dehydroxylation

Dehydroxylation is a chemical reaction in which a hydroxyl group (-OH) is removed from an organic or inorganic substrate. The process commonly produces water as a byproduct and results in the formation of a double bond (in organic substrates) or an oxide network (in inorganic systems). Mechanisms vary with context and may involve dehydration, oxidation, or condensation steps. In organic chemistry, dehydroxylation often refers to dehydration reactions that convert alcohols to alkenes or carbonyl compounds.

In organic synthesis, dehydration of alcohols is a classic dehydroxylation reaction. It typically requires an acid catalyst and proceeds via an E1 or E2 mechanism: loss of water from an alcohol, followed by removal of a beta-hydrogen to form an alkene. Examples include ethanol to ethene with sulfuric acid or alumina catalysts, and secondary alcohols to corresponding alkenes. The reaction is temperature-dependent and can be reversible under some conditions.

In inorganic chemistry and materials science, dehydroxylation describes the removal of surface or lattice hydroxyl groups from metal hydroxides or oxides, often upon heating. This eliminates water and leaves behind oxide or oxynitride networks. Industrially relevant: dehydroxylation of Al(OH)3 to Al2O3, or the treatment of catalysts to produce active oxide supports. The process affects surface properties, acidity, and catalytic activity.

Dehydroxylation is also encountered in biomass processing and materials transformations, where removal of hydroxyl groups can facilitate cracking, deoxygenation, and formation of unsaturated hydrocarbons under controlled conditions.