Phenylacetaldehyde

What Phenylacetaldehyde smells like

Phenylacetaldehyde is a very strong, green-floral aldehyde with a honeyed sweetness and a hyacinth character. Symrise describes it as very strong, green, floral, sweet and hyacinth-type; other data sheets give green, sweet, floral-honey, with harsh hyacinth notes on dilution. Neat it is harsh and green, and it oxidises and polymerises readily, so it is usually supplied stabilised or diluted. Sigma-Aldrich's broader flavour profile adds honey, chocolate, cherry and wine-like notes.

Leading note

Green hyacinth

Clear facets

Honey

Supporting facets

Sweet floral

Faint facets

Rose, bitter almond

Character

Green, sharp, sweet, powerful

• green
• honeyed
• hyacinth
• floral

What makes Phenylacetaldehyde distinctive

Hyacinth with honey. Several materials give a green hyacinth; phenylacetaldehyde adds a distinct honeyed sweetness, and it is the harshest and most powerful of the family's aldehydes.

Concentration and dilution

Harsh and green neat; its hyacinth character is described as appearing on dilution.

How Phenylacetaldehyde is used

Used in small amounts to brighten and sharpen floral accords — rose, hyacinth and lilac — and to add a soft honey effect. It needs restraint, and its instability means stabilised or diluted grades are the norm.

Typical role: modifier (used in small amounts to change the character of a blend).

How Phenylacetaldehyde differs from similar materials

Phenylacetaldehyde Dimethyl Acetal*

The dimethyl acetal is described as less pungent, without the aldehyde's bitter-almond note, and more stable; it adds an earthy, mushroom-like nuance. (compared directly by a cited source)

Hydratropic Aldehyde

Hydratropic aldehyde is fresh, leafy and tart, a lilac-hyacinth green; phenylacetaldehyde is sweeter and honeyed.

Trifernal

Trifernal is a bitter, crushed-foliage green with grass and tomato-leaf notes; phenylacetaldehyde is a sweet, honeyed hyacinth.

p-Tolylacetaldehyde

p-Tolylacetaldehyde (lilac acetaldehyde) is described as green-fruity, forest-like and sweeter.

An asterisk marks a difference that a cited source states directly. The others compare the published descriptions of each material. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.

Formulation considerations

Unstable and prone to polymerisation; often supplied diluted. Covered by an IFRA Standard.

Identity and classification

Type

Aroma chemical

Origin

Occurs in nature

Odour family

Green / Floral

Note position

Top to heart note

Physical form at room temperature

Liquid

CAS number

122-78-1

Molecular formula

C8H8O

Molecular weight

120.15 g/mol

IUPAC name

2-phenylacetaldehyde

The CAS number, formula and molecular weight are taken from PubChem compound 998, whose own record lists this CAS number; checked 19 October 2026.

Safety and compliance

The IFRA Standards Library lists a Standard covering Phenylacetaldehyde:

• "Phenylacetaldehyde" — Restriction, 49th Amendment, published 2020-01

Limits differ by product category and are set out in the Standard itself; this page does not reproduce them. The list above reflects the library as read on 19 October 2026.

Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. Companies notifying the ECHA C&L Inventory classify it (1,836 reports): H302 harmful if swallowed (99.8% of reports); H317 may cause an allergic skin reaction (96.8% of reports); H314 causes severe skin burns and eye damage (80% of reports); H318 causes serious eye damage (78.6% of reports). A skin sensitiser classification concerns handling the neat material and the dose in a finished product; the IFRA Standards, where they apply, set the limits. Unless it is harmonised, this is the notifiers' own classification, not a binding one.

This page is general information, not a safety assessment or a specification. Confirm identity, composition, IFRA status and allergen content from your supplier's documents for the lot you hold.

Materials it works with

• Phenylacetaldehyde Dimethyl Acetal

  Aroma chemical · Green / Floral — green, hyacinth, earthy, floral

• Cinnamyl Alcohol

  Aroma chemical · Floral / Spicy — balsamic, floral, hyacinth, sweet

• Phenylethyl Alcohol

  Aroma chemical · Floral / Green — rose, honeyed, soft, floral

• Hydrocinnamaldehyde

  Aroma chemical · Floral / Green — hyacinth, green, balsamic, floral

Phenylacetaldehyde is also suggested as a partner on the pages for alpha-Terpineol, Anther, Hydratropic Aldehyde, p-Tolylacetaldehyde, Styrallyl Alcohol and Trifernal.

Used in formulas and accords

Used in 8 published formulas

Phenylacetaldehyde is an ingredient in 1 perfume formula and 7 accords in the Formula & Accord Library.

Community formulas

• Gardenia Accord

  Community Formula · Accord · listed as “Phenyl Acetaldehyde 50%”, at 50%

• Mimosa Accord

  Community Formula · Accord · listed as “Phenyl Acetaldehyde”

• Peony Accord

  Community Formula · Accord · listed as “Phenyl Acetaldehyde 50%”, at 50%

• Plumeria Accord

  Community Formula · Accord · listed as “Phenyl Acetaldehyde”

• Tamarind Accord

  Community Formula · Accord · listed as “Phenyl Acetaldehyde 50%”, at 50%

• White Lily Accord

  Community Formula · Accord · listed as “Phenyl Acetaldehyde”

• Wisteria Accord

  Community Formula · Accord · listed as “Phenyl Acetaldehyde”

RUŌOD House Originals

Original compositions by RUŌOD House.

• Galbanum Courtyard

  RUŌOD House Original · listed as “Phenylacetaldehyde 10% DPG”, at 10% in DPG

Further reading

• How to Build a Honey Accord

  A honey accord from phenylacetic acid and its esters: the building blocks, beeswax and honey absolutes, an illustrative vegan version, handling and records.

• Green Notes in Perfumery: Leaf, Galbanum and Violet Leaf

  The green palette — cis-3-hexenol, galbanum, violet leaf, styrallyl acetate — what green notes do, dosage, restrictions and pairings.

Questions about Phenylacetaldehyde

Sources

• PubChem — compound 998, checked 19 October 2026.
• PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
• IFRA — Standards Library, read 19 October 2026.
• The Good Scents Company — phenylacetaldehyde (with Symrise's description) — odour database.
• ChemicalBook — phenylacetaldehyde (CAS 122-78-1) — odour database.
• Fraterworks — phenyl acetic aldehyde — distributor's description.
• Olfactory profile: the RUŌOD Lab team's synthesis of the published descriptions above, reviewed 24 October 2026. Evidence: several independent published descriptions, which agree. Classification and the short description: revision 1. Descriptions of odour are judgement, not measurement.