Edifenphos Property

Melting point:

25°C

Boiling point:

bp0.01 154°

Density 

d420 1.23

vapor pressure 

1.3 x 10^-2Pa (20 °C)

refractive index 

nD22 1.61

storage temp. 

0-6°C

Water Solubility 

56 mg l^-1 (20 °C)

form 

liquid

Merck 

13,3547

BRN 

1988797

CAS DataBase Reference

17109-49-8(CAS DataBase Reference)

NIST Chemistry Reference

Phosphorodithioic acid, o-ethyl s,s-diphenyl ester(17109-49-8)

EPA Substance Registry System

Edifenphos (17109-49-8)

Safety

Hazard Codes 

T,N

Risk Statements 

21-23/25-43-50/53-24/25-23

Safety Statements 

36/37-45-60-61

RIDADR 

UN 2810

WGK Germany 

3

RTECS 

TE3850000

HazardClass 

6.1(b)

PackingGroup 

III

Hazardous Substances Data

17109-49-8(Hazardous Substances Data)

Toxicity

LD50 in female, male rats (mg/kg): 25.5, 66.5 i.p. (Chen)

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H317May cause an allergic skin reaction

H410Very toxic to aquatic life with long lasting effects

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P273Avoid release to the environment.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P301+P310IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician.

Edifenphos Chemical Properties,Usage,Production

Uses

Edifenphos is a foliar applied contact fungicide that provides both protective and curative control of rice blast diseases caused by Pyricularia oryzae. It also controls ear blight and stem rot in rice.

Uses

Fungicide.

Definition

ChEBI: An organic thiophosphate that is the O-ethyl-S,S-diphenyl ester of phosphorodithioic acid. Used to control a variety of fungal diseases on rice including blast, ear blight and stem rot. Edifenphos i moderately toxic to mammals and fish but poses more of a risk to aquatic invertebrates.

Metabolic pathway

Hydrolytic cleavage of the P-0 and P-S linkages affords the major degradation and metabolic pathways of edifenphos. A unique transesterification reaction yielded tri-S-phenyl and di-O-ethyl phosphorus esters as minor products in soil and plant test systems (Scheme 1).

Degradation

The hydrolytic DT₅₀ values of edifenphos (1) at pH 7 and 9 at 25 °C were 19 and 2 days, respectively (PM). [³⁵S]Edifenphods egraded rapidly in aqueous solution when exposed to UV light at 25-28 °C [DT₅₀ ca. 3 days (light exposed) vs. 19 days (dark control)]. Cleavage of the P-S linkage is the primary degradation pathway. Thiophenol (2) was further oxidised to form diphenyl disulfide (3), possibly during sample extraction, isolation and analysis. Stepwise cleavage of the P-S and P-O linkages yielded O-ethyl S-phenyl hydrogen phosphorothioate (4), S-phenyl dihydrogen phosphorothioate (5), benezenesulfonic acid (6) and sulfuric acid as major ³⁵S-containing products, whereas O-ethyl dihydrogen phosphate (7) and phosphoric acid were recovered from the phosphorus portion of the molecule (Murai, 1977).

Toxicity evaluation

Edifenphos shows no delayed neuropathic symptoms. Safety intervals between spray and harvest for rice are 21 days in Japan with 0.2 mg of MRL (Maximum Residue Limit).