3,5,5-Trimethylhexanal (CAS 5435-64-3) — Green Top to middle Note Fragrance Ingredient
3,5,5-Trimethylhexanal
CAS 5435-64-3
What Is 3,5,5-Trimethylhexanal?
3,5,5-Trimethylhexanal is a synthetic fragrance ingredient with a fresh, green, and slightly floral aroma. It is commonly found in modern perfumes and household products like detergents and air fresheners. This aldehyde contributes a crisp, clean character that enhances freshness in formulations. Its importance lies in its ability to bridge citrus and floral notes, creating a bright yet sophisticated scent profile that works well in contemporary fragrances.
Safety Profile
USE WITH AWARENESSWhat Does 3,5,5-Trimethylhexanal Smell Like?
3,5,5-Trimethylhexanal opens with a burst of crisp green freshness, reminiscent of freshly cut grass with a subtle citrus undertone. As it evolves, a delicate floral heart emerges, akin to lily-of-the-valley wrapped in dewy leaves. The dry-down reveals a clean, slightly woody nuance that lingers softly. Its dynamic character makes it versatile, blending seamlessly with both citrus top notes and floral heart accords while maintaining a modern, airy quality throughout.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used to amplify the citrus top notes while adding a sophisticated green freshness that transitions smoothly into the floral heart.
Provides the crisp, watery green accent that complements the citrus and apple notes, enhancing the fragrance’s vibrant character.
Contributes to the clean, ozonic freshness that defines this modern interpretation of a laundry-inspired scent.
Used for its energizing green facets that blend with citrus and herbal notes to create an invigorating effect.
Adds a dewy, vegetal freshness that evokes the scent of rain on tropical leaves and flowers.
2D Molecular Structure
SMILES: CC(CC=O)CC(C)(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
3,5,5-Trimethylhexanal is a branched-chain aldehyde belonging to the family of fatty aldehydes. Synthetic production typically involves the hydroformylation of diisobutylene, followed by purification steps to achieve the desired isomer. Its molecular structure features a terminal aldehyde group that contributes to its reactivity and fresh odor characteristics. The trimethyl branching pattern enhances its volatility while providing steric hindrance that influences its odor profile and stability in formulations.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Approx. 180-190 °C |
| Density | ~0.82 g/cm³ |
| Solubility | Slightly soluble in water, miscible with alcohols and oils |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Fresh top note modifier |
| Functional Fragrance | 0.1-0.5% | Up to 1% | Freshness booster |
| Household Products | 0.05-0.2% | Up to 0.5% | Clean scent enhancer |
Classic Accords
Tip: Stabilize in ethanol before adding to water-based systems to prevent aldehyde reactions.
Alternatives & Comparisons
Offers similar green freshness but with more floralcy and less volatility, suitable for longer-lasting effects.
Provides a more straightforward citrus-aldehyde character when a simpler freshness is desired.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
Not currently restricted by IFRA. General aldehyde precautions apply for formulation stability.
GHS Classification
RIFM Assessment
RIFM assessment confirms safe use at current industry levels with proper handling precautions.
Sustainability
As a synthetic material, 3,5,5-Trimethylhexanal production avoids natural resource depletion. Modern manufacturing processes aim to minimize waste and energy consumption. Its efficiency in formulations (low usage levels) contributes to reduced environmental impact compared to some natural alternatives requiring higher concentrations.
Explore 3,5,5-Trimethylhexanal
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References
- Bauer et al. (2001). Modern Aldehydes in Perfumery. Perfumer & Flavorist. Industry reference
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID6047107
Physical Properties
| Molecular Weight | 142.242 g/mol🔬 EPA CompTox |
| Density | 0.819 g/cm^3🔬 EPA CTX |
| Boiling Point | 171.011 °C🔬 EPA CTX |
| Melting Point | -32.754 °C📊 OPERA |
| Flash Point | 52.782 °C🔬 EPA CTX |
| Refractive Index | 1.416 Dimensionless📊 OPERA |
| Molar Volume | 174.84 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.086 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.086 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.086 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 4.42 Log10 unitless📊 OPERA |
| Water Solubility | 0.002 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 1.888 mmHg🔬 EPA CTX |
| Viscosity | 1.381 cP📊 OPERA |
| Surface Tension | 25.159 dyn/cm📊 OPERA |
| Thermal Conductivity | 126.539 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 | 3 count💻 Computed |
| Aromatic Rings | 0 count💻 Computed |
| Molar Refractivity | 43.856 cm^3/mol📊 OPERA |
| Polarizability | 17.386 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.
