Stearic acid
[CAS# 57-11-4]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives >> Acyclic carboxylic acid
• Name: Stearic acid
• Synonyms: Octadecanoic acid
• Molecular Formula: C₁₈H₃₆O₂
• Molecular Weight: 284.48
• CAS Registry Number: 57-11-4
• EC Number: 200-313-4
• FEMA: 3035
• SMILES: CCCCCCCCCCCCCCCCCC(=O)O

Properties

• Density: 0.847
• Melting point: 67-69 °C
• Boiling point: 361 °C
• Flash point: 196 °C
• Water solubility: 0.1-1 g/100 mL at 23 °C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335-H412
• Safety Statements: P261-P264-P264+P265-P271-P273-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Skin corrosion	Skin Corr.	1B	H314
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	4	H332
Flammable solids	Flam. Sol.	1	H228
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Eye irritation	Eye Irrit.	2A	H319
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Acute toxicity	Acute Tox.	3	H301

Discovery and Applications

Stearic acid is a long-chain fatty acid that was first isolated from animal fats in the early 19th century. The name "stearic acid" is derived from the Greek word "stear," meaning tallow or fat. The compound was discovered by French chemist Michel Eugène Chevreul, who is credited for his pioneering work on fatty acids and their properties. Stearic acid is a saturated fatty acid with the molecular formula C18H36O2 that is commonly found in animal and vegetable fats.

Stearic acid is a white waxy solid at room temperature with a melting point of approximately 69-70°C (156-158°F). It is insoluble in water but soluble in organic solvents such as ethanol and ether. The long hydrocarbon chain and carboxyl group of the compound give it unique physical properties, including the ability to form a solid crystalline structure.

Stearic acid is a key ingredient in a variety of cosmetic formulations, including creams, lotions, and color cosmetics. Stearic acid helps stabilize emulsions, giving products a smooth texture and a longer shelf life. The compound is used in soap production, where it acts as a surfactant and adds hardness to soap bars. Its ability to form stable foam makes it valuable in cleaning products.

Stearic acid is used as a lubricant and binder in tablet formulations. The compound helps improve the consistency and flow of powders, ensuring uniformity in tablet production. Stearic acid is used in the production of capsule coatings, which enhance the release and dissolution of active ingredients.

Stearic acid is used in the production of lubricants and greases. It has anti-wear properties and improves the performance of these products under high pressure conditions. Stearic acid is used as a processing aid in the production of plastics and rubber. It acts as a mold release agent and helps improve the flow and consistency of these materials.

Stearic acid is used as an emulsifier in foods, helping to mix ingredients that normally don't mix well, such as oil and water. This is particularly useful in products such as margarine and baked goods.

Handling stearic acid requires standard safety precautions, using gloves and goggles and avoiding direct contact with the compound. Make sure the area where stearic acid is handled is well ventilated to minimize the risk of inhalation. Store stearic acid in a cool, dry place away from heat sources and incompatible materials. Proper storage helps maintain its quality and effectiveness.

Stearic acid has a relatively low environmental impact, and the compound is biodegradable and breaks down naturally in the environment. However, responsible disposal practices should be followed to minimize any potential environmental impact. Plant-derived stearic acid contributes to sustainable practices across industries and reduces reliance on petrochemicals.

References

2024. Stearic acid-based nanoparticles loaded with antibacterial peptides - Bacitracin and LL-37: Selection of manufacturing parameters, cytocompatibility, and antibacterial efficacy. International Journal of Pharmaceutics, 667.
DOI: 10.1016/j.ijpharm.2024.124876

2024. Effect of lubricants type and particle size on the rheological properties and aerosolization behavior of dry powder inhalers. International Journal of Pharmaceutics, 667.
DOI: 10.1016/j.ijpharm.2024.124911

2024. Temperature-dependent two-stage cultivation: A strategy for lipid and fatty acids production in the terrestrial oleaginous microalga Vischeria sp. WL1. Journal of Applied Phycology, 36(6).
DOI: 10.1007/s10811-024-03383-y