4-Methoxybenzaldehyde diethyl acetal (CAS 2403-58-9) — Sweet Middle Note Fragrance Ingredient

ByThe Good Scents
Sweet · Floral

4-Methoxybenzaldehyde diethyl acetal

CAS 2403-58-9

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

What Is 4-Methoxybenzaldehyde diethyl acetal?

4-Methoxybenzaldehyde diethyl acetal is a synthetic aroma chemical used to impart sweet, powdery, and floral notes to perfumes. It’s commonly found in fine fragrances, soaps, and cosmetics. This ingredient matters because it adds a long-lasting vanilla-like warmth with subtle anisic nuances, enhancing complexity without overwhelming other notes.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
✓ No known major safety concerns
⚠ Check IFRA guidelines for usage limits
CAS
2403-58-9
Formula
Mixture
MW
Variable
Odor Family
Sweet · Floral
Layer 1 · Enthusiast

What Does 4-Methoxybenzaldehyde diethyl acetal Smell Like?

Opens with a bright, sweet vanilla-anise duality reminiscent of freshly baked shortbread. The heart reveals powdery heliotrope facets that float like confectioners’ sugar over warm benzoin. Dry-down shows remarkable tenacity, leaving a smooth balsamic trail that bridges gourmand and floral accords. Like the lingering scent of marzipan left in an antique lace drawer.

Scent Profile

In Famous Fragrances

Fragrance associations may not reflect actual formulations.

Shalimar(Guerlain, 1925)

Used here to amplify the vanilla-oriental core, providing a diffusive sweetness that balances Shalimar’s animalic base.

L'Heure Bleue(Guerlain, 1912)

Contributes to the powdery-orris heart, creating that signature twilight melancholy.

Layer 2

2D Molecular Structure

p-(Diethoxymethyl)anisole

SMILES: CCOC(OCC)C1=CC=C(OC)C=C1

Chemistry, Properties & Perfumer Guide

The Chemistry

A synthetic aromatic acetal derived from anisaldehyde. The diethyl acetal group provides enhanced stability against oxidation compared to the parent aldehyde. Industrial synthesis typically involves acid-catalyzed reaction of 4-methoxybenzaldehyde with ethanol. This protection strategy is common in perfumery to modulate reactivity and volatility.

Physical & Chemical Properties

Boiling PointNot publicly available
DensityNot publicly available

Perfumer Guide

Note Position
Middle
Volatility
Moderate (2-6 hours)
Blending
Excellent
ApplicationTypical %RangeNotes
Fine Fragrance1-3%Up to 5%Base for oriental accords
Soap0.5-1%Up to 2%Stable in alkaline media

Classic Accords

Tip: Use with ionones to create velvety texture in floral bouquets.

Alternatives & Comparisons

1
Anisaldehyde CAS 123-11-5

More direct anisic character but less stable and more volatile.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

No current IFRA restrictions. Monitor for future updates to acetal regulations.

RIFM Assessment

RIFM assessment pending. Expected low concern based on structural analogs.

Sustainability

Synthesized from petrochemical precursors. No known significant environmental hazards at typical usage levels. Biodegradation studies not available.

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References

  1. PubChem Entry PubChem CID unavailable
  2. Arctander, S. (1969). Perfume and Flavor Chemicals.

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

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Ingredient Data Sheet

CAS 2403-58-9

Physical Properties

Molecular Weight210.27 g/mol🔬 PubChem
LogP (Octanol-Water)2.3🔬 PubChem
Boiling Point262 °C🔬 EPA CompTox
Vapor Pressure0.0014 mmHg @ 25°C📊 OPERA
Flash Point86.6 °C🔬 EPA CompTox
Involatility Index0.0001💻 Calculated
log Kp (skin permeability)-2.35💻 Calculated
SMILESCCOC(C1=CC=C(C=C1)OC)OCC🔬 PubChem

Volatility & Performance

Fragrance NoteBase💻 Calculated
Volatility ClassVery slow💻 Calculated
Persistence Score4.9 / 5💻 Calculated

Odor & Flavor

Primary Descriptorsfloralherbalspicysweet• leffingwell
Functional Groupsetheraromatic💻 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: DTXSID7051896

Physical Properties

Molecular Weight 210.273 g/mol🔬 EPA CompTox
Density 1.001 g/cm^3📊 OPERA
Boiling Point 263.523 °C📊 OPERA
Melting Point 25.999 °C📊 OPERA
Flash Point 99.813 °C📊 OPERA
Refractive Index 1.484 Dimensionless📊 OPERA
Molar Volume 209.246 cm^3/mol📊 OPERA

Partition & Solubility

LogP (Octanol-Water) 2.709 Log10 unitless📊 OPERA
LogD (pH 5.5) 2.709 Log10 unitless📊 OPERA
LogD (pH 7.4) 2.709 Log10 unitless📊 OPERA
LogKoa (Octanol-Air) 6.69 Log10 unitless📊 OPERA
Water Solubility 0.005 mol/L📊 OPERA
Henry's Law Constant 0 atm-m3/mole📊 OPERA

Transport Properties

Vapor Pressure 0.006 mmHg📊 OPERA
Viscosity 3.595 cP📊 OPERA
Surface Tension 32.561 dyn/cm📊 OPERA
Thermal Conductivity 136.902 mW/(m*K)📊 OPERA

Molecular Descriptors

Topological Polar Surface Area 27.69 Ų💻 Computed
H-Bond Donors 0 count💻 Computed
H-Bond Acceptors 3 count💻 Computed
Rotatable Bonds 6 count💻 Computed
Aromatic Rings 1 count💻 Computed
Molar Refractivity 59.872 cm^3/mol📊 OPERA
Polarizability 23.735 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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