klorradikaler

Klorradikaler, or chlorine radical (Cl•), is a chlorine atom bearing an unpaired electron. It is highly reactive and short‑lived, driving many radical chain reactions in the gas phase, liquids, and at interfaces. Cl• is a key initiator in atmospheric and combustion chemistry and can influence the lifetimes of pollutants and ozone.

Formation and sources: Cl• is most commonly generated by photodissociation of chlorine-containing species, for example Cl2 + hv -> 2 Cl•. It can also arise from the photolysis or radiolysis of chlorinated solvents, halons, or organochlorine compounds in the atmosphere or flames.

Reactivity and mechanisms: A typical reaction is hydrogen abstraction: Cl• + RH → R• + HCl, producing a carbon‑centered radical and hydrogen chloride. Cl• can also add to carbon–carbon double bonds, forming chlorinated radicals, or recombine with another Cl• to form Cl2, terminating the radical chain. In the atmosphere, Cl• participates in catalytic cycles that destroy ozone: Cl• + O3 → ClO + O2; ClO + O → Cl + O2; net O3 + O → 2 O2.

Environmental and practical significance: Chlorine radicals influence atmospheric chemistry, including ozone depletion in polar regions, degradation of volatile organic compounds, and initiation of combustion and polymerization processes through radical pathways.

Detection and study: Cl• is monitored by techniques such as electron paramagnetic resonance (EPR), laser-induced fluorescence, and differential optical absorption spectroscopy. Accurate knowledge of Cl• concentrations improves models of air quality, combustion, and environmental remediation.