What is Chlorobenzene Definition Structure Formula Preparation Reactions and Uses
Chlorobenzene is a compound that has a chemical formula of C6H5Cl. This liquid is flammable and is also known as a common solvent. Chlorobenzene is commonly used to manufacture chemicals. The main use of this compound is done to produce commodities that include herbicides, rubber, and any other dyestuffs. It is also used as a solvent in various industrial applications and laboratories. It is nitrated to produce a mixture that includes 2-nitrochlorobenzene and 4-nitrochlorobenzene on a huge scale. Then, the mononitro chlorobenzenes are turned into 2-nitrophenol and other elements of chloride. Sometimes, many industries convert Aniline to chlorobenzene to use it as an agent for all the alkenes produced.
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How to Convert Aniline to Chlorobenzene?
The process to convert Aniline to chlorobenzene is quite challenging. You will have to use NaNO2/HCl to convert Aniline to benzene diazonium chloride. It then converts to chlorobenzene as the presence of CuCl affects the entire reaction. This type of reaction is called Sandmeyer Reaction.
The Formula For the Reaction is as follows:
C6H5NH2NaNO2/ HClC6H5N2ClCu2Cl2C6H5C
The entire process is completed in two steps. The temperature at which the reaction occurs stands at 0 degrees to 5 degrees centigrade.
When it comes to Sandmeyer Reaction, there are many types of reactions. You can react with benzene diazonium chloride with other solvents, including CuCI, CuCN, and many more. It forms chlorobenzene, benzonitrile, and many more.
How Can You Convert Benzene to Chlorobenzene?
The process of benzene to chlorobenzene conversion is pretty simple. You will first have to react to Benzene with Chlorine. However, you will have to ensure that a catalyst can replace the Hydrogen atoms with chlorine atoms. The room temperature is suitable for this type of reaction. You can take aluminium, chlorine, and iron in the form of catalysts.
However, it is not advised to take iron as a catalyst because, during the reaction, the particles get permanently altered. Iron has the ability to react with chlorine and form FeCl3 (Iron Chloride).
Also, you can take iron chloride in the form of a catalyst and make it behave like Aluminium Chloride (ALCL3). Then, chlorobenzene is formed when this type of reaction comes in contact with aluminium chloride.
The Process to Convert Chlorobenzene to Aniline
To convert Chlorobenzene to Aniline, you can prepare it commercially with the help of a catalyst, Nitrobenzene. You can also use ammonia on the produced chlorobenzene. All you have to do is reduce Nitrobenzene by carrying out a reaction in aqueous acid with the help of iron borings. As Aniline is considered a weak base, it tends to form salts when you dilute it in mineral acid.
How Can You Convert Chlorobenzene to Benzene?
You can convert chlorobenzene to benzene in three different steps altogether. You can start the reaction by reacting HNO3 with H2SO4 that will form Nitrobenzene. Then, you can reduce it by forming a reaction of Nitrobenzene and Sn+HCL, Fe+HCL, or H2/Pd to produce Aniline. After the reaction is completed, you can then add NaNO2+HCL to the reaction that will form benzene Diazonium Chloride. After that, you can react with Sandmeyer’s Reaction (CuCl) or Gatterman Reaction (Cu Powder). This will form Chlorobenzene.
How Can You Obtain Mono Chlorobenzene?
When you dissolve or suspend Aniline with cold aqueous mineral acid and treatment with sodium nitrite, then a diazonium salt comes into existence. This salt has to be treated with cuprous bromide to form mono chlorobenzene.
When you substitute chlorine at any given spot, then you will see that six carbons remain constant. Therefore, only one possible benzene is formed.
How Can You Prepare Chlorobenzene From Aniline?
You can prepare chlorobenzene from Aniline with the help of Sandmeyer Reaction. You can fit the reaction with diphenyl and extract it from chlorobenzene.
Here is a Step-By-Step Process to Prepare Chlorobenzene From Aniline:
Step 1: Sandmeyer Reaction: It is a chemical reaction that you can use to synthesize the aryl halides from the diazonium salts by using agents of copper salts and catalysts.
