4-Hydroxybenzaldehyde (CAS 123-08-0) — Sweet Heart Note Fragrance Ingredient
4-Hydroxybenzaldehyde
CAS 123-08-0
What Is 4-Hydroxybenzaldehyde?
4-Hydroxybenzaldehyde is a synthetic fragrance ingredient with a sweet, floral, and slightly phenolic character. It’s commonly used in perfumes and flavorings to add depth and complexity. This molecule matters because it serves as a building block for more complex fragrance compounds and contributes to the overall harmony of floral and oriental compositions.
Safety Profile
USE WITH AWARENESSWhat Does 4-Hydroxybenzaldehyde Smell Like?
4-Hydroxybenzaldehyde presents a delicate balance of sweet floralcy and subtle phenolic sharpness. The initial impression is reminiscent of cherry blossoms with a honeyed undertone, evolving into a heart that reveals almond-like nuances. In drydown, it leaves a clean, slightly powdery trail with whispers of vanilla. The overall effect is airy yet substantive, like sunlight filtering through lace curtains in a spring garden.
In Famous Fragrances
Fragrance associations may not reflect actual formulations.
Used as a floral enhancer to amplify the magnolia and orchid notes, contributing to the fragrance’s luminous quality.
Provides subtle sweetness that bridges the grapefruit top notes to the floral heart in this fresh composition.
2D Molecular Structure
SMILES: OC1=CC=C(C=O)C=C1
Chemistry, Properties & Perfumer Guide
The Chemistry
4-Hydroxybenzaldehyde is an aromatic aldehyde with a hydroxyl group para to the formyl group. It’s synthesized through several routes including the Reimer-Tiemann reaction or oxidation of 4-hydroxybenzyl alcohol. The molecule’s planar structure and hydrogen bonding capability influence its volatility and solubility properties. While not chiral itself, it serves as an intermediate for chiral fragrance compounds.
Physical & Chemical Properties
| Melting Point | 115-117 °C |
|---|---|
| Solubility | Soluble in alcohol, slightly in water |
Perfumer Guide
| Application | Typical % | Range | Notes |
|---|---|---|---|
| Fine Fragrance | 0.5-2% | Up to 5% | Floral modifier |
| Soap | 0.1-0.5% | Up to 1% | Stability concerns |
Classic Accords
Tip: Stabilize in ethanol solutions to prevent oxidation during storage.
Alternatives & Comparisons
For stronger sweet vanilla character when phenolic notes are undesirable.
Provides similar floralcy with better diffusion and marine aspects.
Safety, Regulatory & Sustainability
⚠ Regulatory Disclaimer
General reference only. Consult current IFRA Standards Library before formulating.
IFRA Status
No specific restrictions under current IFRA standards.
GHS Classification
RIFM Assessment
RIFM assessment confirms safe use at current industry levels.
Sustainability
Synthesized from petrochemical precursors with moderate environmental impact. Research ongoing into bio-based production from lignin derivatives.
Explore 4-Hydroxybenzaldehyde
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References
- Bauer et al. (2001). Common Fragrance and Flavor Materials. Wiley-VCH.
Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.
Report a data errorIngredient Data Sheet
CAS 123-08-0Physical Properties
| Molecular Weight | 122.12 g/mol🔬 PubChem |
| LogP (Octanol-Water) | 1.4🔬 PubChem |
| Boiling Point | 310 °C🔬 EPA CompTox |
| log Kp (skin permeability) | -2.451💻 Calculated |
| SMILES | C1=CC(=CC=C1C=O)O🔬 PubChem |
Volatility & Performance
| Fragrance Note | Base💻 Calculated |
Odor & Flavor
| Primary Descriptors | almondbalsamichaynuttyphenolicwoody• leffingwell |
| Functional Groups | aldehydephenolaromatic💻 RDKit |
| 4-Hydroxybenzaldehyde has a very faint, sweet-woody-balsamic odor and a sweet taste with little or no other flavor impression. The odor is also reported as vanillic/ nutty.📖 Fenaroli | |
Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.
Physicochemical Properties
DTXSID: DTXSID8059552
Physical Properties
| Molecular Weight | 122.123 g/mol🔬 EPA CompTox |
| Density | 1.37 g/cm^3🔬 EPA CTX |
| Boiling Point | 310.25 °C🔬 EPA CTX |
| Melting Point | 111.076 °C🔬 EPA CTX |
| Flash Point | 124.9 °C🔬 EPA CTX |
| Refractive Index | 1.618 Dimensionless📊 OPERA |
| Molar Volume | 99.529 cm^3/mol📊 OPERA |
Partition & Solubility
| LogP (Octanol-Water) | 1.346 Log10 unitless🔬 EPA CTX |
| LogD (pH 5.5) | 1.369 Log10 unitless📊 OPERA |
| LogD (pH 7.4) | 1.181 Log10 unitless📊 OPERA |
| LogKoa (Octanol-Air) | 6.28 Log10 unitless📊 OPERA |
| Water Solubility | 0.095 mol/L🔬 EPA CTX |
| Henry's Law Constant | 0 atm-m3/mole🔬 EPA CTX |
Transport Properties
| Vapor Pressure | 0 mmHg🔬 EPA CTX |
| Viscosity | 5.467 cP📊 OPERA |
| Surface Tension | 47.239 dyn/cm📊 OPERA |
| Thermal Conductivity | 158.109 mW/(m*K)📊 OPERA |
Molecular Descriptors
| Topological Polar Surface Area | 37.3 Ų💻 Computed |
| H-Bond Donors | 1 count💻 Computed |
| H-Bond Acceptors | 2 count💻 Computed |
| Rotatable Bonds | 1 count💻 Computed |
| Aromatic Rings | 1 count💻 Computed |
| Molar Refractivity | 34.887 cm^3/mol📊 OPERA |
| Polarizability | 13.83 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.
