3-(Methylthio)propionaldehyde (CAS 3268-49-3) — Spicy Top to middle Note Fragrance Ingredient
3-(Methylthio)propionaldehyde
CAS 3268-49-3
What Is 3-(Methylthio)propionaldehyde?
3-(Methylthio)propionaldehyde is a synthetic aroma chemical used in perfumery and flavoring. It has a powerful, onion-like odor at high concentrations but becomes savory and meaty when diluted. Consumers encounter it in savory flavorings and certain perfumes where it adds depth. This ingredient matters because it provides a unique sulfurous character that enhances umami notes in fragrances and food products.
Safety Profile
USE WITH AWARENESSWhat Does 3-(Methylthio)propionaldehyde Smell Like?
At full strength, 3-(Methylthio)propionaldehyde assaults the nose with a pungent, sulfurous onion-garlic intensity. But magic happens at dilution – it transforms into a rich, brothy umami note reminiscent of simmering meat stock. The sulfur edge remains as an intriguing shadow, adding complexity to the otherwise savory profile. In drydown, it leaves a faint metallic whisper that lingers surprisingly long for such a volatile molecule.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used at trace levels to create the savory, meaty illusion in this novelty fragrance.
Provides a subtle animalic depth beneath the oud and rose notes.
2D Molecular Structure
SMILES: CSCCC=O
Chemistry, Properties & Perfumer Guide
The Chemistry
3-(Methylthio)propionaldehyde belongs to the class of sulfur-containing aldehydes. The methylthio (-SCH3) group attached to the propionaldehyde backbone is responsible for its distinctive odor profile. Industrially produced via the reaction of acrolein with methyl mercaptan, this compound demonstrates how minor structural changes (the sulfur substitution) create dramatically different olfactory properties compared to simple aldehydes.
Physical & Chemical Properties
| Boiling Point | Not well documented |
|---|---|
| Density | Not well documented |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Savory Flavors | 0.1-1 ppm | Up to 5 ppm | Provides meaty umami character |
| Fine Fragrance | 0.01-0.1% | Up to 0.5% | Adds animalic complexity |
Classic Accords
Tip: Use in extreme dilution – this material has powerful odor characteristics that can easily overwhelm a composition.
Alternatives & Comparisons
Similar sulfurous character but with more pronounced potato-like notes at dilution.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific IFRA restrictions. General aldehyde precautions apply.
EU Allergen Declaration
Not listed as an EU allergen.
GHS Classification
RIFM Assessment
RIFM has evaluated similar sulfur-containing aldehydes but no specific assessment found for this material.
Sustainability
As a synthetic material, production requires petrochemical feedstocks. The sulfur content necessitates careful waste management during manufacturing to prevent environmental contamination.
Explore 3-(Methylthio)propionaldehyde
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References
- PubChem Compound Summary for 3-(Methylthio)propionaldehyde CID 2723625
- 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 errorPhysicochemical Properties
DTXSID: DTXSID9027528
Physical Properties
| Molecular Weight | 104.17 g/mol🔬 EPA CompTox |
| Density | 1.039 g/cm^3🔬 EPA CTX |
| Boiling Point | 166.36 °C🔬 EPA CTX |
| Melting Point | -63.667 °C🔬 EPA CTX |
| Flash Point | 61.932 °C🔬 EPA CTX |
| Refractive Index | 1.456 Dimensionless📊 OPERA |
| Molar Volume | 105.85 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 0.007 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 1.082 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.082 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 3.47 Log10 unitless📊 OPERA |
| Water Solubility | 0.204 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 1.078 mmHg🔬 EPA CTX |
| Viscosity | 0.731 cP📊 OPERA |
| Surface Tension | 29.97 dyn/cm📊 OPERA |
| Thermal Conductivity | 145.251 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 17.07 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 3 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 28.764 cm^3/mol📊 OPERA |
| Polarizability | 11.403 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.
