Alachlor 甲草胺

甲草胺

简介
英文通用名：alachlor
CAS号：15972-60-8
分子式：C14H20ClNO2
分子量：269.77
化学名称：2-氯-N-(2,6-二乙基苯基)-N-(甲氧甲基)乙酰胺
其他名称： 拉索、澳特拉索、草不绿、Lasso、CP50144、La20

理化性质：
纯品为结晶。熔点40-41℃。23℃时水中溶解度为240ppm。可溶于丙酮、苯、乙醇、乙酸乙酯。挥发性极小。抗紫外线分解。在强酸或碱性条件下分解。在土壤中半衰期约15d。

毒性
对人畜低毒，大鼠急性口服LD50为930毫克/公斤，家兔急性经皮 异丙甲草胺
LD50为13300毫克/公斤，对眼睛和皮肤有刺激作用。

剂型
48%乳油、15%颗粒剂。

特点
是一种选择性芽前除草剂，主要是通过杂草的芽鞘吸收，根部和种子也可有少量吸收。主要杀死出苗前土壤中萌发的杂草，对已出土杂草无效。能被土壤团粒吸附不易淋失，也不易挥发，但可被土壤微生物分解。有效期为35天左右。
适用范围 适用于大豆、玉米、花生、棉花、马铃薯、甘蔗、油菜等作物田，防除稗草、马唐、蟋蟀草、狗尾草、秋稗、臂形草、马齿苋、苋、轮生粟米草、藜、蓼等1年生禾本科杂草和阔叶杂草。对菟丝子也有一定防效。
使用方法
1.在玉米、棉花、花生地上使用 一般于播后出苗前，每亩用48%乳油200-250毫升，对水35公斤左右，均匀喷雾土表。
2.在大豆田使用，于播后出苗前 每亩用48% 乳油200-300毫升，对水35公斤，均匀喷雾土表。用于防除大豆菟丝子，一般在大豆出苗前后，菟丝子缠绕的大豆茎叶，能较好地防除菟丝子，对大豆安全。
3.用于番茄、辣椒、洋葱、萝卜等蔬菜田除草 在播种前或移栽前，每亩用43%甲草胺乳油200毫升，对水40-50公斤，均匀喷雾土表，用耙浅混土后播种或移栽，若施药后覆盖地膜，则用药量应适当减少1/3-1/2。

注意事项
1.甲草胺水溶性差，如遇干旱天气又无灌溉条件，应采用播前混土法。否则药效难于发挥。
2.甲草胺对已出土杂草无效，应注意在杂草种子而萌动高峰而又未出土前喷药，方能获得最大药效。

alachlor
Herbicide
HRAC K3 WSSA 15; chloroacetamide

NOMENCLATURE
Common name alachlor (BSI, E-ISO, ANSI, WSSA, JMAF); alachlore ((m) F-ISO)
IUPAC name 2-chloro-2',6'-diethyl-N-methoxymethylacetanilide
Chemical Abstracts name 2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide
CAS RN [15972-60-8] EEC no. 240-110-8 Development codes CP 50144 (Monsanto); MON 0144 (tech.) (Monsanto)

PHYSICAL CHEMISTRY
Composition ³93% pure. Mol. wt. 269.8 M.f. C14H20ClNO2 Form Yellow white to wine red, odourless solid (room temperature); yellow to red liquid (>40 °C). M.p. 40.5-41.5 ºC B.p. 100 °C/0.0026 kPa V.p. 2.0 mPa (25 ºC) KOW logP = 3.09 Henry 3.2 ´ 10-3 Pa m3 mol-1 (calc.) S.g./density 1.1330 (25 °C) Solubility In water 170.31 mg/l (pH 7, 20 ºC). Soluble in diethyl ether, acetone, benzene, chloroform, ethanol, and ethyl acetate. Slightly soluble in heptane. Stability Hydrolysed by strong acids and alkalis. Stable to u.v. light. Decomposes at 105 ºC. F.p. 137 °C (closed cup); 160 °C (open cup)

COMMERCIALISATION
History Herbicide reported by R. F. Husted et al. (Proc. North Cent. Weed Control Conf., 1966, 21, 44). Introduced by Monsanto Co. Patents US 3442945; US 3547620 Manufacturers Comlets; Crystal; ÉMV; Krishi Rasayan; Makhteshim-Agan; Monsanto; Pilarquim; RPG; Sinon

