Glycolic Acid Formula

Glycolic acid is a colorless, odourless, and hygroscopic crystalline solid with the chemical formula C2H4O3. It is also known as hydroacetic acid, or 2-hydroxyethanoic acid, and its IUPAC name is hydroxyacetic acid. It is a 2-hydroxy monocarboxylic acid that is acetic acid where the methyl group has been hydroxylated. It is an alpha hydroxy acid that has antibacterial, antioxidant, keratolytic, and anti-inflammatory properties. It is functionally related to acetic acid and is slightly stronger than it. The salts or esters of glycolic acid are called glycolates. It is widespread in nature and can be separated from natural sources like sugarcane, sugar beets, pineapple, cantaloupe, and unripe grapes. It is used in the textile industry as a dyeing and tanning agent.

Structure of Glycolic Acid

Glycolic Acid structure

Preparation of Glycolic Acid

• There are different preparation methods to synthesize glycolic acid. However, the most common method is the catalyzed reaction of formaldehyde with synthesis gas, which costs less.
• It can be produced when chloroacetic acid reacts with sodium hydroxide and then undergoes re-acidification.
• It can also be synthesized by electrolytic reduction of oxalic acid.
• Glycolic acid can be separated from natural sources like sugarcane, sugar beets, pineapple, cantaloupe, and unripe grapes.
• It can be prepared by hydrolyzing the cyanohydrin that is derived from formaldehyde.

Physical Properties of Glycolic Acid

Chemical formula	C2H4O3
IUPAC Name	Hydroxyacetic acid
Molar mass	76.05 g/mol
Appearance	White powdery solid
Odour	odourless
Density	1.49 g/cm3
Melting point	75 °C
Boiling point	Decomposes
Solubility	soluble in water, ether, and alcohols, acetone, and acetic acid
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	3
Rotatable Bond Count	1
Acidity (pKa)	3.83

Chemical Properties of Glycolic Acid

• Glycolic acid is used as an intermediate in organic synthesis and several reactions, such as oxidation-reduction, esterification, and long chain polymerization.
• Glycolic acid is used as a monomer in the preparation of Poly(lactic-co-glycolic acid) (PLGA). Glycolic acid reacts with lactic acid to form PLGA using ring-opening co-polymerization.
• Polyglycolic acid (PGA) is prepared from the monomer glycolic acid using polycondensation or ring-opening polymerization.

Uses of Glycolic Acid

• Glycolic acid is widely used in skin care products as an exfoliant and keratolytic.
• It is used in the textile industry as a dyeing and tanning agent.
• It is used in the processing of textiles, leather, and metals.
• It is used as an intermediate in organic synthesis and several reactions, such as oxidation-reduction, esterification, and long chain polymerization.

Hazards

Glycolic acid is a strong acid that causes severe skin and eye irritation at high concentrations (70%). It is harmful if swallowed, and inhalation may irritate the respiratory tract and lungs.

FAQs on Glycolic Acid

Question 1: What is the chemical formula of Glycolic acid?

Answer:

The chemical formula of glycolic acid or hydroxyacetic acid is C₂H₄O₃.

Question 2: What are the uses of Glycolic acid?

Answer:

Glycolic acid is widely used in skin care products as an exfoliant and keratolytic. It is used in the textile industry as a dyeing and tanning agent. It is used in the processing of textiles, leather, and metals. It is used as an intermediate in organic synthesis and several reactions, such as oxidation-reduction, esterification, and long chain polymerization.

Question 3:  What happens when Glycolic acid reacts with lactic acid?

Answer: 

Glycolic acid is used as a monomer in the preparation of Poly(lactic-co-glycolic acid) (PLGA). Glycolic acid reacts with lactic acid to form PLGA using ring-opening co-polymerization.

Question 4: Mention some properties of Glycolic acid.

Answer: 

Glycolic acid is a colorless, odorless, and hygroscopic crystalline solid with the chemical formula C₂H₄O₃. It is highly soluble in water and is also soluble in ether, alcohols, acetone, and acetic acid. Its melting point is 75 °C and it decomposes at high temperatures. Its molar mass is 76.05 g/mol and it has a density of 1.49 g/cm³. It is slightly stronger than acetic acid and is a conjugate acid of glycolate.

Question 5: Mention some hazards of Glycolic acid.

Answer: 

Glycolic acid is a strong acid that causes severe skin and eye irritation at high concentrations (70%). It is harmful if swallowed, and inhalation may irritate the respiratory tract and lungs.

Question 6: How is Glycolic acid prepared?

Answer: 

There are different preparation methods to synthesize glycolic acid. However, the most common method is the catalyzed reaction of formaldehyde with synthesis gas, which costs less. It can be produced when chloroacetic acid reacts with sodium hydroxide and then undergoes re-acidification. It can also be synthesized by electrolytic reduction of oxalic acid.