Isoamyl formate (CAS 110-45-2) — Sweet Top Note Fragrance Ingredient
Isoamyl formate
CAS 110-45-2
What Is Isoamyl formate?
Isoamyl formate is a synthetic ester commonly used in food flavorings and perfumery. It’s what gives artificial banana flavor its distinctive sweet, fruity character. You’ll encounter it in candies, baked goods, and some tropical-inspired fragrances. This ingredient matters because it provides a cost-effective, stable alternative to natural banana extracts while delivering an intensely fruity top note that blends well with other sweet and floral ingredients.
Safety Profile
GENERALLY SAFEWhat Does Isoamyl formate Smell Like?
Isoamyl formate bursts with an intensely sweet, banana-like aroma that’s almost candied in its purity. The initial impression is like biting into a perfectly ripe banana, with a slight rum-like undertone that adds sophistication. As it evolves, the sweetness becomes more nuanced, revealing hints of pear and pineapple. The dry-down is surprisingly clean for such a fruity note, leaving just a whisper of its initial sweetness. In blends, it acts as a bright, uplifting top note that quickly gives way to heart notes.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used here to create the candy-like fruity opening, pairing with red berries to achieve its signature ‘frozen cocktail’ effect. The isoamyl formate provides the banana nuance that makes the composition distinctly tropical.
Contributes to the citrus-grapefruit accord with its fruity sweetness, balancing the bitterness of the citrus notes. The banana facet adds unexpected depth to what could be a straightforward citrus fragrance.
2D Molecular Structure
SMILES: CC(C)CCOC=O
Chemistry, Properties & Perfumer Guide
The Chemistry
Isoamyl formate (isopentyl formate) is an ester formed from isopentanol and formic acid. Industrially produced through Fischer esterification, it’s a clear, colorless liquid with excellent stability. As a small ester (C6H12O2), its volatility makes it ideal for top notes. The molecule’s simple structure lacks chiral centers, eliminating optical activity concerns. Its fruity character comes from the formate ester group, which is particularly effective at producing banana-like aromas even in small concentrations.
Physical & Chemical Properties
| Boiling Point | 123-124 °C |
|---|---|
| Density | 0.876 g/cm³ |
| Flash Point | 25 °C |
| Refractive Index | 1.399 |
| Solubility | Slightly soluble in water, miscible with alcohol |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Used for fruity top notes |
| Functional Fragrance | 1-3% | Up to 10% | In detergents and air fresheners |
| Food Flavoring | 0.01-0.1% | Up to 0.5% | Artificial banana flavor |
Classic Accords
Tip: Use isoamyl formate sparingly in floral compositions to add natural-seeming fruitiness without overwhelming the delicate flowers.
Alternatives & Comparisons
More pear-like than banana, with slightly higher volatility. Preferred when a cleaner fruit note is needed.
Stronger pineapple character, used when a more complex tropical fruit effect is desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions under IFRA standards. Not classified as a sensitizer.
GHS Classification
RIFM Assessment
RIFM evaluation confirms safe use at current industry levels with no significant sensitization potential.
Sustainability
As a purely synthetic material, isoamyl formate doesn’t rely on agricultural production. Its synthesis from petrochemical precursors is energy-efficient with high yields. The environmental impact is primarily from solvent use in production, though modern facilities recover and recycle these effectively. Being biodegradable (OECD 301D), it doesn’t persist in the environment.
Explore Isoamyl formate
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 Isoamyl formate CID 8024
- Fenaroli’s Handbook of Flavor Ingredients (6th Ed)
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPerfumer’s Notes
FEMA #: 2069 | IOFI #: Nature Identical
Isoamyl formate has a plum, fruity characteristic odor suggestive of black currant, with a corresponding sweet taste.
Odor: [‘apple’, ‘black currant’, ‘fruity’, ‘green’, ‘plum’, ‘sweet’, ‘winey’]
MW: 116.16
LogP: 1.8
Ingredient Data Sheet
CAS 110-45-2Physical Properties
| Molecular Weight | 116.16 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.8🔬 PubChem |
| Boiling Point | 123 °C🔬 EPA CompTox |
| Vapor Pressure | 15.31 mmHg @ 25°C📊 OPERA |
| Flash Point | 22.3 °C🔬 EPA CompTox |
| Involatility Index | 1.531💻 Calculated |
| log Kp (skin permeability) | -2.131💻 Calculated |
| SMILES | CC(C)CCOC=O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Fast💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | applefruitygreenplumsweet• leffingwell |
| Functional Groups | ether💻 RDKit |
| “Peculiar green-fruity, deep-sweet odor, almost nauseating undertone. Ethereal-volatile (diffusive) apple-winey topnote. Resembles also Blackcurrant and Plum.”📖 Arctander | |
| Isoamyl formate has a plum, fruity characteristic odor suggestive of black currant, with a corresponding sweet taste.📖 Fenaroli | |
Flavor Notes (Arctander)
| “0.3% soluble in water, miscible with alcohol, perfume and flavor materials, almost insoluble in Glycerin. Pleasant sweet-fruity, winey taste, mostly apple-like. Frequently used in flavor compositions, primarily in imitation Apple. Also for: Apricot, Banana, Blackcurrant, Cherry, Peach, Pineapple, Pl”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 149 ppm📖 van Gemert |
Regulatory Status
| FEMA Number | FEMA 2069⚖️ 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: DTXSID00861734
Physical Properties
| Molecular Weight | 116.16 g/mol🔬 EPA CompTox |
| Density | 0.885 g/cm^3🔬 EPA CTX |
| Boiling Point | 123.5 °C🔬 EPA CTX |
| Melting Point | -93.375 °C🔬 EPA CTX |
| Flash Point | 22.375 °C🔬 EPA CTX |
| Refractive Index | 1.398 Dimensionless📊 OPERA |
| Molar Volume | 131.634 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.634 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 1.634 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.634 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.56 Log10 unitless📊 OPERA |
| Water Solubility | 0.03 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0.001 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 15.193 mmHg🔬 EPA CTX |
| Viscosity | 0.8 cP📊 OPERA |
| Surface Tension | 25.284 dyn/cm📊 OPERA |
| Thermal Conductivity | 136.63 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 | 4 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 31.737 cm^3/mol📊 OPERA |
| Polarizability | 12.581 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.
