2-Methylbutyric acid (CAS 116-53-0) — Musky Top to Mid Note Fragrance Ingredient
2-Methylbutyric acid
CAS 116-53-0
What Is 2-Methylbutyric acid?
2-Methylbutyric acid is a synthetic compound often found in cheese aromas and some fermented foods. It contributes a sharp, cheesy note that can enhance savory or dairy accords in fragrances. While not a dominant scent, it plays a crucial role in creating realistic food-like nuances in perfumery, especially for gourmand or avant-garde compositions.
Safety Profile
GENERALLY SAFEWhat Does 2-Methylbutyric acid Smell Like?
2-Methylbutyric acid hits the nose with an intense, sweaty-cheese punch that quickly evolves into a more rounded, fermented dairy character. Like Parmesan left in a gym bag, it’s challenging but fascinating. Over time, it settles into a warm, animalic hum that blends well with musks and woods. In dilution, it can suggest ripe fruit or even tropical nuances.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to amplify the controversial blood/milk accord, contributing a visceral bodily realism that challenges traditional perfumery boundaries.
Employed sparingly to create the authentic barnyard warmth in this animalic gourmand composition.
2D Molecular Structure
SMILES: CCC(C)C(O)=O
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Methylbutyric acid is a branched short-chain fatty acid. While it occurs naturally in some fermented products, the fragrance industry typically uses synthetic versions for consistency. It’s produced through oxidation of 2-methylbutanol or via Grignard reactions. The molecule’s compact structure gives it high volatility and strong odor impact despite its small size.
Physical & Chemical Properties
| Boiling Point | 176-177 °C |
|---|---|
| Density | 0.934 g/cm³ |
| Molecular Weight | 102.13 g/mol |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.01-0.1% | Up to 0.5% | Used as trace modifier |
| Functional Fragrance | 0.001-0.01% | Up to 0.1% | For dairy/cheese notes |
Classic Accords
Tip: Always dilute below 1% in alcohol before incorporation to prevent overwhelming blends.
Alternatives & Comparisons
Similar cheesy character but sharper and more diffusive. Used when a more pronounced top note is desired.
Even more aggressive dairy note, useful for extreme realism in food flavors.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA. Listed as safe up to 0.2% in finished products.
EU Allergen Declaration
Not listed as an EU allergen.
GHS Classification
RIFM Assessment
RIFM assessment completed in 2015 – no significant safety concerns at typical usage levels.
Sustainability
Synthetic production avoids agricultural impacts. The small quantities needed make its environmental footprint negligible. Some manufacturers offer bio-based versions using fermentation processes for greener credentials.
Explore 2-Methylbutyric acid
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References
- PubChem Compound Summary for 2-Methylbutyric acid CID 8314
- Brennand et al. (1989). Flavor chemistry of dairy products. J. Agric. Food Chem.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 116-53-0Physical Properties
| Molecular Weight | 102.13 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.2🔬 PubChem |
| Boiling Point | 176 °C🔬 EPA CompTox |
| Vapor Pressure | 0.491 mmHg @ 25°C📊 OPERA |
| Flash Point | 77 °C🔬 EPA CompTox |
| Involatility Index | 0.0524💻 Calculated |
| log Kp (skin permeability) | -2.471💻 Calculated |
| SMILES | CCC(C)C(=O)O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | fruitypungent• leffingwell |
| “Pungent, acrid odor reminiscent of Roquefort cheese and other cheeses, but not quite as repulsive and stinging as the odor of n-Valeric acid or iso-Valeric acid.”📖 Arctander | |
| 2-Methylbutyric acid has a pungent, acrid odor similar to Roquefort cheese with an acrid taste. At low dilutions, it has a pleasant, fruity taste.📖 Fenaroli | |
Flavor Notes (Arctander)
| “Acrid-acid taste, which becomes quite pleasant and fruity-sour at dilutions below 10 ppm. It is also used in flavor compositions for its contribution to Cheese flavor, Butter imitation, cream, Chocolate, etc.”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 0.783 ppm (n=3)📖 van Gemert |
Regulatory Status
| FEMA Number | FEMA 2695⚖️ FEMA GRAS |
| GRAS Status | Generally Recognized as Safe⚖️ FEMA GRAS |
| 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: DTXSID5021621
Physical Properties
| Molecular Weight | 102.133 g/mol🔬 EPA CompTox |
| Density | 0.936 g/cm^3🔬 EPA CTX |
| Boiling Point | 176.625 °C🔬 EPA CTX |
| Melting Point | -83.333 °C🔬 EPA CTX |
| Flash Point | 76 °C🔬 EPA CTX |
| Refractive Index | 1.418 Dimensionless📊 OPERA |
| Molar Volume | 106.072 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 6.856 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 0.431 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | -1.366 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.19 Log10 unitless📊 OPERA |
| Water Solubility | 0.441 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 1.084 mmHg🔬 EPA CTX |
| Viscosity | 2.215 cP📊 OPERA |
| Surface Tension | 28.284 dyn/cm📊 OPERA |
| Thermal Conductivity | 141.306 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 37.3 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 2 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 26.736 cm^3/mol📊 OPERA |
| Polarizability | 10.599 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.
