Lithium soap

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Examples of Lithium salts of fatty acids
Oelic Acid Lithium Salt Structural Formula V.4.svg
Lithium oleate, the lithium salt of oleic acid.
Palmitic Acid Lithium Salt Structural Formula V.2.svg
Lithium palmitate, the lithium salt of palmitic acid.
Stearic Acid Lithium Salt Structural Formula V.2.svg
Lithium stearate, the lithium salt of stearic acid.

Lithium soap is a soap consisting of a lithium salt of a fatty acid. [1] [2] Sodium-based and potassium-based soaps are used as cleaning agents in domestic and industrial applications, whereas lithium soaps are used as components of lithium grease (white lithium).

Lithium soaps are produced by saponification of triglycerides, using lithium hydroxide or lithium carbonate as the saponification agent. Lithium soaps are used as lubricant components and form-release agents at relatively high temperatures. [3] The main components of lithium soaps are lithium stearate and lithium 12-hydroxystearate. [4]

Lithium grease

Tube of grease ("Fett" in German) made from lithium soap. LithiumGrease.jpg
Tube of grease ("Fett" in German) made from lithium soap.

Lubricating greases are commonly formulated as mixtures of an oil and a lithium soap thickener. [5] Some formulations include PTFE or other substances, such as molybdenum disulfide.

Lithium grease adheres particularly well to metal, is non-corrosive, may be used under heavy loads, and exhibits good temperature tolerance. It has a dropping point of 190 to 220 °C (370 to 430 °F) and resists moisture, so it is commonly used as lubricant in household products, such as electric garage doors, as well as in automotive applications, such as constant-velocity joints. Lithium greases using a thickener formed by reacting a simple lithium soap with an acid are known as lithium complex greases and have higher dropping points as well as improvements to other properties. [6]

Related Research Articles

A lubricant is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. The property of reducing friction is known as lubricity.

<span class="mw-page-title-main">Soap</span> Substance used for cleaning

Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are used as thickeners, components of some lubricants, and precursors to catalysts.

<span class="mw-page-title-main">Detergent</span> Surfactants with cleansing properties

A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions. There are a large variety of detergents, a common family being the alkylbenzene sulfonates, which are soap-like compounds that are more soluble in hard water, because the polar sulfonate is less likely than the polar carboxylate to bind to calcium and other ions found in hard water.

<span class="mw-page-title-main">Castor oil</span> Vegetable oil obtained by pressing the seeds of the Castor plant

Castor oil is a vegetable oil pressed from castor beans. It is a colourless or pale yellow liquid with a distinct taste and odor. Its boiling point is 313 °C (595 °F) and its density is 0.961 g/cm3. It includes a mixture of triglycerides in which about 90% of fatty acids are ricinoleates. Oleic acid and linoleic acid are the other significant components.

<span class="mw-page-title-main">Tallow</span> Rendered form of beef or mutton fat

Tallow is a rendered form of beef or mutton fat, primarily made up of triglycerides.

<span class="mw-page-title-main">Motor oil</span> Lubricant used for lubrication of internal combustion engines

Motor oil, engine oil, or engine lubricant is any one of various substances used for the lubrication of internal combustion engines. They typically consist of base oils enhanced with various additives, particularly antiwear additives, detergents, dispersants, and, for multi-grade oils, viscosity index improvers. The main function of motor oil is to reduce friction and wear on moving parts and to clean the engine from sludge and varnish (detergents). It also neutralizes acids that originate from fuel and from oxidation of the lubricant (detergents), improves the sealing of piston rings, and cools the engine by carrying heat away from moving parts.

Saponification is a process of converting esters into soaps and alcohols by the action of aqueous alkali. Soaps are salts of fatty acids, which in turn are carboxylic acids with long carbon chains. Sodium stearate is a typical soap.

<span class="mw-page-title-main">Stearic acid</span> Eighteen-carbon straight-chain fatty acid

Stearic acid is a saturated fatty acid with an 18-carbon chain. The IUPAC name is octadecanoic acid. It is a soft waxy solid with the formula CH3(CH2)16CO2H. The triglyceride derived from three molecules of stearic acid is called stearin. Stearic acid is a prevalent FA in nature, found in many animal and vegetable fats, but is usually higher in animal fat than vegetable fat. It has a melting point of 69.4 °C and a pKa of 4.50.

<span class="mw-page-title-main">Synthetic oil</span> Lubricant consisting of artificially made chemical compounds

Synthetic oil is a lubricant consisting of chemical compounds that are artificially modified or synthesised. Synthetic lubricants can be manufactured using chemically modified petroleum components rather than whole crude oil, but can also be synthesized from other raw materials. The base material, however, is still overwhelmingly crude oil that is distilled and then modified physically and chemically. The actual synthesis process and composition of additives is generally a commercial trade secret and will vary among producers.

