The International Union of Pure and Applied Chemistry recommends a systematic approach to the nomenclature of organic compounds. This is referred to as IUPAC nomenclature (often abbreviated to IUPAC). Phenol is a key component of organic chemistry. They are a type of chemical molecule that has a hydroxyl group that is connected to the aromatic ring's carbon atom. Phenol is an aromatic hydrocarbon group having a hydroxyl group that is always attached to a benzene ring. Phenol is also known as phenolic acid, carbolic acid or benzenol acid.
Phenols and Their Names
The phenol molecule is made up of two parts:
- an aryl group
- a hydroxyl group.
So phenols can be classified as mono-, di-, tri-, or polyhydric phenols based on the number of aryl groups attached. Monohydroxybenzene, or C6H5OH, is the IUPAC choice for phenol.
Let us review some basic IUPAC nomenclature rules before moving forward with the naming of phenols. The following rules must be followed when practising nomenclature, according to IUPAC guidelines:
- The longest chain rule is as follows: The parent hydrocarbon should be recognised and labelled according to this criteria.
- The lowest set of locants: This rule implies that the carbon atoms in parent hydrocarbons are numbered.
- Multiple instances of the same substituent: This rule applies to prefixes like di-, tri-, mono-, and poly.
- The naming of distinct substituents: Different substituents in a chemical must be named in alphabetical order.
- Various substituents in the same location are given different names: The compounds are named in ascending alphabetical order according to this criterion.
- Complex substituents must be designated as alkyl groups, which are placed in brackets.
IUPAC has established some guidelines that are followed while naming phenol according to the IUPAC nomenclature.
- Benzenol is the IUPAC designation for phenol. The structure of phenol is formed when a hydroxyl group, or OH group, is bonded to a benzene ring.
- When there are multiple hydroxyl groups on a benzene ring, the prefixes di-, tri-, or poly are used to indicate the number of OH groups on the ring. The nomenclature of this phenol is benzene 1,2,3-diol, for example, if there are three hydroxyl groups connected to the benzene ring.
- The phenol molecule has functional groups connected to it. Carbonyls, alcohols, carboxylic acids, and amines are examples of functional groups that can alter the properties of a molecule. A functional group can likewise be added to phenol in this scenario. 'The Methyl Group,' for example, is an example of this.
- The phenol structure above is referred to as 4-methyl phenol. Furthermore, the labelling of the chemical will alter depending on where this functional group is attached. For example, if the functional group, methyl, is coupled to ortho (a neighboring carbon), the compound's name will be different than if it is attached to para (attached to the third carbon of the hydroxyl carbon).
- Meta is another typical place where the functional group can be linked (attached on the second carbon from the hydroxyl group).