Dicofol 三氯杀螨醇

三氯杀螨醇

三氯杀螨醇1,1-二（对氯苯基）-2,2,2-三氯乙醇，又名开乐散。一般为20%乳油，外观淡黄色至红棕色单相透明油状液体，纯品为固体，在酸性中稳定，遇碱易分解。属于广谱性杀螨剂，对成螨、幼若螨和卵均有效。有较好选择性，不伤害天敌，对害螨以触杀为主，残效期长，无内吸作用。用于防治棉花、果树、花奔多种害螨。

性能
纯品为白色固体，工业品为褐色粘稠状液体。不溶于水，能溶于多种有机溶剂；在酸性液中稳定，在碱性介质中易分解失效。该药对人、畜毒性低，对螨类天敌和作物均较安全，是一种广谱性杀螨剂，以触杀作用为主，无内吸性，残效期长。对有效地防治果树、花卉等作物上多种害螨。本剂对各种红蜘蛛的成螨、幼若螨和卵均有很强杀伤作用，且杀伤作用迅速。该药分解较慢，施药1年后作物仍有少量残留，经数年使用后，能使某些害螨对该药产生不同程度的抗药性。
分子式：C14H9Cl5O 相对分子质量（分子量）：370.48 CAS:115-32-2

制剂
20%三氯杀瞒醇乳油。
属有机氯杀螨剂，杀螨谱广，活性高，对作物安全。该药属神经毒剂，对害螨有较强的触杀作用，无内吸性，对成、若螨和卵均有很强的毒杀作用，残效期近20天。剂型20%乳油。

使用方法
(1)防治柑橘红蜘蛛，在春梢大量抽生期，或幼若螨发生始盛期，用20%乳油800一l000倍液均匀喷雾。防治柑橘锈壁虱，在害螨发生始盛期，或害螨尚未转移危害果实前。用20%乳油l000一l500倍液均匀喷雾。
(2)防治苹果红蜘蛛、山楂红蜘蛛，在苹果开花前后，幼若螨发生始盛期，平均每叶螨数3—4头；夏季平均每叶螨数6—7头时，用20%乳油800一l000倍液均匀喷雾。
(3)防治菊花、玫瑰等花卉上的害螨，在害螨发生始盛期，用20%乳油l000—3000倍液均匀喷雾。

注意事项
(1)本品不能与碱性药物混用。(2)不宜用于茶树、食用菌、蔬菜、瓜类、草莓等作物。(3)在柑橘、苹果等采收前45天，应停止用药。(4)苹果的红玉等品种对该药容易产生药害，使用时要注意安全。

dicofol
Acaricide
IRAC 20

NOMENCLATURE
Common name dicofol (BSI, E-ISO, (m) F-ISO, ESA); kelthane (JMAF); no name (Germany)
IUPAC name 2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethanol
Chemical Abstracts name 4-chloro-a-(4-chlorophenyl)-a-(trichloromethyl)benzenemethanol
CAS RN [115-32-2] EEC no. 204-082-0 Development codes FW-293 (Rohm & Haas) Official codes ENT 23 648

PHYSICAL CHEMISTRY
Composition Tech. is 95% pure, composed of 80% dicofol and 20% its -1-(2-chlorophenyl)-1-(4-chlorophenyl)- isomer ('o,p'-dicofol'). Mol. wt. 370.5 M.f. C14H9Cl5O Form Colourless solid; (tech. is a brown, viscous oil). M.p. 78.5-79.5 ºC B.p. 193 ºC/360 mmHg (tech.) V.p. 0.053 mPa (25 °C, tech.) KOW logP = 4.30 S.g./density 1.45 (25 ºC; tech.) Solubility In water 0.8 mg/l (25 ºC). In acetone, ethyl acetate, toluene 400, methanol 36, hexane, isopropanol 30 (all in g/l, 25 ºC). Stability Stable to acids, but unstable in alkaline media, being hydrolysed to 4,4'-dichlorobenzophenone and chloroform; DT50 (pH 5) 85 d, (pH 7) 64-99 h, (pH 9) 26 min. The 2,4'-isomer is hydrolysed more rapidly. Degraded by light to 4,4'-dichlorobenzophenone. Stable £80 ºC. WP formulations are sensitive to solvents and surfactants, and these may affect acaricidal activity and phytotoxicity. F.p. 193 °C (open cup)

COMMERCIALISATION
History Acaricide reported by J. S. Barker & F. B. Maugham (J. Econ. Entomol., 1956, 49, 458). Introduced by Rohm & Haas Co. (now Dow AgroSciences). First marketed in the US in 1957. Patents US 2812280; US 2812362; US 3102070; US 3194730 Manufacturers Dow AgroSciences; Hindustan; Jiangsu Yangnong; Lainco; Makhteshim-Agan

