entry on MCPA. In: Römpp Online . Georg Thieme Verlag, accessed on February 22, 2014.

[CLP_100.002.146-3] Entry on (4-chloro-2-methylphenoxy) acetic 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 .

[templeman-4] WG Templeman, WA Sexton: The Differential Effect of Synthetic Plant Growth Substances and other Compounds upon Plant Species. I. Seed Germination and Early Growth Responses to Formula-Naphthylacetic Acid and Compounds of the General Formula arylOCH ₂ COOR . In: Proceedings of the Royal Society B: Biological Sciences . tape 133 , no. 872 , August 7, 1946, p. 300-313 , doi : 10.1098 / rspb.1946.0014 .

[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 . In: European Journal of Medicinal Chemistry . 25 1989, pp. 199-201. doi: 10.1016 / 0223-5234 (89) 90116-5 .

[6] 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) . In: Thermochimica Acta . tape 407 , no. 1-2 , December 2003, pp. 25–31 , doi : 10.1016 / s0040-6031 (03) 00287-9 ( PDF ).

[7] General Directorate Health and Food Safety of the European Commission: Entry on MCPA in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on March 25, 2016.