Dichlorvos

Common name dichlorvos (BSI, E-ISO, (m) F-ISO, BAN, ESA); DDVP (JMAF); dichlorfos (USSR); DDVF* (former exception, USSR)

IUPAC name 2,2-dichlorovinyl dimethyl phosphate 

Chemical Abstracts name 2,2-dichloroethenyl dimethyl phosphate 

CAS RN [62-73-7] 

PHYSICAL CHEMISTRY

Mol. wt. 221.0  M.f. C4H7Cl2O4P  Form Colourless liquid; (tech., colourless-to-amber liquid, with an aromatic odour).  B.p. 234.1 ºC/1 ´ 105 Pa (OECD 103); 74 °C/1.3 ´ 102 Pa  V.p. 2.1 ´ 103 mPa (25 ºC) (OECD 104)  KOW logP = 1.9 (OECD 117); 1.42 (separate study)  Henry 2.58 ´ 10-2 Pa m3 mol-1  S.g./density 1.425 (20 ºC) (OECD 109)  Solubility In water c. 18 g/l (25 ºC). Completely miscible with aromatic hydrocarbons, chlorinated hydrocarbons and alcohols; moderately soluble in diesel oil, kerosene, isoparaffinic hydrocarbons, and mineral oils.  Stability Stable to heat. Slowly hydrolysed in water and in acidic media, and rapidly hydrolysed by alkalis, to dimethyl hydrogen phosphate and dichloroacetaldehyde; DT50 (est.) 31.9 d (pH 4), 2.9 d (pH 7), 2.0 d (pH 9) (22 ºC).  F.p. >100 °C (DIN 51758); 172 °C (Pensky-Martens closed cup, 1 ´ 105 Pa) 

APPLICATIONS

Biochemistry Cholinesterase inhibitor. 

Mode of action Insecticide and acaricide with respiratory, contact, and stomach action. Gives rapid knockdown.

 Uses Control of household and public health insect pests, e.g. flies, mosquitoes, cockroaches, bedbugs, ants, etc.; stored-product pests in warehouses, storerooms, etc.; flies and midges in animal houses; sciarid and phorid flies in mushrooms; sucking and chewing insects, and spider mites in a wide range of crops, including fruit, vines, vegetables, ornamentals, tea, rice, cotton, hops, glasshouse crops, etc. Also used as a veterinary anthelmintic. 

Phytotoxicity Non-phytotoxic when used as directed, except to some varieties of chrysanthemum. 

Formulation types AE; EC; GR; HN; KN; OL; SL; Impregnated strip.