Pretilachlor 丙草胺

丙草胺

基本信息：
丙草胺是具有高选择性的水稻田专用除草剂。对水稻安全，杀草谱广。杂草种子在发芽过程中吸收药剂，根部吸收较差。只能作芽前土壤处理。水稻发芽期对丙草胺也比较敏感，为保证早期用药安全，丙草胺常加入安全剂CGA123407使用。
英文通用名： pretilachlor
其他名称： 扫弗特(Sofit)
CAS号：51218-49-6
分子式：C15H22ClNO2
分子量：283.81
化学名称：2-氯-N-(1-甲基-2-甲氧乙基)-N-(2-乙基-6-甲基苯基)乙酰胺
毒性： 对人畜低毒，大鼠经口LD50为6099毫克/公斤，急性经皮LD50>3100毫克/公斤，鱼毒较高，鲤鱼LC50为9.8毫克/公斤。
剂型： 72%乳油、50%乳油、30%乳油。
特点： 是具有高选择性的水稻田专用除草剂。对水稻安全，杀草谱广。杂草种子在发芽过程中吸收药剂，根部吸收较差。只能作芽前土壤处理。水稻发芽期对丙草胺也比较敏感，为保证早期用药安全，丙草胺常加入安全剂CGA123407使用。

理化性质：
无色液体。沸点100℃（0.133kPa），折光率1.5301。蒸气压（20℃）1.73×10-3Pa。在20℃水中溶解度为530ppm，溶于多数有机溶剂。

适用范围：
适用于水稻防除稗草、光头稗、千金子、牛筋草、牛毛毡、窄叶泽泻、水苋菜、异型莎草、碎米莎草、丁香蓼、鸭舌草等1年生禾本科和阔叶杂草。

使用方法：
在水直播田和秧田使用，先整好地，然后催芽播种。播种后2-4天，灌浅水层，每亩用30%乳油100-115毫升，对水30公斤或混细潮土20公斤均匀喷雾或撒施全田，保持水层3-4天。

主要用途：
该品为芽前除草剂，主要用于防除禾本科杂草。产品属2-氯化乙酰替苯胺类除草剂，是细胞分裂抑制剂，用于土壤处理可防除稻田稗草、异型莎草、牛毛毡、鸭舌草、窄叶泽泻等。通常在插秧前3～5d使用。该品单施时对湿插水稻选择性较差，当与解草啶一起使用时对直插水稻有极好的选择性。如该品与解草啶的混剂以600+200gai/ha使用，对鸭舌草、异型莎草、尖瓣花、飘拂草等效果均在90%以上，而对于千金子防效达100%。

注意事项：
1.地整好后要及时播种、用药，否则杂草出土，影响药效。
2.播种的稻谷要根芽正常。切忌有芽无根。
3.在北方稻区使用，施药时期应适当延长，先行试验，再大面积推广，以免产生药害。

pretilachlor
Herbicide
HRAC K3 WSSA 15; chloroacetamide

NOMENCLATURE
Common name pretilachlor (BSI, E-ISO); prétilachlore ((m) F-ISO)
IUPAC name 2-chloro-2',6'-diethyl-N-(2-propoxyethyl)acetanilide
Chemical Abstracts name 2-chloro-N-(2,6-diethylphenyl)-N-(2-propoxyethyl)acetamide
CAS RN [51218-49-6] Development codes CGA 26 423 (Ciba-Geigy)

PHYSICAL CHEMISTRY
Mol. wt. 311.9 M.f. C17H26ClNO2 Form Colourless liquid. B.p. 135 ºC/0.001 mmHg V.p. 0.133 mPa (20 ºC) KOW logP = 4.08 (shake flask) Henry 8.1 ´ 10-4 Pa m3 mol-1 S.g./density 1.076 (20 ºC) Solubility In water 50 mg/l (20 ºC). Very soluble in benzene, hexane, methanol and dichloromethane. Stability Relatively stable to hydrolysis; DT50 (calc.) (20 ºC) >200 d (pH 1-9), 14 d (pH 13). F.p. 129 °C (EEC A9)

