overoxidation

Overoxidation refers to an oxidation process that proceeds beyond the desired oxidation state or product, yielding overoxidized species or degraded material. It can occur in chemical synthesis, electrochemical processes, and biological systems when oxidants are too strong, reaction times are too long, or conditions favor continued oxidation.

In organic chemistry, overoxidation commonly converts aldehydes to carboxylic acids and primary alcohols to carboxylic acids; secondary alcohols may be further oxidized to ketones or beyond. Other examples include oxidation of sulfides to sulfones and phenols to quinones. Overoxidation reduces selectivity and can lead to breakdown of desired functional groups or cleavage of carbon–carbon bonds, complicating synthetic routes.

In electrochemistry and materials science, applying potentials beyond the target can oxidize substrates beyond the intended product and can form insulating oxide films on electrode surfaces. Side reactions such as solvent oxidation or water splitting may occur, decreasing efficiency and causing material degradation.

In biology, overoxidation is associated with oxidative stress, where reactive oxygen species damage biomolecules. Lipids can undergo lipid peroxidation; proteins can form carbonylated derivatives; DNA can incur strand breaks and base modifications. Such overoxidation is linked to aging and various diseases.

Prevention and control include using milder or more selective oxidants, carefully controlling stoichiometry and time, employing protective groups, or quenching excess oxidant. In electrochemistry, controlled potentials, pulsed techniques, and surface catalysts help limit overoxidation.