Product Information

Propionic Acid

Propionic Acid (CAS: 79-09-4) Supplier in Europe

Propionic acid is a naturally occurring carboxylic acid with the chemical formula CH3CH2CO2H. It presents as a colorless liquid with a distinctive pungent and unpleasant smell that is sometimes likened to body odor.

This organic compound is notable for being a short-chain saturated fatty acid and is found both in natural sources and as a product of bacterial fermentation. Its properties make propionic acid an important chemical in various industrial applications, including the manufacturing of cellulose-based plastics, herbicides, and as a preservative in food due to its anti-fungal properties.

The role of propionic acid extends beyond industrial uses; it is also a vital substance in biochemical pathways within the human body. As a metabolic byproduct of bacterial digestion in the intestines, it is involved in energy production processes.

Moreover, as a precursor to larger molecules, it is integral in the synthesis of certain fats and oils. The substance’s impact on energy metabolism and its presence in food preservation highlight its dual importance in both biological and commercial contexts.

In an industrial capacity, propionic acid production engages modern chemical methodologies and often uses renewable resources, aligning with sustainable approaches in chemical manufacturing.

The market for this acid underscores its economic relevance, given its varied applications and the demand across multiple sectors. With its distinct chemical structure and versatility, propionic acid stands as a clear example of an organic compound whose significance stretches from microbiology to large-scale commercial production.

Chemical Properties

Propionic acid exhibits a range of chemical properties that are central to its behavior and applications in various industries. It is recognized for its simple molecular structure, distinct physical state at room temperature, and specific reactivity characteristics.

Molecular Structure

The molecular formula of propionic acid is C₃H₆O₂. Its structure comprises a three-carbon chain with the carboxylic acid functional group (-COOH) at the end.

The first two carbons each possess three hydrogen atoms, whereas the third carbon is double-bonded to an oxygen atom and also bonded to a hydroxyl group (-OH).

Physical State

At room temperature and atmospheric pressure, propionic acid exists as a colorless, oily liquid. It is characterized by a sharp, pungent odor that can be reminiscent of body odor, which is attributable to its volatile nature.


Propionic acid reacts with bases to form propionates (also known as propanoates), which are its corresponding salts. It is considered moderately corrosive to metals and tissue.

Upon heating to decomposition, propionic acid emits smoke and irritating fumes. As an acidic compound, it can participate in typical acid-base reactions and is capable of undergoing esterification with alcohols.

Production and Synthesis

The synthesis of propionic acid can be achieved through various biotechnological and chemical approaches, each with specific pathways and methods.

Biotechnological Production

In biotechnological methods, propionic acid is produced by fermentation using propionibacteria. These microorganisms can convert various substrates such as glucose, glycerol, lactose, and agricultural byproducts into propionic acid.

The process variables, including the type of substrate, bacterial strain, and fermentation conditions, are critical for optimizing the yield and productivity of the acid.

  • Substrates Used:
    • Glucose
    • Glycerol
    • Lactose
    • Agricultural byproducts
  • Key Variables:
    • Bacterial strain selection
    • Fermentation temperature
    • pH regulation

Chemical Synthesis Methods

Chemical synthesis, alternatively, typically involves the hydrocarboxylation of ethylene in the presence of a catalyst such as nickel carbonyl to produce propionic acid. Chemical processes offer a straightforward, albeit less environmentally-friendly, approach compared to biotechnological production.

  • Main Chemical Reaction: Ethylene + CO + H2O → Propionic Acid
  • Catalyst Used:
    • Nickel carbonyl (Ni(CO)4)


Propionic acid serves as a versatile intermediate in a range of industrial applications due to its antimicrobial and preservative properties.

Food Industry

In the food industry, propionic acid and its calcium and sodium salts are primarily used as preservatives. They effectively inhibit the growth of mold and bacteria in baked goods, cheese, and other dairy products.


Propionic acid derivatives, such as ibuprofen and naproxen, exhibit anti-inflammatory, analgesic, and antipyretic properties. These compounds are vital in creating medications that alleviate pain, reduce fever, and manage inflammation.


This acid plays a role in agriculture as a pesticide. Its fungicidal and bactericidal effects are beneficial in preventing spoilage in stored grains and animal feed, thus serving as a preservative to protect agricultural products.

Chemical Industry

Within the chemical industry, propionic acid is used as a building block in the production of herbicides, plastics, and synthetic lubricants. Its utility in manufacturing various chemical compounds underlines its industrial significance.

Safety and Handling

Propionic acid requires careful handling due to its corrosive properties. Below are key safety considerations and toxicological information.


Propionic acid can severely irritate and cause burns to the skin and eyes, with potential for eye damage. Inhalation of vapors may irritate the respiratory tract, leading to symptoms like coughing, wheezing, and shortness of breath. Acute exposure can cause headaches, nausea, vomiting, diarrhea, and abdominal pain.

Safety Guidelines

When handling propionic acid, wear appropriate personal protective equipment (PPE) to prevent skin and eye contact. PPE should include:

  • Protective gloves: Nitrile or PVC.
  • Eye protection: Safety goggles or face shield.
  • Protective clothing: Lab coat or apron resistant to chemicals.

