Magnesium stearate

Magnesium stearate is the magnesium salt of stearic acid.

It is obtained from fats and oils by splitting their glycerides with magnesium, soaps and glycerine. Magnesium stearate is used, for example, in the pharmaceutical industry as an aid in making tablets or granules. Magnesium stearate is also used in some candies.

Magnesium stearate can be made from both animal and vegetable fats. Soy, rapeseed or corn oil is often used.

Magnesium stearate in its form for use in the pharmaceutical industry still contains small amounts of other magnesium salts, e.g. B. palmitic acid and oleic acid. All in all, the result is a fine, almost odorless white powder that feels greasy. It is not soluble in water and ethanol.

Magnesium stearate exhibits properties that make it very suitable as a lubricant. First, it has a lamellar crystal structure that significantly reduces the internal friction of the fabric. It also has a very small particle size of 3 to 15 µm. Magnesium stearate accumulates on the surface of other particles of a powder mixture and thus reduces their friction with each other and with external surfaces, e.g. B. a tablet press.

Technical features:

Empirical formula C36H70MgO4
Molar mass (M) 591.25 g / mol
Density 1.03
Melting point (mp) 140 ° C
CAS No. [557-04-0]

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