Specification :

Clofentezine

Common name: clofentezine
IUPAC name: 3, 6-bis( 2-chlorophenyl) -1, 2, 4, 5-tetrazine
Chemical Abstracts name: 3, 6-bis( 2-chlorophenyl) -1, 2, 4, 5-tetrazine
CAS RN: [ 74115-24-5]

PHYSICAL CHEMISTRY
Mol. wt.: 303.1; M.f.: C14H8Cl2N4; Form Magenta crystals. M.p.: 182.3 º C; V.p.: 1.3x10-4 mPa ( 25 º C) ( gas saturation and glc) . KOW: logP = 4.1 ( 25 º C) . Henry: 1.97x10-4 Pa m3 mol-1 ( calc.) S.g./ density: 1.51 ( 20 ° C) . Solubility: In water 2.5 ug/ l ( pH 5, 22 º C) . In dichloromethane 37, acetone 9.3, hexane 1, ethanol 0.5 ( all in g/ l, 25 º C) . Stability: The a.i. and formulated products are stable to light, heat and air; on hydrolysis ( 22 º C) , DT50 248 h ( pH 5) , 34 h ( pH 7) , 4 h ( pH 9) . F.p.: Low flammability.

APPLICATIONS
Mode of action: Specific acaricide with contact action, and long residual activity. Inhibits embryo development.
Uses: Control of eggs and young motile stages ( but not adults) of Panonychus ulmi and Tetranychus spp. on pome fruit and stone fruit ( 20 g/ hl) , citrus fruit ( 12.5-20 g/ hl) , nuts, vines ( 20 g/ hl) , hops, strawberries ( 200-300 g/ ha) , cucurbits ( 100-400 g/ ha) , cotton ( 150-250 g/ ha) , and ornamentals ( 20-30 g/ hl) . Has no effect on predatory mites or beneficial insect species.
Phytotoxicity: May cause slight injury to glasshouse roses. May cause a slight pink deposit on petals of white or pale flowers.
Formulation types: SC; WP.

MAMMALIAN TOXICOLOGY
Oral: Acute oral LD50 for rats > 5200 mg/ kg.
Skin and eye: Acute percutaneous LD50 for rats > 2100 mg/ kg. Mild eye and skin irritant. Inhalation LC50 ( 4 h) for rats > 9 mg/ l air.
NOEL: ( 2 y) for rats 40 mg/ kg diet; ( 1 y) for dogs 50 mg/ kg diet.
ADI: 0.02 mg/ kg b.w.
Toxicity class: WHO ( a.i.) III ( Table 5) ; EPA ( formulation) III

ECOTOXICOLOGY
Birds: Acute oral LD50 for mallard ducks > 3000, bobwhite quail > 7500 mg/ kg. Dietary LC50 ( 8 d) for mallard ducks and bobwhite quail > 2000 mg/ kg diet.
Fish: LC50 ( 96 h) for rainbow trout > 0.015, bluegill sunfish > 0.25 mg/ l ( limits of solubility) .
Daphnia: LC50 ( 48 h) > 1.45 ug/ l ( limit of solubility) .
Algae: Not toxic to Scenedesmus panonicus up to limit of solubility.
Bees: Acute LD50 ( oral) > 20 ug/ bee; LC50 ( contact) > 1500 ppm.

ENVIRONMENTAL FATE
Animals: In mammals, undergoes metabolism by hydroxylation and exchange of the chlorine atoms on the rings for methylthio groups. Following oral administration, excretion occurs within 24-48 hours in the urine and faeces.
Plants: In metabolism studies, unchanged clofentezine was the major extractable residue. Trace amounts ( 4% ) of 2-chlorobenzonitrile, the major photodegradation product, were also detected.
Soil/ Environment: In soil, the major degradation route leads to 2-chlorobenzoic acid, and finally to CO2. DT50 in soil 65-85 d ( 15 º C) , 28-56 d ( 25 º C) , depending upon soil type. However, in laboratory studies, no leaching occurs. In water, 2-chlorobenzonitrile is the major product formed by hydrolysis and photodegradation, with smaller amounts of other compounds. Low solubility in water makes determination of soil adsorption constants difficult.