Diclofop-Methyl 禾草灵

禾草灵

简介
【中文别名】禾草灵又叫伊洛克桑;(RS)-2-[4-(2,4-二氯苯氧基)苯氧基]丙酸甲酯;2-[4-(2,4-二氯苯氧基)苯氧基]丙酸甲酯
【英文名称】diclofop-methyl
【分子式】 C16H14Cl2O4
【物化性质】
密度 1.3
熔点 39-41°C
沸点 173-175°C (0.1 mbar)
水溶性 0.005 g/100 mL
分子量 341.186

用途属性
【用途】 属内吸性除草剂，通过根及叶被吸收，主要用于麦类、大豆、花生、油菜等作物田防治禾本科杂草。
【特性】 禾草灵是苗后处理剂，主要供叶面喷雾，可被杂草根、茎、叶吸收，但在体内传导性差。根吸收药剂，绝大部分停留在根部，杀伤初生根，只有很少量的药剂传导到地上部。叶片吸收的药剂，大部分分布在施药点上下叶脉中，破坏叶绿叶体，使叶片坏死，但不会抑制植株生长。对幼芽抑制作用强，将药剂施到杂草顶端或节间分生组织附近，能抑制生长，破坏细胞膜，导致杂草枯死。
【产品】 禾草灵产品有36％乳油、28％乳油(加有增效的表面活性剂)。
【适用作物】适用于小麦、大麦、大豆、油菜、花生、向日葵、甜菜、马铃薯、亚麻等作物地防除稗草、马唐、毒麦、野燕麦、看麦娘、早熟禾、狗尾草、画眉草、千金子、牛筋等一年生禾本科杂草。对多年生禾本科杂草及阔叶杂草无效。也不能用于玉米、高粱、谷子、水稻、燕麦、甘蔗等作物地。
【使用方法】
(1)麦田使用。最适宜的施药时期是野燕麦等禾本科杂草2～4叶期，防除稗草和毒麦亦可在分蘖开始时施药。施药适期可以不考虑小麦的生育期，重要的是杂草不能被作物覆盖，影响杂草受药。亩用36％乳油120～200毫升，对水叶面喷雾。用量超过200毫升，对小麦有药害。
禾草灵防除野燕麦受温度、土壤湿度、土壤有机质含量的影响很小，在黑龙江等北方早春低温、干旱的情况下，药效也很稳定。
(2)甜菜、大豆等阔叶作物使用。在作物苗期、杂草2～4叶期，亩用36％乳油170～200毫升，对水叶面喷雾。
禾草灵不能与苯氧乙酸类除草剂2，4一滴丁酯、2甲4氯以及麦草畏、灭草松等混用，也不能与氮肥混用，否则会降低药效。喷施禾草灵的5天前或7～10天后，方可使用上述除草剂和氮肥。
喷施禾草灵后，接触药液的小麦叶片会出现稀疏的退绿斑，但新长出的叶片完全不会受害。对3～4片复叶期的大豆有轻微药害，叶片出现褐色斑点一周后可恢复，对大豆生长无影响。

diclofop-methyl
Herbicide
HRAC A WSSA 1; aryloxyphenoxypropionate

NOMENCLATURE
diclofop-methyl
Chemical Abstracts name methyl 2-[4-(2,4-dichlorophenoxy)phenoxy]propanoate
CAS RN [51338-27-3] unstated stereochemistry; [71283-65-3] (R)- isomer; [75021-72-6] (S)- isomer EEC no. 257-141-8 Development codes Hoe 023408 (Hoechst); AE F023408 (AgrEvo)

diclofop
Common name diclofop (BSI, E-ISO, (m) F-ISO, ANSI, WSSA)
IUPAC name (RS)-2-[4-(2,4-dichlorophenoxy)phenoxy]propionic acid
Chemical Abstracts name (?-2-[4-(2,4-dichlorophenoxy)phenoxy]propanoic acid
CAS RN [40843-25-2] unstated stereochemistry Development codes Hoe 021079 (Hoechst)

