Question

Write an equation for the preparation of hexylbenzene from benzene and other appropriate reagents.

Short answer

Benzene reacts with hexyl chloride and \( AlCl_3 \) to form hexylbenzene and HCl.

Step-by-step solution

Determine the Starting Material

We start with the benzene ring, which is represented as \( C_6H_6 \). This will act as the base structure for our synthesis of hexylbenzene.

Identify the Target Molecule

The target molecule is hexylbenzene, which has the structure \( C_6H_5C_6H_{13} \). This indicates that a hexyl group \( C_6H_{13} \) must be added to the benzene ring.

Select the Appropriate Reagent

To add a hexyl group to benzene, we need an alkyl halide as the reagent. Hexyl chloride \( C_6H_{13}Cl \) is a suitable reagent for this reaction.

Choose the Reaction Type

The Friedel-Crafts alkylation is the appropriate reaction mechanism for adding an alkyl group to benzene. It involves the use of an alkyl halide and a Lewis acid catalyst such as aluminum chloride \( AlCl_3 \).

Write the Reaction Equation

The reaction can be represented as: \[ C_6H_6 + C_6H_{13}Cl \xrightarrow{AlCl_3} C_6H_5C_6H_{13} + HCl \]This equation shows benzene reacting with hexyl chloride in the presence of the catalyst \( AlCl_3 \), forming hexylbenzene and hydrochloric acid as a by-product.

Key concepts

benzene

Benzene is an essential organic compound that serves as a basic building block in organic chemistry. Its chemical formula is \( C_6H_6 \), and it's known for its ring structure made up of six carbon atoms bonded in a planar hexagonal arrangement. These carbon atoms are connected by alternating single and double bonds, forming a resonance-stabilized structure known as the benzene ring.
Benzene is a colorless and highly flammable liquid with a sweet smell. One key feature of benzene is its stability, which is derived from the delocalization of electrons across the carbon atoms (a process known as aromaticity). This property makes benzene less reactive compared to other unsaturated hydrocarbons. Despite its stability, benzene can participate in a variety of reactions, particularly electrophilic substitution reactions, such as Friedel-Crafts alkylation.
Understanding benzene's structure and reactivity is crucial for its application in forming more complex aromatic compounds, like hexylbenzene.

hexylbenzene

Hexylbenzene is an aromatic compound that results from substituting a hydrogen atom in benzene with a hexyl group. The hexyl group is a saturated aliphatic chain consisting of six carbon atoms, denoted as \( C_6H_{13} \). The chemical structure of hexylbenzene can be represented as \( C_6H_5C_6H_{13} \).
In the synthesis of hexylbenzene, the benzene ring provides the aromatic core, while the hexyl group adds a level of structural complexity. This compound maintains the aromatic properties of benzene but also exhibits characteristics imparted by the hexyl chain, such as increased hydrophobicity and boiling point.
Hexylbenzene has applications in the chemical industry, particularly as an intermediate in the production of other chemicals and materials. Additionally, its study helps in understanding the modification and derivatization of aromatic structures.

alkyl halide

Alkyl halides are organic compounds that feature a halogen atom (such as chlorine, bromine, or iodine) bonded to an alkyl group. In the context of Friedel-Crafts alkylation to produce hexylbenzene, hexyl chloride \( C_6H_{13}Cl \) is used as the alkyl halide.
The choice of alkyl halide is crucial because it determines the alkyl group attached to the benzene ring. Alkyl halides are often used in organic synthesis due to their ability to undergo substitution reactions easily, making them excellent reagents for transferring alkyl groups in various chemical processes.

• They are versatile reactants in creating more complex organic molecules.
• The halogen atom makes them highly reactive with nucleophiles and bases.

In Friedel-Crafts alkylation, the alkyl halide reacts with the benzene ring under the influence of a catalyst (like a Lewis acid) to form an alkyl-substituted aromatic compound.

Lewis acid catalyst

A Lewis acid catalyst is an essential component for catalyzing reactions such as Friedel-Crafts alkylation. These catalysts are named after the Lewis theory of acids and bases, which defines an acid as an electron pair acceptor.
In the Friedel-Crafts alkylation process, a common Lewis acid like aluminum chloride \( AlCl_3 \) is employed. The Lewis acid catalyst facilitates the formation of a complex between the alkyl halide and itself, creating a more potent electrophile. This action makes it easier for the benzene ring to undergo substitution, resulting in the desired alkylated product.

• Lewis acids enhance the reactivity of electrophilic centers in a reaction.
• They are essential for the success of many aromatic substitution reactions.

Choosing the right Lewis acid catalyst is vital not only for the reaction's success but also for influencing the reaction's rate and selectivity to produce compounds like hexylbenzene efficiently.