Methyl acetoacetate (CAS 105-45-3) — Sweet Top Note Fragrance Ingredient
Methyl acetoacetate
CAS 105-45-3
What Is Methyl acetoacetate?
Methyl acetoacetate is a synthetic ester used in perfumery for its fruity, sweet aroma. You’ll encounter it in fragrances that aim for a fresh, apple-like character. This ingredient matters because it adds a natural-seeming fruity lift to compositions while being more stable than some natural alternatives.
Safety Profile
GENERALLY SAFEWhat Does Methyl acetoacetate Smell Like?
Methyl acetoacetate opens with a bright, juicy character reminiscent of green apples and unripe strawberries. The heart reveals a candied nuance like pear drops or bubblegum, with a subtle floral undertone. Dry-down is clean and slightly woody, leaving a transparent fruity trail. Compared to ethyl acetoacetate, it’s sharper and more ‘green’.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as primary fruity modifier to create realistic apple top notes without natural material instability.
2D Molecular Structure
SMILES: COC(=O)CC(C)=O
Chemistry, Properties & Perfumer Guide
The Chemistry
Methyl acetoacetate is the methyl ester of acetoacetic acid, belonging to the β-ketoester family. Industrially produced via esterification of acetoacetic acid with methanol. The keto-enol tautomerism gives unique reactivity. Used as precursor in pharmaceutical synthesis and as fragrance building block.
Physical & Chemical Properties
| Boiling Point | 169-170 °C |
|---|---|
| Density | 1.077 g/cm³ |
| Refractive Index | 1.418 |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Functional Fragrances | 0.5-2% | Up to 5% | For fruity freshness |
| Fine Fragrance | 0.1-1% | Up to 3% | Top note modifier |
Classic Accords
Tip: Use with citrus to enhance freshness or with sweet ambers to create fruity-candy effects.
Alternatives & Comparisons
Softer, more pear-like character with better longevity.
More distinctly apple with greener top notes.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted by IFRA.
RIFM Assessment
Recognized as safe at current usage levels in fragrances.
Sustainability
Synthetically produced from petrochemical feedstocks. More sustainable than some natural fruit extracts due to stability requiring fewer reapplications. Biodegradability data suggests moderate environmental persistence.
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References
- PubChem: Methyl acetoacetate CID 7758
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 105-45-3Physical Properties
| Molecular Weight | 116.11 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 0🔬 PubChem |
| Boiling Point | 168.9 °C🔬 EPA CompTox |
| Vapor Pressure | 0.89 mmHg @ 25°C📊 OPERA |
| Flash Point | 70 °C🔬 EPA CompTox |
| Involatility Index | 0.089💻 Calculated |
| log Kp (skin permeability) | -3.408💻 Calculated |
| SMILES | CC(=O)CC(=O)OC🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | applefruitygreen• leffingwell |
| Functional Groups | ketoneesterether💻 RDKit |
| “Ethereal-green, winy odor of moderate to poor tenacity.”📖 Arctander | |
Flavor Notes (Arctander)
| “Sweet-ethereal, somewhat green-fruity, winy taste. This ketoester has been suggested for use in flavor compositions as a modifier for the Ethylester (see Ethyl acetoacetate). It does not fall quite so naturally into the winy or fruity flavor types most commonly”📖 Arctander |
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: DTXSID9026716
Physical Properties
| Molecular Weight | 116.116 g/mol🔬 EPA CompTox |
| Density | 1.077 g/cm^3🔬 EPA CTX |
| Boiling Point | 169.963 °C🔬 EPA CTX |
| Melting Point | -70.455 °C🔬 EPA CTX |
| Flash Point | 68.111 °C🔬 EPA CTX |
| Refractive Index | 1.399 Dimensionless📊 OPERA |
| Molar Volume | 111.671 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | -0.33 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 0.148 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 0.147 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.02 Log10 unitless📊 OPERA |
| Water Solubility | 4.099 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0.941 mmHg🔬 EPA CTX |
| Viscosity | 0.863 cP📊 OPERA |
| Surface Tension | 30.837 dyn/cm📊 OPERA |
| Thermal Conductivity | 148.439 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 43.37 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 3 count💻 Computed |
| Rotatable Bonds | 2 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 27.018 cm^3/mol📊 OPERA |
| Polarizability | 10.711 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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