The key difference between benzoic acid and ethyl benzoate is that the benzoic acid contains a benzene ring attached to a carboxylic acid group, whereas the ethyl benzoate contains a benzene ring attached to an ester group.
Benzoic acid is an aromatic carboxylic acid whereas ethyl benzoate is an aromatic ester. Since these are aromatic compounds, both these compounds have a sweet and pleasant odour.
CONTENTS
1. Overview and Key Difference
2. What is Benzoic Acid
3. What is Ethyl Benzoate
4. Side by Side Comparison – Benzoic Acid vs Ethyl Benzoate in Tabular Form
5. Summary
What is Benzoic Acid?
Benzoic acid is a carboxylic acid with the chemical formula C7H6O2. It is the simplest aromatic carboxylic acid, and it occurs as a colourless crystalline solid. Besides, this compound naturally occurs in many plants because it acts as an intermediate in producing secondary metabolites.
Figure 01: Chemical Structure of Benzoic Acid
Moreover, the molar mass is 122.12 g/mol. It has a pleasant odour. Its melting point is 122 °C, while the boiling point is 250 °C. For industrial needs, we can produce this material via partial oxidation of toluene in the presence of oxygen. Furthermore, the name of this compound comes from its structure, which has a benzene ring with an attached carboxylic acid group.
When considering the uses of benzoic acid, it is important in the production of phenol, as a precursor for the production of plasticizers, a precursor for the production of sodium benzoate, which is a useful food preservative, etc.
What is Ethyl Benzoate?
Ethyl benzoate is an aromatic ester with the chemical formula C9H10O2. The compound is formed from the condensation of benzoic acid and ethanol. It occurs as a colourless liquid which has a sweet, wintergreen odour. The molar mass is 150.177 g/mol. Its melting point is −34 °C while the boiling point ranges from 211 to 213 °C.
Figure 02: Preparation of Ethyl Benzoate
Furthermore, this compound is almost insoluble in water but dissolves in organic solvents. Due to its sweet odour, this compound is used as a component in fragrances and as artificial fruit favours. The most common method of preparation of ethyl benzoate is the acidic esterification of benzoic acid with ethanol in the presence of sulfuric acid as the catalyst.
What is the Difference Between Benzoic Acid and Ethyl Benzoate?
Benzoic acid is a carboxylic acid with the chemical formula C7H6O2 while ethyl benzoate is an aromatic ester with the chemical formula C9H10O2. The key difference between benzoic acid and ethyl benzoate is that the benzoic acid contains a benzene ring attached to a carboxylic acid group, whereas the ethyl benzoate contains a benzene ring attached to an ester group.
Moreover, we can also identify a difference between benzoic acid and ethyl benzoate based on their physical properties. The benzoic acid occurs as a colourless crystalline solid, while the ethyl benzoate occurs as a colourless liquid. Further, when considering the odour of these compounds, benzoic acid has a faint and pleasant odour while ethyl benzoate has a sweet, wintergreen odour. Besides, benzoic acid is poorly water-soluble, but ethyl benzoate is almost insoluble in water, and it is soluble in most organic solvents.
Summary – Benzoic Acid vs Ethyl Benzoate
Benzoic acid is a carboxylic acid which has the chemical formula C7H6O2 while Ethyl benzoate is an aromatic ester which has the chemical formula C9H10O2. Above all, the key difference between benzoic acid and ethyl benzoate is that the benzoic acid contains a benzene ring attached with a carboxylic acid group, whereas the ethyl benzoate contains a benzene ring attached with an ester group.
Reference:
1. “Benzoic Acid.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.
Image Courtesy:
1. “Benzoesäure” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia
2. “Ethyl benzoate esterification” By Minihaa – Own work (CC BY-SA 3.0) via Commons Wikimedia