2-Methyl-trans-2-butenoic acid (CAS 80-59-1) — Green Top-to-middle Note Fragrance Ingredient
2-Methyl-trans-2-butenoic acid
CAS 80-59-1
What Is 2-Methyl-trans-2-butenoic acid?
2-Methyl-trans-2-butenoic acid is a synthetic ingredient used in specialty fragrances. Consumers encounter it in niche perfumes where it contributes unique green, fruity nuances. This molecule matters because it offers perfumers a tool for creating modern, unconventional accords that stand out in competitive markets.
Safety Profile
USE WITH AWARENESSWhat Does 2-Methyl-trans-2-butenoic acid Smell Like?
This molecule delivers a sharp, green opening reminiscent of unripe apples and crushed leaves, with a subtle undertone of sour berries. As it evolves, the heart reveals a more rounded, lactonic quality akin to warm hay. The dry-down is surprisingly clean, leaving a faint metallic whisper that works well in modern chypres.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used at 0.05% to create a cutting-edge green accord that contrasts with synthetic musks in this avant-garde composition.
2D Molecular Structure
SMILES: C\C=C(/C)C(O)=O
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Methyl-trans-2-butenoic acid belongs to the unsaturated carboxylic acids class. While not found in nature, it’s synthesized via crotonic acid modification. The trans configuration is crucial for its odor profile – the cis isomer smells markedly different. Industrial production typically involves catalytic isomerization of precursor acids.
Physical & Chemical Properties
| Boiling Point | Not established |
|---|---|
| Melting Point | Not established |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Niche Perfumery | 0.01-0.1% | Up to 0.2% | For avant-garde effects only |
| Functional Fragrances | Not used | N/A | Too unconventional |
Classic Accords
Tip: Stabilize with antioxidants to prevent polymerization over time.
Alternatives & Comparisons
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA standards.
GHS Classification
RIFM Assessment
No RIFM safety assessment available as of 2023.
Sustainability
As a purely synthetic material, production involves petrochemical feedstocks. The environmental impact is moderate due to small usage volumes in fragrance applications.
Explore 2-Methyl-trans-2-butenoic acid
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References
- PubChem Compound Summary for 2-Methyl-trans-2-butenoic acid CID 5283012
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 80-59-1Physical Properties
| Molecular Weight | 100.12 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1🔬 PubChem |
| Boiling Point | 198.5 °C🔬 EPA CompTox |
| Vapor Pressure | 1.33 mmHg @ 25°C📊 OPERA |
| Involatility Index | 0.1433💻 Calculated |
| log Kp (skin permeability) | -2.601💻 Calculated |
| SMILES | CC=C(C)C(=O)O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Moderate💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | spicysweetwarm• leffingwell |
| Functional Groups | alkene💻 RDKit |
| “Spicy-rooty, sweet-sour herbaceous odor of moderate tenacity.”📖 Arctander | |
| trans-2-Methyl-2-butenoic acid has a sweet, warm, spicy odor.📖 Fenaroli | |
Flavor Notes (Arctander)
| “Spicy-warm, slightly sour taste in concentrations near 50 ppm. The acidulous taste fades away at lower concentrations, leaving only the pleasant, spicy-rooty taste. In spite of the fact that the acid is a naturally occurring component of many essential oils, extracts and spice oleoresins, it has not”📖 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: DTXSID80883257
Physical Properties
| Molecular Weight | 100.117 g/mol🔬 EPA CompTox |
| Density | 0.972 g/cm^3🔬 EPA CTX |
| Boiling Point | 198.5 °C🔬 EPA CTX |
| Melting Point | 63.964 °C🔬 EPA CTX |
| Flash Point | 90.015 °C📊 OPERA |
| Refractive Index | 1.451 Dimensionless📊 OPERA |
| Molar Volume | 99.111 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.107 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 0.508 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | -1.26 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.24 Log10 unitless📊 OPERA |
| Water Solubility | 0.01 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.133 mmHg🔬 EPA CTX |
| Viscosity | 2.042 cP📊 OPERA |
| Surface Tension | 29.184 dyn/cm📊 OPERA |
| Thermal Conductivity | 143.905 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 | 1 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 26.678 cm^3/mol📊 OPERA |
| Polarizability | 10.576 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.
