Isobutyl butyrate (CAS 539-90-2) — Sweet Top Note Fragrance Ingredient

ByThe Good Scents
Sweet · Citrus

Isobutyl butyrate

CAS 539-90-2

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

What Is Isobutyl butyrate?

Isobutyl butyrate is a fruity-smelling compound used in food flavorings and perfumes. You’ll encounter it in tropical fruit-flavored candies, beverages, and some floral fragrances. This ester adds a juicy, pineapple-like sweetness that perfumers use to create bright, summery scents.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
✓ GRAS for food use
✓ No known allergen concerns
CAS
539-90-2
Formula
Mixture
MW
Variable
Odor Family
Sweet · Citrus
Layer 1 · Enthusiast

What Does Isobutyl butyrate Smell Like?

Isobutyl butyrate bursts with a vibrant, candy-like fruitiness—imagine overripe pineapple chunks drizzled with honey. The top note has a slightly fermented, almost rum-like warmth that quickly settles into a clean, jammy sweetness. As it dries down, it reveals a subtle green undertone like the white pith of citrus fruits, preventing it from becoming cloying. The overall effect is like walking through a tropical farmers’ market at peak ripeness.

Scent Profile

In Famous Fragrances

Fragrance associations may not reflect actual formulations.

Virgin Island Water(Creed, 2007)

Used here to amplify the coconut-pineapple cocktail effect, blending with lime and tropical flowers to create a photorealistic beach vacation scent.

Pineapple Vintage(Parfums de Marly, 2018)

Provides the candied pineapple core of this gourmand fragrance, balanced with vanilla and woody notes to prevent excessive sweetness.

Layer 2

2D Molecular Structure

Isobutyl butyrate

SMILES: CCCC(=O)OCC(C)C

Chemistry, Properties & Perfumer Guide

The Chemistry

Isobutyl butyrate is an ester formed from isobutanol and butyric acid. Industrially produced via acid-catalyzed esterification, this compound belongs to the fruity ester family alongside isoamyl acetate and ethyl butyrate. The branched isobutyl group gives it slightly different volatility and odor characteristics compared to straight-chain butyl esters.

Physical & Chemical Properties

Boiling Point157-158 °C
Density0.86 g/cm³
Refractive Index1.403

Perfumer Guide

Note Position
Top
Volatility
Medium (1-2 hours)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.5-3%Up to 5%Used for tropical fruit effects
Functional Fragrance1-5%Up to 10%Shampoos, body washes

Classic Accords

+ Vanilla + Coconut = Pina colada + Hedione + Calone = Tropical floral + Ethyl maltol + Gamma decalactone = Candy fantasy

Tip: Use with citrus top notes to prevent the fruitiness from becoming too heavy.

Alternatives & Comparisons

1
Ethyl butyrate CAS 105-54-4

More straightforward pineapple note with higher volatility, better for fleeting top notes in light fragrances.

2
Isoamyl acetate CAS 123-92-2

Banana-like ester that works well in similar contexts but requires more careful balancing to avoid artificial candy effects.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

No IFRA restrictions (2023 Amendment 51).

RIFM Assessment

RIFM assessment confirms safe use at current levels in fragrances.

Sustainability

Synthesized from petrochemical feedstocks, though production is energy-efficient. Not currently available from bio-based routes. Low environmental persistence due to ready biodegradability.

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References

  1. Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781420090869

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

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Ingredient Data Sheet

CAS 539-90-2

Physical Properties

Molecular Weight144.21 g/mol🔬 PubChem
LogP (Octanol-Water)2.3🔬 PubChem
Boiling Point156.9 °C🔬 EPA CompTox
Vapor Pressure3.725 mmHg @ 25°C📊 OPERA
Flash Point45.6 °C🔬 EPA CompTox
Involatility Index0.3343💻 Calculated
log Kp (skin permeability)-1.947💻 Calculated
SMILESCCCC(=O)OCC(C)C🔬 PubChem

Volatility & Performance

Fragrance NoteTop💻 Calculated
Volatility ClassModerate💻 Calculated
Persistence Score0.5 / 5💻 Calculated

Odor & Flavor

Primary Descriptorsbananafruitypearpineapplerumsweet• leffingwell
Functional Groupsesterether💻 RDKit
Isobutyl butyrate has a fruity, ethereal odor reminiscent of apple or pineapple and a sweet flavor reminiscent of rum.📖 Fenaroli

Regulatory Status

IOFI ClassificationNature Identical📖 Fenaroli
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: DTXSID8047557

Physical Properties

Molecular Weight 144.214 g/mol🔬 EPA CompTox
Density 0.861 g/cm^3🔬 EPA CTX
Boiling Point 156.9 °C🔬 EPA CTX
Melting Point -72.02 °C📊 OPERA
Flash Point 51.338 °C🔬 EPA CTX
Refractive Index 1.411 Dimensionless📊 OPERA
Molar Volume 164.448 cm^3/mol📊 OPERA

Partition & Solubility

LogP (Octanol-Water) 2.76 Log10 unitless🔬 EPA CTX
LogD (pH 5.5) 2.48 Log10 unitless📊 OPERA
LogD (pH 7.4) 2.48 Log10 unitless📊 OPERA
LogKoa (Octanol-Air) 3.94 Log10 unitless📊 OPERA
Water Solubility 0.01 mol/L📊 OPERA
Henry's Law Constant 0 atm-m3/mole📊 OPERA

Transport Properties

Vapor Pressure 3.725 mmHg🔬 EPA CTX
Viscosity 0.91 cP📊 OPERA
Surface Tension 25 dyn/cm📊 OPERA
Thermal Conductivity 131.752 mW/(m*K)📊 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 4 count💻 Computed
Aromatic Rings 0 count💻 Computed
Molar Refractivity 40.845 cm^3/mol📊 OPERA
Polarizability 16.192 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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