Phenyl Acetaldehyde Aroma Chemical
CAS# 122-78-1

Phenyl Acetaldehyde, also widely known as Hyacinthin, is an iconic material discovered in 1908 that opened a new era in recreating the scent of hyacinth flowers in the fragrance industry. Although it is nature-identical and has been found in chicory, the flowers of Lecythis usitata in Brazil, and rose, it is now produced mainly in synthetic form. It is typically synthesized through the vapor-phase isomerization of styrene oxide or from 1,2-phenylethane diol using an aluminum silicate catalyst. An interesting point is that this molecule has no isomeric forms used in perfumery.

Description

Because of its chemical tendency to polymerize very easily into a sticky resinous mass, Phenyl Acetaldehyde is commonly sold on the market in diluted form in Phenyl Ethyl Alcohol. This gives it a more honeyed nuance and reduces some of its original green character. Appearing as a clear to pale yellow liquid, the presence of the benzene ring makes the material prone to discoloration over time. It exudes a green, floral, sweet, and highly penetrating odor, functioning mainly from the top note into the heart note. With its extremely strong diffusion, it serves as a highly effective booster and modifier, often used in rose, citrus, and leather notes. It is also an important precursor for Schiff bases: when reacted with Methyl Anthranilate, it produces an accord with facets of melon, mandarin, and rose; and when reacted with methanol in acidic conditions, it can be converted into Viridine. In alcohol-based perfumes, it may form a diethyl acetal, though this does not negatively affect the olfactory quality. Due to its very powerful odor profile, perfumers generally need to dilute Phenyl Acetaldehyde in safe solvents at 50%, 10%, or 1% in order to control dosage more precisely.

Applications

In practical use, this material appears in a wide range of products, from fine fragrances and scented candles to skincare cosmetics. Under IFRA safety standards, Phenyl Acetaldehyde is strictly restricted because of its sensitization risk, with the maximum permitted level in perfume usually below 0.2%. Users should take special care to store it in a cool environment, with the container tightly closed and protected from direct light, in order to slow oxidation. Thanks to its ability to bring a realistic green-floral freshness, Phenyl Acetaldehyde has become a key soul of many classic perfumes, notably Cacharel Anaïs Anaïs and Guerlain Chamade.