2-Butanone (CAS 78-93-3) — Citrus Top Note Fragrance Ingredient
2-Butanone
CAS 78-93-3
What Is 2-Butanone?
2-Butanone, also known as methyl ethyl ketone (MEK), is a common industrial solvent found in paints, adhesives, and varnishes. It’s occasionally used in perfumery for its sharp, acetone-like aroma. While not a typical fragrance ingredient, it may appear in small amounts to create specific effects or as a byproduct in synthetic processes.
Safety Profile
PROFESSIONAL USEWhat Does 2-Butanone Smell Like?
2-Butanone delivers a sharp, piercing odor reminiscent of nail polish remover with a slightly sweeter, fruitier undertone. The initial harsh acetone-like blast quickly dissipates to reveal a dry, chemical character that lacks the warmth of most fragrance ingredients. In dilution, it can contribute to metallic or industrial accords, but generally functions more as a solvent than a perfumery material.
2D Molecular Structure
SMILES: CCC(C)=O
Chemistry, Properties & Perfumer Guide
The Chemistry
2-Butanone (methyl ethyl ketone) is a simple aliphatic ketone with the formula CH3COCH2CH3. Industrially produced via the catalytic dehydrogenation of 2-butanol or as a byproduct of butane oxidation. Its volatility and solvent properties make it more valuable in industrial applications than perfumery, though it may appear as an intermediate in fragrance synthesis.
Physical & Chemical Properties
| Boiling Point | 79.6 °C |
|---|---|
| Flash Point | -9 °C |
| Density | 0.805 g/cm³ |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Industrial Fragrances | <1% | Trace amounts | Mainly as solvent or synthetic intermediate |
Classic Accords
Tip: Use only in well-ventilated professional settings with proper PPE.
Alternatives & Comparisons
For similar solvent properties with even higher volatility in industrial applications.
Less volatile alternative with similar chemical properties for specialized solvent needs.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not restricted by IFRA but not recommended for fragrance use.
GHS Classification
RIFM Assessment
Not evaluated by RIFM for fragrance use due to industrial solvent classification.
Sustainability
2-Butanone is petroleum-derived with significant environmental release from industrial processes. While not bioaccumulative, its high volatility contributes to atmospheric pollution. Synthetic production from fossil fuels raises sustainability concerns with no current green chemistry alternatives at scale.
Explore 2-Butanone
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: DTXSID3021516
Physical Properties
| Molecular Weight | 72.107 g/mol🔬 EPA CompTox |
| Density | 0.803 g/cm^3🔬 EPA CTX |
| Boiling Point | 79.663 °C🔬 EPA CTX |
| Melting Point | -81.229 °C🔬 EPA CTX |
| Flash Point | -5.257 °C🔬 EPA CTX |
| Refractive Index | 1.367 Dimensionless📊 OPERA |
| Molar Volume | 91.682 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 0.29 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 0.349 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 0.349 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 2.71 Log10 unitless🔬 EPA CTX |
| Water Solubility | 3.275 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 87.597 mmHg🔬 EPA CTX |
| Viscosity | 0.356 cP📊 OPERA |
| Surface Tension | 22.86 dyn/cm📊 OPERA |
| Thermal Conductivity | 144.036 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 17.07 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 1 count💻 Computed |
| Rotatable Bonds | 1 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 20.61 cm^3/mol📊 OPERA |
| Polarizability | 8.17 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.
![4,7,7-Trimethyl-6-thiabicyclo[3.2.1]octane (CAS 68398-18-5) — Woody Top to Middle Note Fragrance Ingredient](https://thegoodscents.company/wp-content/uploads/2026/04/4-7-7-trimethyl-6-thiabicyclo-3-2-1-octane-1-768x439.webp)
