Description
Dienochlor is an obsolete organochlorine insecticide. It has a low aqueous solubility and is quite volatile. Its data suggests it is persistent in soils. It is not toxic to mammals but does high a potential for bioaccumulation. Dienochlor has a moderate toxicity to aquatic invertebrates but considered to be more toxic to fish. It is relatively non-toxic to birds
Chemical Properties
Yellow-brown crystalline solid. Melting point 122-123°C, vapor pressure 1.33×10-3 Pa. Insoluble in water, soluble in aromatic hydrocarbons. Stable to aqueous acids and bases, but loses activity at high temperatures or under ultraviolet light. Activity decreases by 50% after 6 hours at 130°C.
Uses
Acaricide used for control of mites on ornamentals.
Uses
Dienochlor is used for the control of mites (Tetrunychus spp.,
Panonychus ulmi and Polyphagotarsonemus latus) on roses, Chrysanthemums
and other ornamentals.
Definition
ChEBI: Dienochlor is an organochlorine compound.
Production Methods
Dienochlor is commercially produced through the exhaustive chlorination of cyclopentadiene derivatives. The process involves reacting cyclopentadiene with chlorine gas under controlled conditions to form pentachlorocyclopentadiene, which is then dimerized to yield dienochlor. This synthesis requires precise temperature regulation and containment due to the volatility and toxicity of the intermediates and chlorine gas.
Mechanism of action
Contact action, destabilises nerve cell membranes. GABA-gated chloride channel antagonist.
Environmental Fate
Plant. On plants, dienochlor was converted by sunlight to form perchloro ketones (Quistad and Mulholland, 1983).
Chemical/Physical. Dienochlor is unstable when exposed to sunlight. When dienochlor applied as a thin ?lm on glass plates was exposed to sunlight, nonpolar products, a tricyclic chlorocarbon and 3 isomeric perchloro ketones were formed at yields
Dienochlor begins to decompose at 130°C (Worthing and Hance, 1991).
Metabolic pathway
Dienochlor is readily degraded in sunlight to many products, only a few
of which have been identified. It is also metabolised in animals but to
unknown products. In vitro studies have shown that it interacts with thiols
(glutathione, cysteine, efc.) and proteins.
Metabolism
Dienochlor decomposes in simulated sunlight (DT50
1.6 min). Degradation is mainly environmental rather
than metabolic, and photochemical breakdown is rapid. It
decomposes in soils, DT50 3.1 days and DT50 2–3 days on
plants exposed to sunlight.The major degradation products of dienochlor in plants are perchloroketones. It is rapidly degraded in rats.
Degradation
Dienochlor is stable in storage at 54°C for 14 days and at 42°C over
2 years. It undergoes hydrolysis with DT50 values at pH 5,7 and 9 of 184,
93 and 30.5 days, respectively, at 25 °C. It decomposes in simulated sunlight
with a DT50 of 1.6 minutes (PM).
A thin film of dienochlor on glass was readily degraded with a half-life
of <1 hour on exposure to sunlight. Four photoproducts were isolated
from a plethora of products and identified by 13C NMR spectroscopy
(Quistad and Mulholland, 1983). The photocatalysed addition of two
chlorine atoms (from donor dienochlor) afforded the tricyclic photochlorination
product 2 (up to 10% yield). Three isomeric perchloroketones
(3,4 and 5), each resulting from the net addition of one oxygen atom, were
major products, both on glass (up to 14% combined isomers) and on
cucumber and strawberry plants (up to 11% yield). Generally products 2,
3 and 4 were found in similar yields and 5 was the minor of the identified
metabolites. The photochlorination product 2, however, was not detected
on the plants. These products are illustrated in Scheme 1.
Pesticide Type
Acaricide; Insecticide; Ovicide
