- PHBS, 4HBA, p- OHB
- Para- hydroxybenzoic acid
- P- salicylic acid
- P- oxy-benzoic acid
Colorless and odorless, combustible solid
1.46 g · cm -3
213-215 ° C
- PKS1 = 4.61
- PKa2 = 9.3
- Poorly in water (5 g · l-1 at 20 ° C)
- Insoluble in ethanol, ether and acetone
- Poorly soluble in chloroform
- > 5000 mg · kg -1 ( LD50, rat, oral)
- 2200 mg · kg -1 ( LD50, mouse, oral)
Template: Infobox chemical / molecular formula search available
4-hydroxybenzoic acid is a chemical compound selected from the group consisting of hydroxybenzoic acids. It is a degradation product, and an intermediate in the metabolism of the quinones in eukaryotes.
4-hydroxybenzoic acid is commercially produced from potassium phenolate and carbon dioxide in a Kolbe-Schmitt reaction.
In the laboratory, the preparation of potassium salicylate by heating with potassium carbonate to 240 ° C, followed by treatment with acid ( hydrochloric acid).
4-hydroxybenzoic acid formed from several materials: in plants from its adduct with coenzyme A, itself a result of 4- coumaroyl -CoA; in bacteria in the oxidation of benzoic acid ( EC 184.108.40.206 ), or in the degradation of chorismic acid ( EC 220.127.116.11 ), 4- methoxybenzoic acid ( EC 18.104.22.168 ), 4- hydroxybenzaldehyde ( EC 22.214.171.124 ) or 4 -chlorobenzoic acid ( EC 126.96.36.199 ). Furthermore, it may be oxidized decarboxylated to phenol or 3,4- dihydroxybenzoic acid. In the biosynthesis of ubiquinone, it is linked to a Polyprenylrest.
The aqueous solution of 4- hydroxybenzoic acid reaction ( pH 3.3 at a measurement temperature of 20 ° C and a concentration of 1 g / l).
4- hydroxybenzoic acid is technically mainly used for the production of its esters, the parabens.
The effects of 4- hydroxybenzoic acid on human health and the environment are tested under REACH in 2014 under substance evaluation of the Czech Republic.