What is the propagation step?
The propagation phase describes the ‘chain’ part of chain reactions. Once a reactive free radical is generated, it can react with stable molecules to form new free radicals. These new free radicals go on to generate yet more free radicals, and so on.
What is chlorination reaction?
Chlorination: Any reaction or process in which chlorine (and no other elements) are introduced into a molecule. Chlorination of an alkene by electrophilic addition of Cl2. Chlorination of a benzene ring by electrophilic aromatic substitution.
What are the three steps involved in free radical mechanism?
Radical chain reactions have three distinct phases: initiation, propagation, and termination.
Which are three steps of free radical halogenation of alkane?
The radical chain mechanism is characterized by three steps: initiation, propagation and termination.
What is propagation in physics?
In physics, propagation is wave movement. Definitions of propagation. the act of producing offspring or multiplying by such production. synonyms: generation, multiplication.
What is propagation in polymerization?
Propagation. During polymerization, a polymer spends most of its time in increasing its chain length, or propagating. After the radical initiator is formed, it attacks a monomer (Figure 11). In an ethene monomer, one electron pair is held securely between the two carbons in a sigma bond.
What is chlorination Slideshare?
Chlorination is the process of adding the element chlorine to water as a method of water purification to make it fit for human consumption as drinking water. Chlorine is the most widely used disinfectant. As Chlorine compounds will destroy disease-causing organisms quickly — usually after 30 minutes.
What is oxidative chlorination?
Oxidative chlorination has emerged as an environmentally-benign process via the in-situ formation of molecular chlorine from the oxidation of chloride with suitable oxidants. Therefore, mono and biphasic oxidative process based on generating the chlorine from concentrated HCl in presence of oxidant has been developed.
What are the three steps in radical reaction use the chlorination of methane as your basis?
3.4: Chlorination of Methane: The Radical Chain Mechanism
- Step 1: Initiation.
- Step 2: Propagation.
- Step 3: Termination.
What is propagation in chemistry?
Chain propagation (sometimes referred to as propagation) is a process in which a reactive intermediate is continuously regenerated during the course of a chemical chain reaction. The two steps add to give the equation for the overall chain reaction: CH4 + Cl2 → CH3Cl + HCl.
What is chlorine radical?
The chlorine radical removes a hydrogen atom from the methane. That hydrogen atom only needs to bring one electron with it to form a new bond to the chlorine, and so one electron is left behind on the carbon atom. A new free radical is formed – this time a methyl radical, CH3 .
What is chlorination of alkane?
Hint: Chlorination of alkanes means addition of chlorine to alkanes. It is also called halogenation. Generally halogenation occurs in the presence of heat or sunlight. Halogenation is an example of substitution reaction.
How does propagation occur in a halogen reaction?
Propagation in Radical Halogenation The Cl• radicals produced in the initiation step are very unstable. These are the chlorine atoms and you know from general chemistry that halogens exist as diatomic molecules and not atoms. In the next step, these reactive radicals quickly react with ethane by abstracting a hydrogen:
Which is the product of the first propagation step?
The next two steps in the mechanism are called propagation steps. In the first propagation step, a chlorine radical combines with a hydrogen on the methane. This gives hydrochloric acid (HCl, the inorganic product of this reaction) and the methyl radical.
Which is the product of the chlorination reaction?
Chloromethane is formed in the second propagation step like a main product of the chlorination reaction. And new chlorine atom reacts with a new molecule of methane in propagation step 1. Termination: Recombination of two radicals – This is the end of the process.
How many chlorine radicals are formed in the initiation step?
Seeing that there’s two chlorine radicals formed in the initiation step, it would seem natural to bring together the methyl radical and the chlorine radical to form CH 3 –Cl . Right????? Nooooo! Note the number of free radicals has decreased here, not stayed the same.