What Is Aluminum Nitrate?
Aluminum nitrate, with the chemical formula Al(NO3)3, is a salt combining aluminum and nitrate ions. It has a molar mass of 213.0 g/mol, a melting point of 73°C, and a boiling point of 135°C. Among its various hydrates, aluminum nitrate nonahydrate (IX hydrate) is the most commonly used.
Properties of Aluminum Nitrate
Produced by dissolving aluminum in nitric acid and subsequent concentration, aluminum nitrate anhydrate appears as a colorless powder, while the nonahydrate form is a white solid with orthorhombic crystals. Aluminum nitrate acts as an oxidizing agent due to the nitrate ions, is soluble in water and ether, and forms weakly acidic aqueous solutions upon hydrolysis. Stable under standard conditions, it is hygroscopic and deliquescent, transitioning to its hydrate form when exposed to air. Handling requires caution due to its irritant nature, especially to the skin and eyes.
Uses of Aluminum Nitrate
1. Industrial Applications
Aluminum nitrate decomposes into aluminum oxide at temperatures between 1,200 and 1,300°C, a key process in producing aluminum oxide. In the leather industry, it serves as a tanning aid and finishing agent. As a mordant in dyeing, it forms water-insoluble dyes on fibers through the combination of aluminum ions with dye molecules. Its capacity to hold metals like cobalt aids in hydrogenation processes, being utilized as a catalyst in petroleum refining. Additionally, aluminum nitrate is used as a corrosion inhibitor or for metal surface treatment due to its ability to form a protective oxide layer.
It also finds a niche application as a uranium substitute in laboratory experiments related to uranium refining due to its similar crystal properties.
2. Organic Chemistry
In organic synthesis, aluminum nitrate is used to produce aluminum hydroxide by reacting with sodium hydroxide, exploiting its weakly basic nature. Its nitrosative properties allow for the nitrosation of benzene rings and other organic compounds, with nitrate ions serving as catalysts in various organic reactions.
3. Other Uses
Aluminum nitrate acts as an antiperspirant by reacting with sweat gland moisture, blocking the glands and reducing sweat secretion. It is also employed as an abrasive and analytical reagent for different substances.
Other Information on Aluminum Nitrate
Legal Information
Aluminum nitrate is classified as a hazardous and toxic substance under various safety laws, requiring specific labeling and notification, as well as being recognized for its oxidizing properties. It should be handled with appropriate care.