Diethyl phthalate (CAS 84-66-2) — Citrus Fixative Note Fragrance Ingredient
Diethyl phthalate
CAS 84-66-2
What Is Diethyl phthalate?
Diethyl phthalate is a synthetic solvent commonly used in fragrances and cosmetics. It helps blend ingredients and extend scent longevity. While odorless itself, it plays a crucial supporting role in many perfumes and personal care products.
Safety Profile
USE WITH AWARENESSWhat Does Diethyl phthalate Smell Like?
Diethyl phthalate is essentially odorless, functioning primarily as a solvent and fixative. Its neutral character allows it to blend seamlessly with other fragrance components without contributing its own scent profile. In formulations, it helps stabilize volatile top notes and extends the overall lifespan of a fragrance on skin.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Historically used as a solvent and fixative to stabilize the complex floral-aldehyde accord.
Helped balance the vanilla-citrus-oriental composition by preventing separation of ingredients.
Used to extend the longevity of the spicy oriental notes in this intense fragrance.
2D Molecular Structure
SMILES: CCOC(=O)C1=CC=CC=C1C(=O)OCC
Chemistry, Properties & Perfumer Guide
The Chemistry
Diethyl phthalate belongs to the phthalate ester family, synthesized through esterification of phthalic anhydride with ethanol. As a diester, it demonstrates excellent solvent properties for both polar and non-polar compounds. Its molecular structure features two ethyl groups attached to a benzene ring via ester linkages, creating a stable, neutral carrier molecule.
Physical & Chemical Properties
| Boiling Point | 298 °C |
|---|---|
| Density | 1.12 g/cm³ |
| Flash Point | 160 °C |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 1-5% | Up to 10% | As solvent/fixative |
| Cosmetics | 0.5-3% | Up to 5% | Plasticizer in nail polish |
Classic Accords
Tip: Use to modify viscosity and extend longevity without affecting scent profile.
Alternatives & Comparisons
Higher molecular weight alternative with similar solvent properties but different volatility profile.
Non-phthalate alternative with comparable solvent capabilities and better regulatory acceptance.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
IFRA restricted in certain applications (Amendment 49). Not permitted in products intended for children.
GHS Classification
RIFM Assessment
RIFM assessment complete – restricted use recommended due to potential endocrine disruption concerns.
Sustainability
Synthetic production raises fewer environmental concerns than natural alternatives, but phthalate class faces increasing regulatory scrutiny. Future formulations may transition to bio-based plasticizers.
Explore Diethyl phthalate
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References
- IFRA Standards (2022). Amendment 49 – Phthalates. IFRA
- EPA Phthalates Action Plan (2012). EPA
- RIFM Safety Assessment (2018). RIFM
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorPhysicochemical Properties
DTXSID: DTXSID7021780
Physical Properties
| Molecular Weight | 222.24 g/mol🔬 EPA CompTox |
| Density | 1.117 g/cm^3🔬 EPA CTX |
| Boiling Point | 295.858 °C🔬 EPA CTX |
| Melting Point | -38.849 °C🔬 EPA CTX |
| Flash Point | 147.144 °C🔬 EPA CTX |
| Refractive Index | 1.508 Dimensionless📊 OPERA |
| Molar Volume | 198.232 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 2.448 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 2.578 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 2.578 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.75 Log10 unitless📊 OPERA |
| Water Solubility | 0.004 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0.002 mmHg🔬 EPA CTX |
| Viscosity | 6.74 cP📊 OPERA |
| Surface Tension | 37.131 dyn/cm📊 OPERA |
| Thermal Conductivity | 142.769 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 52.6 Ų💻 Computed |
| H-Bond Donors | 0 count💻 Computed |
| H-Bond Acceptors | 4 count💻 Computed |
| Rotatable Bonds | 4 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 59.065 cm^3/mol📊 OPERA |
| Polarizability | 23.415 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.
