NOMENCLATURE

fluazifop-P-butyl

IUPAC name butyl (R)-2-[4-(5-trifluoromethyl-2-pyridyloxy)phenoxy]propionate 

Chemical Abstracts name butyl (R)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoate 

CAS RN [79241-46-6]  Development codes PP005; ICIA0005 (both ICI); SL-118 (Ishihara Sangyo) 

fluazifop-P

Common name fluazifop-P (BSI, draft E-ISO, (m) draft F-ISO, ANSI)

IUPAC name (R)-2-[4-(5-trifluoromethyl-2-pyridyloxy)phenoxy]propionic acid 

Chemical Abstracts name (R)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid 

CAS RN [83066-88-0] 

PHYSICAL CHEMISTRY

fluazifop-P-butyl

Composition Tech. is ³90% pure.  Mol. wt. 383.4  M.f. C₁₉H₂₀F₃NO₄  Form Colourless liquid.  M.p. -20 ºC (glass-like)  B.p. 154 ºC/0.02 mmHg  V.p. 0.033 mPa (20 ºC)  K_OW logP = 4.5 (20 ºC)  Henry 1.1 ´ 10^-2 Pa m³ mol^-1  S.g./density 1.22 (20 ºC)  Solubility In water 1.1 mg/l (20 °C). Miscible with acetone, hexane, methanol, dichloromethane, ethyl acetate, toluene, and xylene.  Stability Fluazifop-P-butyl is stable to u.v. light. Hydrolysis DT₅₀ >30 d (pH 5), 78 d (pH 7), 29 h (pH 9). Aqueous photolysis DT₅₀ 6 d (pH 5).  pKa -3.1 (calc.)  F.p. 83 °C 

fluazifop-P

Mol. wt. 327.3  M.f. C₁₅H₁₂F₃NO₄  Form Pale yellow, glass-like material.  M.p. Glass transition temperature 4 °C  V.p. 7.9 ´ 10^-4 mPa (20 °C)  K_OW logP = 3.1 (pH 2.6, 20 °C), -0.8 (pH 7, 20 °C, est.)  Henry 3 ´ 10^-7 Pa m³ mol^-1 (calc.)  Solubility In purified water 780 mg/l (20 °C).  Stability No significant hydrolysis at pH 5, 7 and 9 (25 °C).  pKa 2.98 

APPLICATIONS

fluazifop-P-butyl

Biochemistry Fatty acid synthesis inhibitor, by inhibition of acetyl CoA carboxylase (ACCase).  Mode of action Fluazifop-P-butyl is quickly absorbed through the leaf surface, hydrolysed to fluazifop-P and translocated through the phloem and xylem, accumulating in the rhizomes and stolons of perennial grasses and the meristems of annual and perennial grasses.  Uses Post-emergence control of wild oats, volunteer cereals, and annual and perennial grass weeds in oilseed rape, sugar beet, fodder beet, potatoes, vegetables, cotton, soya beans, pome fruit, stone fruit, bush fruit, vines, citrus fruit, pineapples, bananas, strawberries, sunflowers, alfalfa, ornamentals, and other broad-leaved crops. Applied at 125-375 g/ha.  Phytotoxicity Non-phytotoxic to broad-leaved crops.  Formulation types EC; EW. 

ANALYSIS

Product analysis for total fluazifop-butyl ((R)- and (S)- isomers) by gc with FID; hplc with u.v. detection is then used to determine the ratio of (R)- to (S)- isomers (CIPAC Handbook, 1995, G, 71-81). Residues (fluazifop-P-butyl, fluazifop-P, free and conjugates) as total acid by hplc. For details, see G. S. Davy et al. in Comp. Anal. Profiles, Chapt. 7. 

MAMMALIAN TOXICOLOGY

fluazifop-P-butyl

Oral Acute oral LD₅₀ for male rats 3680, female rats 2451 mg/kg.  Skin and eye Acute percutaneous LD₅₀ for rabbits >2000 mg/kg. Slight skin and mild eye irritant (rabbits). Not a skin sensitiser (guinea pigs).  Inhalation LC₅₀ (4 h) for rats >5.24 mg/l.  NOEL NOAEL (2 y) for rats 1.0 mg/kg b.w. daily (10 mg/kg diet); (1 y) for dogs 25 mg/kg b.w. daily; (90 d) for rats 9.0 mg/kg b.w. daily (100 mg/kg diet). Multi-generation study (rats) 0.9 mg/kg b.w. daily (10 mg/kg diet); developmental toxicity for rats 5 mg/kg b.w. daily, for rabbits 30 mg/kg b.w. daily.  ADI (EPA) 0.01 mg/kg.  Other Genotoxicity negative.  Toxicity class WHO (a.i.) III

ECOTOXICOLOGY

fluazifop-P-butyl

Birds Acute oral LD₅₀ for mallard ducks >3500 mg/kg.  Fish LC₅₀ (96 h) for rainbow trout 1.3 mg/l.  Daphnia EC₅₀ (48 h) >1.0 mg/l.  Algae EC₅₀ (72 h) for Navicula pelliculosa 0.51 mg/l.  Bees Very low toxicity to bees. LD₅₀ (oral and contact) >0.2 mg/bee.  Worms LC₅₀ >1000 mg/kg. 

fluazifop-P

Fish LC₅₀ (96 h) for rainbow trout 117 mg/l.  Daphnia EC₅₀ (48 h) 240 mg/l.  Algae EC₅₀ (72 h) for Selenastrum capricornutum >56 mg/l. 

ENVIRONMENTAL FATE

fluazifop-P-butyl

Animals In mammals, fluazifop-P-butyl is metabolised to fluazifop-P, which is rapidly excreted.  Plants In plants, fluazifop-P-butyl is rapidly hydrolysed to fluazifop-P, which is then partly conjugated. Ether cleavage gives the pyridone and propionic acid metabolites, which may both be further metabolised or conjugated.  Soil/Environment K_oc 5800. In moist soils, rapid degradation of fluazifop-P-butyl occurs, DT₅₀ <24 h. The major degradation product is fluazifop-P, which is hydrolysed to 5-trifluoromethylpyrid-2-one, and 2-(4-hydroxyphenoxy)propionic acid, both of which are further degraded, ultimately to CO₂. 

fluazifop-P

Soil/Environment In laboratory soil (40% MHC, pH 5.3-7.7), DT₅₀ 2-9 d (20 °C). Field DT₅₀ <4 w. K_oc 39-84. For degradation route, see fluazifop-P-butyl.