4-Allylphenol (CAS 501-92-8) — Green Middle Note Fragrance Ingredient

ByThe Good Scents
Green · Woody

4-Allylphenol

CAS 501-92-8

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

What Is 4-Allylphenol?

4-Allylphenol is a synthetic fragrance ingredient used in niche perfumery. It’s not commonly encountered in everyday products but appears in some avant-garde fragrances. This molecule matters because it offers perfumers a unique phenolic character that bridges herbal and smoky accords.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
✓ Used in fragrance formulations
⚠ Limited safety data available
CAS
501-92-8
Formula
Mixture
MW
Variable
Odor Family
Green · Woody
Layer 1 · Enthusiast

What Does 4-Allylphenol Smell Like?

4-Allylphenol presents a sharp phenolic character reminiscent of medicinal tinctures, evolving into a dry herbal smokiness. The initial punch suggests iodine and bandages, softening into an intriguing bitter-green heart. In drydown, it leaves a persistent woody-herbal trace that adds complexity to modern chypre and fougère structures.

Scent Profile
Layer 2

2D Molecular Structure

Chavicol

SMILES: OC1=CC=C(CC=C)C=C1

Chemistry, Properties & Perfumer Guide

The Chemistry

4-Allylphenol is a simple phenolic compound with an allyl substituent. As a synthetic material, it’s produced through Friedel-Crafts alkylation of phenol with allyl chloride. The molecule lacks chirality but shows moderate polarity due to the hydroxyl group. Its reactivity makes it useful for creating more complex fragrance molecules through further chemical modifications.

Physical & Chemical Properties

Perfumer Guide

Note Position
Middle
Volatility
Moderate (2-4 hours)
Blending
Fair
ApplicationTypical %RangeNotes
Fine Fragrance0.1-0.5%Up to 1%Used as phenolic modifier

Classic Accords

Tip: Use sparingly to add phenolic complexity without overwhelming the composition.

Alternatives & Comparisons

1
Eugenol CAS 97-53-0

Provides similar phenolic character with added clove-like warmth and better safety profile.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

No specific IFRA restrictions

RIFM Assessment

Limited safety assessment available

Sustainability

As a synthetic material, 4-Allylphenol has minimal environmental impact during production. Its efficient synthesis from phenol makes it more sustainable than extracting similar notes from natural sources.

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References

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

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    Ingredient Data Sheet

    CAS 501-92-8

    Physical Properties

    Molecular Weight134.17 g/mol🔬 PubChem
    LogP (Octanol-Water)2.9🔬 PubChem
    Boiling Point234 °C🔬 EPA CompTox
    log Kp (skin permeability)-1.459💻 Calculated
    SMILESC=CCC1=CC=C(C=C1)O🔬 PubChem

    Volatility & Performance

    Fragrance NoteHeart💻 Calculated

    Odor & Flavor

    Primary Descriptorsmedicinalphenolicsmokyspicy• leffingwell
    Functional Groupsphenolalkenearomatic💻 RDKit
    “Powerful, dry, tarry-medicinal "phenolic" odor, very penetrating and persistent.”📖 Arctander
    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: DTXSID60198210

    Physical Properties

    Molecular Weight 134.178 g/mol🔬 EPA CompTox
    Density 1.02 g/cm^3🔬 EPA CTX
    Boiling Point 236.5 °C🔬 EPA CTX
    Melting Point 15.84 °C🔬 EPA CTX
    Flash Point 104.062 °C📊 OPERA
    Refractive Index 1.548 Dimensionless📊 OPERA
    Molar Volume 132.281 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 2.91 Log10 unitless🔬 EPA CTX
    LogD (pH 5.5) 2.572 Log10 unitless📊 OPERA
    LogD (pH 7.4) 2.572 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 6.81 Log10 unitless📊 OPERA
    Water Solubility 0.021 mol/L📊 OPERA
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0.029 mmHg📊 OPERA
    Viscosity 5.002 cP📊 OPERA
    Surface Tension 37.034 dyn/cm📊 OPERA
    Thermal Conductivity 148.217 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 2 count💻 Computed
    Aromatic Rings 1 count💻 Computed
    Molar Refractivity 42.042 cm^3/mol📊 OPERA
    Polarizability 16.667 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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