Examples of free radical reactions, free radical reaction mechanisms

Methane chloride is the best example of this.

The mechanism of free radical reaction is as follows:

Free radical reactions, also known as free radical reactions, are various chemical reactions in which free radicals participate. There is an unpaired electron in the outer shell of the radical electron shell, which has a strong affinity for adding a second electron, so it can act as a strong oxidizing agent.

The most important thing in the atmosphere is OH-free radicals, which can react with various trace gases. In the chemical reactions formed by photochemical smog, there are many free radical reactions that play an important role in the initiation, transmission, and termination processes of the chain reaction.

There are many free radicals that are intermediate products, such as hydrogen peroxide radical (Ho2-), alkoxy radical (Ro-), peroxyalkyl radical (Ro2-), acyl radical (RCO-), etc.

There are five basic types of free radical reactions:

1. React by light, radiation or peroxide to break molecular bonds and produce free radicals;

2. Free radicals and molecules react to produce new free radicals and molecules;

3. Free radicals react with molecules to produce larger free radical reactions;

4. The reaction of free radicals decomposing into small free radicals (and molecules);

5. The reaction of free radicals to each other. It is related to free radical reaction in precipitation acidification, ozone layer depletion and atmospheric photochemical reactions. Therefore, free radical reactions have become an important part of atmospheric chemistry research.

Free Radical Substitution Reaction The reaction in which an atom or group in an organic compound molecule is replaced by another atom or group is called a substitution reaction.

If the substitution reaction is carried out in the way of covalent bond homolysis, that is, it is caused by the free radical generation generated by the molecule through homogeneous cleavage, it is called a free radical substitution reaction. The free radical reaction includes chain initiation, chain transfer, chain termination, and three scattered cluster stages. The chain initiation phase is the stage where free radicals are produced.

Since energy is required for homocleavage of bonds, heat or light is required for the chain initiation stage. The chain transfer stage is the stage of transforming one free radical into another, like a relay race, free radicals are continuously passed on, like a chain after a chain.

The reaction mechanism of ethylbenzene and bromine radical substitution is that ethylbenzene and liquid bromine can be substituted on the side chain under light conditions. One is from the substitution on the benzene ring and the second is from the substitution from the side-chain ethyl. The substitution on the benzene ring is conditioned by using iron as a catalyst, and the substitution site is mainly manifested in the ortho and para positions with the ethyl group to generate o-bromoethylbenzene and p-bromoethylbenzene.

Substitution on the side chain, the condition is light, ethylbenzene and liquid bromine can occur under light conditions, mainly to replace the hydrogen atom on the carbon attached to the benzene ring. As.

The mechanism of the free radical addition reaction is as follows:Free radicals, also known as "free radicals" in chemistry, refer to atoms or groups with unpaired electrons formed by the homogenization of covalent bonds of the molecules of a compound under external conditions such as photothermal and other conditions. (When a covalent bond is ununiformly cracked, the shared electron pairs between the two atoms are completely transferred to one of the atoms, resulting in the formation of positively charged and negatively charged ions, a method of annihilation called bond splitting.)

> radical reactions play an important role in combustion, gas chemistry, polymerization, plasma chemistry, biochemistry, and various other chemical disciplines. In addition, this bonus may occur between one group and one non-group, or between two groups.

Basic steps of free radical addition reaction examples (also known as as a free radical chain mechanism):

1. Start with free radical initiators: free radicals come from non-free radical precursors.

2. Chain propagation: non-free radicals react with free radicals early to produce new free radicals.

3. Chain termination: The two groups react with each other to produce a non-free radical.

The radical reaction depends on a (relatively) weakly bonded reagent, allowing it to form a group in a uniform cleavage form (usually by heat or light). Reagents without such weak bonds may continue to proceed to a different mechanism.

The conditions for a free radical reaction usually include the following:

2. Temperature: Some free radical reactions need to be carried out at high temperatures, such as cleavage, polymerization, oxidation, etc.

3. Solvents: Some free radical reactions need to be carried out in specific solvents, such as alcohols, ketones, alkane solvents, etc.

4. Catalyst: Many free radical reactions need catalysts, which can be used to promote the reaction rate and reduce the activation energy of the reaction, such as copper ions, dibenzoyl peroxide, etc.

5. Special conditions: Some free radical reactions require special conditions to occur, such as free radical oxidation in the presence of oxygen, water and metal cations.

Free radical reactions have applications in many fields, and here are some of them:

1. Chemical synthesis: free radical reaction can be used to synthesize organic molecules, such as chloroform.

2. Pharmaceutical industry: free radical reaction is widely used in the pharmaceutical industry, including drug synthesis, efficacy evaluation and drug storage.

3. Environmental protection: free radical reaction can be used in water treatment, air purification and other environmental protection fields.

4. Food processing: free radical reaction can be used in food processing, such as the preservation treatment of meat and vegetables and the preparation of preservatives.

5. Polymerization reaction: free radical polymerization reaction can be used to produce polymer materials such as plastics and rubber.

6. Photochemical reaction: free radical reaction is a key step in many photochemical reactions, such as the photosensitizer used in photodynamic ** is to play a role through free radical reaction.

7. Life Sciences: Free radical reaction also plays an important role in the field of life elimination science, such as cell signaling, DNA damage repair, etc.

1 Pinyin 2 Annotations.

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The reaction in which free radicals are involved is called free radical reaction. Free radicals are produced by the homogeneous cleavage of covalent bonds between atoms in a molecule under the action of light, radiation, peroxide or high temperature, and there are atoms or clusters of atoms with unpaired valence electrons, called free radicals (formerly known as: free radicals), such as H· (hydrogen radicals), Cl· (chlorine radicals), and CH3 (methyl radicals).

The free radical reaction has the characteristics of chain reaction, and the reaction process goes through three stages: chain initiation (production of active intermediates - free radicals), chain growth (free radicals attack the reactants to generate new free radicals) and chain termination (free radical aging and inactivity). The free radical reaction is carried out by the homogeneous cleavage of covalent bonds, and the presence of acids, pyrine or changes in the polarity of the solvent have little effect on the free radical reaction, but the non-polar solvent favors the free radical reaction. There are two main types of free radical reactions.

One is free radical substitution reactions, such as the chlorination reaction of alkanes. The other type is free radical addition reactions, such as the addition reaction between chlorine and tetrachloroethylene.