2-Methyl-3-buten-2-ol (CAS 115-18-4) — Green Top Note Fragrance Ingredient

Green · Citrus

2-Methyl-3-buten-2-ol

CAS 115-18-4

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

What Is 2-Methyl-3-buten-2-ol?

2-Methyl-3-buten-2-ol is a synthetic fragrance ingredient used in modern perfumery. It’s found in fresh, green, and citrusy fragrances. This molecule contributes to the crisp, uplifting character of many contemporary scents.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
No major safety concerns
Limited toxicity data available
CAS
115-18-4
Formula
Mixture
MW
Variable
Odor Family
Green · Citrus
Layer 1 · Enthusiast

What Does 2-Methyl-3-buten-2-ol Smell Like?

2-Methyl-3-buten-2-ol presents a fresh, green, slightly citrusy aroma with subtle woody undertones. It evolves quickly on the skin, starting with a crisp, almost effervescent top note reminiscent of crushed leaves and unripe citrus peel. The heart reveals a cleaner, more transparent character with hints of wet stones and freshly cut stems. The dry-down is minimal but leaves a faint, pleasant green-woody trace that blends well with other materials.

Scent Profile

In Famous Fragrances

Fragrance associations may not reflect actual formulations.

Layer 2

2D Molecular Structure

2-Methyl-3-buten-2-ol

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

Chemistry, Properties & Perfumer Guide

The Chemistry

2-Methyl-3-buten-2-ol is a simple unsaturated alcohol with molecular formula C5H10O. It’s typically synthesized through hydration of isoprene derivatives or selective oxidation of terpene precursors. The molecule’s reactivity makes it useful as a building block for more complex fragrance compounds. Its volatility contributes to its role as a top note in fragrance compositions.

Physical & Chemical Properties

Perfumer Guide

Note Position
Top
Volatility
High (15-30 min)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.5-2%Up to 5%Fresh top note component
Functional Fragrance0.1-1%Up to 3%Green freshness booster

Classic Accords

+ Citronellol + Galaxolide = Modern Fresh + Hedione + Calone = Aquatic Green

Tip: Use to add transparent green freshness without overwhelming citrus character.

Alternatives & Comparisons

1
Prenol CAS 556-82-1

Similar green character but with more pronounced citrus notes and better stability.

2
Leaf Alcohol CAS 928-96-1

For stronger green, grassy notes when more natural 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

Limited safety assessment available from RIFM.

Sustainability

As a synthetic material, 2-Methyl-3-buten-2-ol has minimal environmental impact in production. Its efficient synthesis from petrochemical precursors makes it a sustainable choice compared to some natural alternatives that require extensive agricultural resources.

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References

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

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    Physicochemical Properties

    DTXSID: DTXSID3047471

    Physical Properties

    Molecular Weight 86.134 g/mol🔬 EPA CompTox
    Density 0.817 g/cm^3🔬 EPA CTX
    Boiling Point 97.78 °C🔬 EPA CTX
    Melting Point -29.444 °C🔬 EPA CTX
    Flash Point 12.497 °C🔬 EPA CTX
    Refractive Index 1.424 Dimensionless📊 OPERA
    Molar Volume 103.717 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 0.66 Log10 unitless🔬 EPA CTX
    LogD (pH 5.5) 0.863 Log10 unitless📊 OPERA
    LogD (pH 7.4) 0.863 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 4.04 Log10 unitless📊 OPERA
    Water Solubility 4.576 mol/L🔬 EPA CTX
    Henry's Law Constant 0 atm-m3/mole🔬 EPA CTX

    Transport Properties

    Vapor Pressure 21.488 mmHg🔬 EPA CTX
    Viscosity 2.568 cP📊 OPERA
    Surface Tension 24.407 dyn/cm📊 OPERA
    Thermal Conductivity 143.449 mW/(m*K)📊 OPERA

    Molecular Descriptors

    Topological Polar Surface Area 20.23 Ų💻 Computed
    H-Bond Donors 1 count💻 Computed
    H-Bond Acceptors 1 count💻 Computed
    Rotatable Bonds 1 count💻 Computed
    Aromatic Rings 0 count💻 Computed
    Molar Refractivity 26.439 cm^3/mol📊 OPERA
    Polarizability 10.481 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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