APPLICATIONS
Biochemistry Acts by inhibition of protein synthesis and root elongation; 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 is attributed to rapid detoxification by glutathione transferases. Mode of action Selective systemic herbicide, absorbed principally by germinating shoots, but also by the roots, with translocation throughout the plant, and accumulation mainly in vegetative parts rather than in reproductive parts. Uses Used pre-emergence at 1.68-4.48 kg/ha to control annual grasses and many broad-leaved weeds in cotton, brassicas, maize, oilseed rape, peanuts, radish, soya beans and sugar cane. Formulation types EC; GR; ME; WG. Selected products: 'Lasso' (Monsanto); 'Alanex' (Makhteshim-Agan); 'Cattch' (RPG); 'Lacorn' (Efthymiadis); 'Satochlor' (ÉMV); 'Sholay' (Rallis); mixtures: 'Cotralin' (+ prometryn) (Efthymiadis)

OTHER PRODUCTS
'Cropstar II' (Monsanto); 'Micro-Tech' (Monsanto); 'Partner' (Monsanto); 'Alac' (Chemia); 'Alagan' (Makhteshim-Agan); 'Alanox' (Crystal); 'Chemiclor' (Chemiplant); 'Dipachlor' (Papaeconomou); 'Pilarzo' (Pilarquim); 'Shroud' (Cedar); 'Top 48' (Cequisa) mixtures: 'Bronco' (+ glyphosate-isopropylammonium) (Monsanto); 'Bullet' (+ atrazine) (Monsanto); 'Freedom' (+ trifluralin) (Monsanto); 'Lariat' (+ atrazine) (Monsanto); 'Alanex Pro' (+ prometryn) (Makhteshim-Agan); 'Alanex TBA' (+ terbuthylazine) (Makhteshim-Agan); 'Alazine' (+ atrazine) (Makhteshim-Agan); 'Aracloro Super' (+ atrazine) (Aragro); 'Galirom' (+ oxyfluorfen) (Makhteshim-Agan); 'Manager' (+ aclonifen) (Bayer CropScience); 'Propachlor Doble' (+ atrazine) (Probelte)

ANALYSIS
Product analysis by glc with FID (J. M. Warner & D. D. Arras in Comp. Anal. Profiles, Chapt. 5; AOAC Methods, 17th Ed., 985.04, 988.03; CIPAC Handbook, 1988, D,4; ibid., 1992, E, 4). Residues in water and in soil determined by glc with ECD or FID; details, and other methods reviewed by J. M. Warner & D. D. Arras, loc. cit. In drinking water, by glc with NPD (AOAC Methods, 17th Ed., 991.07).

MAMMALIAN TOXICOLOGY
Oral Acute oral LD50 for rats 930-1350 mg/kg. Skin and eye Acute percutaneous LD50 for rabbits 13 300 mg/kg. Non-irritating to skin or eyes (rabbits). Contact sensitisation reactions observed in guinea pigs. Inhalation LC50 (4 h) for rats >1.04 mg/l air. NOEL (2 y) for rats 2.5 mg/kg b.w. daily; (1 y) for dogs £1 mg/kg b.w. daily. ADI 0.01 mg/kg b.w. Water GV 20 mg/l (based on incidence of cancer in animals). Other Oncogenic in rats but not in mice; the mechanism of induction has been shown to be not relevant at anticipated exposure levels in humans. Toxicity class WHO (a.i.) III; EPA (formulation) III EC classification R40| Xn; R22| R43| N; R50, R53

ECOTOXICOLOGY
Birds Acute oral LD50 for bobwhite quail 1536 mg/kg. LC50 (5 d) for mallard ducks and bobwhite quail >5620 mg/kg diet. Fish LC50 (96 h) for rainbow trout 1.8, bluegill sunfish 2.8, fathead minnow 5.0, channel catfish 2.1 mg/l. Daphnia EC50 (48 h) 10 mg/l. Algae TL50 (72 h) for Selenastrum capricornutum 12 mg/l. Other aquatic spp. EC50 (48 h) for crayfish >320 mg/l. Bees Not hazardous to bees when used as directed; LD50 32 mg/bee. Worms LC50 (14 d) for earthworms 387 mg/kg dry soil.

ENVIRONMENTAL FATE
Animals Rapidly oxidised by rat liver microsomal oxygenases to 2,6-diethylaniline (Pestic. Biochem. Physiol., 1989, 33, 16; J. Agric. Food Chem., 1989, 37, 1088; P. C. C. Feng et al., Drug Metab. Dispos., 1990, 18, 373). Plants Rapidly metabolised in plants to 2-chloro-2',6'-diethylacetanilide, with further degradation to the aniline derivative. Soil/Environment Rapidly degraded in soil by microbial action to 2-chloro-2',6'-diethylacetanilide, with further degradation to the aniline derivative; DT50 1-30 d. Persists in soil for c. 6-10 w (J. Tiedie et al., J. Agric. Food Chem., 1975, 23, 77; J. K. Lee, Hanguk Nanghwa Hakhoechi, 1986, 29, 182; Rev. Environm. Contam. Toxicol., 1989, 110, 110-114). In surface water, 55% degraded in 28 d.