Lithium Stearate, Lithium Octadecanoate, Lithium Soap, 4485-12-5

LITHIUM STEARATE

Lithium Stearate / Lithium Octadecanoate / Lithium Soap
CAS Number: 4485-12-5
EC Number: 224-772-5

1. PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

Lithium stearate is the lithium salt of stearic acid (octadecanoic acid). It is a white, odorless powder, flake, or granule classified as a metal salt (fatty acid salt). As a "lithium soap," its most important application is as a thickening agent in lithium-based lubricating greases, where it provides excellent thermal stability, water resistance, and mechanical stability. Lithium stearate is produced by the reaction of lithium hydroxide or lithium carbonate with stearic acid. Its high melting point (220°C) and insolubility in water make it suitable for high-temperature applications. Lithium stearate is also used as an emulsifier and stabilizer in cosmetic products, as a release agent and lubricant in plastics production, and as an excipient in the pharmaceutical industry. Compared to other metal stearates (e.g., calcium stearate, zinc stearate, magnesium stearate), lithium stearate has a higher melting point and better water resistance, making it the preferred choice for high-performance lubricant applications.

2. PHYSICAL AND CHEMICAL PROPERTIES

Lithium stearate is a white, odorless powder, flake, or granule. Its true density is approximately 1.02-1.05 g/cm³, while its bulk density ranges from 0.2-0.5 g/cm³ depending on the form. The melting point is approximately 220°C, at which decomposition begins. It is practically insoluble in water but soluble in hot alcohol, hydrocarbons, oils, and ketones. The pH of its aqueous suspension is approximately 9-10, indicating basic character. It is highly hydrophobic (water-repellent). Free fatty acid content is ≤ 0.5%, loss on drying is ≤ 0.5%, and residue on ignition is approximately 25-28%. Lithium oxide (Li₂O) content is approximately 5-6%. Heavy metals are typically ≤ 20 ppm (as Pb). It is stable under normal conditions but incompatible with strong acids and strong oxidizing agents.

3. CHEMICAL PROPERTIES AND REACTIONS

Lithium stearate is a lithium metal salt and a fatty acid soap. Its chemical behavior is determined by the properties of the stearate anion and the lithium cation.

Reaction with Acids:

Lithium stearate reacts with strong acids to form stearic acid and the corresponding lithium salt:

C₁₇H₃₅COOLi + HCl → C₁₇H₃₅COOH + LiCl

Hydrolysis:

Although insoluble in water, lithium stearate can hydrolyze at high temperatures or under extremely acidic or basic conditions.

Thermal Decomposition:

At temperatures above 220°C, lithium stearate decomposes to form lithium carbonate, carbon dioxide, and hydrocarbons.

Complex Formation:

Lithium stearate can form complexes with various organic compounds and polymers, which is important in lubricant and release agent applications.

Saponification:

As a soap (fatty acid salt), lithium stearate exhibits surfactant properties and can stabilize emulsions.

Combustion:

Lithium stearate is combustible and upon burning produces lithium oxide, carbon dioxide, and water.

Redox Reactions:

It can undergo oxidation with strong oxidizing agents.

4. PRODUCTION METHODS

Lithium stearate is produced industrially by the reaction of lithium hydroxide or lithium carbonate with stearic acid.

Detailed Production Process (Direct Reaction - Most Common):

1. Raw Material Preparation: Stearic acid, lithium hydroxide (or lithium carbonate), and catalysts (if required) are prepared. Stearic acid is typically melted.

