Production and application of magnesium stearate

Production and application of magnesium stearate

Magnesium stearate is the magnesium salt of stearic (octadecanoic) acid. It exists as a soap powder, solid at room temperature. It is used in the production of food additives, food products (confectionery, spices), pharmaceutical tablets, capsules and powders.

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The structural formula 

Production

  Fatty acids (stearic and palmitic) used as raw materials for the production of magnesium stearate are obtained from edible fats and oils: cottonseed and palm oil. The separation process includes hydrogenation of oils at high temperature and pressure, after which the extraction of the resulting substance is carried out.

Magnesium stearate is formed as a by-product of the reaction between magnesium salts and sodium stearate. It can also be formed when magnesium oxide is treated with stearic acid. The sodium stearate used in the production of the compound in question can be obtained from plant or animal sources.       

For food applications, the substance is usually produced by one of two processes:

  • Direct

  • Indirect

Direct process production, or melting process, involves the direct reaction of fatty acids with a magnesium source such as magnesium oxide or carbonate to form magnesium salts of fatty acids.

In indirect or precipitation production, sodium soap is obtained by reacting fatty acids with sodium hydroxide or in water and precipitating the product by adding magnesium salts to the soap.

Features

The main characteristics of magnesium stearate that determine its use in various industries:

  • lubricity

  • water-repellent ability

  • the ability to gel

  • stabilizing effect

  • suppression of foaming

  • ability to absorb acids

 Molecular weight  591,24 g/mol
 Physical appearance  White powder
 Melting point  200°C
 Density  1,026 g/sm³


Application

Magnesium stearate is widely used as:

  • filler

  • thickener

  • the binding agent

  • lubricant, -

and an inactive ingredient in production:

  • pharmaceutical tablets

  • capsules

  • powders

For many decades, the compound has been widely used in many food additives as:

  • emulsifier

  • the binder

  • thickener,-

as well as in other areas of production in the role of:

  • an anti-tracking agent

  • lubricating agent

  • separation agent

  • granulating agent

  • defoaming agent

Areas of use

Polymer industry

Thermally stable magnesium stearates are used as lubricants and anti-adhesives in the processing of thermoplastics and thermoplastics.

Pharmaceutical industry

Magnesium stearate is the most widely used lubricant in tablet manufacturing. The lubricating property of the compound is due to the adhesion of the polar part of the compound to granules/powders, while the lipophilic part is oriented outward from the surface of the particle.

Pharmaceutical companies refer to the magnesium salt of stearic acid as a "fluidity agent." Magnesium stearate powder helps to prevent the main ingredients of the capsules from sticking to each other. It also prevents drugs from sticking to machines during the manufacturing process. Magnesium stearate powder helps to improve the quality and consistency of tablets and capsules.

Magnesium stearate increases the time it takes for tablets and capsules to dissolve in the body due to the film it forms on the surface of capsules or tablets. The compound covers the tablet with a film, so digestive enzymes first destroy the coating of the magnesium salt of octadecanoic acid before they gain access to the active drug.

Cosmetic industry

Magnesium stearate plays an important role in the production of various cosmetics. This powder serves as an effective dye, as well as an anti-caking agent and filler. The compound is mainly used in cosmetic products such as:

  • lipstick

  • eyeliner

  • tonal foundations

  • eye shadow

  • deodorants

  • mascara

  • blush

  • face powders

Food industry

Magnesium stearate is used in the food industry as a thickener, binder and emulsifier. This powder also serves as an effective lubricant, defoamer and anti-caking agent. The magnesium salt of stearic acid is used in:

  • a number of food additives

  • spices

  • baking ingredients

  • the composition of chewing gum

  • confectionery products


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