Problem 55 - A Complete Resource Book in Chemistry for JEE Main

Question

Ethyl chloride is converted into diethyl ether in (a) Wurtz reaction (b) Grignard reaction (c) Perkin reaction (d) Williamson synthesis

Step-by-Step Solution

Answer

The conversion of ethyl chloride to diethyl ether is done by Williamson synthesis.

Step 1: Understanding the Reactions

First, let's identify each reaction mentioned. The Wurtz reaction involves combining two alkyl halides with sodium to form a larger alkane. Grignard reaction involves the reaction of alkyl halides with magnesium to form magnesium alkyl halides used in further synthesis. The Perkin reaction is for the synthesis of unsaturated aromatic aldehydes. Williamson synthesis specifically prepares ethers from alkyl halides and an alkoxide ion.

Step 2: Analyzing the Question

The question asks which reaction is used to convert ethyl chloride to diethyl ether. This requires understanding of ether formation from alkyl halides. Among the options, the Williamson synthesis is known for exactly this transformation as it reacts an alkoxide ion with an alkyl halide to form an ether.

Step 3: Identifying the Right Choice

Since the ethyl chloride needs to be converted into diethyl ether, and this involves forming an ether from an alkyl halide, the Williamson synthesis is the appropriate reaction. It uses an alkyl halide like ethyl chloride to create an ether such as diethyl ether by reacting with an alkoxide ion.

Key Concepts

Ether Formation

Ether formation is a process that involves creating a compound where an oxygen atom is connected to two alkyl or aryl groups. This connection is known as an ether linkage. Ethers are characterized by the general formula R-O-R', where R and R' represent organic substituents.
One common method of ether formation is the Williamson synthesis. In this reaction, an alcohol (R-OH) is first deprotonated to form an alkoxide ion, which then reacts with an alkyl halide (R'-X) to produce an ether.
It's vital to control factors such as temperature and solvent type, as these can affect the reaction rate and yield. This method is preferred because it offers a straightforward path to synthesize both symmetrical and asymmetrical ethers.

Alkyl Halides

Alkyl halides are organic compounds containing a halogen atom (such as chlorine, bromine, or iodine) bonded to an alkyl group. They are recognized by their RX structure, where R is an alkyl group and X is a halogen.
They serve as crucial intermediates in many chemical reactions due to their reactivity, especially in substitution and elimination reactions. Their ability to act as a reactive site makes them valuable reagents in synthesis reactions.
In the context of the Williamson synthesis, alkyl halides are used to form ethers. When combined with an alkoxide ion, they create an ether linkage, offering a path to valuable ether compounds.

Alkoxide Ion

An alkoxide ion is the conjugate base of an alcohol, created when an alcohol loses a proton (H+). They are represented by the formula R-O^-, where R refers to an alkyl or aryl group.
Alkoxide ions are very strong bases and excellent nucleophiles. This makes them highly reactive, especially in substitution reactions like the Williamson synthesis.
To form an alkoxide ion, a strong base such as sodium or potassium is used to deprotonate the alcohol. Once formed, the alkoxide ion can attack an alkyl halide to synthesize ethers efficiently.

Synthesis Reactions

Synthesis reactions involve the combination of two or more substances to form a more complex product. They are fundamental in chemistry for creating new compounds.
These reactions are essential in organic chemistry for forming carbon-containing compounds. In the Williamson synthesis, a classic example of a synthesis reaction, an alkoxide ion and an alkyl halide are combined to produce an ether.
Such reactions not only expand our ability to create a variety of chemical compounds but also pave the way for industrial applications and further innovations in chemical synthesis. By understanding synthesis reactions, scientists can design pathways to efficiently produce desired products.