Biphenyl (CAS 92-52-4) — Fragrance Ingredient Profile
Biphenyl
CAS 92-52-4
What Is Biphenyl?
Biphenyl is a synthetic aromatic compound commonly used as a fragrance fixative and solvent in perfumery. It’s found in industrial fragrances, air fresheners, and some functional products. Though not a dominant scent itself, biphenyl helps stabilize volatile fragrance components, making scents last longer on skin and in products.
Safety Profile
USE WITH AWARENESSWhat Does Biphenyl Smell Like?
Biphenyl presents a faint, dry, slightly phenolic aroma reminiscent of mothballs or old books. Its odor profile is more functional than pleasant – a neutral backbone that provides structural support to fragrances without imposing strong character. In compositions, it acts as an invisible scaffold, subtly amplifying woody and musky notes while taming brighter top notes. The dry-down reveals a faint waxy, paraffin-like quality that helps anchor volatile components.
Scent Profile
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as part of the synthetic base to stabilize the iconic aldehyde bouquet and extend longevity of floral notes.
Helps bridge the citrus top notes to vanilla base, providing thermal stability in the complex oriental structure.
2D Molecular Structure
SMILES: C1=CC=C(C=C1)C1=CC=CC=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
Biphenyl (C12H10) consists of two benzene rings connected by a single bond, making it the simplest polycyclic aromatic hydrocarbon. Industrially produced through the dehydrogenation of benzene or as a byproduct of coal tar distillation. The planar structure allows π-π stacking interactions that contribute to its fixative properties. While non-chiral, rotational restriction around the central bond creates conformational isomers that influence vapor pressure and odor diffusion.
Physical & Chemical Properties
| Boiling Point | 255 °C |
|---|---|
| Melting Point | 69 °C |
| Density | 1.04 g/cm³ |
| Vapor Pressure | 0.01 mmHg at 25°C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.1-0.5% | Up to 1% | Fixative for oriental bases |
| Functional Products | 0.05-0.2% | Up to 0.5% | Solvent for air fresheners |
Classic Accords
Tip: Use below 1% to avoid waxy off-notes in delicate compositions.
Alternatives & Comparisons
Similar fixative properties with a more pronounced floral-herbal character, useful when some odor contribution is desired.
For modern musky fixatives without the phenolic aspects of biphenyl.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. IFRA, REACH, EU Cosmetics Regulation standards update periodically. Consult current IFRA Standards Library before formulating. Not legal or regulatory advice.
IFRA Status
Not currently restricted by IFRA. Classified as a high production volume (HPV) chemical.
GHS Classification
RIFM Assessment
RIFM evaluation confirms safe use at current industry levels with proper handling procedures.
Sustainability
Primarily synthesized from petrochemical sources. While energy-intensive in production, its longevity effects can reduce overall fragrance load in products. Not known to bioaccumulate significantly. Industry is investigating bio-based production routes using modified microorganisms.
Explore Biphenyl
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References
- Bickers et al. (2003). Safety assessment of biphenyl. Food and Chemical Toxicology. PMID 12963047
- IFRA Standards Library – Biphenyl IFRA Standards
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 92-52-4Physical Properties
| Molecular Weight | 154.21 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 4🔬 PubChem |
| Boiling Point | 253.9 °C🔬 EPA CompTox |
| Vapor Pressure | 0.005 mmHg @ 25°C📊 OPERA |
| Flash Point | 112.8 °C🔬 EPA CompTox |
| Involatility Index | 0.0004💻 Calculated |
| log Kp (skin permeability) | -0.801💻 Calculated |
| SMILES | C1=CC=C(C=C1)C2=CC=CC=C2🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 4.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | metallicrose• leffingwell |
| Functional Groups | aromatic💻 RDKit |
| “Peculiar odor, gassy-green, remotely reminiscent of Geranium, but overall mild and rather nondescript, choking in high concentration. Sometimes described as "metallic" odor.”📖 Arctander | |
| Biphenyl has a pungent odor, reminiscent of rose on dilution.📖 Fenaroli | |
Sensory Thresholds
| Odor Detection Threshold | 0.06 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: DTXSID4020161
Physical Properties
| Molecular Weight | 154.212 g/mol🔬 EPA CompTox |
| Density | 1.031 g/cm^3🔬 EPA CTX |
| Boiling Point | 255.431 °C🔬 EPA CTX |
| Melting Point | 67.585 °C🔬 EPA CTX |
| Flash Point | 112.91 °C🔬 EPA CTX |
| Refractive Index | 1.571 Dimensionless📊 OPERA |
| Molar Volume | 154.718 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.985 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 3.915 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.915 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.15 Log10 unitless🔬 EPA CTX |
| Water Solubility | 0 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0.016 mmHg🔬 EPA CTX |
| Surface Tension | 38.28 dyn/cm📊 OPERA |
| Thermal Conductivity | 131.758 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 0 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 0 count💻 Computed |
| Rotatable Bonds | 1 count💻 Computed |
| Aromatic Rings | 2 count💻 Computed |
| Molar Refractivity | 50.845 cm^3/mol📊 OPERA |
| Polarizability | 20.156 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.