PHYSICAL CHEMISTRY
diclofop-methyl
Composition Tech. grade is ³93% pure. Mol. wt. 341.2 M.f. C16H14Cl2O4 Form Colourless crystals. M.p. 39-41 ºC V.p. 0.25 mPa (20 ºC); 7.7 mPa (50 ºC) (vapour pressure balance) KOW logP = 4.58 S.g./density 1.30 at 40 ºC Solubility In water 0.8 mg/l (pH 5.7, 20 ºC). In acetone, dichloromethane, dimethyl sulfoxide, ethyl acetate, toluene >500 g/l; in polyethylene glycol 148, methanol 120, isopropanol 51, n-hexane 50 (all in g/l, 20 ºC). Stability Stable to light. In water, DT50 (25 ºC) 363 d (pH 5), 31.7 d (pH 7), 0.52 d (pH 9).

diclofop
Mol. wt. 327.2 M.f. C15H12Cl2O4 Form Yellowish-white solid. M.p. 118-122 °C V.p. 3.1 ´ 10-6 mPa (20 °C); 9.7 ´ 10-6 mPa (25 °C); 1.7 ´ 10-3 mPa (50 °C) (vapour pressure balance) KOW logP = 2.81 (pH 5), 1.61 (pH 7) S.g./density 1.4 (20 °C) Solubility In water 0.453 (pH 5), 122.7 (pH 7), 127.4 (pH 9) (all in g/l, 20 °C). pKa 3.43

COMMERCIALISATION
History Herbicidal activity of diclofop-methyl reported by P. Langelüddeke et al. (Mitt. Biol. Bundesanst. Land.-Forstwirtsch. Berlin-Dahlem, 1975, 165, 169). Introduced by Hoechst AG (now Bayer CropScience). Patents DE 2136828; DE 2223894 Manufacturers Bayer CropScience; Hegang Heyou; Hesenta; Jingma; Sharda; Sundat; Tide

APPLICATIONS
diclofop-methyl
Biochemistry Fatty acid synthesis inhibitor, by inhibition of acetyl CoA carboxylase (ACCase). Destroys the cell membrane, prevents the translocation of assimilates to the roots, reduces the chlorophyll content, and inhibits photosynthesis and meristem activity. Mode of action Diclofop-methyl is a selective systemic herbicide, also with contact action, absorbed primarily by the leaves, with some absorption by the roots in moist soil. Undergoes rapid transformation to diclofop, which is translocated within the plant. Diclofop-methyl (R)-(+)- enantiomer shows significantly greater herbicidal activity by foliar application to 3 weed species than does the (S)-(-)- enantiomer, but there was less difference by soil application (H. J. Nestler & H. Bieringer, Z. Naturforsch. B. Anorg. Chem. Org. Chem., 1980, 35B, 366). Uses For post-emergence control of wild oats, wild millets, and other annual grass weeds in wheat, barley, rye, red fescue, and broad-leaved crops such as soya beans, sugar beet, fodder beet, flax, legumes, oilseed rape, sunflowers, clover, alfalfa, peanuts, brassicas, carrots, celery, beetroot, parsnips, lettuce, spinach, potatoes, cucumbers, peas, beans, tomatoes, fennel, alliums, herbs, etc. Phytotoxicity Phytotoxic to maize, sorghum, oats, sugar cane, rice, and cotton. Formulation types EC. Compatibility Incompatible with most other herbicides. Selected products: 'Hoegrass' (Bayer CropScience); 'Hoelon' (Bayer CropScience); 'Illoxan' (Bayer CropScience); 'Sperto' (Cequisa); 'Taiwan' (Rocca)

