Alcohols, Phenols and Ethers

Introduction

Alcohol, Phenol, Ether are classified as organic compounds. These contain numerous applications in industries for domestic purposes. So, Alcohol is made when a saturated carbon atom is restrained to a hydroxyl (-OH) group. Phenol is now created when a benzene molecule’s hydrogen atom is reinstated by the -OH group. And lastly, Ether is made when an oxygen atom is connected to two alkyl or groups of aryl. 

Classification of Alcohol

Reckoning on the total number of hydroxyl groups that exist, there are three types of Alcohols which are:

Monohydric alcohol

This type of Alcohol contains one- OH groups. For example, CH3CH2-OH.

Dihydric alcohol

This type of Alcohol contains two -OH groups. For example, 1,2,2-Ethanediol.

Trihydric alcohols

This type of Alcohol contains three -OH groups. For example, 1,2,3-Propantriol.

The number of carbon atoms attached to the OH group, there are three types of Alcohol. And they are:

Primary Alcohol

In these types of alcohol, carbon atoms are directly attached to the -OH group.

Secondary Alcohol

In these types of Alcohol, two carbon atoms are directly attached to the -OH group.

Tertiary Alcohol

In these types of alcohol, three carbon atoms are directly attached to the -OH group.

Preparation of Alcohol

Alcohol contains one or more hydroxyl (-OH) groups. Simply Alcohol is not a common occurrence of nature. Instead, alcohol is found in essential or volatile oils, usually contained in floral parts of the plants. 

Some general methods of preparation of Alcohol:-

• The hydrolysis of Halides- when we boil alkyl halides with an aqueous solution of alkyl hydroxide, it provides us with Alcohol from the nucleophilic substitution mechanism. 
• The hydration of Alkenes- the direct hydration takes place by adding water in the existence of a catalyst,
• The indirect hydration takes place by adding sulphuric acid to an alkane, followed by hydrolysis of alkyl hydrogen sulfate.

• Alkenes hydro formalize and create olefins that react with carbon monoxide and hydrogen. This process is called hydroformylation. 
• So, in results, the aldehyde is consecutively hydrogenated to make alcohol.
• The hydroboration of alkenes when alkenes are treated with diborane, alkyl boranes, R3B, are formed. When Alkylboranes is oxidized with alkaline hydrogen peroxide, it produces Alcohol.
• When Grignard reagents interact with appropriate carbonyl compounds, all three types of alcohol (primary, secondary, and tertiary) are formed.

Classification of Phenol

Established by the number of hydroxyl groups attached.

Phenols are divided into three types. And they are:

• Monohydric phenols:
• These types of phenols consist of one -OH group.
• Dihydric phenols: 
• These Phenols are made up of two -OH groups. They can also be ortho-, meta-, or para-derivative.
• Trihydric phenols:
• These types of phenols consist of three -OH groups.

Preparation of Phenol

For a long time, Phenol was usually synthesized from coal tar. Whatsoever, with the growing technology, numerous types of new methods are made to prepare phenols.

They are:

1. Chlorobenzene is a haloarene that is formed by the monosubstitution of the benzene ring. As a result, when chlorobenzene is fused with sodium hydroxide at 623K and 320 atm, sodium phenoxide is produced. Finally, Phenol is produced by the acidification of sodium phenoxide.
2.  Benzene Sulphonic Acid- By reacting benzene with oleum, benzene sulfonic acid can be produced. As a result, when benzene sulphonic acid is treated at a higher temperature with molten sodium hydroxide, it promotes the formation of sodium phenoxide. Finally, the acidification of phenoxide yields Phenol.
3.  Diazonium Salts- Diazonium salts are formed when a primary aromatic amine is treated with nitrous (NaNO2 + HCl) acid at 273 – 278 K. And the reactivity of such diazonium salts is extremely high. When such diazonium salts are heated with water, they eventually hydrolyze to phenols. When diazonium salts are treated with dilute acid, phenols are produced.
4.  Cumene is an organic compound formed by the Friedel-Crafts alkylation of benzene with propylene. Cumene hydroperoxide is produced by the oxidation of cumene in existing air. When cumene hydroperoxide is treated with acid and water, phenols are formed.

Classification of Ether

Established by the alkyl or aryl groups attached to the oxygen atom in Ether, it can be of two kinds. And they are:

Symmetrical Ether

This is also called the name simple ether; the alkyl or the aryl group attached to either side of the oxygen all the atoms are the same—for example, CH3OCH3, C2H5OC2H5, etc.

 Unsymmetrical Ether

This is also known by the name mixed Ether, and the alkyl or the aryl group attached to either side of the oxygen all atoms are not the same—for example, CH3OC2H5, C2H5OC6H5, etc.

Preparation of Ether

There are many ways of preparing Ether. Ethers are organic compounds consisting of oxygen atoms that are restrained with two or different alkyl or aryl groups. 

They are: 

1. The dehydration of Alcohols- the existence of sulphuric acid, dehydration of ethanol yields ethoxyethane at 413 K. Basically, it is the only ideal preparation method through primary alcohols. So, the preparation of ethers by dehydration of an alcohol is a nucleophilic substitution reaction.
2. Williamson’s synthesis- usually, when the alkyl halide reacts with sodium alkoxide, from that reaction, ether is made. Therefore this reaction is referred to as Williamson’s synthesis. In this, the SN2 mechanism for primary alcohols is followed.

Conclusion

The Alcohols and phenols are divided firstly based on the number of hydroxyl groups and secondly, here we see the hybridization of the carbon atom,SP3 or sp2, to which the –OH group is attached. Whereas others are divided based on groups,attached to the oxygen atom. The Alcohols, phenols, and others hold the capability to form intermolecular hydrogen restraining with water making them soluble. Usually, boiling points of ethers show those of alkanes when their solubility is mainly in contrast with those of alcohols having the same molecular mass.