Clopyralid

Structural formula
General
Surname	Clopyralid
other names	3,6-dichloropyridine-2-carboxylic acid 3,6-dichloropicolinic acid
Molecular formula	C 6 H 3 Cl 2 NO 2
Brief description	white, crystalline solid
External identifiers / databases
CAS number 1702-17-6 EC number 216-935-4 ECHA InfoCard 100.015.396 PubChem 15553 ChemSpider 14797 Wikidata Q2188539
properties
Molar mass	192 g mol −1
Physical state	firmly
Melting point	151-152 ° C
solubility	easily in water (143 g l −1 at 20 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 318 P: 280-305 + 351 + 338
Toxicological data	4300 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 .

Clopyralid is a chlorinated derivative of picolinic acid from the group of pyridinecarboxylic acids . The active ingredient is known as a herbicide under the trade name Lontrel .

synthesis

The synthesis of clopyralid starts from 2-picoline , which is chlorinated photochemically . The trichloromethyl group is then oxidized to the carboxy group by nitric acid.

use

Estimated application rate in the USA

Clopyralid is used as an active ingredient in crop protection products. The compound was introduced by Dow Chemical in 1975 as a systemic and selective growth herbicide.

It is preferably used post-emergence in sugar beet and fodder beet against various weeds such as thistles, coltsfoot, cornflowers, knotweed or chamomile. Clopyralid is also used in rapeseed, maize, onion and strawberry cultivation and in ornamental trees. It works best in vigorous weather conditions.

Admission

Effective May 1, 2007, clopyralid was added to the list of plant protection products permitted in the EU. In Switzerland, clopyralid has been removed from the list of plant protection products that do not require a permit.

In Germany, Austria and Switzerland as well as in other EU countries, plant protection products with this active ingredient are approved.

Individual evidence

1. ↑ ^{a b c d e f} Entry on 3,6-dichloropyridine-2-carboxylic acid in the GESTIS substance database of the IFA , accessed on January 8, 2018(JavaScript required) .
2. ↑ ^{a b c} Entry on Clopyralid. In: Römpp Online . Georg Thieme Verlag, accessed on June 12, 2014.
3. ↑ Entry on 3,6-dichloropyridine-2-carboxylic acid in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
4. ↑ Thomas A. Unger: Pesticide Synthesis Handbook . Noyes Publications, Park Ridge NJ 1996, ISBN 0-8155-1401-8 , Clopyralid, pp. 530 ( limited preview in Google Book search).
5. ↑ Orefa-Clopyralid ( Memento from July 15, 2014 in the Internet Archive ) p. 4
6. ↑ Directive 2006/64 / EC of the Commission of July 18, 2006 (PDF) amending Council Directive 91/414 / EEC to include the active substances clopyralid, cyprodinil, fosetyl and trinexapac.
7. ↑ General ordinance regarding the deletion of plant protection products from the list of plant protection products not subject to authorization of April 2, 2015
8. ^ Directorate-General for Health and Food Safety of the European Commission: Entry on clopyralid in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on February 16, 2016.