Practices for safe handling include:

  • Keep away from food and beverages.
  • Ensure proper ventilation in the working area.
  • Avoid breathing in vapors; use fume hoods when possible.
  • Wash hands thoroughly after handling.
  • Store in a cool, dry, well-ventilated place, away from incompatible substances.

In case of contact with skin or eyes, rinse immediately with plenty of water and seek medical attention. If inhaled, move the individual to fresh air and consult a physician if symptoms persist. Always have safety data sheets accessible and follow local regulations and guidelines for the handling and disposal of chemicals.

Environmental Impact

Propionic acid, a widely used chemical, has environmental implications particularly in its biodegradability and emissions. Understanding these factors is crucial for evaluating its overall ecological footprint.


Propionic acid is readily biodegradable, which implies that it can be broken down by microorganisms under aerobic conditions. This characteristic reduces the potential for long-term environmental accumulation. As a naturally occurring carboxylic acid, it can be metabolized by various soil bacteria and plays a role in the carbon cycle.

Emissions and Regulations

Concerning emissions, the production and usage of propionic acid can contribute to the release of volatile organic compounds (VOCs). These emissions are subject to regulation due to their potential to create ground-level ozone and contribute to air pollution.

Regulatory frameworks, like those enforced by the United States Environmental Protection Agency (US EPA), guide the permissible levels of VOCs to mitigate their environmental impact. Regulations may also dictate the use of renewable energy sources in the propionic acid production process to achieve a reduced carbon footprint.

Market and Economics

The propionic acid market has exhibited steady growth, with the Asia and South America regions significantly contributing to the upward trend in demand. This global market is mainly driven by its application in food and feed preservatives.

Supply and Demand

The global supply of propionic acid has been in alignment with its demand, which has been growing at an average annual rate of 3% over recent years.

The most considerable demand comes from the food and feed preservative sectors, particularly in Asia and South America, due to their large agricultural industries and growing food safety concerns.

In 2024, the market size is projected to be at 412.06 kilotons and is expected to rise to 484.93 kilotons by 2029.

Price Trends

The pricing of propionic acid typically reflects the balance between its supply and demand. Economic slowdowns and adoption of alternative preservatives tended to decrease demand and thus, prices.

However, propionic acid prices are expected to remain stable or increase slightly, following past trends suggesting a steady growth in market value from $1.89 billion in 2022 to higher figures by 2030, given no substantial market disruptions occur.

Research and Development

The exploration into propionic acid production has seen significant advancements in both scientific methodology and sustainable innovation. Researchers are actively pursuing alternative production methods to petrochemical routes, tapping into biotechnological processes as potential game-changers in the industry.

Scientific Studies

Recent studies have emphasized the bio-based production of propionic acid, exploring a variety of substrates ranging from glucose and lactose to more unconventional sources like glycerol and hemicelluloses.

They focus on optimizing fermentation processes and investigating the role of different microorganisms in enhancing yield and efficiency. Scientific inquiry in this realm also extends to examining the metabolic pathways of propionic acid synthesis within microbial hosts.

Innovation and Future Prospects

The shift towards sustainable production of propionic acid is evident in the growing number of innovations aiming to lower greenhouse gas emissions and reliance on fossil fuels.

Futuristic prospects include the refinement of biotechnological approaches – with some research underpinned by funding sources such as the European Regional Development Fund.

These efforts not only strive to make fermentation processes commercially viable but also to improve the overall carbon footprint of propionic acid production.

Frequently Asked Questions

In this section, we address some of the most common inquiries regarding propionic acid, aiming to clarify its nomenclature, applications, and safety.

What is the difference between propionic acid and propanoic acid?

The terms propionic acid and propanoic acid refer to the same chemical compound with the formula C3H6O2. “Propionic” is the common name, while “propanoic” is the systematic name following IUPAC nomenclature guidelines.

What are the primary uses of propionic acid in various industries?

Propionic acid is widely used in the production of herbicides, plastics, and synthetic fibers. It is also employed in the pharmaceutical industry, where it is used in the manufacture of some medications.

How does propionic acid function as a preservative in food products?

As a preservative, propionic acid inhibits the growth of mold and some bacteria in food products, thereby extending their shelf life. It is particularly common in baked goods and cheese where it is valued for its anti-fungal properties.

What is the chemical structure of propionic acid?

The chemical structure of propionic acid consists of a three-carbon carboxylic acid with the formula CH3CH2COOH. It has a carboxyl group (-COOH) attached to a two-carbon alkyl chain.

In what ways are derivatives of propionic acid utilized?

Derivatives of propionic acid, such as propionates and propionamides, are utilized in various applications including as plasticizers, solvents, and in the manufacture of food additives and flavorings.

Is propionic acid considered safe for use in food products by regulatory agencies?

Regulatory agencies like the U.S. Food and Drug Administration (FDA) have approved propionic acid and its salts for use as food additives. The safety of propionic acid is subject to concentration limits and guidelines as stipulated by these agencies.