Stearic acid
Chemical name	Octadecanoic acid
Other names	Stearic acid
Chemical formula	C18H36O2
Molar mass	284.47 g/mol
CAS number	[57-11-4]
Density	0.847 g/cm3 at 70 °C
Melting point	69.6 °C
Boiling point	383 °C
Acid value	200-210 mg KOH/g
Disclaimer and references

Stearic acid (IUPAC systematic name: octadecanoic acid) is one of the useful types of saturated fatty acids that comes from many animal and vegetable fats and oils. It is a waxy solid, and its chemical formula is CH₃(CH₂)₁₆COOH. Its name comes from the Greek word stéar (genitive: stéatos), which means tallow. The term stearate is applied to the salts and esters of stearic acid. Image File history File links Download high resolution version (1184x150, 3 KB) Summary Chemical structure of stearic acid created with ChemDraw. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... In physics, Density is defined as mass m per unit volume V. Mathematically, it is expressed as where, in SI units: ρ (rho) is the density of the substance, measured in kg m-3 m is the mass of the substance, measured in kg v is the volume of the substance... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... The boiling point of a substance is the temperature at which it can change its state from a liquid to a gas throughout the bulk of the liquid at a given pressure. ... Uses of KOH can include: KOH is the chemical symbol for Potassium hydroxide A KOH test is a procedure in which KOH is used to dissolve skin and reveal fungal cells under the microscope KOH is used as an anisotropic etchant for silicon in MEMS fabrication. ... The chemical compound potassium hydroxide, (KOH) sometimes known as caustic potash, potassa, potash lye, and potassium hydrate, is a metallic base. ... The International Union of Pure and Applied Chemistry (IUPAC) is an international non-governmental organization devoted to the advancement of chemistry. ... There are millions of possible objects that can be described in science, too many to create common names for every one. ... In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ... The genitive case is a grammatical case that indicates a relationship, primarily one of possession, between the noun in the genitive case and another noun. ... Tallow is rendered beef or mutton fat, processed from suet. ... General formula of a carboxylate ester. ...

Production

Stearic acid is prepared by treating animal fat with water at a high pressure and temperature, leading to the hydrolysis of triglycerides. It can also be obtained from the hydrogenation of some unsaturated vegetable oils. Common stearic acid is actually a mix of stearic acid and palmitic acid, although purified stearic acid is available separately. It has been suggested that Medium Chain Triglycerides be merged into this article or section. ... Hydrogenation is a class of chemical reactions in which the net result is an addition of hydrogen. ... It has been suggested that this article or section be merged with cooking oil. ... Palmitic acid, also called hexadecanoic acid, is one of the most common saturated fatty acids found in animals and plants. ...

Uses

Stearic acid is useful as an ingredient in making candles, soaps, plastics, oil pastels and cosmetics, and for softening rubber. Stearic acid is used to harden soaps, particularly those made with vegetable oil. It has been suggested that Pillar candle be merged into this article or section. ... This article is about the computer protocol. ... This article or section does not adequately cite its references or sources. ... A box of Pentel oil pastels Oil pastel is a painting and drawing medium with characteristics similar to pastels and wax crayons. ... For other uses, see Cosmetic. ... Latex being collected from a tapped rubber tree Rubber is an elastic hydrocarbon polymer which occurs as a milky colloidal suspension (known as latex) in the sap of several varieties of plants. ...

Stearic acid is also used as a parting compound when making plaster castings from a plaster piece mold or waste mold and when making the mold from a shellacked clay original. In this use, powdered stearic acid is dissolved in water and the solution is brushed onto the surface to be parted after casting.

Esters of stearic acid with ethylene glycol, glycol stearate and glycol distearate are used to produce a pearly effect in shampoos, soaps, and other cosmetic products. They are addded to the product in molten form and allowed to crystalize under controlled conditions. General formula of a carboxylate ester. ... Ethylene glycol (monoethylene glycol (MEG), IUPAC name: ethane-1,2-diol) is an alcohol with two -OH groups (a diol), a chemical compound widely used as an automotive antifreeze. ... Stearic acid also called octadecanoic acid is one of the many useful types of saturated fatty acids that comes from many animal and vegetable fats and oils. ...

Reactions

Stearic acid undergoes the typical reactions of unsaturated carboxylic acids, notably reduction to stearyl alcohol, and esterification with a range of alcohols. Stearyl alcohol (also known as octadecyl alcohol or 1-octadecanol) is a substance prepared from stearic acid by the process of catalytic hydrogenation. ...

Metabolism

An isotope labeling study in humans^[1] concluded that the fraction of dietary stearic acid oxidatively desaturated to oleic acid was 2.4 times higher than the fraction of palmitic acid analogously converted to palmitoleic acid. Also, stearic acid was less likely to be incorporated into cholesterol esters. These findings may indicate that stearic acid is less unhealthy than other saturated fatty acids. It has been suggested that Isotopic tracer be merged into this article or section. ... Semi-accurate illustration of a redox reaction Redox reactions include all chemical processes in which atoms have their oxidation number (oxidation state) changed. ... Oleic acid is a monounsaturated omega-9 fatty acid found in various animal and vegetable sources. ... Palmitic acid, also called hexadecanoic acid, is one of the most common saturated fatty acids found in animals and plants. ... Palmitoleic acid, or (Z)-9-hexadecenoic acid, is a monounsaturated fatty acid that is a common constituent of the glycerides of human adipose tissue. ... Cholesterol is a sterol (a combination steroid and alcohol) and a lipid found in the cell membranes of all body tissues, and transported in the blood plasma of all animals. ...

See also

• Magnesium stearate

Magnesium stearate, also called Octadecanoic acid,magnesium salt is a white substance, solid at room temperature, chemical formula C36H70MgO4. ...

References

1. ^ Emken, Edward A. (1994). "Metabolism of dietary stearic acid relative to other fatty acids in human subjects" (PDF). American Journal of Clinical Nutrition 60: 1023S–1028S. Retrieved on 2006-08-07. 

• Merck Index, 11th Edition, 8761.

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External links

• NIST Chemistry WebBook Entry
• Links to external chemical sources