Citral propylene glycol acetal (CAS 10444-50-5) — Citrus Top Note Fragrance Ingredient
Citral propylene glycol acetal
CAS 10444-50-5
What Is Citral propylene glycol acetal?
Citral propylene glycol acetal is a synthetic fragrance ingredient used to stabilize citral, a key citrus-floral note. Found in household cleaners, personal care products, and some fine fragrances. This modified form prevents citral’s oxidation, maintaining a fresh, lemony scent longer in products exposed to air or light.
Safety Profile
GENERALLY SAFEWhat Does Citral propylene glycol acetal Smell Like?
A crisp, bright burst of Meyer lemon zest with subtle lily-of-the-valley undertones. The acetal modification rounds out citral’s sharp edges, creating a more stable citrus note that evolves into a clean, slightly woody dry-down. Compared to pure citral, it lacks the metallic harshness and instead offers a polished, almost candied lemon character.
2D Molecular Structure
SMILES: CC1COC(O1)C=C(C)CCC=C(C)C
Chemistry, Properties & Perfumer Guide
The Chemistry
Citral propylene glycol acetal is a ketal derivative formed by reacting citral (a mixture of geranial and neral) with propylene glycol. This protects citral’s aldehyde groups from oxidation. The resulting compound has improved stability while retaining citral’s characteristic citrus-floral profile. Industrially produced via acid-catalyzed acetalization under controlled conditions.
Physical & Chemical Properties
| Appearance | Colorless to pale yellow liquid |
|---|---|
| Boiling Point | Not well documented |
| Solubility | Soluble in alcohol, oils; insoluble in water |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-3% | Up to 5% | As citral stabilizer |
| Functional Products | 0.5-2% | Up to 3% | For citrus freshness |
Classic Accords
Tip: Use to replace citral in formulations prone to oxidation.
Alternatives & Comparisons
More stable but less fresh-smelling alternative for citrus accords.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No restrictions. Considered more stable alternative to citral.
EU Allergen Declaration
Must declare if citral content exceeds 0.001% in leave-on products.
RIFM Assessment
RIFM-reviewed – safe at current usage levels.
Sustainability
Synthetic production avoids citrus crop variability. No known major environmental concerns at industry usage scales.
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References
- Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press.
- IFRA Standards Library IFRA
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID50864270
Physical Properties
| Molecular Weight | 210.317 g/mol🔬 EPA CompTox |
| Density | 0.93 g/cm^3📊 OPERA |
| Boiling Point | 265.5 °C🔬 EPA CTX |
| Melting Point | -22.927 °C📊 OPERA |
| Flash Point | 104.105 °C📊 OPERA |
| Refractive Index | 1.506 Dimensionless📊 OPERA |
| Molar Volume | 218.938 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 3.823 Log10 unitless📊 OPERA |
| LogD (pH 5.5) | 3.823 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 3.823 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.66 Log10 unitless📊 OPERA |
| Water Solubility | 0.002 mol/L📊 OPERA |
| Henry's Law Constant | 0 atm-m3/mole📊 OPERA |
Transport Properties
| Vapor Pressure | 0.015 mmHg📊 OPERA |
| Viscosity | 3.765 cP📊 OPERA |
| Surface Tension | 29.449 dyn/cm📊 OPERA |
| Thermal Conductivity | 127.748 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 18.46 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 | 65.04 cm^3/mol📊 OPERA |
| Polarizability | 25.784 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.