Step 2: You can follow a two-step reaction that includes converting benzene diazonium chloride by utilizing the Sodium Nitrate solutions and aqueous hydrochloric acid. Then, you can react to the benzene diazonium with cuprous chloride to form chlorobenzene.
FAQs on Chlorobenzene Structure Preparation Properties and Reactions
1. What is chlorobenzene?
Chlorobenzene is an aromatic halogen compound with the molecular formula C6H5Cl, formed by replacing one hydrogen atom of benzene with chlorine. It consists of a benzene ring attached to a chlorine atom. Chlorobenzene is a colorless, flammable liquid with a characteristic almond-like odor and is widely used as an industrial solvent and intermediate in organic synthesis.
2. What is the chemical formula and structure of chlorobenzene?
The chemical formula of chlorobenzene is C6H5Cl, and its structure is a benzene ring bonded to one chlorine atom. Structurally:
- It contains a six-carbon aromatic ring with alternating double bonds.
- One hydrogen of benzene (C6H6) is replaced by Cl.
- The C–Cl bond is polar, but the molecule overall is only slightly polar due to ring symmetry.
3. How is chlorobenzene prepared from benzene?
Chlorobenzene is prepared by the electrophilic substitution of benzene with chlorine in the presence of a Lewis acid catalyst such as FeCl3. The balanced reaction is:
C6H6(l) + Cl2(g) → C6H5Cl(l) + HCl(g) (in presence of FeCl3)
- FeCl3 generates the electrophile Cl+.
- The benzene ring undergoes substitution, not addition.
- Hydrogen chloride (HCl) is formed as a by-product.
4. Why is chlorobenzene less reactive than benzene?
Chlorobenzene is less reactive than benzene toward electrophilic substitution because chlorine shows a strong –I (electron-withdrawing inductive) effect. Although chlorine donates electrons by resonance (+R effect), its –I effect dominates overall, decreasing electron density of the ring and reducing its reactivity compared to benzene.
5. Is chlorobenzene ortho-para directing or meta directing?
Chlorobenzene is an ortho-para directing but deactivating group in electrophilic aromatic substitution reactions. Due to resonance donation (+R effect), chlorine increases electron density at the ortho and para positions. However, because of its –I effect, the overall reactivity of the ring decreases compared to benzene.
6. What happens when chlorobenzene reacts with NaOH?
Chlorobenzene reacts with aqueous NaOH at high temperature and pressure to form phenol (C6H5OH) via nucleophilic aromatic substitution. The reaction is:
C6H5Cl + NaOH → C6H5OH + NaCl (at ~623 K and 300 atm)
- Harsh conditions are required due to the stable C–Cl bond.
- The reaction proceeds through a benzyne intermediate.
7. What are the physical properties of chlorobenzene?
Chlorobenzene is a colorless, volatile liquid with moderate polarity and a boiling point of about 132°C. Its key physical properties include:
- Molecular mass: 112.56 g/mol
- Boiling point: ~132°C
- Insoluble in water but soluble in organic solvents
- Characteristic almond-like odor
8. What are the uses of chlorobenzene?
Chlorobenzene is mainly used as an industrial solvent and chemical intermediate in organic synthesis. Its major uses include:
- Production of phenol and aniline derivatives
- Manufacture of pesticides and dyes
- Solvent for paints, adhesives, and degreasing agents
- Intermediate in pharmaceutical synthesis
9. What is the difference between chlorobenzene and benzyl chloride?
The key difference is that in chlorobenzene the chlorine is directly attached to the aromatic ring, while in benzyl chloride it is attached to a side-chain carbon.
- Chlorobenzene: C6H5Cl (aryl halide, C–Cl bonded to ring carbon)
- Benzyl chloride: C6H5CH2Cl (alkyl halide, C–Cl bonded to CH2)
- Chlorobenzene is less reactive toward nucleophilic substitution.
- Benzyl chloride reacts readily due to resonance stabilization of the benzyl carbocation.
10. Why does chlorobenzene not undergo nucleophilic substitution easily?
Chlorobenzene does not easily undergo nucleophilic substitution because the C–Cl bond has partial double bond character due to resonance. The lone pair on chlorine overlaps with the benzene ring, strengthening the C–Cl bond and making it shorter and stronger than in alkyl halides. As a result, harsh conditions are required for substitution reactions.
