4-Methyl-3-penten-2-one (CAS 141-79-7) — Citrus Top Note Fragrance Ingredient

ByThe Good Scents
Citrus · Green

4-Methyl-3-penten-2-one

CAS 141-79-7

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

What Is 4-Methyl-3-penten-2-one?

4-Methyl-3-penten-2-one is a synthetic ketone used in fragrances to add fruity, woody, and slightly spicy nuances. It’s found in perfumes, air fresheners, and some cleaning products. This ingredient matters because it contributes to fresh, modern scent profiles, often enhancing citrus or green accords with its sharp yet pleasant character.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
✓ Safe in regulated concentrations
⚠ Moderate skin sensitivity potential
CAS
141-79-7
Formula
Mixture
MW
Variable
Odor Family
Citrus · Green
Layer 1 · Enthusiast

What Does 4-Methyl-3-penten-2-one Smell Like?

4-Methyl-3-penten-2-one opens with a sharp, fruity burst reminiscent of unripe apples and green bananas. The heart reveals a woody undertone with hints of acetone-like sharpness, settling into a dry, slightly spicy base. Its evolution is linear but persistent, adding a crisp freshness that blends well with citrus and herbal notes.

Scent Profile

In Famous Fragrances

Fragrance associations may not reflect actual formulations.

Eau Dynamisante(Clarins, 1987)

Used here to enhance the citrus-green accord, providing a crisp, invigorating top note that complements the herbal heart.

Layer 2

2D Molecular Structure

4-Methylpent-3-en-2-one

SMILES: CC(C)=CC(C)=O

Chemistry, Properties & Perfumer Guide

The Chemistry

4-Methyl-3-penten-2-one is a simple unsaturated ketone, part of the methylpentenone family. It is synthesized via aldol condensation of acetone or through oxidation of terpenes. Its structure allows for moderate volatility, making it useful in top notes. No chirality is present due to its symmetrical structure.

Physical & Chemical Properties

Boiling Point130-132 °C
Density0.865 g/cm³

Perfumer Guide

Note Position
Top
Volatility
Medium (30-90 min)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.5-2%Up to 5%Adds crispness to citrus accords
Functional Fragrance1-3%Up to 8%Enhances fresh cleaning product scents

Classic Accords

Tip: Use sparingly to avoid overpowering other top notes.

Alternatives & Comparisons

1
Mesitylene CAS 108-67-8

A less sharp alternative with similar fruity-woody characteristics, used when milder effects are desired.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

No IFRA restrictions currently apply.

EU Allergen Declaration

Not listed as an EU allergen.

GHS Classification

H315 Skin irritation H319 Eye irritation

RIFM Assessment

RIFM assessment confirms safe use at current industry levels.

Sustainability

Synthesized from petrochemical precursors, this molecule has a moderate environmental footprint. Efforts to derive it from bio-based acetone could improve sustainability.

Explore 4-Methyl-3-penten-2-one

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References

  1. PubChem: 4-Methyl-3-penten-2-one PubChem CID

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

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Ingredient Data Sheet

CAS 141-79-7

Physical Properties

Molecular Weight98.14 g/mol🔬 PubChem
LogP (Octanol-Water)1.4🔬 PubChem
Boiling Point130 °C🔬 EPA CompTox
Vapor Pressure9 mmHg @ 25°C📊 OPERA
Flash Point22.8 °C🔬 EPA CompTox
Involatility Index0.9791💻 Calculated
log Kp (skin permeability)-2.305💻 Calculated
SMILESCC(=CC(=O)C)C🔬 PubChem

Volatility & Performance

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

Odor & Flavor

Primary Descriptorshoneyminty• leffingwell
Functional Groupsketonealkene💻 RDKit
“However, the pure material has a fairly pleasant odor, almost honey-like in dilution - reminiscent of iso-Phorol and iso-Phorone, and one can observe a breadlike sweetness in this volatile fragrance.”📖 Arctander
The commercial grade of 4-methyl-3-penten-2-one exhibits an unpleasant odor. The pure material has a pleasant, honey-like odor.📖 Fenaroli

Sensory Thresholds

Odor Detection Threshold3.7947 ppm (n=2)📖 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: DTXSID1029170

Physical Properties

Molecular Weight 98.145 g/mol🔬 EPA CompTox
Density 0.858 g/cm^3🔬 EPA CTX
Boiling Point 130.519 °C🔬 EPA CTX
Melting Point -52.263 °C🔬 EPA CTX
Flash Point 28.253 °C🔬 EPA CTX
Refractive Index 1.418 Dimensionless📊 OPERA
Molar Volume 118.112 cm^3/mol📊 OPERA

Partition & Solubility

LogP (Octanol-Water) 1.7 Log10 unitless🔬 EPA CTX
LogD (pH 5.5) 1.212 Log10 unitless📊 OPERA
LogD (pH 7.4) 1.212 Log10 unitless📊 OPERA
LogKoa (Octanol-Air) 3.36 Log10 unitless📊 OPERA
Water Solubility 0.292 mol/L🔬 EPA CTX
Henry's Law Constant 0 atm-m3/mole🔬 EPA CTX

Transport Properties

Vapor Pressure 9.416 mmHg🔬 EPA CTX
Surface Tension 23.238 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 1 count💻 Computed
Aromatic Rings 0 count💻 Computed
Molar Refractivity 29.776 cm^3/mol📊 OPERA
Polarizability 11.804 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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