Chemical Properties Malic Acid

Various chemical properties of Malic Acid are,

• Malic acid is a weak organic acid with a pKa of 3.4
• Malic acid is a reactive molecule due to the presence of both a hydroxyl group and a carboxyl group, which can participate in various chemical reactions.
• Malic acid can undergo decarboxylation, a reaction that results in the loss of a carboxyl group and the formation of a new molecule
• Malic acid can be reduced to form the alcohol lactol or the aldehyde tartaric aldehyde
• Malic acid can undergo isomerization to form tartaric acid
• Malic acid can form complexes with metal ions such as calcium and magnesium
• Malic acid can undergo hydration, a reaction in which water is added to the molecule.

Various chemical reactions of Malic Acid are,

Esterification Reaction

Esterification is a reaction in which an acid reacts with an alcohol to form an ester and water. In the case of malic acid, esterification can occur as follows

C₄H₆O₅ + ROH -> C₄H₆O₄-R + H₂O

where “R” represents an alcohol molecule, and “C₄H₆O₄-R” represents the resulting ester.

In this reaction, the hydroxyl group (-OH) from the alcohol reacts with the carboxyl group (-COOH) from the malic acid to form an ester bond (-COOR) and water. The resulting ester is characterized by its distinctive flavour and fragrance and is commonly used in the food and fragrance industries.

Esterification reactions are typically catalyzed by acids or bases, and the conditions and reaction rate can be controlled by adjusting the concentration of reactants, the presence of catalysts, and the temperature.

Reaction With Base

Malic acid can react with a base to form its conjugate base, salt, and water. The reaction can be represented as follows

C₄H₆O₅ + MOH -> C₄H₆O₄-M + H₂O

Where “M” represents the base and “C₄H₆O₄-M” represents the salt formed by the reaction.

In this reaction, the hydroxyl group (-OH) from the base reacts with the carboxyl group (-COOH) from the malic acid to form the salt and water. The reaction is an example of proton transfer, as the hydrogen ion (proton) from the carboxyl group is transferred to the hydroxyl group of the base.

Malic acid is a naturally occurring organic acid found in many fruits and vegetables. It has a tart taste and is used as a food additive to enhance the flavour of certain products. In addition to its culinary use, malic acid is also used in skin care products and dietary supplements due to its potential health benefits, such as improved energy metabolism and reduced muscle fatigue.

• IUPAC name for malic acid is 2-hydroxy butane dioic acid.
• Chemical formula of malic acid is C₄H₆O₅

Let’s learn about Malic Acid its structure, properties and others in detail.