[Chemistry Class Notes] on Alcohol, Phenol, and Ether Pdf for Exam

The terms Alcohols Phenols and Ethers belong to the class of organic compounds. These compounds have a huge application count in industries for domestic purposes. When the hydroxyl (-OH) group bonds with the saturated carbon atom, we receive Alcohol. And the dehydration of alcohol forms Ether. Based on the hydroxyl group, there are three types of alcohol named Monohydric, Dihydric, and Trihydric.

These compounds are the organic compound classes that find diverse usage in a wide range of industries and for domestic purposes.

• Alcohol is formed while the saturated carbon atom is bonded to a hydroxyl (-OH) group.

• Phenol is formed when the hydrogen atom present in a benzene molecule gets replaced by the -OH group.

• The ethers are formed when an oxygen atom is connected to either two aryl or alkyl groups.

Let us look at more detail about the types of alcohol, ether, and phenol, including their classification, with a few examples:

Classification of Alcohol

Based on the number of attached hydroxyl groups, alcohol can be classified into three types, as listed below:

• Monohydric alcohols: These contain one -OH group. An example is CH3CH2-OH.

• Dihydric alcohols: These contain two -OH groups. An example is 1,2-Ethanediol.

• Trihydric alcohols: These contain three -OH groups. An example is 1,2,3-Propantriol.

Based on the number of carbon atoms that are attached to the carbon that is bonded directly with the -OH group, alcohols are classified into three types.

• Primary alcohols – Here, one carbon atom is attached directly.

• Secondary alcohols – Here, two carbon atoms are attached directly.

• Tertiary alcohols – Here, three carbon atoms are attached directly.
  

Classification of Phenol

Based on the number of hydroxyl groups count attached, phenols are classified into three types, as listed below:

• Monohydric phenols – These contain one -OH group.

• Dihydric phenols – These contain two -OH groups, maybe “ortho-,” “meta-” or “para-” derivatives.

• Trihydric phenols – These contain three -OH groups.
  

Classification of Ether

Based on the aryl or alkyl groups type attached to the oxygen atom in ether, we can classify it into two types.

• Symmetrical Ether – It is also called the simple ether; the aryl or the alkyl group that is attached to either side of the oxygen atoms are similar. Examples can be given as C₂H₅OC₂H₅, CH₃OCH₃, and more.

• Unsymmetrical Ether – Unsymmetrical ether – We can also refer this to as mixed either, which is the aryl or the alkyl group, attached to either side of the oxygen atoms and are not similar. Examples can be given as C₂H₅OC₆H₅, CH₃OC₂H₅, and more.
  

Nomenclature of Alcohols, Phenols, and Ethers

1. Nomenclature of Alcohols

Alcohols is three major classes which are listed below.

• Monohydric Alcohol

• Dihydric Alcohol

• Trihydric Alcohol

Let us now discuss the nomenclature of these alcohols.

Monohydric alcohols are given with the general formula C_nH_2n+1OH, where n = 1, 2, and so on. Also, we can represent them as R-OH, where R denotes an alkyl group.

Common System

In the common system, we can name monohydric alcohols as Alkyl Alcohol. We can get their names by adding the name alcohol after the alkyl group name is present in the molecule. For example, the CH3-OH compound has one methyl group with an alcohol group. Therefore, we call it Methyl Alcohol.

Dihydric alcohols are given with the general formula, (CH2)n(OH)2, where n= 2,3,4, and so on. Due to their sweet taste, we refer to them as Glycols. Based on the two hydroxyl group’s relative position, we can classify these as α, β, ϒ, ….., ω-glycols, and more. Let us look at their nomenclature system.

Common System

In the common system, we name the α- glycols simply by adding the word Glycol after the end of the alkene name. In contrast, the β, ϒ … ω – glycols get their names the same as the corresponding polyethylene glycols. For example,

The formula of trihydric alcohols can be given as(CH2)n(OH)3 where n = 3, 4, 5, ….., and so on. We do not have any general nomenclature rules in this system. So, there is only the IUPAC rule. In the trihydric alcohol IUPAC system, we call them Alkanethiols and use Arabic numerals to indicate the OH group position.

2. Nomenclature of Phenols

Phenol is the simplest derivative of benzene. It is also the common name and an accepted IUPAC name as well. We can name the substituted phenols as the derivatives of phenols both in IUPAC and the common system.

In this common system, we can indicate the substituent position that is on the benzene ring with respect to the –OH group, by adding the prefix like meta (m-) for 1,3, ortho (o-) for 1:2, and para (p-) for 1,4.

Nomenclature of Ethers

Common System

We can get the common names of ethers simply by naming the two aryl or alkyl groups linked to oxygen atoms as separate words in alphabetical order and adding ether at the end. In the case of symmetrical ethers, we use the “di” prefix before the alkyl or the aryl group name.

 

Tests to distinguish between Phenol, Alcohol, and Ether

To differentiate and identify if the given compound is an alcohol, phenol, or ether, the following tests can be employed:

(i) To differentiate between alcohols and phenols:

 

(ii) To differentiate between phenols and ethers:

 

(iii) To differentiate between Alcohol and ether:

 

In this way, alcohols, phenols, and ethers compounds can be distinguished. There are several other methods too, for example, different physical properties such as density, specific gravity, flashpoints, etc.