Benzothiazole (CAS 95-16-9) — Balsamic Base Note Fragrance Ingredient
Benzothiazole
CAS 95-16-9
What Is Benzothiazole?
Benzothiazole is a synthetic compound used in perfumery to add rubbery, smoky, and leathery nuances. It’s found in trace amounts in some fragrances aiming for industrial or avant-garde effects. While not common in mainstream perfumes, it’s valued by niche perfumers for its ability to create unconventional scent profiles.
Safety Profile
PROFESSIONAL USEWhat Does Benzothiazole Smell Like?
Benzothiazole delivers a sharp, rubbery opening with pronounced smoky-leathery facets that evoke burning tires or hot machinery. The initial industrial harshness gradually softens into a persistent metallic undertone, leaving a dry, mineralic trail. Its tenacity makes it useful for creating abstract urban accords, though it requires careful dosing to avoid overwhelming compositions.
2D Molecular Structure
SMILES: S1C=NC2=CC=CC=C12
Chemistry, Properties & Perfumer Guide
The Chemistry
Benzothiazole is a bicyclic aromatic compound containing fused benzene and thiazole rings. Typically synthesized through cyclization reactions of o-aminothiophenol derivatives, it’s part of a class of sulfur-nitrogen heterocycles. While naturally occurring in some roasted foods, perfumery uses exclusively synthetic material due to purity requirements. The molecule’s planar structure and sulfur atom contribute to its distinctive odor profile.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | 227-228 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.01-0.1% | Up to 0.5% | Used sparingly for leather/smoky effects |
| Functional Fragrance | 0.001-0.01% | Up to 0.05% | Industrial masking applications |
Classic Accords
Tip: Always pre-dilute to 1% or lower before incorporating into blends due to overwhelming strength.
Alternatives & Comparisons
Offers similar rubbery character but with popcorn-like nuances, less aggressive than benzothiazole.
Provides leathery effects with more woody-ambery facets rather than rubbery harshness.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA but recommended for professional use only due to limited safety data.
GHS Classification
RIFM Assessment
Not currently evaluated by RIFM. Use with caution until full safety assessment conducted.
Sustainability
As a synthetic material, benzothiazole production avoids natural resource depletion but requires petrochemical feedstocks. Manufacturing involves sulfur chemistry which demands careful waste management. Some producers are exploring greener synthesis routes using catalytic methods.
Explore Benzothiazole
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References
- Arctander, S. (1969). Perfume and Flavor Chemicals. Allured Publishing.
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 95-16-9Physical Properties
| Molecular Weight | 135.19 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2🔬 PubChem |
| Boiling Point | 227 °C🔬 EPA CompTox |
| Vapor Pressure | 0.01 mmHg @ 25°C📊 OPERA |
| Flash Point | 107 °C🔬 EPA CompTox |
| Involatility Index | 0.0009💻 Calculated |
| log Kp (skin permeability) | -2.105💻 Calculated |
| SMILES | C1=CC=C2C(=C1)N=CS2🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 2.9 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | burntsulfurous• leffingwell |
| Functional Groups | aromatic💻 RDKit |
| Benzothiazole has a delicate, persistent, rose-like odor similar to that of quinoline. -📖 Fenaroli | |
Sensory Thresholds
| Odor Detection Threshold | 0.08 ppm📖 van Gemert |
Regulatory Status
| IOFI Classification | Nature Identical📖 Fenaroli |
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: DTXSID7024586
Physical Properties
| Molecular Weight | 135.18 g/mol🔬 EPA CompTox |
| Density | 1.243 g/cm^3🔬 EPA CTX |
| Boiling Point | 230.4 °C🔬 EPA CTX |
| Melting Point | 11.379 °C🔬 EPA CTX |
| Flash Point | 101.838 °C🔬 EPA CTX |
| Refractive Index | 1.689 Dimensionless📊 OPERA |
| Molar Volume | 106.253 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.009 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 2.052 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.052 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.08 Log10 unitless📊 OPERA |
| Water Solubility | 0.03 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 19.553 mmHg🔬 EPA CTX |
| Viscosity | 2.98 cP📊 OPERA |
| Surface Tension | 54.289 dyn/cm📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 12.89 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 0 count💻 Computed |
| Aromatic Rings | 2 count💻 Computed |
| Molar Refractivity | 40.571 cm^3/mol📊 OPERA |
| Polarizability | 16.084 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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