<span class="mw-page-title-main">Palmitic acid</span> Chemical compound

Palmitic acid is a fatty acid with a 16-carbon chain. It is the most common saturated fatty acid found in animals, plants and microorganisms. Its chemical formula is CH3(CH2)14COOH, and its C:D is 16:0. It is a major component of the oil from the fruit of oil palms, making up to 44% of total fats. Meats, cheeses, butter, and other dairy products also contain palmitic acid, amounting to 50–60% of total fats. Palmitates are the salts and esters of palmitic acid. The palmitate anion is the observed form of palmitic acid at physiologic pH (7.4). Palmitic acid is the most common SFA found in plants, animals, and many microorganisms. Major sources of C16:0 are palm oil, palm kernel oil, coconut oil, and milk fat.

The dropping point of a lubricating grease is an indication of the heat resistance of the grease and is the temperature at which it passes from a semi-solid to a liquid state under specific test conditions. It is dependent on the type of thickener used and the cohesiveness of the oil and thickener of a grease. The dropping point indicates the upper temperature limit at which a grease retains its structure though is not necessarily the maximum temperature at which a grease can be used.

<span class="mw-page-title-main">Petroleum product</span> Products ultimately derived from crude oil

Petroleum products are materials derived from crude oil (petroleum) as it is processed in oil refineries. Unlike petrochemicals, which are a collection of well-defined usually pure organic compounds, petroleum products are complex mixtures. Most petroleum is converted into petroleum products, which include several classes of fuels.

Whale oil is oil obtained from the blubber of whales. Oil from the bowhead whale was sometimes known as train-oil, which comes from the Dutch word traan.

Silicone grease, sometimes called dielectric grease, is a waterproof grease made by combining a silicone oil with a thickener. Most commonly, the silicone oil is polydimethylsiloxane (PDMS) and the thickener is amorphous fumed silica. Using this formulation, silicone grease is a translucent white viscous paste, with exact properties dependent on the type and proportion of the components. More specialized silicone greases are made from fluorinated silicones or, for low-temperature applications, PDMS containing some phenyl substituents in place of methyl groups. Other thickeners may be used, including stearates and powdered polytetrafluorethylene (PTFE). Greases formulated from silicone oils with silica thickener are sometimes referred to as silicone paste to distinguish them from silicone grease made with silicone oil and a soap thickener.

Grease is a solid or semisolid lubricant formed as a dispersion of thickening agents in a liquid lubricant. Grease generally consists of a soap emulsified with mineral or vegetable oil.

<span class="mw-page-title-main">Extreme pressure additive</span>

Extreme pressure additives, or EP additives, are additives for lubricants with a role to decrease wear of the parts of the gears exposed to very high pressures. They are also added to cutting fluids for machining of metals.

Oil additives are chemical compounds that improve the lubricant performance of base oil. The manufacturer of many different oils can utilize the same base stock for each formulation and can choose different additives for each specific application. Additives comprise up to 5% by weight of some oils.

Dry lubricants or solid lubricants are materials that, despite being in the solid phase, are able to reduce friction between two surfaces sliding against each other without the need for a liquid oil medium.

Lithium 12-hydroxystearate (C18H35LiO3) is a chemical compound classified as a lithium soap. In chemistry, "soap" refers to salts of fatty acids. Lithium 12-hydroxystearate is a white solid. Lithium soaps are key component of many lubricating greases.

A metallic soap is a metallic salt of a fatty acid. Theoretically, soaps can be made of any metal, although not all enjoy practical uses. Varying the metal can strongly affect the properties of the compound, particularly its solubility.

References

  1. Tharwat F. Tadros (1 April 2014). An Introduction to Surfactants. De Gruyter. pp. 6–. ISBN   978-3-11-031213-3.
  2. Arno Cahn (30 May 2003). 5th World Conference on Detergents: Reinventing the Industry : Opportunities and Challenges. The American Oil Chemists Society. pp. 182–. ISBN   978-1-893997-40-0.
  3. The Significance of Tests of Petroleum Products: A Report. ASTM International. 1934. pp. 152–. GGKEY:FWTS3ZUUWJL.
  4. Uttam Ray Chaudhuri (19 April 2016). Fundamentals of Petroleum and Petrochemical Engineering. CRC Press. pp. 89–. ISBN   978-1-4398-5161-6.
  5. Angelo Nora, Alfred Szczepanek, Gunther Koenen, "Metallic Soaps" in Ullmann’s Encyclopedia of Industrial Chemistry 2005 Wiley-VCH, Weinheim. doi : 10.1002/14356007.a16_361
  6. David Turner. "Grease Selection: Lithium vs. Lithium Complex". Machinery Lubrication. Retrieved 2020-11-26.