Oxybenzone

Oxybenzone

Names
IUPAC name (2-Hydroxy-4-methoxyphenyl)-phenylmethanone
Other names Oxybenzone Benzophenone-3 2-Hydroxy-4-methoxybenzophenone
Identifiers
CAS Number	131-57-7 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:34283 N
ChEMBL	ChEMBL1625 Y
ChemSpider	4471 Y
DrugBank	DB01428 N
ECHA InfoCard	100.004.575
KEGG	D05309 Y
PubChem	4632
UNII	95OOS7VE0Y Y
InChI InChI=1S/C14H12O3/c1-17-11-7-8-12(13(15)9-11)14(16)10-5-3-2-4-6-10/h2-9,15H,1H3 Y Key: DXGLGDHPHMLXJC-UHFFFAOYSA-N Y InChI=1/C14H12O3/c1-17-11-7-8-12(13(15)9-11)14(16)10-5-3-2-4-6-10/h2-9,15H,1H3 Key: DXGLGDHPHMLXJC-UHFFFAOYAX
SMILES O=C(c1ccc(OC)cc1O)c2ccccc2
Properties
Chemical formula	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	1 1 0
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 YN ?)
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.