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In chemistry, chain propagation (sometimes just referred to as propagation) is a process in which a reactive intermediate is continuously regenerated during the course of a chemical chain reaction. For example, in the chlorination of methane , there is a two-step propagation cycle involving as chain carriers a chlorine atom and a methyl radical ...
In the propagation phase, the lipid radical reacts with oxygen (O 2) or a transition metal, forming a peroxyl radical (LOO •). This peroxyl radical continues the chain reaction by reacting with a new unsaturated fatty acid, producing a new lipid radical (L •) and lipid hydroperoxide (LOOH). These primary products can further decompose into ...
The reaction 2 H 2 + O 2 → 2 H 2 O provides an example of chain branching. The propagation is a sequence of two steps whose net effect is to replace an H atom by ...
Chain initiation is the initial generation of a chain carrier, which is an intermediate such as a radical or an ion which can continue the reaction by chain propagation. Initiation steps are classified according to the way that energy is provided: thermal initiation, high energy initiation, and chemical initiation, etc. Thermal initiation uses ...
Even though all these steps can appear in one chain reaction, the minimum necessary ones are Initiation, propagation, and termination. An example of a simple chain reaction is the thermal decomposition of acetaldehyde (CH 3 CHO) to methane (CH 4) and carbon monoxide (CO). The experimental reaction order is 3/2, [4] which can be explained by a ...
Chain propagation (two steps) A radical abstracts a hydrogen atom from methane, leaving a primary methyl radical. The methyl radical then abstracts Cl • from Cl 2 to give the desired product and another chlorine radical. Methane chlorination: propagation The radical will then participate in another propagation reaction: the radical chain.
The free radical chain reaction is sometimes referred to as the Bolland-Gee mechanism [6] [7] or the basic autoxidation scheme (BAS) [8] and was originally based on the oxidation of rubbers, [9] but remains generally accurate for many materials. It can be divided into three stages: initiation, propagation, and termination. [10]
The termination step can vary, in both its actual chemical reaction and when it will occur. [6] Lipid peroxidation is a self-propagating chain reaction and will proceed until the lipid substrate is consumed and the last two remaining radicals combine, or a reaction which terminates it occurs. [3]