Alkoksidit

Alkoksidit, or alkoxides, are chemical compounds containing the alkoxide anion RO−, where R is an alkyl or aryl group. They commonly occur as salts of metal cations such as sodium, potassium, or calcium, for example sodium methoxide (NaOCH3), sodium ethoxide (NaOEt), and potassium tert-butoxide (KOtBu). Organometallic alkoxides such as titanium isopropoxide Ti(OiPr)4 or aluminum isopropoxide Al(OiPr)3 are covalent metal–alkoxide species used as precursors in materials synthesis.

Preparation and properties vary by class. Alkoxide salts are typically prepared by reacting an alkali metal with an alcohol: 2 ROH + 2 M → 2 MOR + H2. They can also be formed by deprotonating alcohols with strong bases or by transesterification under suitable conditions. Alkoxides are generally strong bases and good nucleophiles, highly reactive toward water and acids, and they are often soluble in organic solvents. Many alkoxides are moisture- and air-sensitive, requiring storage under inert atmosphere to prevent hydrolysis and degradation.

Uses and applications are diverse. In organic synthesis, alkoxides function as bases and nucleophiles, enabling reactions such as deprotonations and the Williamson ether synthesis to form ethers. They also serve as catalysts or ligands in various transformations. In materials chemistry, metal alkoxides are widely used as precursors for sol–gel processes to prepare metal oxides (for example SiO2, TiO2) with controlled porosity and purity, via hydrolysis and condensation reactions.

Safety and handling emphasize their caustic nature and sensitivity to moisture. Proper storage, handling in inert environments, and appropriate personal protective equipment are standard precautions.