Metolachlor (Metholachlor) 异丙甲草胺

异丙甲草胺

异丙甲草胺纯品为无色液体，比重(20℃)为1.12，沸点100℃，闪点110～180℃。在水中溶解度530mg/kg(20℃)，可与大多数有机溶剂混溶，常温贮存稳定期两年以上。异丙甲草胺72%乳油为棕黄色液体，乳化性能良好，可与许多除草剂相混，常温贮存稳定性两年以上。异丙甲草胺运用于旱地作物、蔬菜作物和果园、苗圃使用，可防除牛筋草、马唐、狗尾草、棉草等一年生禾本科杂草以及苋菜、马齿苋等阔叶杂草和碎米莎草、油莎草。

基本介绍
异丙甲草胺
英文名：METOLACHLOR
分子式：C15H22ClNO2
分子量：283.8
结构式：
异丙甲草胺为酰胺类除草剂。
商品名称：都尔(dual)，
化学名称： 2-乙基-6-甲基-N?(1’-甲基-2’-甲氧乙基)氯代乙酰替苯胺[2-ethyl-6-methyl-N-?(1’-?methyl-2’-methoxy-ethyl)chloroacetanilide]。

概述
异丙甲草胺主要通过幼芽吸收，向上传导，抑制幼芽与根的生长。作用机制主要抑制发芽种子的蛋白质合成，其次抑制胆碱渗入磷脂，干扰卵磷脂形成。由于禾本科杂草幼芽吸收异丙甲草胺的能力比阔叶杂草强，因而该药防除禾本科杂草的效果远远好于阔叶杂草。
按我国农药毒性分级标准，异丙甲草胺属低毒除草剂。原药大鼠急性经口LD50为2780 mg/kg，原药大鼠急性经皮LD50>3170mg/kg。对兔眼睛无刺激作用，对兔皮肤有轻微刺激作用，在实验条件下，未见对动物有致畸、致突变、致癌作用。
异丙甲草胺在实验室条件下对鱼有毒，对鸟低毒，对蜜蜂有胃毒，无接触毒性。

检验方法
进口都尔72%乳油的有效成分含量的测定可采用气相色谱法。异丙甲草胺标准品和试样均用内标溶液(十八烷氯仿溶液)溶解，用4.5%OV-225/Chromosor b W HP(80～100目)玻璃柱(?3mm×1m）分离，以氮气为载气，用FID检测，先根据标准品和内标的色谱峰面积及标准品的质量求出校正因子，再根据试样和内标的色谱峰面积及试样的质量计算有效成分含量。

其它介绍
都尔是广谱性播后苗前除草剂。对多种作物如：大豆、玉米、棉花、花生、马铃薯、白菜、菠菜、蒜、
向日葵、芝麻、油菜、萝卜、甘蔗等农作物上使用，也可以在果园及其他豆科、十字花科、茄科、菊科和伞形科作物上使用，能防除一年生禾本科杂草及部分双子叶杂草。芝麻田可在播后苗前每亩用50%甲草胺草胺乳油100～150毫升，加水30～50公斤喷雾于地表，对禾本科草和阔叶草有较好防效。

作用特点
都尔主要通过植物的幼芽即单子叶和胚芽鞘、双子叶植物的下胚轴吸收向上传导。出苗后主要靠根吸收向上传导，抑制幼芽与根的生长。如果土壤墒情好，杂草被杀死在幼芽期；如果土壤水分少，杂草出土后随着降雨土壤湿度增加，杂草吸收都尔叶皱缩后整株枯死。因此施药应在杂草发芽前进行。

药剂特性
都尔为酰胺类选择性除草剂。纯品为无色液体，无臭味，可溶于大多数有机溶剂，在20℃以上时可部分溶于水。对人畜低毒。 都尔是选择性芽前土壤处理剂。对单子叶杂草，主要被种子上部的幼芽吸收；对双子叶杂草可以被幼芽和根部吸收，抑制蛋白质的分解。土中持效期20-50天。
主要剂型

