Difference Between Acetic Acid and Glacial Acetic Acid

Acetic acid and glacial acetic acid are two common terms that are often used interchangeably. However, there are significant differences between the two, including their chemical properties, physical characteristics, and uses. In this essay, we will discuss the differences between acetic acid and glacial acetic acid.

What is Acetic Acid?

Acetic acid (CH3COOH) is one of the simplest carboxylic acids. Under the IUPAC system nomenclature, the name of acetic acid is ethanoic acid. Acetic acid is synthesized in decomposition and acetic fermentation. In nature, it is found in plant and animal organisms, both in a free state and in the form of esters and other derivatives.

In the past, acetic acid has been produced by acetic fermentation of the ethyl alcohol contained in the wine. By the action of bacterial enzymes, the alcohol of the wine is oxidized by the oxygen of the air to acetic acid. Industrial method for the production of acetic acid is the direct catalytic oxidation of acetaldehyde or butane. It may also be industrially produced by carbonylation of methanol, catalyzed by rhodium-iodine.

Acetic acid is a colorless liquid with a pungent smell and sour taste. It dissolves very well in water. Due to the greater polarity of the bond, the O-H carboxylic acids form stronger intermolecular hydrogen bonds than the alcohols, which determines the unrestricted solubility of acetic acid.

The chemical properties of acetic acid are determined by its carboxyl functional group and by the methyl moiety. The acid participates in chemical reactions with breakage of the bonds in the carboxyl group.

Acetic acid shows the typical chemical properties of the organic acids. In water solution, the acetic acid is dissociated according to the equation:

$$CH3COOH → CH3COO¯ + H$$

The degree of electrolytic dissociation is significantly lower than that of strong inorganic acids, so acetic is a weak acid. It reacts with highly electropositive metals, basic oxides, basic hydroxides, and salts of weaker acids. The obtained salts are called acetates (ethanoates).

Reactions with oxides, hydroxides, and salts break the O-H bond in the carboxyl group.

The reaction of acetic acid with alcohols in the presence of strong acids is called esterification, it leads to the production of esters.

Acetic acid also participates in reactions affecting the methyl group – substitution reactions in the hydrocarbon moiety.

In the form of vinegar, acetic acid solutions (5 to 18%) are used in the food industry and in the households. Acetic acid is used for fixation of photographic films, to remove calcium deposits from cranes and boilers, to treat a jellyfish sting, etc. It is also used as a preservative for silage, as it inhibits the growth of bacteria and fungi.

What is Glacial Acetic Acid?

The pure, anhydrous acetic acid is a colorless, hygroscopic liquid. At temperatures below 16.7°C, it forms ice-like crystals. That’s why it is called glacial acetic acid.

The glacial acetic acid boils at high temperature (118 °C). Reason for this is the formation of stable hydrogen bonds between any two molecules of acetic acid in the form of a cyclic dimer. The point of flammability is 39°C. The density at 25 °C is 1.05 g/mL.

For centuries, chemists have thought that glacial acetic acid and acid in vinegar are two different substances.

The glacial acetic acid is corrosive and its vapors irritate the eyes and nose. In contact with eyes and skin, it can lead to injuries.

Upon contact of acetic acid with crystallized glacial acetic acid the pure acetic acid attaches to the crystal.

The glacial acetic acid is a great polar base solvent. It is often used in the production of −

• Terephthalic acid

• Propylene terephthalate

• Synthetic camphor

• Aniline

Differences: Acetic Acid and Glacial Acetic Acid

The primary difference between acetic acid and glacial acetic acid is their concentration. Acetic acid is typically sold in concentrations ranging from 5% to 80%, depending on its intended use. Glacial acetic acid, as mentioned earlier, is almost entirely pure, with a concentration of 99.5% or higher. This difference in concentration means that glacial acetic acid is much stronger and more potent than regular acetic acid.

Another difference between the two types of acid is their physical properties. Acetic acid is a liquid at room temperature, with a boiling point of 118°C. It has a density of 1.05 g/mL and a melting point of 16.6°C. Glacial acetic acid, on the other hand, is a crystalline solid at room temperature, with a melting point of 16.6°C. It has a density of 1.05 g/mL and a boiling point of 118.1°C.

In terms of their chemical properties, both acetic acid and glacial acetic acid are weak acids. They react with bases to form salts and water. However, because of its higher concentration, glacial acetic acid is more corrosive than regular acetic acid. It can cause severe burns if it comes into contact with the skin, eyes, or mucous membranes.

Both acetic acid and glacial acetic acid are widely used in a variety of industries. Acetic acid is used as a preservative in the food industry, as well as in the production of plastics, textiles, and pharmaceuticals. It is also used as a solvent in the production of certain chemicals. Glacial acetic acid, because of its higher concentration, is primarily used in industrial applications, such as the production of cellulose acetate, photographic film, and as a solvent for various chemicals.

The following table highlights the major differences between Acetic Acid and Glacial Acetic Acid −

Characteristics	Acetic Acid	Glacial Acetic Acid
Definition	Acetic acid is a colorless, liquid acid (CH3COOH), with a pungent smell and sour taste.	The pure, anhydrous acetic acid, forming ice-like crystals at temperatures below 16.7°C, is called glacial acetic acid.
Water content	Acetic acid contains water.	Glacial acetic acid does not contain water.
Crystallization	Acetic acid does not form crystals.	At temperatures below 16.7°C, the glacial acetic acid forms ice-like crystals.
Occurrence in the nature	In the nature, the acetic acid is found in plant and animal organisms.	The pure, anhydrous acetic acid does not occur in the nature.

Conclusion

In conclusion, acetic acid and glacial acetic acid are two distinct compounds with different properties, concentrations, and uses.

Acetic acid is a weak acid that is widely used in the production of a variety of products, while glacial acetic acid is a highly concentrated form of acetic acid that is primarily used in industrial applications.

Understanding the differences between these two compounds is essential for their safe and effective use.