alpha-Methylbenzyl propionate (CAS 120-45-6) — Sweet Top to Middle Note Fragrance Ingredient
alpha-Methylbenzyl propionate
CAS 120-45-6
What Is alpha-Methylbenzyl propionate?
Alpha-Methylbenzyl propionate is a synthetic fragrance ingredient commonly found in perfumes, body care products, and household items like soaps and detergents. It adds a fruity, floral character with a hint of sweetness. This versatile molecule helps create balanced floral bouquets and enhances fruity accords, making it valuable for perfumers seeking longevity and diffusion in modern fragrance compositions.
Safety Profile
GENERALLY SAFEWhat Does alpha-Methylbenzyl propionate Smell Like?
Alpha-Methylbenzyl propionate unfolds with a bright, juicy opening reminiscent of ripe pears and apricots with a subtle green nuance. The heart reveals a smooth floralcy, like rose petals dipped in honey, balanced by a clean, soapy undertone. As it dries down, it leaves a delicate powdery trail with whispers of vanilla and almond, creating a comforting skin-scent effect. The overall impression is of a sun-warmed orchard fruit basket lined with fresh linen.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a fruity-floral bridge between the grapefruit top and jasmine heart, adding diffusion and a soft, rounded quality to the composition.
Contributes to the vibrant fruity opening while preventing the violet leaf from becoming too sharp, creating the signature ‘sunshine in a bottle’ effect.
2D Molecular Structure
SMILES: CCC(=O)OC(C)C1=CC=CC=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
Alpha-Methylbenzyl propionate is an ester formed from the reaction of alpha-methylbenzyl alcohol (hydratropic alcohol) with propionic acid. As a chiral molecule, its sensory properties can vary between enantiomers. Industrial synthesis typically involves acid-catalyzed esterification under controlled conditions. The compound’s stability and moderate volatility make it particularly useful in fragrance applications where both top-note impact and heart-note persistence are desired.
Physical & Chemical Properties
| Molecular Weight | 178.23 g/mol |
|---|---|
| Boiling Point | ~230 °C (estimated) |
| Density | ~1.01 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 10% | Fruity-floral modifier |
| Soaps | 0.5-2% | Up to 3% | Adds fruity freshness |
| Shampoos | 0.2-1% | Up to 1.5% | Boosts floralcy without harshness |
Classic Accords
Tip: Use to soften harsh green notes and add diffusion to heavy florals.
Alternatives & Comparisons
More floral and less fruity, with greater tenacity. Choose when needing more jasmine-like character.
Rosier and honeyed profile. Better for rose reconstructions where fruity aspects should be subdued.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted under current IFRA standards (as of 49th Amendment).
RIFM Assessment
Considered safe as used in fragrance compositions based on RIFM’s 2020 assessment.
Sustainability
As a fully synthetic material, alpha-Methylbenzyl propionate has consistent quality without natural resource constraints. Production typically follows green chemistry principles with high atom economy in esterification processes. Being petroleum-derived, its environmental impact depends on the energy sources used in manufacturing.
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References
- Bauer et al. (2001). Common Fragrance and Flavor Materials. Wiley-VCH. ISBN 9783527619569
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 120-45-6Physical Properties
| Molecular Weight | 178.23 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 2.5🔬 PubChem |
| Boiling Point | 91 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -2.012💻 Calculated |
| SMILES | CCC(=O)OC(C)C1=CC=CC=C1🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
Odor & Flavor
| Primary Descriptors | floralfruitygreensweet• leffingwell |
| Functional Groups | esteretheraromatic💻 RDKit |
| “Fruity-floral, sweet and green odor, more refined (less harsh) than the Acetate, more typical of Gardenia and Jasmin, with some resemblance to the green topnotes of Tuberoso. In the opinion of many perfumers, this ester is by far superior to the Acetate with respect to attractive, sweet, soft, yet distinctly green-fruity notes. However, a very highly purified Acetate can be virtually free from harsh notes, too.”📖 Arctander | |
| a-Methylbenzyl propionate has a floral, sweet, green odor typical of gardenia and jasmine.📖 Fenaroli | |
Flavor Notes (Arctander)
| “It is also used frequently in flavor compositions, e. g. in the difficult Gooseberry and other berry imitations, fruit complexes, etc.”📖 Arctander |
Regulatory Status
| FEMA Number | FEMA 2689⚖️ FEMA GRAS |
| GRAS Status | Generally Recognized as Safe⚖️ FEMA GRAS |
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: DTXSID9047091
Physical Properties
| Molecular Weight | 178.231 g/mol🔬 EPA CompTox |
| Density | 1 g/cm^3🔬 EPA CTX |
| Boiling Point | 206 °C🔬 EPA CTX |
| Melting Point | -60 °C🔬 EPA CTX |
| Flash Point | 99.758 °C📊 OPERA |
| Refractive Index | 1.497 Dimensionless📊 OPERA |
| Molar Volume | 176.002 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.976 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 2.976 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.976 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.87 Log10 unitless📊 OPERA |
| Water Solubility | 0.002 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.031 mmHg📊 OPERA |
| Viscosity | 3.823 cP📊 OPERA |
| Surface Tension | 34.138 dyn/cm📊 OPERA |
| Thermal Conductivity | 135.533 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 26.3 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 3 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 51.478 cm^3/mol📊 OPERA |
| Polarizability | 20.408 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.