5%、72%乳油。

防除对象及使用方法
都尔可防除稗、马唐、狗尾草、画眉草等一年生杂草及马齿苋、苋、藜等阔叶性杂草。适用于马铃薯、十字花科、西瓜和茄科蔬菜等菜田除草。
（l）直播甜椒、甘蓝、大萝卜、小萝卜、大白菜、小白菜、油菜、西瓜、育苗花椰菜等菜田除草，于播种后至出苗前，亩用72%乳油100克，兑水喷雾处理土壤。
（2）移栽蔬菜田，如甘蓝、花椰菜、甜（辣）椒等，于移栽缓苗后，亩用72%乳油100克，兑水定向喷雾，处理土壤。

注意事项
（l）瓜类、茄果类蔬菜使用浓度偏高时易产生药害，施药时要慎重。
（2）药效易受气温和土壤肥力条件的影响。温度偏高时和砂质土壤用药量宜低；反之，气温较低时和粘质土壤用药量可适当偏高。

metolachlor
Herbicide
HRAC K3 WSSA 15; chloroacetamide

NOMENCLATURE
Common name metolachlor (BSI, E-ISO, ANSI, WSSA); métolachlore ((m) F-ISO)
IUPAC name 2-chloro-6'-ethyl-N-(2-methoxy-1-methylethyl)aceto-o-toluidide
Chemical Abstracts name 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide
CAS RN [51218-45-2] EEC no. 257-060-8 Development codes CGA 24 705 (Ciba-Geigy)

PHYSICAL CHEMISTRY
Composition Racemic mixture of (1S)- and (1R)- isomers. Mol. wt. 283.8 M.f. C15H22ClNO2 Form Colourless to light tan liquid. M.p. -62.1 °C B.p. 100 ºC/0.001 mmHg V.p. 4.2 mPa (25 ºC) (OECD 104) KOW logP = 2.9 (25 ºC) Henry 2.4 ´ 10-3 Pa m3 mol-1 (calc.) S.g./density 1.12 (20 ºC) Solubility In water 488 mg/l (25 ºC) (OECD 105). Miscible with benzene, toluene, ethanol, acetone, xylene, hexane, dimethylformamide, dichloroethane, cyclohexanone, methanol, octanol, and dichloromethane. Insoluble in ethylene glycol, propylene glycol, and petroleum ether. Stability Stable up toc. 275 ºC. Hydrolysed by strong alkalis and strong mineral acids. On hydrolysis in buffer (20 ºC), DT50 (calc.) >200 d (2£pH £10). F.p. 190 °C (1013 mbar)

COMMERCIALISATION
History Herbicide reported by H. R. Gerber et al. (Proc. Br. Weed Control Conf., 12th, 1974, 2, 787). Introduced by Ciba-Geigy AG (now Syngenta AG) and first marketed in 1976. Patents BE 800471; GB 1438311; GB 1438312 Manufacturers Drexel; Sannong; Sharda; Sundat; Syngenta

APPLICATIONS
Biochemistry Cell division inhibitor; more recent research suggests chloroacetamides may inhibit synthesis of very long chain fatty acids (J. Schmalfuss et al., Abstr. Meeting WSSA, Toronto, 40, 117-118, 2000; P. Böger, Abstr. III Int. Weed Control Congr., Brazil 2000). Maize tolerance of chloroacetamides is attributed to rapid detoxification by glutathione transferases. Mode of action Selective herbicide, absorbed predominantly by the hypocotyls and shoots. Inhibits germination. Uses Control of annual grasses and some broad-leaved weeds in maize, sorghum, cotton, sugar beet, fodder beet, sugar cane, potatoes, peanuts, soya beans, safflowers, sunflowers, various vegetables, fruit and nut trees, and woody ornamentals. Applied pre-emergence, pre-plant incorporated or early post-emergence at, 1.0-2.5 kg/ha. Often used in combination with broad-leaved herbicides, to extend the spectrum of activity. Phytotoxicity Well tolerated by most broad-leaved crops, maize, sorghum (safened with fluxofenim or oxabetrinil). Formulation types EC; FW; GR; SC.

