Ethephon
Ethephon
General product information
ETHEPHON 85% TC, 75% TC, 480G/LT SLNOMENCLATURE
Common name: Ethephon
Other name: ethephon (ANSI, Canada); chorethephon (New Zealand)
Iupac name: 2-chtoroethylphosphonic acid
Chemical abstracts name: (2-chloroethyl)phosphonic acid
Type: Plant growth regulator
CAS RN: [16672-87-O] 1
PHYSICAL CHEMISTRY
M.F: C2HeClO3P
Mol.wt.: 144.5
Style/Appearance: Colourless solid: (tech. is a clear liquid)
M.p.: 74-75℃
B.p.: 1265℃ (decamp.)
V.p.: 0.01 mPa (20℃)
F.p.: 1
S.g./density: 1.4090.02 (20℃) (tech.)
Solubility: In water c. 1 kg/l (23℃). Readily soluble in methanol, ethanol, isopropanol, acetone, diethyl ether, and other polar organic solvents. Sparingly soluble in non-polar organic solvents such as benzene and toluene. Insoluble in kerosene and diesel oil.
Stability: Stable in aqueous solutions having pH 5. At higher pH, decomposition occurs with the liberation of ethylene. Sensitive to u.v. y: 1.55 10-9 Pa m3 mol-1 (talc.)
KowlogP: logP -2.20 (25℃, unstated pH)
Pka: pKal 2.5, pKa2 7.2
APPLICATION
Formulation type(s): EC; SL
Biochemistry: 1
Mode of action: Plant growth regulator with systemic properties. Penetrates into the plant tissues, and is decomposed to ethylene, which affects the growth processes.
Uses: To promote pre-harvest ripening in apples, currants, blackberries, blueberries, cranberries, morello cherries, citrus fruit, figs, tomatoes, sugar beet and fodder beet seed crops, coffee, capsicums, etc.; to accelerate post-harvest ripening in bananas, mangoes, and citrus fruit; to facilitate harvesting by loosening of the fruit in currants, gooseberries, cherries, and apples; to increase flower bud development in young apple trees; to prevent lodging in cereals, maize, and flax: to induce flowering of Bromeliads; to stimulate lateral branching in azaleas, geraniums, and roses; to shorten the stem length in forced daffodils; to induce flowering and regulate ripening in pineapples; to accelerate ball opening in cotton; to modify sex expression in cucumbers and squash: to increase fruit setting and yield in cucumbers; to improve the sturdiness of onion seed crops; to hasten the yellowing of mature tobacco leaves; to stimulate latex flow in rubber trees, and resin flow in pine trees; to stimulate early uniform hull split in walnuts; etc.
MAMALIAN TOXICOLOGY
Reviews: FAO/WHO 80 (see part 2 of the Bibliography). 3. Hennighausen et al., Pharmazie, 32, 181 (1977).
Oral: Acute oral LD50for rats 3030 mg/kg tech.).
Skin & Eye: Acute percutaneous LD50 for rabbits 1560 mg/kg (tech.). Irritating to skin and eyes.
Inhalation: LC50 (4 h) for rats 6.26 mg/l (tech.).
Noel: (2 y) for rats 3000 ppm diet.
ADI: (JMPR) 0.05 mg/kg b.w. [1997].
Toxicity class: WHO (a.i.) III (Table 5); EPA (formulation) l (tech.)
EC hazard: Xn; R20/21 C; R34 R52, R53: for preparations containing ≥25%, C; R20/21, R34: for 25% concn.≥10%,C; R34: for 10%concn.≥5%, Xi; R36/37/38
ENVIRONMENTAL FATE
Plants: In plants, ethephon rapidly undergoes degradation to ethylene.
Animals: In animals, ethephon is rapidly excreted intact via the urine, and as ethylene via the expired air.
Soil / environment: Rapidly degraded in soil, and strongly adsorbed; unlikely to teach.
Analysis: Product analysis by measuring the ethylene produced on treatment with concentrated tlkali. Residues determined by conversion to the dimethyl ester, measured by git with NPD or FPD ,Pestle. Anal. Man., Vol. II; Anal. Methods Residues Pestic., 1988, Part II; W. P. Cochrane, J. Assoc. Off. Anal. Chem., 1976, 59, 617).