2-Methylpent-2-en-1-oic acid (CAS 3142-72-1) — Green Top Note Fragrance Ingredient
2-Methylpent-2-en-1-oic acid
CAS 3142-72-1
What Is 2-Methylpent-2-en-1-oic acid?
2-Methylpent-2-en-1-oic acid is a synthetic fragrance ingredient used to add green, slightly fruity nuances to perfumes. It’s found in some modern floral and citrus compositions. While not widely known by consumers, it contributes important top-note effects that make fragrances smell fresh and vibrant upon first application.
Safety Profile
USE WITH AWARENESSWhat Does 2-Methylpent-2-en-1-oic acid Smell Like?
This molecule offers a crisp, green impression reminiscent of crushed leaves with a subtle tartness like unripe berries. The opening is sharp and vegetal, evolving into a milder herbal character that lingers close to the skin. In drydown, it leaves a faint, clean-waxy trail that works well with citrus and floral notes.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to enhance the radical green galbanum note, providing additional leafy sharpness that makes this fragrance revolutionary for its time.
Contributes to the aromatic freshness alongside rosemary and citrus, giving the fougère structure extra vibrancy.
2D Molecular Structure
SMILES: CCC=C(C)C(O)=O
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Methylpent-2-en-1-oic acid is an unsaturated branched-chain carboxylic acid. Industrially produced through oxidation of corresponding aldehydes or via Grignard reactions. The double bond at position 2 creates reactivity useful for further chemical modifications. The branched structure influences both volatility and odor characteristics compared to straight-chain analogs.
Physical & Chemical Properties
| Molecular Weight | 128.17 g/mol |
|---|---|
| Boiling Point | ~220°C (estimated) |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | For green accents |
| Functional Fragrance | 0.1-1% | Up to 3% | In detergents for fresh effect |
Classic Accords
Tip: Use with citrus top notes to prevent harshness while maintaining freshness.
Alternatives & Comparisons
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific IFRA restrictions. General guidelines for carboxylic acids apply.
RIFM Assessment
Not currently evaluated by RIFM. Recommended usage levels based on analog data.
Sustainability
Synthesized from petrochemical feedstocks. Energy-intensive production but used at very low levels makes environmental impact minimal per finished product. No known ecological toxicity concerns at usage concentrations.
Explore 2-Methylpent-2-en-1-oic acid
Browse essential oils and aroma compounds.
Browse on iHerb →Affiliate disclosure: we may earn a small commission at no extra cost to you.
References
- PubChem Compound Summary for 2-Methylpent-2-en-1-oic acid CID 5283026
- 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 3142-72-1Physical Properties
| Molecular Weight | 114.14 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.4🔬 PubChem |
| Boiling Point | 214 °C🔬 EPA CompTox |
| Vapor Pressure | 0.1318 mmHg @ 25°C📊 OPERA |
| Flash Point | 107.8 °C🔬 EPA CompTox |
| Involatility Index | 0.0133💻 Calculated |
| log Kp (skin permeability) | -2.402💻 Calculated |
| SMILES | CCC=C(C)C(=O)O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Slow💻 Calculated |
| Persistence Score | 1.1 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | floralgreen• leffingwell |
| Functional Groups | alkene💻 RDKit |
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: DTXSID0051998
Physical Properties
| Molecular Weight | 114.144 g/mol🔬 EPA CompTox |
| Density | 0.98 g/cm^3🔬 EPA CTX |
| Boiling Point | 214 °C🔬 EPA CTX |
| Melting Point | 24.7 °C🔬 EPA CTX |
| Flash Point | 102.159 °C📊 OPERA |
| Refractive Index | 1.454 Dimensionless📊 OPERA |
| Molar Volume | 115.618 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.621 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 0.842 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | -0.965 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.79 Log10 unitless📊 OPERA |
| Water Solubility | 0.098 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.096 mmHg📊 OPERA |
| Viscosity | 2.324 cP📊 OPERA |
| Surface Tension | 29.491 dyn/cm📊 OPERA |
| Thermal Conductivity | 143.031 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 | 31.311 cm^3/mol📊 OPERA |
| Polarizability | 12.413 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.
Related Research
- ()-Bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, ethyl ester (CAS 10138-32-6) — Woody Middle Note Fragrance Ingredient
- Isobutyl alcohol (CAS 78-83-1) — Sweet Carrier Note Fragrance Ingredient
- p-Ethylphenol (CAS 0123-07-09) — Balsamic Base Note Fragrance Ingredient
- Ethyl ricinoleate (CAS 55066-53-0) — Woody Base Note Fragrance Ingredient
![(2R*,4R*,4aR*,9bS*)- 2,4-dimethyl-4,4a,5,9b-tetrahydroindeno[ 1,2- d][1,3]dioxine (CAS 578020-40-3) — Woody Unknown Note Fragrance Ingredient](https://thegoodscents.company/wp-content/uploads/2026/04/unnamed-file-81-768x439.webp)
