3732. Ethephon

Nomenclature

CAS number: 16672-87-0
P-(2-Chloroethyl)phosphonic acid; 2-chloroethanephosphonic acid; CEPA; camposan; Cerone (Bayer CropSci.); Ethrel (Bayer CropSci.); Prep (Bayer CropSci.).
C2H6ClO3P; mol wt 144.49.
C 16.62%, H 4.19%, Cl 24.54%, O 33.22%, P 21.44%.

Description and references

Ethylene-releasing agent used to control growth and ripening of fruit crops. Prepn: Kabachnik, Rossiiskaya, Izv. Akad. Nauk SSSR Otd. Khim. Nauk 1946, 403-410, C.A. 42, 7242e (1948); Beilstein EIII 4, 1780. Toxicity data: G. Hennighausen et al., Pharmazie 32, 181 (1977). Review of use in viticulture: E. Szyjewicz et al., Am. J. Enol. Vitic. 35, 117-123 (1984).

Chemical structure

Properties

Very hygroscopic needles from benzene (must be dried over P2O5). mp 74-75°. Freely sol in water, methanol, acetone, ethylene glycol, propylene glycol. Slightly sol in benzene, toluene. Practically insol in petr ether. Aq solns are stable below pH 3.5. Above pH 3.5 hydrolysis begins with the release of free ethylene. LD50 orally in mice: 2850 mg/kg (Hennighausen).

Caution

Spray formulations are quite acidic, about pH 1.0. May be irritating to exposed skin and eyes, or if inhaled.

Use

Plant growth regulator.