Phloroglucinol
Overview
 
Phloroglucinol is a benzenetriol
Benzenetriol
Benzenetriols or trihydroxybenzenes are aromatic chemical compounds and polyphenols in which three hydroxyl groups are substituted onto a benzene ring....

. It is an organic compound that is used in the synthesis
Organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...

 of pharmaceuticals and explosives. This molecule exists in two forms, or tautomer
Tautomer
Tautomers are isomers of organic compounds that readily interconvert by a chemical reaction called tautomerization. This reaction commonly results in the formal migration of a hydrogen atom or proton, accompanied by a switch of a single bond and adjacent double bond...

s, 1,3,5-trihydroxybenzene, which has phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

-like, and 1,3,5-cyclohexanetrione (phloroglucin), which has ketone
Ketone
In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

-like character. These two tautomers are in equilibrium. Phloroglucinol is a useful intermediate because it is polyfunctional.

From water, phloroglucinol crystallizes as the dihydrate, which has a melting point of 116-117 °C, but the anhydrous form melts much higher, at 218-220 °C.
 
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