2-Methylbutyl 3-methylbutanoate (CAS 2445-77-4) — Sweet Top Note Fragrance Ingredient
2-Methylbutyl 3-methylbutanoate
CAS 2445-77-4
What Is 2-Methylbutyl 3-methylbutanoate?
2-Methylbutyl 3-methylbutanoate is a synthetic fragrance ingredient used to create fruity, apple-like aromas in perfumes and flavored products. You’ll encounter it in body sprays, candles, and some food flavorings. This ester adds a crisp, juicy character that perfumers use to build fresh top notes and enhance fruity accords.
Safety Profile
GENERALLY SAFEWhat Does 2-Methylbutyl 3-methylbutanoate Smell Like?
A vibrant burst of green apple peel with a juicy, slightly tart edge reminiscent of just-picked Granny Smiths. The top note has a sparkling quality like biting into crisp fruit, evolving into a sweeter, rounder aroma akin to apple juice concentrate. Dry-down reveals a faint woody undertone that prevents cloying sweetness, leaving a clean, refreshing trail. Exceptionally diffusive in the first 30 minutes before settling into a soft fruity hum.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Forms the photorealistic apple core of this single-note fragrance, providing both the tart peel and juicy flesh aspects without synthetic harshness.
Used sparingly to enhance the citrus top with fruity facets, contributing to the fragrance’s signature ‘sun-kissed skin’ effect.
2D Molecular Structure
SMILES: CCC(C)COC(=O)CC(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
This branched ester belongs to the aliphatic ester class, synthesized through Fischer esterification between 2-methylbutanol and 3-methylbutanoic acid. The branched structure enhances volatility while reducing harshness compared to straight-chain esters. No chiral centers are present in this molecule. Industrial production typically uses acid catalysis under reflux conditions, with yields optimized through water removal.
Physical & Chemical Properties
| Boiling Point | ~180-190 °C (estimated) |
|---|---|
| Density | ~0.86 g/cm³ (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Fruity top note enhancer |
| Body Care | 0.1-1% | Up to 3% | Freshness booster |
Classic Accords
Tip: Combine with ionones to create more complex fruity-floral effects without losing diffusion.
Alternatives & Comparisons
For a more straightforward apple note with less sweetness and better stability in citrus-heavy blends.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted under current IFRA standards (Amendment 49).
RIFM Assessment
No specific RIFM assessment published; considered low risk based on ester class data.
Sustainability
Synthesized from petrochemical feedstocks but requires minimal energy input compared to complex fragrance molecules. Biodegradation studies predict rapid breakdown in aquatic environments. No known ecological toxicity at usage levels.
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References
- Bauer et al. (2001). Common Fragrance and Flavor Materials.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 2445-77-4Physical Properties
| Molecular Weight | 172.26 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 3.1🔬 PubChem |
| Boiling Point | 191 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -1.55💻 Calculated |
| SMILES | CCC(C)COC(=O)CC(C)C🔬 PubChem |
Volatility & Performance
| Fragrance Note | Heart💻 Calculated |
Odor & Flavor
| Primary Descriptors | appleearthyfruityherbal• leffingwell |
| Functional Groups | esterether💻 RDKit |
| “Herbaceous-fruity, slightly earthy odor of moderate tenacity.”📖 Arctander | |
| 2-Methylbutyl-3-methylbutanoate has an herbaceous, fruity, somewhat earthy fragrance and a sweet, herbaceous, fruity flavor.📖 Fenaroli | |
Flavor Notes (Arctander)
| “Sweet-fruity, powerful, balsamic-herbaceous taste in dilutions below 50 ppm. This ester is used in flavor compositions, mainly in artificial essential oils, e.g. Peppermint. It does not supply any "minty" effect, but it adds the sweet-balsamic, herbaceous note which is characteristic of the non-ment”📖 Arctander |
Regulatory Status
| 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: DTXSID4041440
Physical Properties
| Molecular Weight | 172.268 g/mol🔬 EPA CompTox |
| Density | 0.855 g/cm^3🔬 EPA CTX |
| Boiling Point | 193 °C🔬 EPA CTX |
| Melting Point | -68.31 °C📊 OPERA |
| Flash Point | 61.244 °C📊 OPERA |
| Refractive Index | 1.42 Dimensionless📊 OPERA |
| Molar Volume | 197.838 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.69 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.69 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.69 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.59 Log10 unitless📊 OPERA |
| Water Solubility | 0.002 mol/L📊 OPERA |
| Henry's Law Constant | 0.001 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.812 mmHg📊 OPERA |
| Viscosity | 1.232 cP📊 OPERA |
| Surface Tension | 25.346 dyn/cm📊 OPERA |
| Thermal Conductivity | 126.997 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 | 5 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 50.07 cm^3/mol📊 OPERA |
| Polarizability | 19.849 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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