Aluminiumphosphat

Aluminiumphosphat, commonly referred to as aluminum phosphate (chemical formula AlPO4), is an inorganic compound made of aluminum cations and phosphate anions. It occurs in several crystalline forms, built from a three-dimensional network of AlO4 and PO4 tetrahedra. A naturally occurring mineral form is berlinite (AlPO4), which is isostructural with quartz.

Preparation and forms: Aluminum phosphate is typically prepared by reacting aluminum salts with phosphoric acid under controlled conditions, followed by filtration and drying. In the solid state it exists as anhydrous AlPO4 and various hydrated forms. It can be synthesized as framework materials known as aluminophosphate molecular sieves (ALPOs), which are microporous materials used as catalysts and adsorbents.

Properties and reactions: It is generally insoluble in water and exhibits thermal stability up to high temperatures. As a solid acid, AlPO4 can catalyze certain reactions when integrated with active metal sites. Its porous ALPO frameworks provide shape-selective catalysis and hydrocarbon processing capabilities.

Applications: ALPO materials (for example ALPO-5) are used as catalysts and catalyst supports in petrochemical processes. Aluminum phosphate is also used as a binder or cement in refractory materials and has historically been used as a dental luting cement. In some vaccines, aluminum phosphate is used as an adjuvant to enhance immune response.

Safety: As with many aluminum compounds, soluble forms may be corrosive or irritant; solid AlPO4 is relatively inert but should be handled with normal laboratory precautions to avoid respiratory or dermal exposure.