Phenoxyethanol
Phenoxyethanol is the organic compound with the formula C6H5OC2H4OH. It is a colorless oily liquid. It can be classified as a glycol ether and a phenol ether. It is a common preservative in vaccine formulations.[1] It has a faint rose-like aroma.[2]
Use
Phenoxyethanol has germicidal and germistatic properties.[3] It is often used together with quaternary ammonium compounds.
Phenoxyethanol is used as a perfume fixative; an insect repellent; an antiseptic;[4] a solvent for cellulose acetate, dyes, inks, and resins; a preservative for pharmaceuticals, cosmetics and lubricants;[5] an anesthetic in fish aquaculture;[6][7] and in organic synthesis.
It is an alternative to formaldehyde-releasing preservatives.[8] In Japan and the European Union, its concentration in cosmetics is restricted to 1%.[9]
History and synthesis
Phenoxyethanol was first prepared by W. H. Perkin Jr. and his graduate student Edward Haworth in 1896.[10] They reacted sodium, phenol and 2-chloroethanol in anhydrous ethanol.[11] Starting from the 1920s, it has been commercially available as a cellulose acetate solvent under the trademark of "Phenyl cellosolve".[12]
The compound is produced in the industry by the hydroxyethylation of phenol (Williamson synthesis), for example, in the presence of alkali-metal hydroxides or alkali-metal borohydrides.[13]
Efficacy
Phenoxyethanol is effective against gram-negative and gram-positive bacteria, and the yeast Candida albicans.[14]
| Aromatic alcohol | Concentration (%) | Contact time (minutes) | |||
|---|---|---|---|---|---|
| Escherichia coli | Pseudomonas aeruginosa | Proteus mirabilis | Staphylococcus aureus | ||
| Benzyl alcohol | 1 | >30 | >30 | >30 | >30 |
| Phenethyl alcohol | 1.25 | 2.5 | 2.5 | 2.5 | >30 |
| 2.5 | 2.5 | 2.5 | 2.5 | 5 | |
| Phenoxyethanol | 1.25 | 15 | 2.5 | 2.5 | >30 |
| 2.5 | 2.5 | 2.5 | 2.5 | >30 | |
Safety
Phenoxyethanol is a vaccine preservative and potential allergen, which may result in a nodular reaction at the site of injection. Possible symptoms include rashes, eczema, and possible death.[15] It reversibly inhibits NMDAR-mediated ion currents.[16]
Environmental considerations
In view of phenoxyethanol's widespread use, its biodegradation has been examined. One pathway entails initial conversion to phenol and acetaldehyde.[17]
References
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