What is the bromination of aromatic compounds?
The bromination of benzene is an example of an electrophilic aromatic substitution reaction. In this reaction, the electrophile (bromine) forms a sigma bond to the benzene ring, yielding an intermediate. Then, a proton is removed from the intermediate to form a substituted benzene ring. Created by Sal Khan.
How do aromatic compounds undergo bromination?
In bromination of an aromatic ring, molecular bromine (Br2) is reacted with iron tribromide (FeBr3) to form the strongly electrophilic bromine cation and FeBr4. Following this, the aromatic ring is reacted with the bromine cation and adds to the ring to form a benzenonium cation.
Does bromine react with aromatic compounds?
Aromatic compounds react by electrophilic aromatic substitution reactions, in which the aromaticity of the ring system is preserved. For example, benzene reacts with bromine to form bromobenzene. Many functional groups can be added to aromatic compounds via electrophilic aromatic substitution reactions.
What is the rate-determining, step in electrophilic aromatic substitution?
When the electrophile adds to the aromatic ring, it produces a carbocation intermediate. The first step of electrophilic aromatic substitution is usually the rate-determining step. Since a new sigma bond forms in the first step, the intermediate is called a sigma complex.
How do you chlorinate benzene?
Benzene reacts with chlorine or bromine in the presence of a catalyst, replacing one of the hydrogen atoms on the ring by a chlorine or bromine atom. The reactions happen at room temperature. The catalyst is either aluminum chloride (or aluminum bromide if you are reacting benzene with bromine) or iron.
How do you add CH3 to benzene?
An alkyl group can be added to a benzene molecule by an electrophile aromatic substitution reaction called the Friedel‐Crafts alkylation reaction. One example is the addition of a methyl group to a benzene ring. The mechanism for this reaction begins with the generation of a methyl carbocation from methylbromide.
Which effect does by CH3 substituent on aromatic electrophilic substitution?
Substituent Effects on Electrophilic Aromatic Substitution The electron-donating CH3 group activates the benzene ring to electrophilic attack. Ortho and para products predominate. The CH3 group is called an ortho, para director.
What is the rate determining step in the bromination of benzene?
Step 1: Formation of a strong electrophile, in this case an electrophilic bromine cation. Step 2: Pi electrons of benzene react with the bromine cation to form the sigma comoplex, resonance stabilized benzenonium intermediate. This step is the rate determining step.
What catalyst is used in the bromination of benzene?
The electrophilic substitution reaction between benzene and chlorine or bromine. Benzene reacts with chlorine or bromine in an electrophilic substitution reaction, but only in the presence of a catalyst. The catalyst is either aluminum chloride (or aluminum bromide if you are reacting benzene with bromine) or iron.
How ch3 is formed?
A methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms — CH3. In formulas, the group is often abbreviated Me. Such hydrocarbon groups occur in many organic compounds. It is a very stable group in most molecules.