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Oxybenzone

Oxybenzone
Oxybenzone
Names
IUPAC name
(2-Hydroxy-4-methoxyphenyl)-phenylmethanone
Other names
Oxybenzone
Benzophenone-3
2-Hydroxy-4-methoxybenzophenone
Identifiers
131-57-7 YesY
3D model (Jmol) Interactive image
ChEBI CHEBI:34283 N
ChEMBL ChEMBL1625 YesY
ChemSpider 4471 YesY
DrugBank DB01428 N
ECHA InfoCard 100.004.575
KEGG D05309 YesY
PubChem 4632
UNII 95OOS7VE0Y YesY
Properties
C14H12O3
Molar mass 228.25 g·mol−1
Density 1.20 g cm−3
Melting point 62 to 65 °C (144 to 149 °F; 335 to 338 K)
Boiling point 224 to 227 °C (435 to 441 °F; 497 to 500 K)
Acidity (pKa) 7.6 (H2O)
Hazards
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 140.5 °C (284.9 °F; 413.6 K)
Lethal dose or concentration (LD, LC):
LD50 (median dose)
>12800 mg/kg (oral in rats)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YesYN ?)
Infobox references

Oxybenzone or benzophenone-3 (trade names Milestab 9, Eusolex 4360, Escalol 567, KAHSCREEN BZ-3) is an organic compound. It is a pale-yellow solid that is readily soluble in most organic solvents. Oxybenzone belongs to the class of aromatic ketones known as benzophenones. It is a component of many sunscreen lotions.

Being a conjugated molecule, oxybenzone absorbs at lower energies than many aromatic molecules. As in related compounds, the hydroxyl group is hydrogen bonded to the ketone. This interaction contributes to oxybenzone's light-absorption properties. At low temperatures, however, it is possible to observe both the phosphorescence and the triplet-triplet absorption spectrum. At 175 K the triplet lifetime is 24 ns. The short lifetime has been attributed to a fast intramolecular hydrogen transfer between the oxygen of the C=O and the OH.

Oxybenzone is produced by Friedel-Crafts reaction of benzoyl chloride with 3-methoxyphenol(3-hydroxyanisole).

Oxybenzone is used in plastics as an ultraviolet light absorber and stabilizer. It is used, along with other benzophenones, in sunscreens, hair sprays, and cosmetics because they help prevent potential damage from sunlight exposure. It is also found, in concentrations up to 1%, in nail polishes. Oxybenzone can also be used as a photostabilizer for synthetic resins. Benzophenones can leach from food packaging, and are widely used as photo-initiators to activate a chemical that dries ink faster.

As a sunscreen, it provides broad-spectrum ultraviolet coverage, including UVB and short-wave UVA rays. As a photoprotective agent, it has an absorption profile spanning from 270 to 350 nm with absorption peaks at 288 and 350 nm. It is one of the most widely used organic UVA filters in sunscreens today. It is also found in nail polish, fragrances, hairspray, and cosmetics as a photostabilizer. Despite its photoprotective qualities, much controversy surrounds oxybenzone because of its possible hormonal and photoallergenic effects, leading many countries to regulate its use.


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