Alminium mono stearate
| Formula | CH3(CH2)16COOAl(OH)2 |
| Chemical formula | CH3(CH2)16COOAl(OH)2 |
| Molar mass | 344.47 g/mol |
| Density | ~ 0.961 g/cm3 (25°C) |
| CAS number | 7047-84-9 |
| EC Number | 230-325-5 |
| Storage | Store at 5 to 25 °C |
| SDS | available |
| Boiling point | 313 °C |
| Flash point | >113 °C |
| Description | Conforms | ||
| Identification | Conforms | ||
| Solubility | Conforms | ||
| Loss on drying | ≤ | 2 | % |
| Heavy metals | ≤ | 50 | ppm |
| Free fatty acids | ≤ | 4 | % |
| Ash | ≤ | 10 | % |
| Assay (Al 2 O 3) | 14.5 – 16.4 | % | |
| Assay (Al) | 3.7 – 4.3 | % | |
| Fixed oil | Conforms |
Aluminium monostearate is a white, fine, odorless powder composed of aluminium and stearic acid, classified as a metallic soap. It is widely used in pharmaceutical and laboratory formulations for its thickening, stabilizing, and emulsifying properties, especially in oil-based systems.
🏭⚗️ Production
Aluminium monostearate is produced by reacting aluminium salts (such as aluminium sulfate or aluminium chloride) with sodium or potassium stearate in aqueous or alcoholic solution. The resulting precipitate is filtered, washed, and dried to obtain the final powder form. The reaction yields a coordination compound where aluminium binds with stearate anions.
🔬 Properties
Its chemical formula is approximately C₁₈H₃₅O₂Al, with a molar mass of about 344.48 g/mol (depending on purity and hydration state). It is practically insoluble in water and ethanol, but disperses well in oils and forms gels. It melts at elevated temperatures and has excellent oil-absorbing and thickening properties. The compound is chemically stable and non-volatile under normal storage conditions.
🧪 Applications
In pharmaceutical formulations, aluminium monostearate is used as a gelling agent in the preparation of sustained-release injectable suspensions, ointments, and suppositories. It helps modify drug release by forming a gel matrix in oily vehicles. In laboratory settings, it is used in topical drug research and in the preparation of hydrophobic gels. It also finds applications in cosmetics and personal care products as a stabilizer and emulsifier.
⚠️ Safety
Aluminium monostearate is generally regarded as safe (GRAS) for pharmaceutical and cosmetic use when used in appropriate concentrations. However, as with all fine powders, inhalation of dust should be avoided. Contact with eyes and skin may cause mild irritation in sensitive individuals. Proper personal protective equipment such as gloves, masks, and goggles is recommended during handling. It should be stored in tightly sealed containers in a cool, dry environment, away from strong acids or oxidizers.