2. Reaction: Molten stearic acid is reacted with lithium hydroxide or lithium carbonate. The reaction is typically carried out at 150-200°C under an inert atmosphere (e.g., nitrogen) with stirring:

C₁₇H₃₅COOH + LiOH → C₁₇H₃₅COOLi + H₂O

2 C₁₇H₃₅COOH + Li₂CO₃ → 2 C₁₇H₃₅COOLi + CO₂ + H₂O

3. Water Removal: The water or carbon dioxide formed during the reaction is removed by vacuum or inert gas flow.

4. Cooling and Solidification: The reaction mixture is cooled to solidify the lithium stearate.

5. Milling and Sieving: The solid lithium stearate is milled to the desired particle size and sieved.

6. Packaging: The final product is packaged in 25 kg bags, drums, or FIBCs.

Reaction Equation (with Lithium Hydroxide):

C₁₇H₃₅COOH + LiOH → C₁₇H₃₅COOLi + H₂O

5. COMPARISON WITH OTHER METAL STEARATES

Lithium stearate has a higher melting point, excellent water resistance, and superior thermal stability compared to other metal stearates. These properties make it the preferred choice for high-temperature and heavy-duty lubricant applications. Calcium stearate, zinc stearate, and magnesium stearate have lower melting points and are more commonly used in plastics, rubber, cosmetics, and pharmaceutical applications.

6. APPLICATIONS AND INDUSTRIAL USES

Lithium stearate has a wide range of applications across various industries due to its unique properties. Its most important application is as a thickening agent in lubricating greases.

6.1. Lubricating Greases (Most Important Application)

Lithium stearate is the primary thickening agent in the production of lithium-based lubricating greases. Together with lithium-12-hydroxystearate, it forms greases that provide high-temperature resistance, excellent water resistance, good mechanical stability, and long service life. Lithium-based greases are widely used in automotive (chassis, bearings, suspension), industrial (conveyor belts, motors, gearboxes), and aerospace applications. Lithium stearate's high melting point (220°C) and excellent thermal stability make it suitable for high-temperature applications. Its hydrophobic property provides excellent water resistance for applications exposed to water.

6.2. Cosmetics and Personal Care Products

Lithium stearate is used in cosmetic products as an emulsifier, stabilizer, consistency agent, and lubricant. It is found in creams, lotions, makeup products, sunscreens, deodorants, and baby powders.

6.3. Plastics and Polymer Industry

Lithium stearate is widely used in the plastics and polymer industry as a release agent, lubricant, anti-blocking agent, stabilizer, and dispersing agent. It is used in the processing of PVC, polyethylene, polypropylene, polystyrene, and other polymers.

6.4. Pharmaceutical Industry

Lithium stearate is used as an excipient in the pharmaceutical industry, although it is not as common as magnesium stearate. It is used as a lubricant in tablet production and as a stabilizer in some pharmaceutical formulations.

6.5. Paints and Coatings

Lithium stearate is used in the paint and coating industry as a flatting agent, suspension agent, lubricant, and water repellent.

6.6. Rubber Industry

Lithium stearate is used in the rubber industry as a release agent, lubricant, and anti-blocking agent.

6.7. Other Applications

7. SAFETY AND HEALTH INFORMATION

Lithium stearate is generally considered to have low toxicity, but dust inhalation may cause mild irritation.

7.1. Toxicological Data

7.2. Health Effects

8. FIRST AID MEASURES

9. SAFETY INFORMATION (GHS CLASSIFICATION)

Lithium stearate is not classified as a hazardous substance under GHS. However, fine powder may cause respiratory irritation.

Signal Word: WARNING

Hazard Statements (H-Codes):

Precautionary Statements (P-Codes):

10. FIREFIGHTING MEASURES

11. ACCIDENTAL RELEASE MEASURES

12. STORAGE AND HANDLING

Lithium stearate should be stored in cool, dry, well-ventilated areas in tightly closed original containers. It should be kept away from heat, moisture, and ignition sources. Contact with strong acids and strong oxidizing agents should be avoided. Proper grounding should be used to prevent static electricity accumulation.

Handling Notes:

• Avoid dust generation (use enclosed systems, local exhaust ventilation)

• Avoid contact with skin and eyes (use protective gloves and goggles)

• Avoid breathing dust (use dust mask or respirator)

• Keep away from ignition sources

13. TRANSPORT INFORMATION

Lithium stearate is not classified as a dangerous good for transport. It is shipped in 25 kg bags, drums, or FIBCs. During transport, protect from moisture, impact, and excessive heat.

