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 Products--ˇ·HERBICIDES |
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GLYPHOSATE
Herbicide
HRAC G WSSA 9; glycine derivative
For a general
review, see "Glyphosate, A Unique Global Herbicide". |
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NOMENCLATURE
glyphosate
Common name glyphosate (BSI, E-ISO, (m) F-ISO,
ANSI, WSSA, JMAF)
IUPAC name N-(phosphonomethyl)glycine
Chemical Abstracts name N-(phosphonomethyl)glycine
CAS RN [1071-83-6]
EEC no. 213-997-4 Development codes MON-0573 (Monsanto); CP 67573 (Monsanto) |
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glyphosate-ammonium
CAS RN [40465-66-5] monoammonium salt; [69254-40-6]
diammonium salt; [114370-14-8] unspecified
ammonium salt Development codes MON 8750 (Monsanto) |
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glyphosate-isopropylammonium
CAS RN [38641-94-0]
EEC no. 254-056-8 Development codes MON 0139 (Monsanto); MON 77209 (Monsanto) |
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| glyphosate-sodium
CAS RN [34494-03-6]
Development
codes MON 8722 (Monsanto) |
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glyphosate-trimesium
IUPAC name trimethylsulfonium N-(phosphonomethyl)glycinate
Chemical Abstracts name N-(phosphonomethyl)glycine trimethylsulfonium
salt
Other names sulfosate CAS RN [81591-81-3]
Development
codes SC 0224; ICIA0224 (ICI) |
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PHYSICAL
CHEMISTRY
glyphosate
Composition Tech. is ³95% pure. Zwitterion structure (P. Knuuttila
& H. Knuuttila, Acta Chem. Scand.,
1979, 33, 623). Mol. wt. 169.1 M.f. C3H8NO5P Form Colourless crystals. M.p. 189.5?.5 ˇăC B.p. Decomp. >200 ˇăC V.p. 1.31 ´ 10-2 mPa (25 ˇăC) KOW logP <-3.2 (pH 2-5, 20 ˇăC), (OECD 107; EEC
A8) Henry <2.1 ´ 10-7 Pa m3 mol-1 S.g./density 1.705 (20 ˇăC) Solubility In water 11.6 g/l (25 ºC). Insoluble
in common organic solvents, e.g. acetone, ethanol
and xylene. The alkali-metal and amine salts
are readily soluble in water. Stability Glyphosate and all its salts are non-volatile,
do not photochemically degrade and are stable
in air. Glyphosate is stable to hydrolysis at
pH 3, 6 and 9 (5-35 ˇăC). pKa 5.77?.03, 2.18?.02 (20? ˇăC), (OECD 112)
F.p. Not flammable |
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glyphosate-ammonium
Composition Tech. is 95.2% pure. Mol. wt. 186.1 M.f. C3H11N2O5P Form Odourless, white powder. M.p. Decomp. >190 ˇăC, without melting
V.p. 9 ´ 10-3 mPa (25 ˇăC) KOW logP <-3.7 Henry 1.16 ´ 10-8 Pa m3 mol-1 (calc.) S.g./density 1.433 (22 ˇăC)
Solubility In water 144?9 g/l (pH 3.2). Essentially insoluble in organic solvents.
Stability Stable over 5 days at 50 ˇăC (pH 4, 7 and 9). pKa See isopropylammonium salt F.p. Not flammable |
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glyphosate-isopropylammonium
Composition As a wet cake, contains c. 62%
w/w isopropylamine salt, c. 35% water. Mol. wt. 228.2 M.f. C6H17N2O5P Form Odourless, white powder. M.p. Occurs in 2 steps, 143-164 ˇăC and 189-223 ˇăC B.p. Decomposes without boiling V.p. 2.1 ´ 10-3 mPa (25 ˇăC) KOW logP = -5.4 Henry 4.6 ´ 10-10 Pa m3 mol-1 (25 ˇăC, calc.) S.g./density 1.482 (20 ˇăC)
Solubility In water 1050 g/l (25 ˇăC, pH 4.3). In dichloromethane 0.184, methanol 15.88
(both in g/l, 20 ˇăC).
pKa 5.77?.03, 2.18?.02 (20? ˇăC), (OECD 112) |
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glyphosate-sodium
Mol. wt. 191.1 M.f. C3H7NNaO5P Form Odourless, white powder. M.p. Decomp. >260 ˇăC V.p. 7.56 ´ 10-3 mPa (25 ˇăC) KOW See isopropylammonium salt Henry 4.27 ´ 10-9 Pa m3 mol-1 (calc.) S.g./density 1.622 (20 ˇăC)
Solubility In water 335?1.5 g/l of solution (or 414?1.8 g/l of water) (pH 4.2, 20 ˇăC).
