What is lithium 12-hydroxystearate used for?

Lithium 12-hydroxystearate is a widely used lithium soap that plays a crucial role in the formulation of lubricating greases. Here’s a detailed overview of its properties, uses, and production processes.

Chemical Properties of lithium 12-hydroxystearate

• Chemical Formula: C₁₈H₃₅LiO₃
• Appearance: White solid.
• Dropping Point: Approximately 200 °C (392 °F), making it suitable for high-temperature applications.
• Oxidation Stability: Exhibits excellent resistance to oxidation, contributing to the longevity and performance of greases.

1. Lubricating Greases

Lithium 12-hydroxystearate is primarily used as a thickener in lubricating greases. It is favored for several reasons:

• High Performance: Greases made with lithium 12-hydroxystearate are known for their superior mechanical stability and resistance to water, making them ideal for various industrial applications.
• Versatility: It is used in multipurpose greases suitable for automotive, industrial, and marine applications. The grease can operate effectively at temperatures up to 130 °C (266 °F) continuously and can withstand short-term exposure to higher temperatures.
• Applications: Commonly used in bearings, chassis lubrication, open and enclosed gears, and various machinery including agricultural and construction equipment.

2. Specialty Applications

Beyond general lubrication, lithium 12-hydroxystearate is also employed in more specialized formulations:

• High Load Conditions: Its mechanical stability makes it suitable for applications requiring high load resistance.
• Extreme Pressure (EP) Greases: When combined with other additives, it can be formulated into EP greases that provide additional protection under extreme conditions.

<h2>Production Process</h2>

The production of lithium 12-hydroxystearate typically involves the following steps:

1. Mixing Ingredients: A mixture of base oil, hydrogenated castor oil, and lithium hydroxide is prepared.
2. Saponification: The mixture undergoes saponification to form a soap-oil sol state. This involves heating the mixture to specific temperatures (around 155–175 °C) while adding lithium hydroxide.
3. Cooling and Homogenization: After reaching the desired consistency, the mixture is cooled rapidly and subjected to grinding and homogenization to achieve the final product.

Advantages

• Water Resistance: Greases formulated with lithium 12-hydroxystearate have good water resistance, although they may soften in the presence of large amounts of water.
• Thermal Stability: They maintain performance across a wide temperature range, making them suitable for both high and low-temperature applications.
• Compatibility: While lithium greases are generally less compatible with other soap types compared to calcium-based greases, they remain a preferred choice due to their overall performance characteristics.

Lithium 12-hydroxystearate is an essential component in the lubrication industry, known for its effectiveness as a thickener in high-performance greases. Its unique properties allow it to excel in various applications, making it one of the most widely used lubricating agents across multiple sectors. The ongoing demand for lithium-based products continues to shape its production methodologies and application development.

References

1. Silva, L.S.; Lima, L.C.B.; Silva, F.C.; Matos, J.M.E.; Santos, M.R.M.C.; Santos Júnior, L.S.; Sousa, K.S.; da Silva Filho, E.C. Dye anionic sorption in aqueous solution onto a cellulose surface chemically modified with aminoethanethiol. Chem. Eng. J. 2013, 218, 89–98. [Google Scholar] [CrossRef]
2. CMI, https://www.echemi.com/produce/pr22120151498-lithium-12-hydroxystearate.html