Octocrylene is an

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

used as an ingredient in

sunscreen Sunscreen, also known as sunblock, sun lotion or sun cream, is a photoprotection, photoprotective topical product for the Human skin, skin that helps protect against sunburn and prevent skin cancer. Sunscreens come as lotions, sprays, gels, fo ...

s and cosmetics. It is an

ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

formed by the

Knoevenagel condensation In organic chemistry, the Knoevenagel condensation () reaction is a type of chemical reaction named after German chemist Emil Knoevenagel. It is a modification of the aldol condensation. A Knoevenagel condensation is a nucleophilic addition o ...

of 2-ethylhexyl cyanoacetate with

benzophenone Benzophenone is a naturally occurring organic compound with the formula (C6H5)2CO, generally abbreviated Ph2CO. Benzophenone has been found in some fungi, fruits and plants, including grapes. It is a white solid with a low melting point and ros ...

. It is a viscous, oily liquid that is clear and colorless. The extended

conjugation Conjugation or conjugate may refer to: Linguistics *Grammatical conjugation, the modification of a verb from its basic form *Emotive conjugation or Russell's conjugation, the use of loaded language Mathematics *Complex conjugation, the change o ...

of the

acrylate Acrylates (IUPAC: prop-2-enoates) are the salts, esters, and conjugate bases of acrylic acid. The acrylate ion is the anion . Often, acrylate refers to esters of acrylic acid, the most common member being methyl acrylate. These acrylates contain ...

portion of the molecule absorbs UVB and short-wave UVA (

ultraviolet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...

) rays with wavelengths from 280 to 320 nm, protecting the skin from

direct DNA damage Direct may refer to: Mathematics * Directed set, in order theory * Direct limit of (pre), sheaves * Direct sum of modules, a construction in abstract algebra which combines several vector spaces Computing * Direct access (disambiguation), a ...

. The ethylhexanol portion is a

fatty alcohol Fatty alcohols (or long-chain alcohols) are usually high-molecular mass, straight-chain primary alcohols, but can also range from as few as 4–6 carbon atoms to as many as 22–26, derived from natural fats and oils. The precise chain length vari ...

, adding

emollient A moisturizer, or emollient, is a cosmetic preparation used for protecting, moisturizing, and lubricating the skin. These functions are normally performed by sebum produced by healthy skin. The word "emollient" is derived from the Latin verb ''mo ...

and oil-like (water resistant) properties.

Safety

Octocrylene can penetrate into the skin where it acts as a

photosensitizer Photosensitizers are light absorbers that alter the course of a photochemical reaction. They usually are catalysts. They can function by many mechanisms; sometimes they abstract an electron from the substrate, and sometimes they abstract a hydro ...

, resulting in an increased production of free radicals under illumination. It may also pass through the skin, into the blood stream, eventually being metabolized and excreted in urine in form of its metabolites. Octocrylene can convert to

through a retro-

aldol condensation An aldol condensation is a condensation reaction in organic chemistry in which two carbonyl moieties (of aldehydes or ketones) react to form a β-hydroxyaldehyde or β-hydroxyketone (an aldol reaction), and this is then followed by dehydration t ...

. The reaction occurs slowly over time, yielding significant concentration of benzophenone in all commercial cosmetics tested formulated with octocrylene. In coral, octocrylene has been shown to accumulate in the form of fatty acid conjugates and trigger mitochondrial dysfunction.

Regulation

Palau Palau, officially the Republic of Palau, is an island country in the Micronesia subregion of Oceania in the western Pacific Ocean. The Republic of Palau consists of approximately 340 islands and is the western part of the Caroline Islands ...

has banned the sale and use of three reef-toxic UV filters including octocrylene in its Responsible Tourism Education Act of 2018. The

United States Virgin Islands The United States Virgin Islands, officially the Virgin Islands of the United States, are a group of Caribbean islands and a territory of the United States. The islands are geographically part of the Virgin Islands archipelago and are located ...

has also banned the use of sunscreens containing octocrylene, requiring that all visitors use "non-nano mineral sunscreen" containing zinc oxide and titanium dioxide.

References

{{Sunscreening agents Cyanoacetate esters Household chemicals Sunscreening agents 2-Ethylhexyl esters