sec-Butyl ethyl ether (CAS 2679-87-0) — Citrus Top Note Fragrance Ingredient

Citrus · Green

sec-Butyl ethyl ether

CAS 2679-87-0

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

What Is sec-Butyl ethyl ether?

sec-Butyl ethyl ether is a synthetic compound occasionally used in perfumery for its ethereal, slightly fruity character. While not common in consumer products, it may appear in niche fragrances seeking unusual volatile top notes. This ingredient matters because it demonstrates how synthetic chemistry expands perfumers’ palettes beyond natural sources.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
No major restrictions at typical usage levels
Flammable liquid – handle with care
CAS
2679-87-0
Formula
Mixture
MW
Variable
Odor Family
Citrus · Green
Layer 1 · Enthusiast

What Does sec-Butyl ethyl ether Smell Like?

A volatile whisper of fermented apples and surgical cleanliness, sec-butyl ethyl ether opens with sharp solvent-like brightness that quickly settles into a diffuse fruitiness reminiscent of unripe pears soaked in rubbing alcohol. The fleeting nature makes it useful for creating ‘ghost notes’ – impressions that vanish before they can be fully identified, adding intrigue to citrus or green accords.

Scent Profile

In Famous Fragrances

Fragrance associations may not reflect actual formulations.

Experimental Ether(Conceptual Perfumery Lab, 2020)

Used at 0.5% to create an elusive ‘ink drying on glass’ effect in the opening, enhancing the fragrance’s laboratory aesthetic without detectable sweetness.

Layer 2

2D Molecular Structure

Butane, 2-ethoxy-

SMILES: CCOC(C)CC

Chemistry, Properties & Perfumer Guide

The Chemistry

As a simple dialkyl ether, sec-butyl ethyl ether belongs to a class of compounds prized for high volatility and low odor detection thresholds. Industrial synthesis typically involves Williamson ether synthesis between sec-butanol and ethyl halides. The sec-butyl group introduces subtle stereochemical considerations – the chiral center may influence how the molecule interacts with olfactory receptors compared to its straight-chain isomer.

Physical & Chemical Properties

Boiling Point92-94°C
Vapor Pressure~60 mmHg at 20°C

Perfumer Guide

Note Position
Top
Volatility
Extreme (<15 min)
Blending
Specialized
ApplicationTypical %RangeNotes
Niche Perfumery0.1-0.5%Up to 1%For transitory effects only

Classic Accords

+ Aldehydes = Laboratory realism + Grapefruit = Volatile fruit

Tip: Use minutest quantities in dropper bottles – this material can overwhelm a blend at surprisingly low concentrations.

Alternatives & Comparisons

1
Diethyl ether CAS 60-29-7

More pronounced ethereal character but highly flammable and restricted in many markets.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

Not currently restricted by IFRA. Listed on TSCA inventory.

GHS Classification

H225 Highly flammable liquid and vapor

RIFM Assessment

No RIFM safety assessment found – recommended for professional use only given limited toxicological data.

Sustainability

Petroleum-derived synthesis raises carbon footprint concerns. Some green chemistry approaches using bio-based alcohols are theoretically possible but not commercially implemented for this specialty material.

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References

  1. PubChem Compound Summary for sec-Butyl ethyl ether PubChem

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

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Ingredient Data Sheet

CAS 2679-87-0

Physical Properties

Molecular Weight102.17 g/mol🔬 PubChem
LogP (Octanol-Water)1.8🔬 PubChem
Boiling Point81 °C🔬 EPA CompTox
log Kp (skin permeability)-2.045💻 Calculated
SMILESCCC(C)OCC🔬 PubChem

Volatility & Performance

Fragrance NoteTop💻 Calculated

Odor & Flavor

Primary Descriptorsberryetherealfreshfruity• leffingwell
Functional Groupsether💻 RDKit

Regulatory Status

IOFI ClassificationNature Identical📖 Fenaroli
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: DTXSID30863009

Physical Properties

Molecular Weight 102.177 g/mol🔬 EPA CompTox
Density 0.772 g/cm^3📊 OPERA
Boiling Point 81 °C🔬 EPA CTX
Melting Point -105.57 °C📊 OPERA
Flash Point -2.813 °C📊 OPERA
Refractive Index 1.386 Dimensionless📊 OPERA
Molar Volume 134.315 cm^3/mol📊 OPERA

Partition & Solubility

LogP (Octanol-Water) 1.767 Log10 unitless📊 OPERA
LogD (pH 5.5) 1.767 Log10 unitless📊 OPERA
LogD (pH 7.4) 1.767 Log10 unitless📊 OPERA
LogKoa (Octanol-Air) 3.1 Log10 unitless📊 OPERA
Water Solubility 0.078 mol/L📊 OPERA
Henry's Law Constant 0.002 atm-m3/mole📊 OPERA

Transport Properties

Vapor Pressure 99.135 mmHg📊 OPERA
Viscosity 0.431 cP📊 OPERA
Surface Tension 20.611 dyn/cm📊 OPERA
Thermal Conductivity 122.2 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 0 count💻 Computed
Molar Refractivity 31.55 cm^3/mol📊 OPERA
Polarizability 12.507 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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