| IUPAC name
| Other names
|Molar mass||126.11 g/mol|
|Melting point||219 °C (426 °F; 492 K)|
|1.06 g/100 ml (20 °C)|
|Solubility||Miscible with acetone, diethyl ether, ethanol, isopropanol, methanol, pyridine|
|Safety data sheet||Sigma-Aldrich|
|Lethal dose or concentration (LD, LC):|
LD50 (Median dose)
|5000 mg/kg (rat, oral)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Phloroglucinol is an organic compound with the formula C6H3(OH)3.
Phloroglucinol is one of three isomeric benzenetriols. The other two isomers are hydroxyquinol (1,2,4-benzenetriol) and pyrogallol (1,2,3-benzenetriol).
Phloroglucinol is a weak triprotic acid. The first two pKa's are 8.5 and 8.9.
As an enol, phloroglucinol in principle exists in equilibrium with keto tautomers. Evidence for this equilibrium is provided by the formation of the oxime:
- C6H3(OH)3 + 3 NH2OH → (CH2)3(C=NOH)3 + 3 H2O
But it behaves also like a benzenetriol as the three hydroxyl groups can be methylated to give 1,3,5-trimethoxybenzene.
Phloroglucinol is a colorless solid, though air oxidation will give it a beige tint, which is soluble in water, alcohols and ether.
From water, phloroglucinol crystallizes as the dihydrate, which has a melting point of 116–117 °C, but the anhydrous form melts at a much higher temperature, at 218–220 °C. It does not boil intact, but it does sublime.
Phloroglucinol is sold by chemical suppliers.
A complex but good purity route involves nitrating benzene to trinitrobenzene, which is reduced to triaminobenzene, then treated with an alkaline hydroxide to yield phlorogluciol. This latter reaction is noteworthy, because ordinary aniline derivatives are usually unreactive toward hydroxide.
Can be obtained from phloretin.
- Reagent in the Tollens' test for pentoses
- Wiesner test for the detection of lignin
- Gunzberg's test for the qualitative detection of free hydrochloric acid in gastric juice
- Synthesis of trinitrophloroglucinol
- Preparation of TATB
- Synthesis of leptospermone
Phloroglucinol is irritant and exposure to large amounts may be harmful.
Phloroglucinol is used as a treatment for gallstones, spasmodic pain and other related gastrointestinal disorders.
In closed airtight bottles.
Can be neutralized with a solution of Fenton's reagent.