ISOXATHION Chemical Properties

Melting point:

<25℃

Boiling point:

160°C (rough estimate)

Density 

1.48 g/ml

vapor pressure 

<1.3 x 10^-4 Pa (25 °C)

storage temp. 

0-6°C

solubility 

Chloroform (Slightly), Methanol (Slightly)

Water Solubility 

1.9 mg l^-1 (25 °C)

pka

-6.17±0.28(Predicted)

form 

liquid

color 

Colourless to Pale Yellow

Specific Gravity

1.48

BRN 

1222135

EPA Substance Registry System

Isoxathion (18854-01-8)

Safety Information

Hazard Codes 

T,N

Risk Statements 

24/25-50/53

Safety Statements 

28-36/37-45-60-61

RIDADR 

3018

WGK Germany 

3

HazardClass 

6.1(b)

PackingGroup 

III

HS Code 

29349990

Hazardous Substances Data

18854-01-8(Hazardous Substances Data)

ISOXATHION Usage And Synthesis

Description

Isoxathion is a pale yellow liquid, bp 160 ?C/0.15 mm Hg, vp <0.133mPa (25 ?C). Solubility in water is 1.9 mg/L (25 ?C). It is readily soluble in most organic solvents. Log Kow = 3.88. It is unstable to alkali.

Uses

Isoxathion is used to control sucking pests, leaf miners and some chewing pests in a variety of fruit, vegetables and ornamental plants.

Uses

Isoxathion is used as a pesticide.

Definition

ChEBI: An organic thiophosphate that is O,O-diethyl hydrogen phosphorothioate in which the hydrogen of the hydroxy group is replaced by a 5-phenyl-1,2-oxazol-3-yl group.

Synthesis

The industrial production of isoxathion begins with the synthesis of a substituted phenol derivative, which undergoes thiophosphorylation using reagents such as O,O-dimethyl phosphorochloridothioate to introduce the organophosphate moiety. This step is typically carried out under controlled temperature and anhydrous conditions to prevent hydrolysis and ensure high yield. The resulting intermediate is then subjected to aromatic substitution with a heterocyclic compound, often a pyridyl or thiazole derivative, to enhance insecticidal potency and selectivity.

Metabolic pathway

The principal route of isoxathion metabolism in soil, plants and mammals is by hydrolysis, probably via the oxon to 3-hydroxy-5-phenylisoxazole which is rapidly conjugated in both plants and rats. In soils, and to a lesser extent in plants and mammals, further metabolism of 3-hydroxy- 5-phenylisoxazole proceeds via opening of the isoxazole ring to give various metabolites of which benzoic acid is one of the more important. De-ethylation of the phosphate moiety has not been observed.

Metabolism

The principal degradation route of isoxathion in animals, plants, and soil is cleavage of P?O-isoxazole through oxidative desulfuration to the oxon followed by hydrolysis to 3-hydroxy-5-phenylisoxazole, which is conjugated in both plants and rats.

Toxicity evaluation

The acute oral LD₅₀ for rats is 112 mg/kg. NOEL (2 yr) for rats is 1.2 mg/kg b.w. DT₅₀ in soil is 9–40 d.

Degradation

Isoxathion is unstable to alkalis (PM). The hydrolysis product, 3-hydroxy- 5-phenylisoxazole (2), yielded 5-phenyl-3H-oxazolin-2-one (3) as the major photoproduct via a photolytic rearrangement (Nakagawa et al.,1974).

ISOXATHION(18854-01-8)Related Product Information

• Linezolid
• Mifepristone
• Lincomycin
• Nitenpyram
• ISOXATHION OXON,ISOXATHION OXON STANDARD
• Phosphorothioic acid, O-(4-chloro-5-phenyl-3-isoxazolyl) O,O-diethyl e ster
• Methyl isoxathion
• 5-PHENYLISOXAZOLE
• ISOXATHION