Basic Information

Chinese Name: 丙酸

English Name: Propanoic Acid; Propionic Acid

CAS No.: 79-09-4

Molecular Formula: C₃H₆O₂

Molecular Weight: 74.08 g/mol

Structural Formula: CH₃CH₂COOH

Appearance: A colorless, transparent liquid with a pungent, rancid odor, miscible with water, ethanol, ether and other organic solvents.

Melting Point: -20.8 °C

Boiling Point: 141.1 °C

Density: 0.993 g/cm³ (25 °C)

Flash Point: 52 °C (closed cup)

Solubility: Miscible with water, methanol, ethanol, acetone, ether, chloroform; soluble in most organic solvents.

Acidity: Weak organic carboxylic acid, acidic in aqueous solution, can react with bases to form salts, and undergo esterification, acylation and other reactions.

Solvent Properties

Solubility:Highly miscible with water, freely miscible with common organic solvents such as methanol, ethanol, acetone, ether, chloroform, benzene, and ethyl acetate. It can also dissolve some organic compounds and inorganic salts, showing good solvent compatibility.

Solvent Characteristics: As a polar protic solvent, it has a certain polarity due to the presence of the carboxyl group, which can form hydrogen bonds with other polar substances, thereby improving the solubility of the solute. Its solvent power is between formic acid and acetic acid, suitable for reactions requiring mild polar solvent conditions.

Influence of Temperature on Solubility: The solubility in water does not change significantly with temperature, and it remains miscible in a wide temperature range (from low temperature to boiling point). When mixed with non-polar solvents, the solubility increases slightly with the increase of temperature.

Compatibility Note: It is incompatible with strong oxidants, strong bases and some active metals (such as sodium and potassium). Chemical reactions may occur when mixed, so mixing and storage with the above substances should be avoided during use.

Main Applications

Food and Feed Preservative:As a commonly used food-grade preservative, it can effectively inhibit the growth and reproduction of mold, yeast and some bacteria, extend the shelf life of products. It is widely used in bread, pastries, cakes, dairy products, feed and other fields, and can be used alone or in combination with other preservatives such as propionate.

Organic Synthesis Intermediate: It is an important intermediate in organic synthesis, and can synthesize a variety of chemical products through esterification, acylation, amidation and other reactions. For example, it reacts with alcohols to form propanoates (used in spices and plasticizers), reacts with thionyl chloride to form propionyl chloride (used in pharmaceutical synthesis), and reacts with ammonia to form propionamide (used in pesticide synthesis).

Industrial Raw Material: Used in the production of plasticizers, coatings, adhesives, solvents and other industrial products. It can also be used as a raw material for polymer synthesis (such as polyacrylic acid derivatives) to improve the performance of polymer materials.

Other Applications: Used in the pharmaceutical field to synthesize drugs such as antibiotics and anti-inflammatory drugs; used in the spice field to prepare fruit flavors and edible flavors; also applied in water treatment, leather tanning and other industries.

Safety

Hazard Classification:Corrosive liquid (Category 1), flammable liquid (Category 3), harmful to the human body.

Hazardous Properties:It has strong corrosiveness and can cause severe burns to the skin and eyes; ingestion or inhalation will irritate the respiratory tract and digestive tract, causing discomfort such as coughing, nausea and vomiting; it is flammable, and its vapor can form an explosive mixture when in contact with air, which may cause combustion and explosion when exposed to open flame and high temperature.

Operational Precautions: Operate in a well-ventilated fume hood and wear personal protective equipment (acid-resistant gloves, goggles, protective clothing, gas mask); avoid contact with skin, eyes and mucous membranes; keep away from open flames, heat sources and oxidants, and no smoking is allowed at the operation site; use explosion-proof electrical equipment during operation.

Storage Requirements: Store hermetically in a cool, dry and well-ventilated warehouse, away from open flames and heat sources, with a storage temperature not exceeding 30℃; store separately from oxidants, strong bases, active metals and other substances to avoid mixed storage; the warehouse should be equipped with fire-fighting equipment and emergency treatment equipment.

First Aid Measures:

Skin Contact: Immediately rinse the contaminated area with plenty of flowing clean water for at least 15 minutes, then apply a neutralizing agent (such as sodium bicarbonate solution) and seek medical advice in time.

Eye Contact: Immediately separate the eyelids, rinse with plenty of clean water or normal saline for at least 15 minutes, and seek medical attention immediately.

Inhalation: Immediately move to a well-ventilated place, keep the respiratory tract unobstructed, give oxygen if breathing is difficult, and seek medical advice in time.

Ingestion: Do not induce vomiting, drink plenty of water to dilute, and seek medical attention immediately (carry the product label if possible).