2-Heptanol (CAS 543-49-7) — Green Top-middle Note Fragrance Ingredient

ByThe Good Scents
Green · Citrus

2-Heptanol

CAS 543-49-7

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

What Is 2-Heptanol?

2-Heptanol is a synthetic alcohol used in perfumery for its fresh, slightly green aroma. It’s found in trace amounts in some citrus and herbal fragrances. This ingredient matters because it adds a crisp, clean character to compositions, often working behind the scenes to enhance other notes without being detectable on its own.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
✓ No major restrictions
⚠ Mild skin sensitivity possible at high concentrations
CAS
543-49-7
Formula
Mixture
MW
Variable
Odor Family
Green · Citrus
Layer 1 · Enthusiast

What Does 2-Heptanol Smell Like?

2-Heptanol presents a fresh, slightly green aroma with waxy undertones reminiscent of unripe banana peel. Its top note carries a crisp, almost metallic sharpness that quickly mellows into a clean laundry-like character. The dry-down reveals subtle herbal facets, like crushed grass stems after rain. While not dominant, it provides excellent lift to citrus accords and adds diffusion to green compositions.

Scent Profile
Layer 2

2D Molecular Structure

2-Heptanol

SMILES: CCCCCC(C)O

Chemistry, Properties & Perfumer Guide

The Chemistry

2-Heptanol is a secondary alcohol with a seven-carbon chain. Industrially produced via oxidation of heptene or reduction of 2-heptanone. Its molecular structure allows moderate volatility while maintaining sufficient tenacity for perfumery use. The stereochemistry (chiral center at C-2) creates two enantiomers with slightly different olfactory profiles, though commercial material is typically racemic.

Physical & Chemical Properties

Boiling Point160-162 °C
Density0.818 g/cm³
Refractive Index1.421

Perfumer Guide

Note Position
Top-middle
Volatility
Medium (1-3 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.1-0.5%Up to 1%Background modifier
Functional Products0.05-0.2%Up to 0.5%Freshness enhancer

Classic Accords

Tip: Use to add diffusion and lift to green-floral compositions without adding sweetness.

Alternatives & Comparisons

1
2-Octanol CAS 123-96-6

Similar profile with longer persistence and slightly more waxy character.

2
1-Heptanol CAS 111-70-6

Primary alcohol version with sharper green notes but less blending versatility.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

No IFRA restrictions. Listed as safe for all applications.

GHS Classification

H315 Skin irritation

RIFM Assessment

RIFM evaluation confirms safe use at current industry levels.

Sustainability

Synthesized from petrochemical feedstocks via efficient catalytic processes. No known ecological concerns at production scale. Biodegradation occurs via standard alcohol metabolic pathways.

Explore 2-Heptanol

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References

  1. PubChem Compound Summary for 2-Heptanol PubChem CID 10976

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

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Physicochemical Properties

DTXSID: DTXSID1047158

Physical Properties

Molecular Weight 116.204 g/mol🔬 EPA CompTox
Density 0.819 g/cm^3🔬 EPA CTX
Boiling Point 159.525 °C🔬 EPA CTX
Melting Point 25 °C🔬 EPA CTX
Flash Point 65.085 °C🔬 EPA CTX
Refractive Index 1.421 Dimensionless📊 OPERA
Molar Volume 141.965 cm^3/mol📊 OPERA

Partition & Solubility

LogP (Octanol-Water) 2.31 Log10 unitless🔬 EPA CTX
LogD (pH 5.5) 2.35 Log10 unitless📊 OPERA
LogD (pH 7.4) 2.35 Log10 unitless📊 OPERA
LogKoa (Octanol-Air) 4.9 Log10 unitless📊 OPERA
Water Solubility 0.028 mol/L🔬 EPA CTX
Henry's Law Constant 0 atm-m3/mole🔬 EPA CTX

Transport Properties

Vapor Pressure 1.05 mmHg🔬 EPA CTX
Viscosity 3.474 cP📊 OPERA
Surface Tension 26.203 dyn/cm📊 OPERA
Thermal Conductivity 142.714 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 4 count💻 Computed
Aromatic Rings 0 count💻 Computed
Molar Refractivity 35.973 cm^3/mol📊 OPERA
Polarizability 14.261 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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