Butanoic acid, 2-methyl-, 5-hexen-1-yl ester (CAS 155514-23-1) — Green Top to middle Note Fragrance Ingredient
Butanoic acid, 2-_methyl-_, 5-_hexen-_1-_yl ester
CAS 155514-23-1
What Is Butanoic acid, 2-_methyl-_, 5-_hexen-_1-_yl ester?
Butanoic acid, 2-methyl-, 5-hexen-1-yl ester is a synthetic fragrance compound primarily encountered in laboratory settings and industrial fragrance production. It contributes to complex scent profiles in perfumes and functional products. This ester matters in perfumery for its ability to add fruity, green nuances to compositions, though consumers rarely encounter it as a standalone ingredient.
Safety Profile
USE WITH AWARENESSWhat Does Butanoic acid, 2-_methyl-_, 5-_hexen-_1-_yl ester Smell Like?
This ester delivers a crisp, fruity-green character reminiscent of unripe apples and fresh-cut grass with subtle tropical undertones. The top note presents a sharp, almost effervescent quality that quickly mellows into a rounded fruitiness. As it evolves, a faint woody-musky base emerges, creating an intriguing contrast with the initial brightness. The dry-down reveals surprising persistence for an ester, leaving a clean, slightly soapy trail that works well in modern citrus-floral compositions.
2D Molecular Structure
SMILES: CCC(C)C(=O)OCCCCC=C
Chemistry, Properties & Perfumer Guide
The Chemistry
This branched-chain ester belongs to the class of aliphatic carboxylic acid esters, synthesized through esterification reactions between 2-methylbutanoic acid and 5-hexen-1-ol. The molecule features both a methyl branch and an unsaturated hexenyl chain, contributing to its distinctive olfactory profile. Industrial production typically employs acid-catalyzed Fischer esterification under controlled conditions. The presence of the double bond introduces potential for isomerism, though commercial samples are typically mixtures of isomers.
Physical & Chemical Properties
| Boiling Point | Not available |
|---|---|
| Density | Not available |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Used as a fruity-green modifier |
| Functional Products | 0.1-1% | Up to 3% | Adds freshness to detergents |
Classic Accords
Tip: Use in trace amounts to brighten citrus top notes without overpowering delicate florals.
Alternatives & Comparisons
Similar fruity-green profile but with greater stability in formulations due to saturated alkyl chain.
Offers more pronounced green leaf character while maintaining fruity undertones.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA standards.
RIFM Assessment
No formal RIFM assessment available due to limited commercial use.
Sustainability
As a synthetic material, this ester avoids agricultural sourcing concerns but requires petrochemical feedstocks. Production typically involves moderate energy inputs. The compound’s potency means small quantities can achieve desired effects, reducing overall material consumption in formulations. No known ecological toxicity concerns at typical usage levels.
Explore Butanoic acid, 2-_methyl-_, 5-_hexen-_1-_yl ester
Browse essential oils and aroma compounds.
Browse on iHerb →Affiliate disclosure: we may earn a small commission at no extra cost to you.
Physicochemical Properties
DTXSID: DTXSID30889027
Physical Properties
| Molecular Weight | 184.279 g/mol🔬 EPA CompTox |
| Density | 0.876 g/cm^3📊 OPERA |
| Boiling Point | 225.251 °C📊 OPERA |
| Melting Point | -58.357 °C📊 OPERA |
| Flash Point | 87.335 °C📊 OPERA |
| Refractive Index | 1.434 Dimensionless📊 OPERA |
| Molar Volume | 209.062 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.877 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.877 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.877 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 5.24 Log10 unitless📊 OPERA |
| Water Solubility | 0.001 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.074 mmHg📊 OPERA |
| Viscosity | 1.65 cP📊 OPERA |
| Surface Tension | 27.477 dyn/cm📊 OPERA |
| Thermal Conductivity | 136.032 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 | 7 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 54.469 cm^3/mol📊 OPERA |
| Polarizability | 21.593 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.
![Benzenemethanaminium, N-ethyl-N-[4-[[4-[ethyl[(3-sulfophenyl)methyl]amino]phenyl](2-sulfophenyl)met -hylene]-2,5-cyclohexadien-1-ylidene]-3-sulfo-, inner salt, disodium salt (CAS 3844-45-9) — Citrus N/A Note Fragrance Ingredient](https://thegoodscents.company/wp-content/uploads/2026/04/benzenemethanaminium-n-ethyl-n-4-4-ethyl-1-3-768x439.webp)
![2H-Pyran, 3,6-dihydro-4-methyl-2-[(2,2,3-trimethyl-3-cyclopenten-1-yl)methyl]- (CAS 947237-75-4) — Woody Base Note Fragrance Ingredient](https://thegoodscents.company/wp-content/uploads/2026/04/2h-pyran-3-6-dihydro-4-methyl-2-1-1-768x439.webp)