Stability Stable over 5 days at 50 ˇăC (pH 4, 7 and 9). |
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glyphosate-trimesium
Mol. wt. 245.2 M.f. C6H16NO5PS Form White solid. M.p. Decomp. 150 ˇăC V.p. <0.01 mPa (20 ºC) KOW logP = -2.9 Henry <2 ´ 10-9 Pa m3 mol-1 (calc.) S.g./density 1.42 Solubility In water >1000 g/l. In acetone, chlorobenzene, ethanol, kerosene, xylene
<5 (all in g tech./l).
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| APPLICATIONS
Biochemistry Inhibits 5-enolpyruvylshikimate-3-phosphate
synthase (EPSPS), an enzyme of the aromatic
acid biosynthetic pathway. This prevents synthesis
of essential aromatic amino acids needed for
protein biosynthesis.
Mode of action Non-selective systemic herbicide, absorbed
by the foliage, with rapid translocation throughout
the plant. Inactivated on contact with soil.
Uses Control of annual and perennial grasses and broad-leaved weeds, pre-harvest,
post-planting/pre-emergence and in stubble,
in cereals, peas, beans, oilseed rape, flax
and mustard, at c. 1.5-2 kg/ha; as a
directed spray in vines and olives, at c.
4.3 kg/ha; in orchards, pasture, forestry and
industrial weed control, at c. 4.3 kg/ha.
As an aquatic herbicide, at c. 2 kg/ha.
Formulation types SG; SL.
Compatibility Mixing with other herbicides may reduce the
activity of glyphosate.
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ANALYSIS
Product analysis
by hplc (AOAC Methods, 1995, 983.10;
CIPAC Handbook, 1985, 1C, 2130).
Residues determined by gc (Pestic.
Anal. Man., 1979, II ) or by hplc
with o-phthalaldehyde post-column reaction
specific for primary amines (J. Agric. Food
Chem., 34(6), 955-960 (1986)). In
environmental water, by hplc determination
by o-phthalaldehyde post-column reaction
system (AOAC Methods, 1995, 991.08, 10.6.18). |
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MAMMALIAN
TOXICOLOGY
glyphosate
Reviews FAO/WHO 47, 49, 80, 82 (see part 2 of
the Bibliography).
Oral Acute oral LD50 for rats 5600,
mice 11 300, goats 3530 mg/kg.
Skin and eye Acute percutaneous LD50 for rabbits >5000 mg/kg. Eye irritant; non-irritating
to skin (rabbits).
Inhalation LC50 (4 h) for rats >4.98 mg/l air. NOEL In 2 y feeding trials, no ill-effects were observed in rats receiving 410
mg/kg diet daily (average) and, in 1 y feeding
trials, no ill-effects were observed in dogs
receiving 500 mg/kg daily (highest dose treated). ADI (JMPR) 0.3 mg/kg b.w. [1986, 1997] (for sum of glyphosate and its metabolite
AMPA).
Water GV Unnecessary to recommend a guideline value because not hazardous to health
at concentrations normally found in drinking
water. Other Not mutagenic, not carcinogenic, not
teratogenic, not neurotoxic. No adverse effects
on reproduction. Toxicity class WHO (a.i.) III (Table 5); EPA (formulation) III EC hazard (Xi; R41) |
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glyphosate-ammonium
Oral Acute oral LD50 for rats 4613 mg/kg. Skin and eye Acute percutaneous LD50 for rabbits
>5000 mg/kg. Slight eye irritant; not a skin
irritant (rabbits). Inhalation LC50 >1.9 mg/l air. Toxicity class EPA (formulation) III |
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glyphosate-isopropylammonium
Oral Acute oral LD50 for rats >5000, goats 5700 mg/kg. Skin and eye Acute percutaneous LD50 for rabbits
>5000 mg/kg. Slight eye irritant; not a skin
irritant (rabbits). Inhalation LC50 (4 h) for rats >1.3 mg/l air. NOEL In a 6 mo capsule trial, no ill-effects were observed in dogs receiving 300
mg/kg daily (highest dose treated).
Toxicity class EPA (formulation) III |
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glyphosate-sodium
Skin and eye Acute oral LD50 for rats >5000 mg/kg. Slight eye irritant;
not a skin irritant (rabbits).
glyphosate-trimesium
Oral Acute oral LD50 for male rats 748, female rats 755, mice 1250
mg/kg.
Skin and eye Acute percutaneous LD50 for rabbits >2000 mg/kg. Inhalation LC50 (4 h) for rats 6.2 mg/l air. NOEL 100 mg/kg daily. No teratogenic effect observed. ADI 25 mg/kg b.w. EC hazard (Xn; R22) |
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ECOTOXICOLOGY
glyphosate
Birds Acute oral LD50 for bobwhite quail >3851 mg/kg. Dietary
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