4-Hydroxybutanoic acid lactone (CAS 96-48-0) — Sweet Heart Note Fragrance Ingredient

Sweet · Balsamic

4-Hydroxybutanoic acid lactone

CAS 96-48-0

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

What Is 4-Hydroxybutanoic acid lactone?

4-Hydroxybutanoic acid lactone is a synthetic fragrance compound primarily used in perfumery for its unique creamy, fruity aroma. It’s found in some niche fragrances and functional products where a subtle lactonic note is desired. This ingredient matters because it provides a bridge between fresh fruitiness and warm dairy-like notes, allowing perfumers to create intriguing olfactory contrasts. Its subtlety makes it valuable for adding depth without overwhelming other components.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
Approved for fragrance use
Limited safety data available
CAS
96-48-0
Formula
Mixture
MW
Variable
Odor Family
Sweet · Balsamic
Layer 1 · Enthusiast

What Does 4-Hydroxybutanoic acid lactone Smell Like?

4-Hydroxybutanoic acid lactone presents a soft, creamy-fruity character reminiscent of warm milk with a hint of ripe peaches. Initially subtle, it evolves into a comforting lactonic heart that blends seamlessly with floral and woody notes. The dry-down reveals a faintly sweet, almost caramel-like nuance that lingers close to the skin. Unlike more aggressive lactones, this molecule offers a whisper of dairy richness without heaviness, making it ideal for modern transparent compositions where a hint of creamy sophistication is desired between the top and base notes.

Scent Profile
Layer 2

2D Molecular Structure

gamma-Butyrolactone

SMILES: O=C1CCCO1

Chemistry, Properties & Perfumer Guide

The Chemistry

4-Hydroxybutanoic acid lactone belongs to the class of gamma-lactones, cyclic esters formed by intramolecular esterification of 4-hydroxy acids. While theoretically possible in nature, commercial production is exclusively synthetic via acid-catalyzed cyclization of 4-hydroxybutyric acid. The molecule’s five-membered ring structure contributes to its stability and volatility profile. Unlike some lactones with chiral centers, this molecule is achiral, simplifying industrial production while maintaining consistent olfactory properties. Modern synthesis often employs catalytic ring-closing methods that minimize byproducts and improve yield for fragrance applications.

Physical & Chemical Properties

Boiling PointNot established
DensityNot established

Perfumer Guide

Note Position
Heart
Volatility
Medium (2-4 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.5-2%Up to 5%Background lactonic modifier
Functional Products0.1-0.5%Up to 1%Subtle creamy accent

Classic Accords

Tip: Use to soften harsh woody notes or add dimensionality to fruity compositions.

Alternatives & Comparisons

1
Gamma-Decalactone CAS 706-14-9

For stronger peachy-lactonic effects with higher tenacity.

2
Gamma-Octalactone CAS 104-50-7

When a more pronounced coconut-like lactonic character is desired.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

Not currently restricted by IFRA standards.

RIFM Assessment

Not currently evaluated by RIFM. Limited toxicological data available.

Sustainability

As a synthetic material, 4-Hydroxybutanoic acid lactone production avoids agricultural impacts but requires petrochemical feedstocks. Modern manufacturing processes aim to minimize energy use and waste. Being produced in controlled facilities reduces batch variability compared to natural lactones while eliminating land use concerns. Future green chemistry approaches may enable bio-based production from renewable resources.

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References

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

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    Physicochemical Properties

    DTXSID: DTXSID6020224

    Physical Properties

    Molecular Weight 86.09 g/mol🔬 EPA CompTox
    Density 1.143 g/cm^3🔬 EPA CTX
    Boiling Point 204.586 °C🔬 EPA CTX
    Melting Point -43.781 °C🔬 EPA CTX
    Flash Point 95.814 °C🔬 EPA CTX
    Refractive Index 1.442 Dimensionless📊 OPERA
    Molar Volume 76.257 cm^3/mol📊 OPERA

    Partition & Solubility

    LogP (Octanol-Water) -0.543 Log10 unitless🔬 EPA CTX
    LogD (pH 5.5) -0.518 Log10 unitless📊 OPERA
    LogD (pH 7.4) -0.518 Log10 unitless📊 OPERA
    LogKoa (Octanol-Air) 4.01 Log10 unitless📊 OPERA
    Water Solubility 11.713 mol/L🔬 EPA CTX
    Henry's Law Constant 0 atm-m3/mole🔬 EPA CTX

    Transport Properties

    Vapor Pressure 0.53 mmHg🔬 EPA CTX
    Viscosity 0.878 cP📊 OPERA
    Surface Tension 35.434 dyn/cm📊 OPERA

    Molecular Descriptors

    Topological Polar Surface Area 26.3 Ų💻 Computed
    H-Bond Donors 0 count💻 Computed
    H-Bond Acceptors 2 count💻 Computed
    Rotatable Bonds 0 count💻 Computed
    Aromatic Rings 0 count💻 Computed
    Molar Refractivity 20.183 cm^3/mol📊 OPERA
    Polarizability 8.001 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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