COMMERCIALISATION
History Introduced by Ciba-Geigy AG (now Syngenta AG) in 1988. Patents BE 800471; GB 1438311; GB 1438312 Manufacturers Sharda; 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). Mode of action Selective herbicide. It is taken up readily by the hypocotyls, mesocotyls and coleoptiles, and, to a lesser extent, by the roots of germinating weeds. Uses Herbicide effective against main annual grasses, broad-leaved weeds and sedges in transplanted and seeded rice, at 1-1.25 kg/ha. Phytotoxicity Applied alone, pretilachlor will cause injury to direct-seeded rice. Formulation types EC; GR. Selected products: 'Rifit' (transplanted rice) (Syngenta); 'Solnet' (transplanted rice) (Syngenta); 'Gorbo' (Sumitomo Chemical Takeda); mixtures: 'Sofit' (+ fenclorim) (direct-sown rice) (Syngenta); 'Sing' (+ pyributicarb) (Sankyo Agro); 'Sparkstar G' (+ pyrazosulfuron-ethyl+ dimethametryn+ esprocarb) (Nissan, Syngenta)

OTHER PRODUCTS
Mixtures: 'Hayate' (+ daimuron+ dimethametryn+ imazosulfuron) (Sumitomo Chemical Takeda); 'Kusa Kont' (+ benzobicyclon) (SDS Biotech KK, Syngenta, Sankyo Agro); 'Kusahope D' (+ pyrazolynate+ dimethametryn) (Sankyo Agro); 'Kusanain' (+ pyributicarb+ bensulfuron-methyl+ dimethametryn) (DuPont); 'Pulgman' (+ daimuron+ ethoxysulfuron) (Bayer CropScience); 'Sheriff' (+ cyhalofop-butyl+ dimethametryn+ imazosulfuron) (Otsuka, Sumitomo Chemical Takeda); 'Slasher' (+ pyrazolynate+ bromobutide+ dimethametryn) (Sankyo Agro); 'Topran' (+ pyrazolynate+ ethoxysulfuron) (Bayer CropScience); 'Urifos' (+ pyrazolynate+ benfuresate+ dimethametryn) (Sankyo Agro); 'Wydori A' (+ azimsulfuron+ bensulfuron-methyl+ dimethametryn) (Nihon Nohyaku) Discontinued products: 'Erijan' * (Ciba) mixtures: 'Kusahope' * (+ pyrazolynate) (Sankyo); 'Tabijin A' * (+ pyriminobac-methyl+ azimsulfuron+ bensulfuron-methyl+ cyhalofop-butyl) (Kumiai)

ANALYSIS
Product analysis by glc. Residues determined by glc with MCD or TID. Details available from Syngenta.

MAMMALIAN TOXICOLOGY
Oral Acute oral LD50 for rats 6099 mg/kg. Skin and eye Acute percutaneous LD50 for rats >3100 mg/kg. Moderate irritant to skin; non-irritant to eyes (rabbits). Inhalation LC50 (4 h) for rats >2.8 mg/l air. NOEL (2 y) for rats 30, mice 300 ppm; (0.5 y) for dogs 300 ppm. ADI 0.018 mg/kg. Toxicity class WHO (a.i.) U EC classification (R38, R43)

ECOTOXICOLOGY
Birds Non-toxic to birds; LD50 for Japanese quail >10 000 mg/kg. LC50 for Japanese quail >1000 ppm. Fish LC50 (96 h) for rainbow trout 0.9, catfish 2.7, crucian carp 2.3 mg/l. Daphnia LC50 13 mg/l. Algae EC50 for Selenastrum capricornutum 0.002 mg/l. Bees LD50 (contact) 93 mg/bee.

ENVIRONMENTAL FATE
Animals Substitution of the chlorine atom for glutathione to form a conjugate. Cleavage of the ether bond to yield an ethyl alcohol derivative. Both metabolites are susceptible to further degradation. Plants Substitution of the chlorine atom to form a conjugate. Cleavage of the ether bond to yield an ethyl alcohol derivative. Hydrolytic and reductive removal of the chlorine atom. Soil/Environment Applied to paddy water, pretilachlor disappeared from the water by adsorption to the soil, where it is rapidly degraded under practical conditions, median DT50 (lab.) 30 d. Due to strong soil adsorption, unlikely to leach.