Phenol is the organic compound with formula C6H5OH. It is a white solid. It has an OH group (hydroxyl group) bonded to a benzene ring. It is an alcohol. Because the aromatic group attracts electrons, it is quite acidic.
Phenol has a pKa of about 10. For normal alcohols this number is usually around 15. However, phenol is less acidic than compounds like carboxylic acids. The reason for this high acidity is the resonance stabilization of the molecule when it becomes an anion.
Phenol can do electrophilic aromatic substitution reactions very well. This is because the lone pair on the oxygen atom can give electrons through the benzene ring to an electrophile. Because the lone pair is so high in energy however, sometimes phenol reacts too many times.
Phenol was first discovered in 1834. It was found as a product of burning coal. One of its first uses was to kill germs in surgery. It is still used today in some analgesics. During the Second World War, phenol was also used by the Nazis. They used it in concentration camps to quickly kill small groups of people.
- Dr. Robert Jay Lifton. "The Nazi Doctors, Chapter 14, Killing with Syringes: Phenol Injections". Retrieved 24 February 2013.