Magnesium Stearate (MS)
CAS NO.:557-04-0
Packaging specification: 10 kg/bag
Quality standard: CP2015 USP current version
Main use: This product has functions such as lubrication, anti adhesion, and flow aid. It is mainly used as a lubricant, flow aid, or anti adhesion agent for tablets and capsules in pharmaceutical preparations.
Magnesium stearate, with the chemical formula C36H70MgO4 and a molecular weight of 591.24, is an organic compound that is a white, sand free powder with a smooth feeling when in contact with the skin. Insoluble in water, ethanol, or ether, magnesium stearate is mainly used as a lubricant, anti adhesive, and flow aid. Especially suitable for the granulation of oils and extracts, the particles produced have good flowability and compressibility. Used as a flow aid in direct tablet pressing. Magnesium stearate can also be used as a filter aid, clarifier, and defoamer, as well as a suspension aid and thickener for liquid formulations.
Synthesis method of magnesium stearate
1. Preparation of sodium stearate: Dissolve 4.25 parts of sodium hydroxide in 50 parts of water, raise the temperature to 85 ºC for later use. Put 25 parts of stearic acid into a reaction kettle, heat 500 parts of water, stir and dissolve, and adjust the temperature to 85-90 ºC. Slowly add the prepared sodium hydroxide solution to the stearic acid aqueous solution under stirring, maintain the temperature at 75-80 ºC, and stir until the reaction reaches the endpoint. The product sodium stearate solution is kept warm for future use.
Preparation of magnesium stearate: Dissolve 15 parts of magnesium sulfate in 150 parts of water, raise the temperature to 55 ºC, and slowly add it to the prepared sodium stearate solution. Conduct a double decomposition reaction under stirring, and the resulting magnesium stearate precipitates as a solid. After the reaction is completed, the clear liquid is separated by standing, and then washed with water, centrifuged and dehydrated, and dried at 80-85 ºC to obtain the finished product.
2. Neutralize 46.6g of stearic acid with 164mL of 1mol/L sodium hydroxide solution to obtain 50g of sodium stearate in 2L of water. Heat the prepared sodium stearate solution to 80 ºC, add 20g of magnesium chloride solution in 100mL of water dropwise, continuously stir, and quickly precipitate white precipitates. After cooling, filter out, wash with water until there are no chloride ions present, and finally wash with ethanol. Place 10g of the product in a vacuum dryer with concentrated sulfuric acid for 4 weeks to obtain the product Mg (C18H35O2) 2.2H2O. Dissolve the remaining product in benzene and heat it under reflux for 20 minutes. Pour out the upper yellow liquid layer while it is hot and evaporate it to dryness. The obtained solid can be recrystallized with benzene to obtain the product Mg (C18H35O2) 2.
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