Chem Explorers

Exploring Propanoic Acid: Properties Production and Uses

Propanoic acid, more commonly known as propionic acid, is a colorless, liquid organic acid with a pungent, unpleasant smell. Despite its unpleasant odor, propionic acid is a useful compound that has a wide range of applications in various industries.

Its chemical properties, as well as the natural and industrial processes for its production, make it a subject of interest to scientists and researchers. In this article, we will discuss everything you need to know about propanoic acid, from its formula and properties to its production processes.

Propanoic Acid


The molecular formula for propanoic acid is C3H6O2, while its structural formula is CH3CH2COOH. The compound belongs to the class of carboxylic acids, which distinguish themselves by having a carboxyl group (-COOH) attached to a hydrocarbon chain.

The carboxyl group is what gives carboxylic acids their distinct chemical properties. In the case of propanoic acid, the carboxyl group contributes to its acidity and polarity, making it soluble in water and other polar solvents.

Chemical Properties

Propanoic acid has a density of 0.99 g/cm and a boiling point of 141.1C. Its melting point is -21C, and at room temperature, the compound is a clear, colorless liquid.

Propanoic acid has a crystalline structure, meaning it forms crystals when solidified. The compound is highly corrosive and has a pungent odor that can irritate the eyes and mucous membranes.

Propionic Acid Production

Natural Production

Propionic acid naturally occurs in certain foods, including Swiss cheese, and is produced in the gut by propionic bacteria. The most significant natural source of propanoic acid, however, is through the fermentation of sugars by bacteria and yeast.

During this process, glucose, fructose, or sucrose is converted into lactic acid, ethanol, acetic acid, and propionic acid. The fermentation reaction is carried out in an anaerobic environment, meaning in the absence of oxygen.

Industrial Production

While natural production of propionic acid has its uses, industrial-scale production is done using chemical reactions. One of these processes is the Reppe process, which involves the reaction of propylene with carbon monoxide and methanol in the presence of a catalyst.

Another method for producing propionic acid is the Lardon process, which involves reacting ethylene and carbon monoxide with sodium propionate. The resulting compound is then hydrolyzed to form propionic acid.

Mixed acid fermentations are bacterial cultures that are used to produce propionic acid as well as other organic acids, including acetic and lactic acids, through fermentation. Propionic bacteria are added to the culture to ensure the production of viable amounts of propionic acid.

In mixed acid fermentation, the culture is taken through a series of steps, including pre-treatment, enzymatic hydrolysis, fermentation, and purification, to produce high-quality propionic acid.


The chemical properties and various production methods for propanoic acid make it a compound of great interest in the scientific and industrial communities. Its uses range from food preservatives to agricultural chemicals, and the compound has potential applications in the biofuel industry.

Through this article, we have explored the formula and properties of propanoic acid, as well as the natural and industrial processes used for its production.

Uses of Propionic Acid

Propionic acid is a versatile compound that has several applications across various industries. In this section, we will discuss the different uses of propionic acid and how it is employed in various products.

Inhibiting growth of fungi and moulds

One of the primary uses of propanoic acid is as a preservative in the food, cosmetics, and animal feed industries. Propionic acid and its salts, which are known as propionates, are commonly used to inhibit the growth of fungi and moulds.

These salts work by reducing the pH level in the environment, making it less hospitable for microorganisms. Propionates are used in baked goods, dairy products, and processed meats to prevent spoilage and increase the shelf life of these products.

In addition to its use as a preservative, propionic acid is also used as a taste ingredient. In certain types of cheese, propionic acid is produced through the action of bacteria and contributes to the characteristic nutty, sweet flavor of the cheese.

Industrial applications

Propionic acid is used in several industrial applications, including the production of plastics, pesticides, and rubber. In the plastics industry, propionic acid is a precursor to the production of propionate esters, which are used to make polyvinyl propionate.

This type of plastic is used in coatings and adhesives and has excellent water resistance. In the pesticide industry, propionic acid and its derivatives are used to combat pests that affect crops and plants.

The compound is effective in controlling pests such as aphids, spider mites, and scale insects. Propionic acid is also employed in the production of rubber, where it is used as a coagulant during the manufacturing of natural rubber.

Use in food and cosmetics

Propionic acid is widely used in the food and cosmetics industries owing to its effectiveness in inhibiting mould growth. In food production, propionic acid is used to protect against mould formation in baked goods, cheeses, meat products, and animal feed.

Propionate salts such as calcium and sodium propionate are used as a more convenient alternative to pure propionic acid, as they are easier to handle and disperse. In cosmetics, propionic acid is often used as a preservative to prevent bacteria growth in skincare, hair care, and cosmetic products.

The compound is also used as a flavouring ingredient and is added to toothpaste, mouthwash, and other oral care products to improve the taste. While propionic acid is widely used in food and cosmetics, measures are put in place to ensure its safety.

The European Food Safety Authority (EFSA) has set limits to the amount of propionic acid that can be added to food products, and the U.S. Food and Drug Administration (FDA) has categorized it as a Generally Recognized as Safe (GRAS) substance.


Propionic acid is a highly versatile compound that finds its application across various industries. Its ability to inhibit mould growth makes it an effective preservative in food and cosmetics.

It is also used in the production of plastics, pesticides, and rubber. The compound’s safety and effectiveness have made it a useful and widely accepted ingredient in several consumer products.

Propionic acid, also known as propanoic acid, is a versatile compound that has several applications across various industries. Its chemical properties, production processes, and uses have been explored in detail throughout the article.

Propionic acid is used as a preservative in the food and cosmetics industries and in the production of plastics, pesticides, and rubber. Its safety and effectiveness have made it widely accepted as a crucial ingredient in several consumer products.

Overall, propanoic acid is an important compound worth understanding due to its many uses and potential benefits. FAQs:


Is propionic acid safe for use? Yes, propionic acid has been deemed safe for use in consumer products by regulatory bodies such as the FDA and EFSA.

2. What are the primary uses of propionic acid?

Propionic acid is primarily used as a preservative in the food, cosmetics, and animal feed industries, as well as in the production of plastics, pesticides, and rubber. 3.

How is propionic acid produced? Propionic acid can be naturally produced through fermentation or synthetically produced using chemical reactions such as the Reppe and Lardon processes.

4. Why is propionic acid important?

Propionic acid is important due to its preservative and anti-mould properties, as well as its uses in various industrial processes. It has the potential to improve the shelf life of food products and enhance the properties of plastics and rubber.

5. Can propionic acid be harmful?

While propionic acid is safe for use in consumer products, prolonged exposure to the compound can cause irritation to the eyes, skin, and/or respiratory system. It is essential to handle propionic acid with appropriate safety precautions.

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