Monocrotopos Research Paper

Monocrotophos

IUPAC name: dimethyl[(E)-4-(methylamino)-4-oxobut-2-en-2-yl]phosphate

Molecular formula: C7H14NO5P

Molecular weight: 223.2

Structural formula: CAS number: 6923-22-4

Physical properties: (Tomlin, 1997)

Boiling Point: At 0.07 Pascal 125oC

Melting Point: 54-55oC

Vapor Pressure: 3*104 Pascal

Solubility in water: miscible

Log Poctanol/water: -0.22

Chemical properties:

Pure Monocrotophos is in crystalline form. Crystals are colorless and hygroscopic in nature. Commercial product is a clear viscous liquid which is reddish brown to dark brown in color. Odour resembles that of ester but in milder form. It forms unstable complex with low molecular weight alcohols and glycols. It is stable in ketones and high molecular weight alcohols

Photolytic half-life in water is 30 days. It has relatively low degradation under aerobic condition, NMFS (2008). Chlorpyrifos is used for varied purposes. In agriculture, it is commonly used as a foliar spray to prevent pesticide infestation in standing crops, vegetables, fruits. It is directly applied to soil before plantation of any crops to ward off soil borne insects. Wooden furniture is protected from termites by incorporation of chlorpyrifos in primers or paints. It is applied to soil before construction of buildings. Chlorpyrifos is neurotoxin as it inhibits cholinesterase at low level of exposure. Along with neurotoxin, it is an endocrine disrupter with anti-androgenic and estrogenic properties. It decreases the level of cortisol and thyroxin in serum of human blood. Chlorpyrifos is acute and chronically toxic to aquatic animals. It results in motor in-coordination, delayed maturation, growth and reproduction impairment, deformities and depressed population. It is genotoxic, immunotoxic, embryo toxic, neurotoxic, teratogenic and endocrine disruptor, hence it is non-systemic pesticide. Half life of dissociation of Chlorpyrifos is significantly more in organic soils than mineral soils. Dissociation is slow in water containing clay minerals, humus, dissolved organic matter and suspended sediments, Gebremariam et al. (2012). Rate of hydrolysis of Chlorpyrifos is affected by pH, moisture, temperature as well as formulation and application rates. Stability of Chlorpyrifos decreases with increasing pH i.e. alkalinity, U.S. EPA (1999). It is estimated that rate of dissociation doubles with each increase of 10oC, Racke et al. (1994). Dissociation of chlorpyrifos is more rapid in alkaline condition, Baskaran et al.