OTHER PRODUCTS
Mixtures: 'Indiana' (+ pendimethalin) (BASF); 'Pyracur' (+ chloridazon) (BASF); 'Zeazin Mix Extra' (+ prometryn+ atrazine) (Istrochem) Discontinued products mixtures: 'Bicep II' * (+ atrazine+ benoxacor) (Syngenta); 'Bicep' * (+ atrazine) (USA) (Syngenta); 'Broadstrike Dual' * (+ flumetsulam) (Syngenta); 'Dual II' * (+ benoxacor) (USA) (Syngenta); 'Dual S' * (+ benoxacor) (Syngenta); 'Dual' * (+ benoxacor+ carbendazim) (Novartis); 'Dualin' * (+ linuron) (Novartis); 'Duelor + Safeneur' * (+ benoxacor) (France) (Syngenta); 'Gardoprim Plus' * (+ terbuthylazine) (Syngenta); 'Primagram' * (+ atrazine) (Novartis); 'Primextra Safeneur' * (+ atrazine+ benoxacor) (Syngenta); 'Primextra' * (+ atrazine+ benoxacor) (Europe) (Novartis); 'Zintan' * (+ pyridate+ terbuthylazine) (Syngenta); 'Turbo' * (+ metribuzin) (Bayer)

ANALYSIS
Product analysis by glc with FID (AOAC Methods, 17th Ed., 985.06; CIPAC Handbook, 1988, D, 134). Residues determined by glc with TID or MCD. In drinking water, by glc with NPD (AOAC Methods, 17th Ed., 991.07). Detailsavailable from Syngenta.

MAMMALIAN TOXICOLOGY
Oral Acute oral LD50 for rats 2780 mg/kg. Skin and eye Acute percutaneous LD50 for rats >3170 mg/kg. Mild skin and eye irritant (rabbits). May cause skin sensitisation (guinea pigs). Inhalation LC50 (4 h) for rats >1.75 mg/l air. NOEL (90 d) for rats 300 mg/kg diet (c. 15 mg/kg daily), for mice 100 mg/kg diet (c. 100 mg/kg daily), for dogs 300 mg/kg diet (c. 9.7 mg/kg daily). ADI 0.1 mg/kg b.w. Water GV 10 mg/l (TDI 3.5 mg/kg b.w.). Toxicity class WHO (a.i.) III; EPA (formulation) III EC classification (R43)

ECOTOXICOLOGY
Birds Acute oral LD50 for mallard ducks and bobwhite quail >2150 mg/kg. Dietary LC50 (8 d) for bobwhite quail and mallard ducks >10 000 mg/kg. Fish LC50 (96 h) for rainbow trout 3.9, carp 4.9, bluegill sunfish 10 mg/l. Daphnia LC50 (48 h) 25 mg/l. Algae EC50 for Scenedesmus subspicatus 0.1 mg/l. Bees LD50 (oral and contact) >110 mg/bee. Worms LC50 (14 d) for earthworms 140 mg/kg soil.

ENVIRONMENTAL FATE
Animals Rapidly oxidised by rat liver microsomal oxygenases via dechlorination, O-demethylation and side-chain oxidation (J. Agric. Food Chem., 1989, 37, 1088). Plants In plants, metabolism involves natural product conjugation of the chloroacetyl group, and hydrolysis and sugar conjugation at the ether group. Final metabolites are polar, water-soluble, and non-volatile. Soil/Environment Major aerobic metabolites are derivatives of oxanilic and sulfonic acids. DT50 in soil c. 20 d (field). Koc 121-309.