What Is Thiophenol?
Thiophenol, also known as benzenethiol, phenyl mercaptan, or mercaptobenzene, is a liquid where one hydrogen on the benzene ring is replaced by a thiol group (-SH). It is clear, colorless, or pale yellow, and has a characteristic rotten egg odor. Thiophenol is insoluble in water but soluble in ethanol and acetone. As a toxic substance, it requires careful handling due to its potential to irritate the eyes and skin.
Uses of Thiophenol
Thiophenol is used in pharmaceuticals and agrochemicals, as an organic synthetic intermediate, anti-polymerization agent, antioxidant, and in photosynthesis research. Specific applications include:
1. Nucleophiles:
Its thiol group functions as a nucleophile, useful for deprotecting protective groups, such as the nosyl (Ns) group in amines.
2. Leaving Group:
As a leaving group, thiophenol is involved in glycosylation reactions, where its removal is enhanced by N-iodosuccinimide (NIS) and trifluoromethanesulfonic acid (TfOH), facilitating the linking of different compounds.
3. Electron and Proton Source in Photosynthesis Study:
Thiophenol, being highly acidic, serves as a source of electrons and protons in photosynthesis research.
Other Information on Thiophenol
1. Properties of Thiophenol:
It has a characteristic odor and should be used in a draft. Odor can be eliminated with hypochlorous acid. Thiophenol is more prone to deprotonation than phenol and decomposes easily under light, acid, or heat, producing harmful gases. It’s advised to store it shielded from light and in an inert gas.
2. Thiophenol Production Method:
Thiophenol is synthesized mainly by the Freunderberg-Schonberg reaction, where phenol is thiocarbamated or thiocarbonated, and then converted to thiophenol. In industrial products, carbon disulfide is sometimes added to reduce the flash point.