The key difference between aliphatic and aromatic carboxylic acid is that aliphatic carboxylic acid compounds have a linear structure in their R group, whereas aromatic carboxylic acid has a cyclic structure with alternating double and single bonds in its R group.
Carboxylic acid is an organic compound having the functional group -COOH. This functional group is usually attached to the R group. This R group can be either aliphatic or aromatic. Therefore, we can identify two types of carboxylic acids: aliphatic carboxylic acids and aromatic carboxylic acids.
CONTENTS
1. Overview and Key Difference
2. What is Aliphatic Carboxylic Acid
3. What is Aromatic Carboxylic Acid
4. Aliphatic vs Aromatic Carboxylic Acid in Tabular Form
5. Summary – Aliphatic vs Aromatic Carboxylic Acid
What is Aliphatic Carboxylic Acid?
Aliphatic carboxylic acid is a hydrocarbon containing a carboxylic acid functional group attached to the open chain compounds or closed chains that are not aromatic. Aliphatic carboxylic acid has a wide range of chemicals that can perform a wide variety of industrial functions. Most of them occur naturally, and they also serve an important function in nutrition; we can find them as intermediates in normal biochemical processes.
We can name an aliphatic carboxylic acid according to the IUPAC nomenclature; the names are derived from the longest carbon chain containing the carboxylic acid functional group via dropping the final -e from the name of the parent alkane and by adding the suffix -oic which is followed by the word “acid.” We need to number the chain that begins with the carbon of the carboxyl group.
An aliphatic carboxylic acid compound can be saturated or unsaturated. This means if the aliphatic carboxylic acid compound consists of double or triple bonds between the carbon atoms in the main carbon chain, we call it unsaturated, whereas saturated aliphatic carboxylic acids have only single bonds between carbon atoms in the carbon chain.
What is Aromatic Carboxylic Acid?
Aromatic carboxylic acid is a hydrocarbon consisting of a carboxylic acid functional group attached to a closed ring structure having alternating double and triple bonds. The most important aromatic dicarboxylic acids that we know are phthalic acid, isophthalic acid, and terephthalic acid. These three structures differ from each other according to the ortho, meta, and para isomeric structures.
It is possible to prepare aromatic carboxylic acid compounds via the oxidation of alkylbenzenes. The vigorous oxidation of alkyl benzene compound with acidic or alkaline potassium permanganate of chromic acid can lead to the formation of aromatic carboxylic acid compounds.
Usually, aromatic acids are stronger than aliphatic acids because the aromatic ring causes the formation of stronger hydrogen bonds between molecules. We can classify aromatic carboxylic acids into groups according to the substituents that are bonded to the carboxylic carbon atom. Moreover, an aromatic acid has an aryl group that is bound to the carboxyl group.
What is the Difference Between Aliphatic and Aromatic Carboxylic Acid?
The key difference between aliphatic and aromatic carboxylic acid is that aliphatic carboxylic acid compounds have a linear structure in their R group, whereas aromatic carboxylic acid has a cyclic structure with alternating double and single bonds in its R group. Moreover, there can be either saturated or unsaturated forms of aliphatic carboxylic acids whereas aromatic carboxylic acids only have unsaturated forms.
The below infographic presents the differences between aliphatic and aromatic carboxylic acid in tabular form for side-by-side comparison.
Summary – Aliphatic vs Aromatic Carboxylic Acid
Carboxylic acid compounds are very important hydrocarbon compounds. We can classify them basically into two groups; they are aliphatic and aromatic carboxylic acids. The key difference between aliphatic and aromatic carboxylic acid is that aliphatic carboxylic acid compounds have a linear structure in their R group whereas aromatic carboxylic acid has a cyclic structure with alternating double and single bonds in its R group.
Reference:
1. “Aliphatic Carboxylic Acid.” An Overview | ScienceDirect Topics.
Image Courtesy:
1. “Carboxylic-acid” By De.Nobelium – Own work (Public Domain) via Commons Wikimedia
2. “Depside” By Hbf878 – Own work (CC0) via Commons Wikimedia