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PHYSICAL CHEMISTRY
2,*-D
Composition: Tech. is �*6% pure.�
Mol. wt.: **1.0�
M.f.: C8H6Cl2O3�
Form: Colourless powder, with a slight phenolic odour.�
M.p.: **0.5 �C�
V.p.? 1.*6 � ***2 mPa (*5 �C, OECD **4)�
KOW? logP = 2.***2.*3 (pH 1), 0.***0.*3 (pH 5)�
Henry?1.*2 � ***5 Pa m3 mol*1 (calc.)�
S.g./density? 1.**8 (*0 �C)�
Solubility? In water **1 (pH 1), *0 **1 (pH 5), *3 **0 (pH 7), *4
**6 (pH 9) (all in mg/l, *5 �C). In ethanol ***0, diethyl ether
**3, heptane 1.1, toluene 6.7, xylene 5.8 (all in g/kg, *0 �C); in
octanol **0 g/l (*5 �C). Insoluble in petroleum oils.
Mono-n-butylamine salt: In water *8 g/l (*0 �C).�
Stability? 2,*-D is a strong acid, and forms water-soluble salts
with alkali metals and amines. Hard water leads to precipitation of
the calcium and magnesium salts, but a sequestering agent is
included in formulations to prevent this. Photolytic DT*0
(simulated sunlight) 7.5 d.�
pKa?2.*3�
APPLICATIONS
Biochemistry: Synthetic auxin (acting like indolylacetic
acid).�
Mode of action: Selective systemic herbicide. Salts are readily
absorbed by the roots, whilst esters are readily absorbed by the
foliage. Translocation occurs, with accumulation principally at the
meristematic regions of shoots and roots. Acts as a growth
inhibitor.�
Uses: Post-emergence control of annual and perennial broad-leaved
weeds in cereals, maize, sorghum, grassland, established turf,
grass seed crops, orchards (pome fruit and stone fruit),
cranberries, asparagus, sugar cane, rice, forestry, and on non-crop
land (including areas adjacent to water), at 0.***2.3 kg/ha.
Control of broad-leaved aquatic weeds. The isopropyl ester can also
be used as a plant growth regulator to prevent premature fruit fall
in citrus fruit. Phytotoxicity Phytotoxic to most broad-leaved
crops, especially cotton, vines, tomatoes, ornamentals, fruit
trees, oilseed rape and beet.�
Formulation types: EC; GR; SP; SL.
