5-Methyl-2-phenyl-2-hexenal

What 5-Methyl-2-phenyl-2-hexenal smells like

JECFA, as published by PubChem, describes 5-methyl-2-phenyl-2-hexenal as a colourless to slightly yellow liquid with a cocoa-like aroma. Fraterworks, selling it as Cocoa Hexenal, describes a rich, bitter cocoa character with aldehydic sharpness, nutty brown facets and subtle green, vegetative notes, the backbone of chocolate accords where pyrazines alone fall short.

Leading note

Cocoa

• cocoa
• chocolate

What makes 5-Methyl-2-phenyl-2-hexenal distinctive

An aldehyde that smells of cocoa powder.

Concentration and dilution

Fraterworks sells it pure and at 10% in DPG and says its power demands restraint.

How 5-Methyl-2-phenyl-2-hexenal is used

Fraterworks uses it for chocolate and cocoa notes in gourmand fragrances and to add depth to oriental and amber compositions.

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

How 5-Methyl-2-phenyl-2-hexenal differs from similar materials

Chocovan

Chocovan is a full cocoa-and-vanilla base; this aldehyde is the dry cocoa-powder note on its own.

Each difference compares the published descriptions of the two materials. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.

Identity and classification

Type

Aroma chemical

Origin

Synthetic

Odour family

Gourmand

Note position

Heart note

Physical form at room temperature

Liquid

CAS number

21834-92-4

Molecular formula

C13H16O

Molecular weight

188.26 g/mol

IUPAC name

(E)-5-methyl-2-phenylhex-2-enal

The CAS number, formula and molecular weight are taken from PubChem compound 5370602, whose own record lists this CAS number; checked 24 October 2026.

Safety and compliance

Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. Companies notifying the ECHA C&L Inventory classify it (1,491 reports): H317 may cause an allergic skin reaction (97% 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

• Cacao Absolute

  Absolute · Gourmand — chocolate, cocoa, roasted, bitter

• Vanillin

  Aroma chemical · Gourmand / Amber — vanilla, sweet, creamy

• 2,3,5-Trimethylpyrazine

  Aroma chemical · Gourmand — roasted, nutty, cocoa, earthy

Used in formulas and accords

Used in 4 published formulas

5-Methyl-2-phenyl-2-hexenal is an ingredient in 2 perfume formulas and 2 accords in the Formula & Accord Library.

Community formulas

• Chocolate Accord

  Community Formula · Accord · listed as “5-Methyl-2-Phenyl-2-Hexenal (CAS: 21834-92-4)”

• Hazelnut Accord

  Community Formula · Accord · listed as “5 Methyl 2 Phenyl 2 Hexanal”

RUŌOD House Originals

Original compositions by RUŌOD House.

• Cardamom Crema

  RUŌOD House Original · listed as “5-Methyl-2-phenyl-2-hexenal 1% DPG”, at 1% in DPG

• Cocoa Moss

  RUŌOD House Original · listed as “5-Methyl-2-phenyl-2-hexenal 1% DPG”, at 1% in DPG

Further reading

• Building a Gourmand Accord: Vanilla, Caramel and Beyond

  The materials of gourmand perfume — vanillin, ethyl maltol, coumarin, lactones, roasted notes — how to keep them wearable, and color and crystal problems.

Questions about 5-Methyl-2-phenyl-2-hexenal

Sources

• PubChem — compound 5370602, checked 24 October 2026.
• PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
• PubChem — 5-Methyl-2-phenyl-2-hexenal (CID 5370602): JECFA organoleptic description — odour database.
• Fraterworks — Cocoa Hexenal — distributor's description.
• Olfactory profile: the RUŌOD Lab team's synthesis of the published descriptions above, reviewed 26 October 2026. Evidence: more than one published description. Classification and the short description: revision 1. Descriptions of odour are judgement, not measurement.