14. REGULATORY INFORMATION

Regulatory Status:

15. OTHER NAMES AND DATABASE IDENTIFIERS

Database Identifiers:

16. ENVIRONMENTAL INFORMATION

17. APPLICATION SUMMARY TABLE

18. PHYSICAL FORMS

19. COMPARISON WITH LITHIUM-12-HYDROXYSTEARATE

Lithium-12-hydroxystearate is a newer thickening agent used in lithium complex greases and provides superior performance compared to lithium stearate.

20. SUMMARY AND CRITICAL WARNINGS

SUMMARY:

Lithium stearate (C₁₈H₃₅LiO₂, CAS 4485-12-5) is the lithium salt of stearic acid (octadecanoic acid). It is a white, odorless powder, flake, or granule classified as a metal salt (fatty acid salt). The molecular weight is 290.42 g/mol, and the melting point is approximately 220°C. It is practically insoluble in water but soluble in hot alcohol, hydrocarbons, oils, and ketones. It is produced by the reaction of lithium hydroxide or lithium carbonate with stearic acid. Its most important application is as a thickening agent in lubricating greases, where it provides excellent thermal stability, water resistance, and mechanical stability. It is also used as an emulsifier and stabilizer in cosmetic products, as a release agent and lubricant in plastics production, and as an excipient in the pharmaceutical industry. It has low toxicity and is not classified as a hazardous substance under GHS. It is stored in cool, dry, well-ventilated areas, protected from heat and moisture. Packaging: 25 kg bags, drums, or FIBCs.

Key Properties:

Major Application Areas:

Key Safety Points:

• LOW TOXICITY: Acute toxicity is low (LD50 > 5,000 mg/kg)

• COMBUSTIBLE DUST: Avoid dust cloud formation; use explosion-proof equipment

• MILD IRRITANT: May cause mild skin and eye irritation

• WATER INSOLUBLE: Insoluble in water; soluble in organic solvents

• STORAGE: Store in cool, dry, well-ventilated area, away from heat and moisture

• USE PPE: Dust mask, gloves, safety goggles (if dust formation occurs)

CRITICAL WARNINGS:

Thickener in Lubricating Greases: Lithium stearate is the primary thickening agent in the production of lithium-based lubricating greases. It provides a high melting point (220°C), excellent thermal stability, and water resistance. Lithium-based greases are widely used in automotive, industrial, and aerospace applications.

Advantages Over Other Metal Stearates: Lithium stearate has a higher melting point, excellent water resistance, and superior thermal stability compared to calcium stearate, zinc stearate, and magnesium stearate. These properties make it the preferred choice for high-temperature and heavy-duty lubricant applications.

Cosmetic Use: Lithium stearate is used as an emulsifier and stabilizer in cosmetic products. It provides anti-adhesion and lubricating properties on the skin. It is found in creams, lotions, makeup products, sunscreens, and deodorants.

Plastic Use: Lithium stearate is used as a release agent, lubricant, anti-blocking agent, and stabilizer in plastics production. It is used in the processing of PVC, polyethylene, polypropylene, and other polymers.

Dust Explosion: Lithium stearate dust can reach explosive concentrations in air. Explosion-proof equipment, proper grounding, and dust collection systems should be used to prevent explosion risk. Static electricity accumulation should be avoided.

Environment: Lithium stearate is readily biodegradable due to its fatty acid component. It has low toxicity to aquatic organisms. Large discharges to water bodies should be avoided.

Important Disclaimer: This Technical Data Sheet (TDS) is for informational purposes only. The information provided is based on available data and is believed to be accurate. However, the user is solely responsible for determining the suitability of the product for their specific application and for complying with all applicable regulations and safety requirements. For complete safety, handling, storage, and regulatory compliance information, always refer to the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier. Users are responsible for testing the product in their own processes and applications. All local, national, and international regulations must be followed when working with lithium stearate.