2-Hexenoic acid, 2-methyl-, methyl ester, (2E)- (CAS 16493-96-2) — Green Top Note Fragrance Ingredient

Green · Sweet

2-Hexenoic acid, 2-methyl-, methyl ester, (2E)-

CAS 16493-96-2

Origin
synthetic
Note
Top
IFRA
Generally safe
Data as of: Apr 2026

What Is 2-Hexenoic acid, 2-methyl-, methyl ester, (2E)-?

2-Hexenoic acid, 2-methyl-, methyl ester is a synthetic fragrance ingredient with a fruity, green aroma. It’s used in perfumes and personal care products to add fresh, slightly tart nuances. This ester provides a crisp top note that enhances fruity and floral compositions, making it valuable for creating modern, vibrant scents.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
No major safety concerns at typical usage levels
Limited toxicology data – use standard precautions
CAS
16493-96-2
Formula
Mixture
MW
Variable
Odor Family
Green · Sweet
Layer 1 · Enthusiast

What Does 2-Hexenoic acid, 2-methyl-, methyl ester, (2E)- Smell Like?

A bright, green-fruity ester with a tart apple-like freshness that evolves into a softer, slightly woody dry-down. The opening is reminiscent of unripe berries with a crisp, slightly acidic edge, while the heart reveals a delicate floralcy akin to apple blossoms. As it settles, the scent becomes more rounded with subtle musky undertones that prevent it from being overly sharp. The overall effect is like biting into a just-picked green apple with the faintest hint of tropical fruit in the background.

Scent Profile
Layer 2

Chemistry, Properties & Perfumer Guide

The Chemistry

This methyl ester belongs to the α,β-unsaturated ester class, synthesized through esterification of 2-methyl-2-hexenoic acid. The (2E)-configuration gives it specific stereochemical properties that influence both its odor profile and reactivity. Industrial production typically involves acid-catalyzed reactions of the corresponding carboxylic acid with methanol. The double bond in the 2-position contributes to its fresh, green character while making it somewhat reactive to oxidation.

Physical & Chemical Properties

AppearanceColorless to pale yellow liquid
Boiling PointEstimated 180-190°C
DensityApprox. 0.89-0.92 g/cm³

Perfumer Guide

Note Position
Top
Volatility
Medium (1-3 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.5-2%Up to 5%Fresh top note modifier
Personal Care0.1-0.5%Up to 1%Fruity accent
Household Products0.05-0.2%Up to 0.5%Green freshness booster

Classic Accords

Tip: Stabilize with antioxidants to prevent oxidative degradation of the double bond.

Alternatives & Comparisons

1
Methyl 2-methylbutyrate CAS 868-57-5

For a more straightforward fruity effect without green nuances.

2
Methyl 2-octenoate CAS 7367-81-9

When a longer-lasting, more tropical fruit character is desired.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

General reference only. Consult current IFRA Standards Library before formulating.

IFRA Status

Not currently restricted by IFRA standards.

RIFM Assessment

No comprehensive RIFM assessment available as of current data.

Sustainability

As a synthetic material, this ester avoids agricultural land use but depends on petrochemical feedstocks. Production likely involves standard esterification processes with moderate energy requirements. No known environmental persistence or bioaccumulation concerns have been identified for this specific compound.

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References

    Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.

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