Chain Termination Step
| Formula / Notation | R• + R• → R-R; R• + X• → RX |
|---|---|
| Also Known As | Radical termination, chain-ending step, inhibition (chain reaction) |
What is Chain Termination Step?
The chain termination step is the final step in a free-radical chain reaction mechanism in which two radicals combine to form a stable non-radical product, ending the chain. Common termination steps include radical coupling (e.g., Cl• + Cl• → Cl₂) and disproportionation. Termination steps reduce the overall rate of the chain reaction.
Formula & Notation
Other Names / Synonyms: Radical termination, chain-ending step, inhibition (chain reaction)
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The chain termination step is the final step in a free-radical chain reaction mechanism in which two radicals combine to form a stable non-radical product, ending the chain. Common termination steps include radical coupling (e.g., Cl• + Cl• → Cl₂) and disproportionation. Termination steps reduce the overall rate of the chain reaction.
Controlled chain termination is essential in radical polymerisation to regulate polymer molecular weight and distribution. Inhibitors such as hydroquinone or BHT prevent premature polymerisation of monomer storage. In nuclear reactors, control rods cause neutron absorption (termination) to shut down…
Absence of effective termination in explosive decompositions or runaway polymerisations is extremely dangerous. Stabilisers must be present in stored radical-polymerisable monomers (styrene, acrylates). Monomer should be tested for inhibitor concentration before use in exothermic polymerisations.
The formula or notation for Chain Termination Step is: R• + R• → R-R; R• + X• → RX