beta-Naphthyl isobutyl ether (CAS 2173-57-1) — Floral Middle Note Fragrance Ingredient

Floral · Woody

beta-Naphthyl isobutyl ether

CAS 2173-57-1

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

What Is beta-Naphthyl isobutyl ether?

Beta-Naphthyl isobutyl ether is a synthetic fragrance ingredient used to add floral and slightly woody nuances to perfumes. You’ll encounter it in fine fragrances and some body care products. This molecule matters because it provides a cost-effective alternative to certain natural floral extracts, allowing perfumers to create stable, long-lasting floral accords without reliance on seasonal botanicals.

Safety Profile

USE WITH AWARENESS
Generally safeUse with awarenessProfessional use
IFRA-compliant at standard usage levels
Moderate skin sensitivity potential
CAS
2173-57-1
Formula
Mixture
MW
Variable
Odor Family
Floral · Woody
Layer 1 · Enthusiast

What Does beta-Naphthyl isobutyl ether Smell Like?

Beta-Naphthyl isobutyl ether opens with a crisp, slightly medicinal floral character reminiscent of orange blossoms dipped in rubbing alcohol. The sharp top rapidly softens into a heart of powdery naphthalene-like floralcy with an unexpected fruity undertone. In drydown, it reveals a dry woody facet with persistent floral whispers. The overall effect is like smelling a vintage sachet through a thin veil of isopropyl alcohol – simultaneously nostalgic and clean.

Scent Profile

In Famous Fragrances

Fragrance associations may not reflect actual formulations.

Tabu(Dana, 1932)

Used here to reinforce the animalic floralcy, adding a synthetic edge that complements the civet and patchouli base.

Emeraude(Coty, 1921)

Provides a clean floral counterpoint to the vanilla-heavy oriental base, preventing excessive sweetness.

Layer 2

2D Molecular Structure

2-(2-Methylpropoxy)naphthalene

SMILES: CC(C)COC1=CC2=CC=CC=C2C=C1

Chemistry, Properties & Perfumer Guide

The Chemistry

Beta-Naphthyl isobutyl ether belongs to the aromatic ether class, synthesized through Williamson ether synthesis by reacting beta-naphthol with isobutyl bromide under basic conditions. The resulting molecule features a naphthalene ring system connected to an isobutyl group via an oxygen bridge. While not found in nature, its structure mimics certain floral lactones. The absence of chiral centers makes it optically inactive, contributing to consistent olfactory performance across batches.

Physical & Chemical Properties

AppearanceColorless to pale yellow liquid
Refractive Index1.57-1.59 (20°C)
SolubilityInsoluble in water, soluble in alcohol and oils

Perfumer Guide

Note Position
Middle
Volatility
Moderate (2-4 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.5-2%Up to 5%Floral modifier in oriental compositions
Soap0.1-0.5%Up to 1%Provides floral persistence in alkaline media

Classic Accords

Tip: Use with citrus fractions to brighten its potentially heavy floral character.

Alternatives & Comparisons

1
Benzyl salicylate CAS 118-58-1

For cleaner floral effects with less powderiness, though lacks the woody drydown.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

Not currently restricted under IFRA standards.

GHS Classification

H315 Skin irritation

RIFM Assessment

Listed in RIFM database with no significant safety concerns at standard usage levels.

Sustainability

As a purely synthetic material, beta-Naphthyl isobutyl ether avoids agricultural impacts but relies on petrochemical feedstocks. Its synthesis generates minimal waste compared to natural extract production. The material’s stability reduces preservative needs in finished products.

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References

  1. Arctander, S. (1969). Perfume and Flavor Chemicals. Montclair, NJ.

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

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Physicochemical Properties

DTXSID: DTXSID1051484

Physical Properties

Molecular Weight 200.281 g/mol🔬 EPA CompTox
Density 1.09 g/cm^3🔬 EPA CTX
Boiling Point 303.2 °C🔬 EPA CTX
Melting Point 31.567 °C🔬 EPA CTX
Flash Point 132.649 °C📊 OPERA
Refractive Index 1.568 Dimensionless📊 OPERA
Molar Volume 197.449 cm^3/mol📊 OPERA

Partition & Solubility

LogP (Octanol-Water) 5.1 Log10 unitless🔬 EPA CTX
LogD (pH 5.5) 4.292 Log10 unitless📊 OPERA
LogD (pH 7.4) 4.292 Log10 unitless📊 OPERA
LogKoa (Octanol-Air) 7.42 Log10 unitless📊 OPERA
Water Solubility 0 mol/L🔬 EPA CTX
Henry's Law Constant 0 atm-m3/mole📊 OPERA

Transport Properties

Vapor Pressure 0.001 mmHg🔬 EPA CTX
Viscosity 8.273 cP📊 OPERA
Surface Tension 37.366 dyn/cm📊 OPERA
Thermal Conductivity 126.125 mW/(m*K)📊 OPERA

Molecular Descriptors

Topological Polar Surface Area 9.23 Ų💻 Computed
H-Bond Donors 0 count💻 Computed
H-Bond Acceptors 1 count💻 Computed
Rotatable Bonds 3 count💻 Computed
Aromatic Rings 2 count💻 Computed
Molar Refractivity 64.631 cm^3/mol📊 OPERA
Polarizability 25.622 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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