Nopol (CAS 128-50-7) — Green Top-middle Note Fragrance Ingredient

ByThe Good Scents
Green · Woody

Nopol

CAS 128-50-7

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

What Is Nopol?

Nopol is a synthetic fragrance ingredient used in perfumes and household products for its fresh, woody-green character. It’s commonly found in air fresheners, detergents, and masculine fragrances. This versatile material adds a crisp, modern edge to compositions, often enhancing pine or citrus notes without overpowering.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
✓ Safe in regulated products
⚠ Check IFRA guidelines for usage limits
CAS
128-50-7
Formula
Mixture
MW
Variable
Odor Family
Green · Woody
Layer 1 · Enthusiast

What Does Nopol Smell Like?

Nopol opens with a sharp, invigorating greenness reminiscent of snapped pine needles and crushed juniper berries. The initial burst evolves into a cleaner woody character, like freshly sanded cedar planks with a subtle camphoraceous edge. Dry-down reveals a faintly soapy, almost ozonic quality that lingers close to the skin.

Scent Profile
Layer 2

2D Molecular Structure

Bicyclo[3.1.1]hept-2-ene-2-ethanol, 6,6-dimethyl-

SMILES: CC1(C)C2CC1C(CCO)=CC2

Chemistry, Properties & Perfumer Guide

The Chemistry

Nopol is a bicyclic tertiary alcohol derived from β-pinene. Industrially produced via acid-catalyzed hydration of β-pinene, it’s valued for its stability and resistance to oxidation. The molecule’s rigid structure contributes to its tenacious green-woody odor profile, while the hydroxyl group allows for derivatization into various esters.

Physical & Chemical Properties

Boiling Point198 °C
Density0.95 g/cm³

Perfumer Guide

Note Position
Top-middle
Volatility
Medium (2-4 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance1-3%Up to 5%Fresh top notes
Functional Fragrance3-8%Up to 15%Cleaning products

Classic Accords

Tip: Use with citrus top notes to enhance freshness without citrus volatility.

Alternatives & Comparisons

1
Pinanol CAS 473-55-2

Similar pine character but with sweeter, more balsamic undertones.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

No IFRA restrictions currently apply.

RIFM Assessment

RIFM assessment confirms safe use at current industry levels.

Sustainability

Synthesized from renewable turpentine feedstocks. Production has relatively low environmental impact compared to petroleum-derived synthetics.

Explore Nopol

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References

  1. PubChem Compound Summary for Nopol PubChem

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

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Layer 3 · Practical

  • Odor Profile: camphoreous, citrus, pine, woody
  • FEMA GRAS: 3938
  • Molecular Weight: 166.26 g/mol
  • LogP (XLogP): 2.10

Ingredient Data Sheet

CAS 128-50-7

Physical Properties

Molecular Weight166.26 g/mol🔬 PubChem
LogP (Octanol-Water)2.1🔬 PubChem
Boiling Point230 °C🔬 EPA CompTox
log Kp (skin permeability)-2.223💻 Calculated
SMILESCC1(C2CC=C(C1C2)CCO)C🔬 PubChem

Volatility & Performance

Fragrance NoteHeart💻 Calculated

Odor & Flavor

Primary Descriptorscamphoraceouscitruspinewoody• leffingwell
Functional Groupsalcoholalkene💻 RDKit
10-Hydroxymethylene-2-pinene has a sweet, citrus, pine-like odor.📖 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: DTXSID10861780

Physical Properties

Molecular Weight 166.264 g/mol🔬 EPA CompTox
Density 0.988 g/cm^3📊 OPERA
Boiling Point 231.277 °C📊 OPERA
Melting Point 50.077 °C📊 OPERA
Flash Point 97.267 °C📊 OPERA
Refractive Index 1.501 Dimensionless📊 OPERA
Molar Volume 169.991 cm^3/mol📊 OPERA

Partition & Solubility

LogP (Octanol-Water) 3.252 Log10 unitless📊 OPERA
LogD (pH 5.5) 3.252 Log10 unitless📊 OPERA
LogD (pH 7.4) 3.252 Log10 unitless📊 OPERA
LogKoa (Octanol-Air) 7.71 Log10 unitless📊 OPERA
Water Solubility 0.002 mol/L🔬 EPA CTX
Henry's Law Constant 0 atm-m3/mole📊 OPERA

Transport Properties

Vapor Pressure 0.016 mmHg📊 OPERA
Viscosity 15.212 cP📊 OPERA
Surface Tension 31.705 dyn/cm📊 OPERA
Thermal Conductivity 132.82 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 2 count💻 Computed
Aromatic Rings 0 count💻 Computed
Molar Refractivity 50.117 cm^3/mol📊 OPERA
Polarizability 19.868 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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