Glycerol (CAS 56-81-5) — Citrus Base Note Fragrance Ingredient
Glycerol
CAS 56-81-5
What Is Glycerol?
Glycerol, also known as glycerin, is a clear, odorless liquid commonly found in skincare products, soaps, and some food items. It acts as a humectant, drawing moisture into the skin or product. While not a fragrance ingredient itself, glycerol is crucial in perfumery as a solvent and fixative, helping to stabilize and prolong the scent of fragrances.
Safety Profile
GENERALLY SAFEWhat Does Glycerol Smell Like?
Glycerol itself is odorless, serving primarily as a carrier or fixative in fragrances. It provides a smooth, slightly sweet base that enhances the longevity of other aromatic compounds without contributing its own scent. In formulations, it helps blend and stabilize volatile top notes, allowing for a more controlled release of fragrance over time.
2D Molecular Structure
SMILES: OCC(O)CO
Chemistry, Properties & Perfumer Guide
The Chemistry
Glycerol is a simple polyol compound with three hydroxyl groups, making it highly soluble in water and hygroscopic. It is typically synthesized from propylene via epichlorohydrin or through the saponification of fats and oils. Glycerol’s ability to form hydrogen bonds gives it excellent solvent properties and makes it useful in a wide range of applications beyond perfumery, including food, pharmaceuticals, and personal care products.
Physical & Chemical Properties
| Boiling Point | 290 °C |
|---|---|
| Density | 1.261 g/cm³ |
| Melting Point | 17.8 °C |
| Flash Point | 160 °C |
| Solubility | Miscible with water and alcohol |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 10% | Used as a fixative and solvent |
| Skincare | 5-15% | Up to 20% | Humectant and moisturizer |
| Soaps | 3-10% | Up to 15% | Adds smoothness and moisture retention |
Classic Accords
Tip: Use glycerol to stabilize and prolong the scent of volatile top notes in alcohol-based perfumes.
Alternatives & Comparisons
A less viscous alternative with similar humectant properties, often used in place of glycerol in formulations where lower viscosity is desired.
Another polyol used as a solvent and humectant, offering slightly different solubility and sensory characteristics compared to glycerol.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Glycerol is not restricted by IFRA and is considered safe for use in all cosmetic and fragrance applications.
RIFM Assessment
RIFM has evaluated glycerol and confirmed its safety for use in fragrances at typical usage levels.
Sustainability
Glycerol is often derived as a byproduct of biodiesel production, making it a sustainable choice in many formulations. Its biodegradability and non-toxic nature further enhance its environmental profile. Synthetic glycerol is also widely available, ensuring a stable supply chain.
Explore Glycerol
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References
- PubChem. Glycerol. National Library of Medicine. PubChem CID: 753
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPerfumer’s Notes
FEMA #: 2525 | IOFI #: Nature Identical
Glycerol is a sweet-tasting, syrupy liquid. It has not more than a slight characteristic odor, which is neither harsh nor disagreeable. Glycerol is a trihydric alcohol. It is hygroscopic and its solutions are neutral.
MW: 92.09
LogP: -1.8
Ingredient Data Sheet
CAS 56-81-5Physical Properties
| Molecular Weight | 92.09 g/mol🔬 PubChem |
| LogP (Octanol-Water) | -1.8🔬 PubChem |
| Boiling Point | 290 °C🔬 EPA CompTox |
| Vapor Pressure | 0.0025 mmHg @ 25°C📊 OPERA |
| Flash Point | 160 °C🔬 EPA CompTox |
| Involatility Index | 0.0003💻 Calculated |
| log Kp (skin permeability) | -4.54💻 Calculated |
| SMILES | C(C(CO)O)O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Base💻 Calculated |
| Volatility Class | Very slow💻 Calculated |
| Persistence Score | 1.4 / 5💻 Calculated |
Odor & Flavor
| Functional Groups | alcohol💻 RDKit |
| “Pure toluene has a sweet-gassy odor, milder than that of Benzene. It is much less toxic than Benzene (estimated 20 to 50 times less toxic to human skin and respiratory system).”📖 Arctander | |
| Glycerol is a sweet-tasting, syrupy liquid. It has not more than a slight characteristic odor, which is neither harsh nor disagreeable. Glycerol is a trihydric alcohol. It is hygroscopic and its solutions are neutral.📖 Fenaroli | |
Flavor Notes (Arctander)
| “The title aromatic hydrocarbon is not a perfume or flavor material, but it is included in this work because it is used as a solvent for extraction of active ingredients in plant materials, etc.”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 20 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: DTXSID9020663
Physical Properties
| Molecular Weight | 92.094 g/mol🔬 EPA CompTox |
| Density | 1.262 g/cm^3🔬 EPA CTX |
| Boiling Point | 290 °C🔬 EPA CTX |
| Melting Point | 18.131 °C🔬 EPA CTX |
| Flash Point | 177.221 °C🔬 EPA CTX |
| Refractive Index | 1.49 Dimensionless📊 OPERA |
| Molar Volume | 70.95 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | -1.802 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | -2.025 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | -1.8 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.41 Log10 unitless📊 OPERA |
| Water Solubility | 14.535 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0 mmHg🔬 EPA CTX |
| Viscosity | 64.121 cP📊 OPERA |
| Surface Tension | 49.674 dyn/cm📊 OPERA |
| Thermal Conductivity | 216.366 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 60.69 Ų💻 Computed |
| H-Bond Donors | 3 count💻 Computed |
| H-Bond Acceptors | 3 count💻 Computed |
| Rotatable Bonds | 2 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 20.511 cm^3/mol📊 OPERA |
| Polarizability | 8.131 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.
