P-Hydroxybenzoic acid

4-Hydroxybenzoic acid

Names
IUPAC name 4-Hydroxybenzoic acid
Other names p-Hydroxybenzoic acid para-Hydroxybenzoic acid PHBA 4-hydroxybenzoate
Identifiers
CAS Number	99-96-7 Y
3D model (Jmol)	Interactive image Interactive image
ChEBI	CHEBI:30763 Y
ChemSpider	132 Y
DrugBank	DB04242 Y
ECHA InfoCard	100.002.550
EC Number	202-804-9
KEGG	C00156 Y
PubChem CID	135
InChI InChI=1S/C7H6O3/c8-6-3-1-5(2-4-6)7(9)10/h1-4,8H,(H,9,10) Y Key: FJKROLUGYXJWQN-UHFFFAOYSA-N Y InChI=1/C7H6O3/c8-6-3-1-5(2-4-6)7(9)10/h1-4,8H,(H,9,10) Key: FJKROLUGYXJWQN-UHFFFAOYAQ
SMILES O=C(O)c1ccc(O)cc1 c1cc(ccc1C(=O)O)O
Properties
Chemical formula	C7H6O3
Molar mass	138.121 g/mol
Appearance	white crystalline
Odor	odorless
Density	1.46 g/cm3
Melting point	214.5 °C (418.1 °F; 487.6 K)
Boiling point	n/a decomposes
Solubility in water	0.5 g/100 mL
Solubility	soluble in alcohol, ether, acetone slightly soluble in chloroform negligible in CS2
log P	1.58
Acidity (pKa)	4.54
Hazards
Main hazards	Irritant
Safety data sheet	HMDB
NFPA 704	0 2 0
Autoignition temperature	250 °C (482 °F; 523 K)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	2200 mg/kg (oral, mouse)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

4-Hydroxybenzoic acid, also known as p-hydroxybenzoic acid (PHBA), is a monohydroxybenzoic acid, a phenolic derivative of benzoic acid. It is a white crystalline solid that is slightly soluble in water and chloroform but more soluble in polar organic solvents such as alcohols and acetone. 4-Hydroxybenzoic acid is primarily known as the basis for the preparation of its esters, known as parabens, which are used as preservatives in cosmetics and some ophthalmic solutions. It is isomeric with 2-hydroxybenzoic acid, known as salicylic acid, a precursor to aspirin.

It is found in plants of the genus Vitex such as V. agnus-castus or V. negundo, and in Hypericum perforatum (St John's wort). It is also found in Spongiochloris spongiosa, a freshwater green alga.

The compound is also found in Ganoderma lucidum, a medicinal mushroom with the longest record of use.

Cryptanaerobacter phenolicus is a bacterium species that produces benzoate from phenol via 4-hydroxybenzoate.

4-Hydroxybenzoic acid can be found naturally in Cocos nucifera. It is one of the main catechins metabolites found in humans after consumption of green tea infusions. It is also found in wine, in vanilla, in Macrotyloma uniflorum (horse gram) and in Phyllanthus acidus (Otaheite gooseberry).