[Chemistry Class Notes] Ether Preparation Pdf for Exam

Ether is a colourless, pleasant-smelling volatile liquid which is highly inflammable. It is used as the anaesthetic and as an intermediary or a solvent in the industrial processes. It is commonly called diethyl ether or ethyl ether. It is the organic compound which belongs to a large group of compounds that are known as ethers. The molecular structure is made using two ethyl groups and it is joined through the oxygen atom and represented by C₂H₅OC₂H₅. Here we will learn about the different preparation methods of ether. Ethers are fundamentally classified into 2 classes: Symmetrical ethers and Asymmetrical ethers. 

Preparation of ether by dehydration of alcohol

In this method, the alcohols dehydrate for producing ethers and alkenes in various conditions, in the presence of protic acids. In the presence of sulphuric acid, we obtain ethoxyethane at 413K and dehydration of ethanol at 443K. This is the best method for preparing ether, with the necessary alcohol. This method is the nucleophilic substitution reaction. The alcohol that is used in the reactions performs two roles – one acts as the nucleophile and the other acts as the substrate.

This reaction can follow two mechanisms Sₙ1 or Sₙ2. The choice of mechanism depends whether protonated alcohol loses water along with the attack or before the attack of the 2nd alcohol molecule. Generally the 2nd and 3rd alcohol follow S1 mechanism whereas primary alcohols follow S2 mechanism.

Preparation of ether through Williamson Synthesis

This is the most versatile and flexible method for preparing ethers. This process is named after an English chemist called Alexander Williamson who was responsible for inventing this method in the 19th century. This method makes use of alkoxide ion for attacking the alkyl halide substituting alkoxy (-O-R) group for halide. Alkyl halide should be unobstructed otherwise the elimination will compete with desired substitution. 

Williamson Ether synthesis is executed as the Sₙ2 reaction having primary alkyl halide in the presence of alkoxide ion. Here it is important to note that the ethers’ structure was proved because of this chemical reaction. Sₙ2 way is essential for synthesis in this reaction since it is useful only in the case of alkyl halide being primary or secondary.

The ethers that are obtained via this process contain more carbon atoms than any of the basic materials and hence they tend to be more complex structures. This is a vital process in organic chemistry. Sodium chloride and Diethyl ether are formed when the Sodium Ethoxide and the Chloroethane react with each other. The chemical denotation for this reaction is as follows:

Na + C₂H₅O⁻ + C₂H₅Cl = C₂H₅OC₂H₅ + Na⁺ Cl⁻

Conclusion

This is all about the preparation of ether, the processes, and their reactions. Focus on how the reactants produce ether and other products. Find out the mechanism of these reactions and understand the underlying concept of these preparation processes of ether.