OTHER PRODUCTS
diclofop-methyl
'Cerlon' (Bayer CropScience); 'Colt' (Bayer CropScience); 'Iloxan' (Bayer CropScience) mixtures: 'Baghera' (+ fenoxaprop-P-ethyl+ mefenpyr-diethyl) (Bayer CropScience); 'Corniche' (+ fenoxaprop-P-ethyl) (Bayer CropScience); 'Dopler' (+ fenoxaprop-P-ethyl+ mefenpyr-diethyl) (Bayer CropScience); 'Tigress Ultra' (+ fenoxaprop-P-ethyl) (Bayer CropScience); 'Zeus' (+ fenoxaprop-P-ethyl+ mefenpyr-diethyl) (Bayer CropScience) Discontinued products mixtures: 'Tigress' * (+ fenoxaprop-P-ethyl) (AgrEvo)

ANALYSIS
Product analysis by glc (CIPAC Handbook,1985, 1C, 2096). Details of glc methods for product and residue analysis are available from Bayer CropScience.

MAMMALIAN TOXICOLOGY
diclofop-methyl
Oral Acute oral LD50 for rats 481-693 mg/kg (in sesame oil), dogs 1600 mg/kg (highest dose without induction of vomiting). Skin and eye Acute percutaneous LD50 for rats >5000 mg/kg. Inhalation LC50 for rats >1.36 mg/l air. NOEL (2 y) for rats 0.1 mg/kg b.w.; (15 mo) for dogs 0.44 mg/kg b.w. ADI 0.001 mg/kg b.w. (AgrEvo proposed value). Other Non-mutagenic in the Ames test. Toxicity class WHO (a.i.) III; EPA (formulation) III EC classification Xn; R22, R43| N; R50, R53

diclofop
Oral Acute oral LD50 for female rats 586 mg/kg. Skin and eye Acute percutaneous LD50 for rats 1657 mg/kg.

ECOTOXICOLOGY
diclofop-methyl
Birds Acute oral LD50 for Japanese quail >10 000 mg/kg. Dietary LC50 (5 d) for bobwhite quail >1600, mallard ducks >1100 mg/kg b.w. Fish LC50 (96 h) for rainbow trout 0.23 mg/l. Daphnia LC50 (48 h) 0.23 mg/l. Algae EC50 (72 h) for Scenedesmus subspicatus 1.5 mg/l, (120 h) for Selenastrum capricornutum 0.53 mg/l. Bees Non-toxic to bees under field conditions and application rate of 1.134 kg a.i./ha. Worms LC50 (14 d) for earthworms >1000 mg/kg soil, dry weight.

diclofop
Fish LC50 (96 h) for rainbow trout 21.9, golden orfe 79.9 mg/l.

ENVIRONMENTAL FATE
Animals When fed to rats, diclofop-methyl is almost totally absorbed and then rapidly excreted; c. 90% is recovered unchanged in faeces and urine after 2 d, and 99% after 7 d. Accumulation of residues in the body is unlikely; low levels of total residues were found in organs and tissues 7 d after a single dose of 1.8 mg/kg b.w. Metabolites are identical with those in plants. Plants Diclofop-methyl is taken up rapidly and almost completely by plants, with little translocation. It is hydrolysed relatively quickly (DT50 in sugar beet 3 d), first to an isomeric mixture of hydrolysed free acids and their conjugates with glucuronic and sulfuric acid, and then to 4-(2,4-dichlorophenoxy)phenol. Total radioactive residues at the time of harvest in wheat, sugar beet and soya beans are generally low, below or around the determination limits (0.01 to 0.1 mg/kg). The same applies to rotation crops. Soil/Environment In soil, diclofop-methyl is metabolised to diclofop, which then undergoes further degradation to 4-(2,4-dichlorophenoxy)phenol, hydroxylated free acids and CO2. In various soils in field trials: DT50 1-57 d, DT90 30-281 d. Irrigation studies indicate low levels of leaching. From model calculations, a hazard to groundwater or to drinking water supplies can be excluded, even in sandy soil. Soil adsorption Koc 14 000-24 400 mg/kg.