4-Hydroxybenzoic acid

4-Hydroxybenzoic acid
Skeletal formula
Ball-and-stick model
Names
Preferred IUPAC name
4-Hydroxybenzoic acid
Other names
p-Hydroxybenzoic acid
para-Hydroxybenzoic acid
PHBA
4-hydroxybenzoate
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.002.550 Edit this at Wikidata
EC Number
  • 202-804-9
KEGG
UNII
  • InChI=1S/C7H6O3/c8-6-3-1-5(2-4-6)7(9)10/h1-4,8H,(H,9,10) checkY
    Key: FJKROLUGYXJWQN-UHFFFAOYSA-N checkY
  • InChI=1/C7H6O3/c8-6-3-1-5(2-4-6)7(9)10/h1-4,8H,(H,9,10)
    Key: FJKROLUGYXJWQN-UHFFFAOYAQ
  • O=C(O)c1ccc(O)cc1
  • c1cc(ccc1C(=O)O)O
Properties
C7H6O3
Molar mass 138.122 g·mol−1
Appearance White crystalline solid
Odor Odorless
Density 1.46 g/cm3
Melting point 214.5 °C (418.1 °F; 487.6 K)
Boiling point N/A, decomposes[1]
0.5 g/100 mL
Solubility
log P 1.58
Acidity (pKa) 4.54
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Irritant
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
0
0
250 °C (482 °F; 523 K)
Lethal dose or concentration (LD, LC):
2200 mg/kg (oral, mouse)
Safety data sheet (SDS) HMDB
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

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, and with 3-hydroxybenzoic acid.

  1. ^ "4-Hydroxybenzoic acid" (PDF). International Programme on Chemical Safety (IPCS). Archived from the original (PDF) on 24 September 2015. Retrieved 10 January 2015.