Metallic soap

Last updated

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. [1] Varying the metal can strongly affect the properties of the compound, particularly its solubility.

Contents

Alkali, alkaline earth soaps

Smarties, like many candies, contain calcium stearate, a metallic soap. Giant-Smarties-US.jpg
Smarties, like many candies, contain calcium stearate, a metallic soap.

Alkali metal and alkaline earth soaps are white solids. [1] The most commonly encountered are traditional household soaps, which are the fatty acid salts of sodium (hard soap) and potassium (soft soap). Lithium soap or greases, such as lithium stearate, are insoluble in water and find use in lubricating grease.

Calcium and magnesium soaps are most commonly encountered as soap scum but the pure materials have a variety of uses. Magnesium stearate and calcium stearate are used as excipients, lubricants, release agents, and food additives, with the later use being covered by the generic E numbers of E470b and E470 respectively.

Other metal soaps

Aluminium soaps are used as thickening agents, in the production of cosmetics. [1] Other examples include mixed calcium/zinc soaps which are used as heat stabilizer for polyvinyl chloride. Soaps of iron, cobalt and manganese are used as drying agents in paints and varnishes and work by promoting the oxidation and crosslinking of unsaturated oils. [2]

Related Research Articles

<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.

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">Stearin</span> Chemical compound

Stearin, or tristearin, or glyceryl tristearate is an odourless, white powder. It is a triglyceride derived from three units of stearic acid. Most triglycerides are derived from at least two and more commonly three different fatty acids. Like other triglycerides, stearin can crystallise in three polymorphs. For stearin, these melt at 54 (α-form), 65, and 72.5 °C (β-form).

<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.

An anticaking agent is an additive placed in powdered or granulated materials, such as table salt or confectioneries, to prevent the formation of lumps (caking) and for easing packaging, transport, flowability, and consumption. Caking mechanisms depend on the nature of the material. Crystalline solids often cake by formation of liquid bridge and subsequent fusion of microcrystals. Amorphous materials can cake by glass transitions and changes in viscosity. Polymorphic phase transitions can also induce caking.

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">Magnesium stearate</span> Chemical compound

Magnesium stearate is the chemical compound with the formula Mg(C
18
H
35
O
2
)
2
. It is a soap, consisting of salt containing two equivalents of stearate (the anion of stearic acid) and one magnesium cation (Mg2+). Magnesium stearate is a white, water-insoluble powder. Its applications exploit its softness, insolubility in many solvents, and low toxicity. It is used as a release agent and as a component or lubricant in the production of pharmaceuticals and cosmetics.

<span class="mw-page-title-main">Zinc stearate</span> Chemical compound

Zinc stearate is a "zinc soap" that is widely used industrially. In this context, soap is used in its formal sense, a metal salt of a fatty acid: in this case stearic acid. It is a white solid that repels water. It is insoluble in polar solvents such as alcohol and ether but soluble in aromatic hydrocarbons and chlorinated hydrocarbons when heated. It is the most powerful mold release agent among all metal soaps. It contains no electrolyte and has a hydrophobic effect. Its main application areas are the plastics and rubber industry, where it is used as a releasing agent and lubricant which can be easily incorporated.

<span class="mw-page-title-main">Lithium soap</span>

Lithium soap is a soap consisting of a lithium salt of a fatty acid. 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.

Sodium atoms have 11 electrons, one more than the stable configuration of the noble gas neon. As a result, sodium usually forms ionic compounds involving the Na+ cation. Sodium is a reactive alkali metal and is much more stable in ionic compounds. It can also form intermetallic compounds and organosodium compounds. Sodium compounds are often soluble in water.

<span class="mw-page-title-main">Calcium stearate</span> Chemical compound

Calcium stearate is a carboxylate salt of calcium, classified as a calcium soap. The salt is a component of some lubricants, surfactants, as well as many foodstuffs. It is a white waxy powder.

<span class="mw-page-title-main">Cleaning agent</span> Substance used to remove dirt or other contaminants

Cleaning agents or hard-surface cleaners are substances used to remove dirt, including dust, stains, foul odors, and clutter on surfaces. Purposes of cleaning agents include health, beauty, removing offensive odor, and avoiding the spread of dirt and contaminants to oneself and others. Some cleaning agents can kill bacteria and clean at the same time. Others, called degreasers, contain organic solvents to help dissolve oils and fats.

Polymer stabilizers are chemical additives which may be added to polymeric materials, such as plastics and rubbers, to inhibit or retard their degradation. Common polymer degradation processes include oxidation, UV-damage, thermal degradation, ozonolysis, combinations thereof such as photo-oxidation, as well as reactions with catalyst residues, dyes, or impurities. All of these degrade the polymer at a chemical level, via chain scission, uncontrolled recombination and cross-linking, which adversely affects many key properties such as strength, malleability, appearance and colour.

Soap scum or lime soap is the white solid composed of calcium stearate, magnesium stearate, and similar alkaline earth metal derivatives of fatty acids. These materials result from the addition of soap and other anionic surfactants to hard water. Hard water contains calcium and magnesium ions, which react with the surfactant anion to give these metallic or lime soaps.

Lithium stearate is a chemical compound with the formula LiO2C(CH2)16CH3. It is formally classified as a soap (a salt of a fatty acid). Lithium stearate is a white soft solid, prepared by the reaction of lithium hydroxide and stearic acid.

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.

Lithium laurate is an metallorganic compound with the chemical formula LiO2C(CH2)10CH3. It is classified as a metallic soap, i.e. a metal derivative of a fatty acid. In contrast to the lubricants lithium stearate and lithium 12-hydroxystearate, lithium laurate is of minor commercial value..

Lanthanum stearate is a metal-organic compound, a salt of lanthanum and stearic acid with the chemical formula C
54
H
108
LaO
6
. The compound is classified as a metallic soap, i.e. a metal derivative of a fatty acid.

Cerium stearate is a metal-organic compound, a salt of cerium and stearic acid with the chemical formula C
54
H
105
CeO
6
. The compound is classified as a metallic soap, i.e. a metal derivative of a fatty acid.

References

  1. 1 2 3 Nora, Angelo; Szczepanek, Alfred; Koenen, Gunther (2001). "Metallic Soaps". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a16_361.
  2. Whitmore, Willet; Lauro, Michael (1930). "Metallic Soaps - Their Uses, Preparation, and Properties". Industrial & Engineering Chemistry. 22 (6): 646–649. doi:10.1021/ie50246a026.