Clomazone

Structural formula
General
Surname	Clomazone
other names	2- (2-chlorophenyl) methyl-4,4-dimethyl-3-isoxazolidinone; Dimethazone;
Molecular formula	C 12 H 14 ClNO 2
Brief description	light brown, viscous liquid
External identifiers / databases
EC number	617-258-0
ECHA InfoCard	100.125.682
PubChem	54778
Wikidata	Q2187383
properties
Molar mass	239.70 g mol −1
Physical state	liquid
density	1.19 g cm −3
Melting point	25 ° C
boiling point	275 ° C
Vapor pressure	<0.001 hPa (25 ° C)
solubility	hardly soluble in water (1.1 g l −1 at 20 ° C); soluble in acetone, acetonitrile, chloroform, cyclohexanone, dimethylformamide, dioxane, heptane, hexane, methanol, methylene chloride, toluene and xylene;
safety instructions
GHS labeling of hazardous substances Caution
H and P phrases	H: 302 + 332-315-319
	P: 261-301 + 312 + 330-305 + 351 + 338
Toxicological data	1369 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 .

Clomazone is a chemical compound from the group of oxazolidinones , which was patented by FMC in 1983 as a selective herbicide and introduced in the early 1990s.

Extraction and presentation

Clomazon can be obtained from 2-chlorobenzaldehyde and hydroxylamine . Their product reacts further with a cyanoborohydride to form N - ((2-chlorophenyl) methyl) hydroxylamine, which gives the end product through reaction with dimethylchloromethylacetyl chloride .

properties

Clomazone is a light brown, viscous liquid that is sparingly soluble in water. It is stable to hydrolysis in acidic, neutral and basic environments.

use

Estimated 2011 US application rate

Clomazone is used as a herbicide mainly in rapeseed, but also in soy, corn, peas, sugar beet and, increasingly, rice cultivation. It is used pre-emergence and up to 5 days after sowing . The active ingredient inhibits DXP synthase in the carotenoid synthesis and thus u. a. the formation of the leaf pigment chlorophyll .

Admission

Oilseed rape plants treated with clomazone

The use of the active ingredient clomazone as a herbicide was permitted in the EU on November 1, 2008.

In August 2011 there had been reports of health impairments after the application of clomazone-containing plant protection products in Mecklenburg-Western Pomerania and leaf lightening on plants had been observed in the vicinity of treated areas. The Federal Office for Consumer Protection and Food Safety (BVL) then decided to suspend approval. Clomazone has an above-average vapor pressure at typical field temperatures and can therefore not only cause damage to neighboring areas by drift , but also by evaporation.

Since the BVL considered a connection between the reported symptoms due to the pesticides in question to be unlikely, the suspension of the authorization was lifted in January 2012 and at the same time amended application provisions were set.

So now 100 m distance to localities and areas for the general public as well as 5 m distance to all other areas must be kept. The product must not be used if the forecast maximum daily temperature corresponds to the melting point of Clomazone (25 ° C). In addition, residents must be informed at their request at least one day before the planned use of clomazone-containing pesticides. The treatment of the areas must be precisely documented and the documentation must always be carried with you when using plant protection.

In Germany, Austria and Switzerland are pesticides (eg. As Centium CS Command) approved this drug.

In 2011, about 400 tons of clomazone were applied in the USA.

Individual evidence

↑ ^a ^b ^c ^d ^e Entry on clomazone. In: Römpp Online . Georg Thieme Verlag, accessed on May 25, 2014.
↑ ^a ^b ^c ^d ^e ^f ^g ^h data sheet Clomazone, PESTANAL at Sigma-Aldrich , accessed on May 18, 2017 ( PDF ).
↑ ^a ^b Entry Clomazone at Extoxnet.
↑ Patent US4405357 : Herbicidal 3-isoxazolidinones and hydroxamic acids. Applied May 11, 1981 , Published September 20, 1983 , Applicant: FMC Corporation, Inventor: Jun H. Chang. ‌
↑ Thomas A. Unger: Pesticide Synthesis Handbook . William Andrew, 1996, ISBN 0-08-095716-1 , pp. 488 ( limited preview in Google Book search).
↑ US EPA-Pesticides: Clomazone , accessed January 21, 2015.
↑ Yurdagul Ferhatoglu, Michael Barrett: Studies of clomazone mode of action . In: Pesticide Biochemistry and Physiology . tape 85 , no. 1 , May 2006, p. 7-14 , doi : 10.1016 / j.pestbp.2005.10.002 .
↑ Directive 2007/76 / EC of the Commission of December 20, 2007 amending Council Directive 91/414 / EEC to include the active substances fludioxonil, clomazone and prosulfocarb .
↑ Bavarian State Research Center for Agriculture: New application regulations for rape herbicides containing clomazone: Rape herbicide market in upheaval in 2012 .

↑ BVL - Press and Background Information - Change in authorization for plant protection products with the active ingredient Clomazone. Retrieved June 6, 2019 .

↑ Requirements for all products containing clomazone

^ Directorate-General for Health and Food Safety of the European Commission: Entry on Clomazone in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on March 13, 2016.

[roempp-1] Entry on clomazone. In: Römpp Online . Georg Thieme Verlag, accessed on May 25, 2014.

[Sigma-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h data sheet Clomazone, PESTANAL at Sigma-Aldrich , accessed on May 18, 2017 ( PDF ).

[Extoxnet-3] Entry Clomazone at Extoxnet.

[4] Patent US4405357 : Herbicidal 3-isoxazolidinones and hydroxamic acids. Applied May 11, 1981 , Published September 20, 1983 , Applicant: FMC Corporation, Inventor: Jun H. Chang. ‌

[Thomas_A._Unger-5] Thomas A. Unger: Pesticide Synthesis Handbook . William Andrew, 1996, ISBN 0-08-095716-1 , pp. 488 ( limited preview in Google Book search).

[EPA-6] US EPA-Pesticides: Clomazone , accessed January 21, 2015.

[7] Yurdagul Ferhatoglu, Michael Barrett: Studies of clomazone mode of action . In: Pesticide Biochemistry and Physiology . tape 85 , no. 1 , May 2006, p. 7-14 , doi : 10.1016 / j.pestbp.2005.10.002 .

[8] Directive 2007/76 / EC of the Commission of December 20, 2007 amending Council Directive 91/414 / EEC to include the active substances fludioxonil, clomazone and prosulfocarb .

[LFL-9] Bavarian State Research Center for Agriculture: New application regulations for rape herbicides containing clomazone: Rape herbicide market in upheaval in 2012 .

[BVL-10] BVL - Press and Background Information - Change in authorization for plant protection products with the active ingredient Clomazone. Retrieved June 6, 2019 .

[syngenta-11] Requirements for all products containing clomazone

[PSM-12] Directorate-General for Health and Food Safety of the European Commission: Entry on Clomazone in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on March 13, 2016.