RESMETHRIN

Chemical Properties

Off-white to tan waxy solid or colorless crys- tals. Chrysanthemum-like odor. Commercial products may be dissolved in flammable organic solvents

Uses

Resmethrin is used to control a wide range of insects in horticultural, household, public health and animal health situations. It has some agricultural use but this is limited. The more active 1Rtrans form has a similar range of uses and is also used in stored grain products.

Definition

ChEBI: Resmethrin is a member of furans and a cyclopropanecarboxylate ester. It has a role as a pyrethroid ester insecticide and an agrochemical. It is functionally related to a chrysanthemic acid.

General Description

Colorless crystals or waxy solid. Insoluble in water. Used as an insecticide.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

A pyrethroid derivative.

Agricultural Uses

Insecticide: Resmethrin is currently used for mosquito control (by aerial application) in the USA, and may can also be used in greenhoused to control white fly. Resmethrin is a synthetic Type I pyrethroid insecticide registered for control of insects in residential, commercial and industrial settings, and in animal living areas. Resmethrin is also registered for use in food-handling establishments and as a restricted use pesticide when used in ULV spray to control adult mosquitoes in the interest of public health[83]. Restricted Use Pesticide (RUP) when formulated for use in mosquito abatement and pest control treatments at nonagricultural sites. Restricted due to extreme fish toxicity. Not approved for use in EU countries.

Trade name

(d-trans-isomer); SBP® 1382 (d-trans-isomer); d-transSBP® 1382 (d-trans-isomer); SBP®-1390; S. B. PENICK 1382®; SCOURGE®; SUN-BUGGER®; SYNTHRIN®; SYNTOX®; VECTRIN®; WHITMIRE® PT-110

Safety Profile

Poison by ingestion, andintravenous routes. Moderately toxic by inhalation andskin contact. When heated to decomposition it emits acridand irritating fumes.

Potential Exposure

Resmethrin is pyrethroid insecticide used for mosquito control (by aerial application) in the USA, and may can also be used in greenhouses to control white fly. Resmethrin is a synthetic Type I pyrethroid insecticide registered for control of insects in residential, commercial, and industrial settings, and in animal living areas. It is also registered for use in food handling estab- lishments and as a restricted use pesticide when used in ULV spray to control adult mosquitoes in the interest of public health . A United States Restricted Use Pesticide (RUP) when formulated for use in mosquito abatement and pest control treatments at nonagricultural sites. Restricted due to extreme fish toxicity.

Metabolic pathway

14C-resmethrin are individually administered orally to white leghorn hens, and more than 90% of the radioactivity is eliminated in the excreta within 24 h of treatment. The metabolic routes for both resmethrin isomers arise from ester hydrolysis and oxidation of the hydrolytic products. Some of these metabolites are further conjugated with glucuronic acid, sulfate, or other unidentified compounds before excretion.

Shipping

UN3352 Pyrethroid pesticide, liquid toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials. UN3349 Pyrethroid pesticide, solid toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous material

Degradation

The resmethrins are reasonably stable but they are sensitive to base hydrolysis forming the chrysanthemic acid isomers (2) and 5-benzyl-3- furylmethanol (3). They are also sensitive to oxidation and to photodecomposition. Photo-oxidation involves degradation of the furan ring to yield a cyclic ozonide peroxide by addition of oxygen across the unsaturated system forming the hydroxylactone derivative (4), the benzyloxylactone derivative (5) and the hydroxycyclopentenolone (6) (Ueda et al., 1974). These chemical and photochemical reactions are shown in Scheme 1.
Degradation also occurs in the acid moiety by reactions analogous to those described under phenothrin, for example, oxidation at the isobutylene substituent to afford a variety of alcohols, aldehydes and carboxylic acids. These two sites of weakness in the resmethrin molecule result in considerable photo-instability (though they are more stable than the pyrethrins) and to a complex mixture of degradation products.

Incompatibilities

Decomposed by air, light, alkaline media, and temperatures .175℃. May react violently with strong oxidizers, bromine, 90% hydrogen peroxide, phos- phorus trichloride, silver powders or dust. Incompatible with silver compounds. Mixture with some silver compounds forms explosive salts of silver oxalate.

Waste Disposal

Incineration would be an effective disposal procedure where permitted. If an efficient incinerator is not available, the product should be mixed with large amounts of combustible material and contact with the smoke should be avoided. In accordance with 40CFR165. Follow recommendations for the disposal of pesticides and pesticide containers . Bury in noncrop land away from water. It would be better to mix the prod- uct with lime. Incineration would be an effective disposal procedure where permitted. If an efficient incinerator is not available, the product should be mixed with large amount of combustible material. Recommendable methods: Hydrolysis, landfill, incineration, and open burning. Not recommendable method: Discharge to sewer. Mix with saw- dust and burn at a remote place .