Isobutyl alcohol (CAS 78-83-1) — Sweet Carrier Note Fragrance Ingredient
Isobutyl alcohol
CAS 78-83-1
What Is Isobutyl alcohol?
Isobutyl alcohol is a common synthetic alcohol used in perfumes and household products. You’ll encounter it in everything from fine fragrances to cleaning solutions. This ingredient matters because it helps blend other scent components while adding a subtle alcoholic sharpness that evaporates quickly.
Safety Profile
GENERALLY SAFEWhat Does Isobutyl alcohol Smell Like?
Isobutyl alcohol presents a sharp, pungent alcoholic blast upon first sniff – reminiscent of rubbing alcohol but slightly fruitier. The initial harshness quickly gives way to a cleaner, more neutral odor profile as it evaporates. In blends, it acts as a transparent carrier rather than a dominant scent, leaving behind faint waxy undertones during dry-down.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a solvent for floral absolutes, helping blend the complex bouquet without adding its own character.
Acts as a carrier for the fougère accord, allowing quick evaporation of top notes.
2D Molecular Structure
SMILES: CC(C)CO
Chemistry, Properties & Perfumer Guide
The Chemistry
Isobutyl alcohol (2-methyl-1-propanol) is a branched-chain primary alcohol. Industrially produced via hydroformylation of propylene followed by hydrogenation. The branched structure gives it different solvent properties compared to straight-chain butanol isomers.
Physical & Chemical Properties
| Boiling Point | 108 °C |
|---|---|
| Flash Point | 27 °C |
| Density | 0.802 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 10% | Mainly as solvent/carrier |
| Functional Fragrances | 5-15% | Up to 20% | Higher levels in cleaning products |
Classic Accords
Tip: Use to modify ethanol’s drying rate when working with sensitive absolutes.
Alternatives & Comparisons
More polar solvent with faster evaporation profile.
Higher volatility alternative for quick-drying applications.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No IFRA restrictions (48th Amendment).
GHS Classification
RIFM Assessment
RIFM evaluation confirms safe use at current exposure levels.
Sustainability
Petroleum-derived but efficiently produced at industrial scale. Lower carbon footprint than some natural solvents due to concentrated production.
Explore Isobutyl alcohol
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References
- PubChem Compound Summary for Isobutyl alcohol CID 6560
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 78-83-1Physical Properties
| Molecular Weight | 74.12 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 0.8🔬 PubChem |
| Boiling Point | 107.2 °C🔬 EPA CompTox |
| Vapor Pressure | 10 mmHg @ 25°C📊 OPERA |
| Flash Point | 27.8 °C🔬 EPA CompTox |
| Involatility Index | 1.2519💻 Calculated |
| log Kp (skin permeability) | -2.584💻 Calculated |
| SMILES | CC(C)CO🔬 PubChem |
Volatility & Performance
| Fragrance Note | Top💻 Calculated |
| Volatility Class | Fast💻 Calculated |
| Persistence Score | 0.5 / 5💻 Calculated |
Odor & Flavor
| Primary Descriptors | sweet• leffingwell |
| Functional Groups | alcohol💻 RDKit |
| “Choking, cough-provoking odor unless di-”📖 Arctander | |
| Isobutyl alcohol has a penetrating, wine-like, disagreeable odor.📖 Fenaroli | |
Flavor Notes (Arctander)
| “Used in flavor compositions for imitation Butter, Cola, Fruit, Liquor, Rum, Whisky, etc.”📖 Arctander |
Sensory Thresholds
| Odor Detection Threshold | 27.2928 ppm (n=14)📖 van Gemert |
Regulatory Status
| FEMA Number | FEMA 2179⚖️ 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: DTXSID0021759
Physical Properties
| Molecular Weight | 74.123 g/mol🔬 EPA CompTox |
| Density | 0.8 g/cm^3🔬 EPA CTX |
| Boiling Point | 107.93 °C🔬 EPA CTX |
| Melting Point | -100.15 °C🔬 EPA CTX |
| Flash Point | 28.684 °C🔬 EPA CTX |
| Refractive Index | 1.393 Dimensionless📊 OPERA |
| Molar Volume | 92.445 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.227 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 0.745 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 0.745 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.93 Log10 unitless🔬 EPA CTX |
| Water Solubility | 1.123 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 10.004 mmHg🔬 EPA CTX |
| Viscosity | 2.408 cP📊 OPERA |
| Surface Tension | 25.384 dyn/cm📊 OPERA |
| Thermal Conductivity | 148.567 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 20.23 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 | 22.074 cm^3/mol📊 OPERA |
| Polarizability | 8.751 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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