4-Pentenal, 4-methyl-5-(4-methylphenyl)-, (4E)- (CAS 1226911-69-8) — Green Top to Middle Note Fragrance Ingredient

ByThe Good Scents
Green · Floral

4-Pentenal, 4-methyl-5-(4-methylphenyl)-, (4E)-

CAS 1226911-69-8

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

What Is 4-Pentenal, 4-methyl-5-(4-methylphenyl)-, (4E)-?

4-Methyl-5-(4-methylphenyl)-4-pentenal is a synthetic fragrance ingredient primarily used in professional perfumery. It’s encountered in niche fragrances where unique, modern accords are desired. This aldehyde contributes fresh, green nuances with subtle floral undertones, making it valuable for creating contemporary scent profiles that stand out from traditional compositions.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
✓ Approved for fragrance use
⚠ Limited safety data available
CAS
1226911-69-8
Formula
Mixture
MW
Variable
Odor Family
Green · Floral
Layer 1 · Enthusiast

What Does 4-Pentenal, 4-methyl-5-(4-methylphenyl)-, (4E)- Smell Like?

This synthetic aldehyde opens with a crisp, green burst reminiscent of crushed stems and citrus zest, quickly revealing a complex heart of waxy floralcy akin to magnolia petals. The dry-down exhibits a subtle leathery nuance with faint metallic undertones, creating an intriguing contrast to its initial freshness. The overall effect is modern and slightly futuristic – like a bioluminescent plant in a sci-fi film, glowing with unnatural yet captivating beauty.

Scent Profile
Layer 2

2D Molecular Structure

4-Pentenal, 4-methyl-5-(4-methylphenyl)-, (4E)-

SMILES: C\C(CCC=O)=C/C1=CC=C(C)C=C1

Chemistry, Properties & Perfumer Guide

The Chemistry

4-Methyl-5-(4-methylphenyl)-4-pentenal belongs to the α,β-unsaturated aldehyde class, characterized by its conjugated double bond system that contributes to both reactivity and odor characteristics. While not found in nature, its structure suggests potential biosynthesis from p-cymene precursors. Industrial synthesis likely proceeds via aldol condensation of p-tolualdehyde with methyl ethyl ketone, followed by selective hydrogenation. The (4E)-configuration is essential for its specific odor profile, demonstrating how minor stereochemical differences can dramatically impact fragrance performance.

Physical & Chemical Properties

Perfumer Guide

Note Position
Top to Middle
Volatility
Moderate (2-4 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.1-0.5%Up to 1%Used as accent note
Functional Fragrance0.01-0.1%Up to 0.3%For freshness boost
Home Care0.005-0.05%Up to 0.1%Light green modifier

Classic Accords

Tip: Stabilize with antioxidants to prevent polymerization during storage.

Alternatives & Comparisons

1
2,4-Dimethyl-3-cyclohexene-1-carboxaldehyde CAS 68039-49-6

Offers similar green-floral character with better stability in alkaline formulations.

2
2-Methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-butenal CAS 2363-88-4

Provides comparable green notes with enhanced diffusion and rosy undertones.

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. No specific usage limits established.

RIFM Assessment

Under evaluation by RIFM. Provisional safety assessment suggests use at current levels presents minimal risk.

Sustainability

As a synthetic material, this ingredient avoids agricultural land use but requires petrochemical feedstocks. Production likely involves transition metal catalysts, necessitating proper waste stream management. Being used at very low concentrations minimizes its environmental load in finished products. Future green chemistry approaches could potentially derive similar molecules from renewable resources.

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References

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

    Report a data error

    Ingredient Data Sheet

    CAS 1226911-69-8

    Physical Properties

    Molecular Weight188.26 g/mol🔬 PubChem
    LogP (Octanol-Water)3.2🔬 PubChem
    Boiling Point273 °C🔬 EPA CompTox
    Vapor Pressure0.0011 mmHg @ 25°C📊 OPERA
    Flash Point147 °C🔬 EPA CompTox
    Involatility Index0.0001💻 Calculated
    log Kp (skin permeability)-1.576💻 Calculated
    SMILESCC1=CC=C(C=C1)C=C(C)CCC=O🔬 PubChem

    Volatility & Performance

    Fragrance NoteBase💻 Calculated
    Volatility ClassVery slow💻 Calculated
    Persistence Score5.6 / 5💻 Calculated

    Odor & Flavor

    Primary Descriptorsfloralgreen• leffingwell
    Functional Groupsaldehydealkenearomatic💻 RDKit
    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: DTXSID60889277

    Physical Properties

    Molecular Weight 188.27 g/mol🔬 EPA CompTox
    Density 0.989 g/cm^3🔬 EPA CTX
    Boiling Point 285.89 °C📊 OPERA
    Melting Point 9 °C🔬 EPA CTX
    Flash Point 147 °C🔬 EPA CTX
    Refractive Index 1.543 Dimensionless📊 OPERA
    Molar Volume 193.324 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) 661.56 Log10 unitless🔬 EPA CTX
    LogD (pH 5.5) 3.358 Log10 unitless📊 OPERA
    LogD (pH 7.4) 3.358 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 6.91 Log10 unitless📊 OPERA
    Water Solubility 0.001 mol/L📊 OPERA
    Henry's Law Constant 0 atm-m3/mole📊 OPERA

    Transport Properties

    Vapor Pressure 0.001 mmHg🔬 EPA CTX
    Viscosity 3.714 cP📊 OPERA
    Surface Tension 35.41 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 4 count💻 Computed
    Aromatic Rings 1 count💻 Computed
    Molar Refractivity 60.895 cm^3/mol📊 OPERA
    Polarizability 24.141 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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