Mercaptans are easily oxidized. A weak oxidant (such as air, iodine, iron oxide, manganese dioxide, etc.) can oxidize the thiol to a disulfide. The conjugated pair of oxygen formed by the thiol and the disulfide is a common mechanism in the body, such as a cysteine-cystine-oxygen pair. The disulfide bond in the resulting disulfide plays an important role in maintaining the spatial structure of the protein.

The mercaptan is oxidized with a strong oxidizing agent (such as potassium permanganate, nitric acid, periodic acid), and passed through the intermediate sulfenic acid or sulfinic acid to finally form a sulfonic acid. This method can be used for the preparation of fatty sulfonic acids.

Catalytic hydrogenation of mercaptans can achieve desulfurization and produce corresponding hydrocarbons. Hydrodesulfurization in petroleum refining is based on this reaction. There is a small amount of mercaptan in the oil. The presence of mercaptan not only makes the gasoline have an unpleasant odor, but also turns into toxic and corrosive sulfur dioxide and sulfur trioxide when burned.