4-Hydroxybenzoic acid

4-Hydroxybenzoic acid
4-Hydroxybenzoic acid
Identifiers
CAS number 99-96-7 YesY
PubChem 135
ChemSpider 132 YesY
DrugBank DB04242
KEGG C00156 YesY
ChEBI CHEBI:30763 YesY
ChEMBL CHEMBL441343 YesY
Jmol-3D images Image 1
Image 2
Properties
Molecular formula C7H6O3
Molar mass 138.12 g/mol
Density 1.46 g/cm³
Melting point

214-217 °C

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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

4-Hydroxybenzoic acid 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. It is isomeric with 2-hydroxybenzoic acid, known as salicylic acid, a precursor to aspirin.

Contents

Natural occurrence

4-Hydroxybenzoic acid can be found naturally in Cocos nucifera[1]. It is one of the main catechins metabolites found in humans after consumption of green tea infusions.[2]

Açaí oil, obtained from the fruit of the açaí Palm (Euterpe oleracea), is rich in p-hydroxybenzoic acid (892 ± 52 mg/kg), protocatechuic acid (630 ± 36 mg/kg) and ferulic acid (101 ± 5.9 mg/kg).[3]

Chemical production

4-Hydroxybenzoic acid is produced commercially from potassium phenoxide and carbon dioxide in the Kolbe-Schmitt reaction.[4]

4-Hydroxybenzoic acid can also be produced in the laboratory by heating potassium salicylate with potassium carbonate to 240 °C, followed by treating with acid.[5]

Chemical reactions

It is about 10x less acidic than benzoic acid, Ka = 3.3 x 10−5 M at 19 °C:

HOC6H4CO2H \overrightarrow{\leftarrow} HOC6H4CO2 + H+

Safety

4-Hydroxybenzoic acid is popular antioxidant in part because of its low toxicity. The LD50 is 2200 mg/kg in mice (oral).

References

  1. ^ Profiling C6–C3 and C6–C1 phenolic metabolites in Cocos nucifera. Gargi Dey, Moumita Chakraborty and Adinpunya Mitra, Journal of Plant Physiology, Volume 162, Issue 4, 22 April 2005, Pages 375-381 doi:10.1016/j.jplph.2004.08.006
  2. ^ Catechin metabolites after intake of green tea infusions. P. G. Pietta, P. Simonetti, C. Gardana, A. Brusamolino, P. Morazzoni and E. Bombardelli, BioFactors, 1998, Volume 8, Issue 1-2, pp. 111–118, doi:10.1002/biof.5520080119
  3. ^ Pacheco-Palencia LA, Mertens-Talcott S, Talcott ST (Jun 2008). "Chemical composition, antioxidant properties, and thermal stability of a phytochemical enriched oil from Acai (Euterpe oleracea Mart.)". J Agric Food Chem 25 (56): 4631–6. doi:10.1021/jf800161u. PMID 18522407. 
  4. ^ Edwin Ritzer and Rudolf Sundermann “Hydroxycarboxylic Acids, Aromatic” in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi: 10.1002/14356007.a13_519
  5. ^ C. A. Buehler and W. E. Cate (1943), "p-Hydroxybenzoic acid", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV2P0341 ; Coll. Vol. 2: 341 

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Look at other dictionaries:

  • Hydroxybenzoic acid — may refer to any of three isomeric chemical compounds:* Salicylic acid (2 hydroxybenzoic acid, o hydroxybenzoic acid) * 3 Hydroxybenzoic acid ( m hydroxybenzoic acid) * p Hydroxybenzoic acid (4 hydroxybenzoic acid) …   Wikipedia

  • hydroxybenzoic acid — noun a crystalline derivative of benzoic acid • Hypernyms: ↑hydroxy acid * * * (|)hī|dräksē+... noun Etymology: hydroxybenzoic International Scientific Vocabulary hydroxy + benzoic : any of three crystalline monohydroxy derivatives HOC6H4COOH of… …   Useful english dictionary

  • 3-Hydroxybenzoic acid — IUPAC name 3 Hydroxybenzoic acid …   Wikipedia

  • p-hydroxybenzoic acid — noun see hydroxybenzoic acid …   Useful english dictionary

  • para-hydroxybenzoic acid — noun see hydroxybenzoic acid …   Useful english dictionary

  • hydroxybenzoic acid — hy·droxy·ben·zo·ic acid ben .zō ik n any of three crystalline derivatives C7H6O3 of benzoic acid that contain one hydroxyl group per molecule: as a) the colorless para substituted acid used in making several of its esters that are effective… …   Medical dictionary

  • hydroxybenzoic acid — noun Any of three isomeric phenolic derivatives of benzoic acid …   Wiktionary

  • 2-hydroxybenzoic acid — noun a white crystalline substance with a bitter aftertaste; used as a fungicide or in making aspirin or dyes or perfumes • Syn: ↑salicylic acid • Hypernyms: ↑hydroxy acid • Substance Holonyms: ↑aspirin, ↑acetylsalicylic acid, ↑ …   Useful english dictionary

  • hydroxybenzoic — Salicylic Sal i*cyl ic, a. (Chem.) Pertaining to, derived from, or designating, an acid formerly obtained by fusing salicin with potassium hydroxide, and now made in large quantities from phenol (carbolic acid) by the action of carbon dioxide on… …   The Collaborative International Dictionary of English

  • hydroxybenzoic — adjective Of or pertaining to hydroxybenzoic acid or its derivatives …   Wiktionary

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