APPLICATIONS
Biochemistry Site II electron transport inhibitor. Mode of action Non-systemic acaricide with contact action. Uses Non-systemic acaricide with little insecticidal activity, recommended (at 0.50-2.0 kg/ha) for control of many species of phytophagous mite (including Panonychus, Phyllocoptruta, Tetranychus, and Brevipalpus spp.) on a wide range of crops, including fruit, vines, ornamentals, vegetables, and field crops. Phytotoxicity Non-phytotoxic when used as directed, but aubergines and pears may be injured. Formulation types DP; EC; SC; WP. Compatibility Incompatible with highly alkaline materials. WP formulations are sensitive to solvents and surfactants, which may affect acaricidal activity and phytotoxicity. Selected products: 'Acarin' (Makhteshim-Agan); 'AK 20' (Ingeniería Industrial); 'Cekudifol' (Cequisa); 'Dimite' (Nagarjuna Agrichem); 'Hilfol' (Hindustan); 'Might' (Devidayal); 'Mitigan' (Makhteshim-Agan); mixtures: 'Cekudit-combi' (+ dimethoate+ tetradifon) (Cequisa); 'Vapcothion' (+ tetradifon) (Vapco)

OTHER PRODUCTS
'Kelthane' (Dow AgroSciences); 'Agrothane' (AgroSan); 'Colonel-S' (Indofil); 'Ditranil' (Papaeconomou); 'Kelteran' (Aragro); 'Remadion' (Sedagri) mixtures: 'Cekudit' (+ tetradifon) (Cequisa) Discontinued products mixtures: 'Childion' * (+ tetradifon) (Hortichem)

ANALYSIS
Product analysis by hplc (CIPAC Handbook, 1988, D, 67; AOAC Methods, 17th Ed., 986.06), by potentiometric titration of the hydrolysable chlorine (ibid., 976.02*) or by glc. Residues determined by glc (Pestic. Anal. Man., 1979, 201-A, 201-G, 201-I; M. A. Luke et al., J. Assoc. Off. Anal. Chem., 1981, 64, 1187; Anal. Methods Pestic. Plant Growth Regul., 1972, 6, 415; Man. Pestic. Residue Anal., 1987, I, S8, S9, S12, S19).

MAMMALIAN TOXICOLOGY
Reviews FAO/WHO 65, 67 (see part 2 of the Bibliography). IARC ref. 30 class 3 Oral Acute oral LD50 for male rats 595, female rats 578 mg/kg; rabbits 1810 mg tech./kg. Skin and eye Acute percutaneous LD50 for rats >5000, rabbits >2500 mg/kg. Inhalation LC50 (4 h) for rats >5 mg/l air. NOEL In 2 y combined oncogenic and feeding trials, NOEL for rats 5 mg/kg diet (0.22 mg/kg daily for males, 0.27 mg/kg daily for females). In 2-generation reproduction study, NOEL for rats 5 mg/kg diet (0.5 mg/kg daily). In 1 y feeding study, NOEL for dogs 30 mg/kg diet (0.82 mg/kg daily); in 13 w trial, for mice, 10 ppm (2.1 mg/kg b.w. daily). ADI (JMPR) 0.002 mg/kg [1992]. Toxicity class WHO (a.i.) III; EPA (formulation) II or III EC classification Xn; R21/22| Xi; R38| R43| N; R50, R53

ECOTOXICOLOGY
Birds LC50 (5 d) for bobwhite quail 3010, Japanese quail 1418, ring-necked pheasants 2126, mallard ducks 1651 ppm. In eggshell quality and reproduction studies, NOAEL for American kestrel 2, mallard ducks 2.5, bobwhite quail 110 mg/kg diet. Fish LC50 (96 h) for channel catfish 0.30, bluegill sunfish 0.51, largemouth bass 0.45, fathead minnow 0.183, sheepshead minnow 0.37 mg/l. LC50 (24 h) for rainbow trout 0.12 mg/l. Life-cycle NOEC for fathead minnow 0.0045 mg/l; early life-stage rainbow trout NOEC 0.0044 mg/l. Daphnia LC50 (48 h) 0.14 mg/l. Algae EC50 (96 h) for Scenedesmus 0.075 mg/l. Other aquatic spp. LC50 (96 h) for mysid shrimp (Mysidopsis bahia) 0.06 mg/l; EC50 for oyster shell 0.15, fiddler crab 64, invertebrate early life stage (Hyalella) 0.19 mg/l. Bees Not toxic to bees; LD50 (contact) >50 mg tech./bee; (oral) >10 mg tech./bee. Worms LC50 (7 d) 43.1 ppm, (14 d) 24.6 ppm.

ENVIRONMENTAL FATE
Animals In rats, following oral administration, 4,4'-dichlorobenzophenone and 2,2'-dichloro-1,1'-bis(chlorophenyl)ethanol are the principal metabolites. The same metabolites have been detected in laying hens and dairy goats. Plants The principal metabolite in plants is 4,4'-dichlorobenzophenone. Soil/Environment Soil photodegradation DT50 (silt loam) 30 d. Aqueous photodegradation DT50 (pH 5, sensitised conditions) 1-4 d; (unsensitised conditions) 15-93 d. Soil metabolism (aerobic) in silt loam 61 d (2,4'-isomer 7 d); (anaerobic) 16 d. Soil adsorption Koc 8383 (sand), 8073 (sandy loam), 5868 (silty loam), 5917 (clay loam). Field dissipation DT50 60-100 d. No mobility of parent or metabolites detected. Dichlorobenzophenone is a major degradate in all processes.