2-Hydroxyacetophenone (CAS 118-93-4) — Floral Top to Heart Note Fragrance Ingredient

ByThe Good Scents
Floral · Sweet

2-Hydroxyacetophenone

CAS 118-93-4

Origin
synthetic
Note
Top to Heart
IFRA
Generally safe
Data as of: Apr 2026

What Is 2-Hydroxyacetophenone?

2-Hydroxyacetophenone is a synthetic aroma compound with a sweet, floral, and slightly phenolic scent. It is commonly used in perfumes, soaps, and detergents to add a honey-like note. This ingredient matters because it enhances floral accords and provides a cost-effective alternative to natural extracts, making fragrances more accessible without sacrificing quality.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
✓ Safe in regulated products
⚠ Check for skin sensitivity
CAS
118-93-4
Formula
Mixture
MW
Variable
Odor Family
Floral · Sweet
Layer 1 · Enthusiast

What Does 2-Hydroxyacetophenone Smell Like?

2-Hydroxyacetophenone opens with a bright, sweet floral note reminiscent of orange blossoms and honey. As it evolves, a subtle phenolic undertone emerges, adding depth without overpowering. The dry-down is soft and slightly powdery, making it versatile in floral and oriental compositions. Its behavior is linear but blends well with other notes.

Scent Profile

In Famous Fragrances

Fragrance associations may not reflect actual formulations.

Chanel No. 5(Chanel, 1921)

Used to enhance the floral bouquet, adding a honeyed sweetness that complements the rose and jasmine heart.

J'adore(Dior, 1999)

Provides a subtle floral sweetness that balances the fruity top notes and rich ylang-ylang heart.

Layer 2

2D Molecular Structure

2-Hydroxyacetophenone

SMILES: CC(=O)C1=CC=CC=C1O

Chemistry, Properties & Perfumer Guide

The Chemistry

2-Hydroxyacetophenone is a phenolic ketone, synthesized via Friedel-Crafts acylation of phenol. It is a white crystalline solid with a sweet floral odor. The compound is stable under normal conditions but may degrade under strong UV light. Its molecular structure allows for versatile use in fragrance formulations.

Physical & Chemical Properties

Boiling Point198 °C
Melting Point86 °C
Density1.09 g/cm³

Perfumer Guide

Note Position
Top to Heart
Volatility
Medium (1-3 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance1-3%Up to 5%Enhances floral accords
Soap0.5-2%Up to 3%Adds sweetness without discoloration

Classic Accords

Tip: Use in moderation to avoid overpowering the composition.

Alternatives & Comparisons

1
Phenylacetaldehyde CAS 122-78-1

Offers a stronger floral note but is less stable.

2
Benzyl Acetate CAS 140-11-4

Provides a sweeter, fruitier note but lacks depth.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

General reference only. Consult current IFRA Standards Library before formulating.

IFRA Status

Not restricted by IFRA.

RIFM Assessment

RIFM has assessed this ingredient as safe for use in fragrances.

Sustainability

Synthesized from petrochemical sources, 2-Hydroxyacetophenone is not biodegradable. However, its low usage levels minimize environmental impact. Efforts are underway to develop greener synthesis methods.

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References

  1. PubChem: 2-Hydroxyacetophenone CID 118-93-4
  2. IFRA Standards IFRA

Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.

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Ingredient Data Sheet

CAS 118-93-4

Physical Properties

Molecular Weight136.15 g/mol🔬 PubChem
LogP (Octanol-Water)1.9🔬 PubChem
Boiling Point213 °C🔬 EPA CompTox
Vapor Pressure0.0075 mmHg @ 25°C📊 OPERA
Involatility Index0.0007💻 Calculated
log Kp (skin permeability)-2.182💻 Calculated
SMILESCC(=O)C1=CC=CC=C1O🔬 PubChem

Volatility & Performance

Fragrance NoteHeart💻 Calculated
Volatility ClassVery slow💻 Calculated
Persistence Score3.1 / 5💻 Calculated

Odor & Flavor

Primary Descriptorsalmondcherrycinnamoncoumarinichay• leffingwell
Functional Groupsketonephenolaromatic💻 RDKit
Data Sources & Attribution
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: DTXSID7040285

Physical Properties

Molecular Weight 136.15 g/mol🔬 EPA CompTox
Density 1.131 g/cm^3🔬 EPA CTX
Boiling Point 218 °C🔬 EPA CTX
Melting Point 6.5 °C🔬 EPA CTX
Flash Point 94.936 °C📊 OPERA
Refractive Index 1.552 Dimensionless📊 OPERA
Molar Volume 119.394 cm^3/mol📊 OPERA

Partition & Solubility

LogP (Octanol-Water) 1.92 Log10 unitless🔬 EPA CTX
LogD (pH 5.5) 1.99 Log10 unitless📊 OPERA
LogD (pH 7.4) 1.975 Log10 unitless📊 OPERA
LogKoa (Octanol-Air) 6.61 Log10 unitless📊 OPERA
Water Solubility 0.046 mol/L📊 OPERA
Henry's Law Constant 0 atm-m3/mole🔬 EPA CTX

Transport Properties

Vapor Pressure 0.03 mmHg🔬 EPA CTX
Viscosity 7.014 cP📊 OPERA
Surface Tension 42.182 dyn/cm📊 OPERA
Thermal Conductivity 149.929 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 38.162 cm^3/mol📊 OPERA
Polarizability 15.129 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.

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