The key difference between benzoic acid and benzaldehyde is that benzoic acid has a –COOH functional group attached to the benzene ring, whereas benzaldehyde has a –CHO functional group attached to the benzene ring.
Both benzoic acid and benzaldehyde are organic compounds. They differ from each other according to chemical properties, physical properties, uses, etc.
CONTENTS
1. Overview and Key Difference
2. What is Benzoic Acid
3. What is Benzaldehyde
4. Benzoic Acid vs Benzaldehyde in Tabular Form
5. Summary – Benzoic Acid vs Benzaldehyde
What is Benzoic Acid?
Benzoic acid is the simplest aromatic carboxylic acid having the molecular formula C6H5COOH. The molar mass of benzoic acid is about 122.12 g/mol. One benzoic acid molecule is composed of a benzene ring substituted with a carboxylic acid group (-COOH).
At room temperature and pressure, benzoic acid is a white crystalline solid. It is slightly soluble in water. Benzoic acid has a pleasant odour. The melting point of benzoic acid solid is about 122.41 °C. The boiling point of benzoic acid is given as 249.2 °C, but at 370 °C, it decomposes.
Figure 01: Solid State Appearance of Benzoic Acid
Benzoic acid can undergo electrophilic aromatic substitution due to the electron-withdrawing property of the carboxylic group. Carboxylic acid can provide the aromatic ring with pi electrons. Then it becomes rich in electrons. Therefore, electrophiles can react with the aromatic ring.
Benzoic acid is a fungistatic compound that is widely used as a food preservative. This means it can prevent fungi growth in food. Benzoic acid can be naturally found in some fruits, such as berries.
What is Benzaldehyde?
Benzaldehyde can be defined as an aromatic aldehyde having the chemical formula C6H5CHO. It has a phenyl group attached to an aldehyde functional group. Moreover, it is the simplest aromatic aldehyde. It occurs as a colorless liquid and has an almond-like characteristic odor. Its molar mass is 106.12 g/mol. Its melting point is -57.12 °C, while its boiling point is 178.1 °C.
Figure 02: The Chemical Synthesis of Benzaldehyde
When considering the production of benzaldehyde, the main routes of production are liquid phase chlorination and oxidation of toluene. However, this compound occurs naturally in many foods as well, for example, in almonds. Therefore, one of the major uses of this compound is its use as an almond flavor in foods and scented products.
What is the Difference Between Benzoic Acid and Benzaldehyde?
Benzoic acid and benzaldehyde are important organic compounds for many industrial purposes. The key difference between benzoic acid and benzaldehyde is that benzoic acid has a –COOH functional group attached to the benzene ring, whereas benzaldehyde has a –CHO functional group attached to the benzene ring. Benzoic acid is a carboxylic acid compound, whereas benzaldehyde is an aldehyde compound.
Moreover, benzoic acid appears as a white crystalline solid with needle-like crystals, while benzaldehyde occurs as a colorless liquid with the odor of almond. Furthermore, benzoic acid is used in the manufacture of perfumes, dyes, topical medications, and insect repellents, while benzaldehyde is used to flavor foods with almond flavor, in some cosmetic products and personal care products as an ingredient, in dye manufacturing, soap manufacturing, odor control, etc.
The below infographic presents the differences between benzoic acid and benzaldehyde in tabular form for side-by-side comparison.
Summary – Benzoic Acid vs Benzaldehyde
Benzoic acid is the simplest aromatic carboxylic acid having the molecular formula C6H5COOH, while benzaldehyde is an aromatic aldehyde having the chemical formula C6H5CHO. The key difference between benzoic acid and benzaldehyde is that benzoic acid has a –COOH functional group attached to the benzene ring, whereas benzaldehyde has a –CHO functional group attached to the benzene ring.
Reference:
1. “Benzaldehyde Hazard Summary Benzaldehyde Odor Threshold.” New Jersey Department of Health and Senior Services.
Image Courtesy:
1. “Benzoic acid substance photo” By Rillke – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Benzaldehyde synthesis from benzyl alcohol” By Claudio Pistilli – Own work (CC BY-SA 4.0) via Commons Wikimedia