1-Penten-3-one (CAS 1629-58-9) — Green Top Note Fragrance Ingredient

ByThe Good Scents
Green · Sweet

1-Penten-3-one

CAS 1629-58-9

Origin
synthetic
Note
Top
IFRA
Use with awareness
Data as of: Apr 2026

What Is 1-Penten-3-one?

1-Penten-3-one is a synthetic fragrance ingredient primarily used in perfumery for its sharp, green character. It’s found in trace amounts in some modern fragrances. This molecule matters because it adds a crisp, vegetal edge to compositions, helping create fresh-cut grass or unripe fruit effects.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
✓ Used safely at low concentrations
⚠ Strong odor – requires careful dosing
CAS
1629-58-9
Formula
Mixture
MW
Variable
Odor Family
Green · Sweet
Layer 1 · Enthusiast

What Does 1-Penten-3-one Smell Like?

1-Penten-3-one delivers an intensely green, piercing aroma reminiscent of freshly crushed tomato leaves or cut green bell peppers. Its sharpness carries metallic undertones that evolve into a more vegetal heart. The dry-down reveals a faintly fatty, almost rubbery character that lingers subtly. Used above threshold, it can dominate compositions with its aggressive greenness.

Scent Profile
Layer 2

2D Molecular Structure

Ethyl vinyl ketone

SMILES: CCC(=O)C=C

Chemistry, Properties & Perfumer Guide

The Chemistry

1-Penten-3-one is an α,β-unsaturated ketone with the molecular formula C5H8O. It’s synthesized through aldol condensation reactions or oxidation of corresponding alcohols. The molecule’s reactivity comes from its conjugated double bond system, making it useful for further chemical modifications. Its simple structure belies a powerful odor impact.

Physical & Chemical Properties

Boiling PointNot available
DensityNot available

Perfumer Guide

Note Position
Top
Volatility
High (30-90 min)
Blending
Challenging
ApplicationTypical %RangeNotes
Fine Fragrance0.01-0.1%Up to 0.5%Used sparingly for green accents
Functional Fragrance0.001-0.01%Up to 0.05%Trace amounts for freshness

Classic Accords

Tip: Always pre-dilute to 1% or lower before blending due to intense odor impact.

Alternatives & Comparisons

1
Leaf Alcohol CAS 928-96-1

Milder green note without metallic sharpness

2
Stemone CAS 67634-15-5

Softer tomato leaf character with better blending

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

No IFRA restrictions currently apply.

RIFM Assessment

Not currently assessed by RIFM.

Sustainability

As a synthetic material, 1-Penten-3-one has minimal environmental impact in production. Its high potency means very small quantities are needed, reducing overall chemical usage. No natural sources are commercially viable for this molecule.

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References

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

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    Ingredient Data Sheet

    CAS 1629-58-9

    Physical Properties

    Molecular Weight84.12 g/mol🔬 PubChem
    LogP (Octanol-Water)1🔬 PubChem
    Boiling Point38 °C🔬 EPA CompTox
    Vapor Pressure21.8776 mmHg @ 25°C📊 OPERA
    Flash Point-10 °C🔬 EPA CompTox
    Involatility Index2.5709💻 Calculated
    log Kp (skin permeability)-2.503💻 Calculated
    SMILESCCC(=O)C=C🔬 PubChem

    Volatility & Performance

    Fragrance NoteTop💻 Calculated
    Volatility ClassFast💻 Calculated
    Persistence Score0.5 / 5💻 Calculated

    Odor & Flavor

    Primary Descriptorspungent• leffingwell
    Functional Groupsketonealkene💻 RDKit
    1-Penten-3-one has a powerful, penetrating odor. This compound is also reported as having a pungent, mustard odor. It polymerizes readily with heat or in the presence of alkali.📖 Fenaroli

    Sensory Thresholds

    Odor Detection Threshold0.0189 ppm (n=15)📖 van Gemert

    Regulatory Status

    IOFI ClassificationNature Identical📖 Fenaroli
    Data Sources & Attribution
    Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.

    Physicochemical Properties

    DTXSID: DTXSID5025318

    Physical Properties

    Molecular Weight 84.118 g/mol🔬 EPA CompTox
    Density 0.852 g/cm^3🔬 EPA CTX
    Boiling Point 103.25 °C🔬 EPA CTX
    Melting Point -63.082 °C📊 OPERA
    Flash Point -9.925 °C🔬 EPA CTX
    Refractive Index 1.399 Dimensionless📊 OPERA
    Molar Volume 103.283 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 0.945 Log10 unitless📊 OPERA
    LogD (pH 5.5) 0.945 Log10 unitless📊 OPERA
    LogD (pH 7.4) 0.945 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 3.27 Log10 unitless📊 OPERA
    Water Solubility 0.469 mol/L📊 OPERA
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 29.829 mmHg📊 OPERA
    Surface Tension 25.501 dyn/cm📊 OPERA

    Molecular Descriptors

    Topological Polar Surface Area 17.07 Ų💻 Computed
    H-Bond Donors 0 count💻 Computed
    H-Bond Acceptors 1 count💻 Computed
    Rotatable Bonds 2 count💻 Computed
    Aromatic Rings 0 count💻 Computed
    Molar Refractivity 24.968 cm^3/mol📊 OPERA
    Polarizability 9.898 Å^3📊 OPERA

    Data Sources:

    🔬 EPA Experimental data from U.S. EPA CompTox Chemicals Dashboard & CTX APIs. 📊 OPERA Predicted using EPA's OPERA QSAR models. 💻 Computed Calculated from SMILES using RDKit.

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