Butyl butyrate (CAS 109-21-7) — Sweet Top Note Fragrance Ingredient

Sweet · Citrus

Butyl butyrate

CAS 109-21-7

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

What Is Butyl butyrate?

Butyl butyrate is a fruity-smelling ester commonly used in food flavorings and perfumes. You’ll encounter it in pineapple-flavored candies and tropical fruit fragrances. This ingredient matters because it provides an authentic, juicy pineapple note that’s more stable than natural extracts, allowing consistent flavor and scent profiles in products.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
FDA-approved for food use
No known skin sensitization
CAS
109-21-7
Formula
Mixture
MW
Variable
Odor Family
Sweet · Citrus
Layer 1 · Enthusiast

What Does Butyl butyrate Smell Like?

Butyl butyrate bursts with an intense, sun-ripened pineapple aroma – all golden sweetness with a hint of tropical humidity. The top note is almost effervescent, like freshly opened canned pineapple juice. As it evolves, it develops a creamier character reminiscent of piña colada, with subtle vanilla undertones emerging in the dry-down. The scent maintains remarkable persistence for a fruity note, never turning cloying or artificial.

Scent Profile

In Famous Fragrances

Fragrance associations may not reflect actual formulations.

Virgin Island Water(Creed, 2007)

Used here to amplify the tropical pineapple-coconut accord, blending seamlessly with lime and rum notes to create a photorealistic Caribbean cocktail effect.

Pineapple Vintage(Parfums Vintage, 2014)

Forms the core pineapple note in this Aventus-inspired fragrance, providing longevity and brightness that natural pineapple extracts couldn’t achieve.

Layer 2

2D Molecular Structure

Butyric acid n-butyl ester

SMILES: CCCCOC(=O)CCC

Chemistry, Properties & Perfumer Guide

The Chemistry

Butyl butyrate is an ester formed by the condensation of butanol and butyric acid. Industrially produced via acid-catalyzed esterification, it’s a clear, colorless liquid at room temperature. As a small ester (C8H16O2), it exhibits relatively high volatility which contributes to its strong initial impact in fragrance compositions. The molecule lacks chiral centers, making synthetic production straightforward without stereochemical considerations.

Physical & Chemical Properties

Boiling Point166 °C
Density0.872 g/cm³
Flash Point49 °C
Refractive Index1.406
SolubilitySlightly soluble in water

Perfumer Guide

Note Position
Top
Volatility
Medium-high (30-90 min)
Blending
Good
ApplicationTypical %RangeNotes
Fine Fragrance0.5-2%Up to 5%Tropical fruit accords
Functional Fragrance0.1-0.5%Up to 1%Cleaning products
Flavoring10-50 ppmUp to 100 ppmFruit flavors

Classic Accords

+ Ethyl maltol + Coconut = Piña colada + Aldehyde C-10 + Jasmine = Tropical bouquet

Tip: Combine with green notes like stemone to prevent the pineapple note from becoming too candied.

Alternatives & Comparisons

1
Ethyl butyrate CAS 105-54-4

More diffusive with apple-like qualities; use when a lighter, less tropical fruit character is desired.

2
Hexyl butyrate CAS 2639-63-6

Longer-lasting with pear nuances; better for base note fruity effects in fine fragrances.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

No IFRA restrictions – unrestricted use in all categories.

RIFM Assessment

RIFM evaluation confirms safe use at current industry levels with wide margins of safety.

Sustainability

Synthetic production from petrochemical sources offers consistent quality with lower land/water use than natural pineapple extracts. However, manufacturers are exploring bio-based routes using fermentation-derived butanol to improve sustainability. Proper containment during production prevents environmental release of this moderately volatile compound.

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References

  1. Burdock, G.A. (2010). Fenaroli’s Handbook of Flavor Ingredients. CRC Press. ISBN 9781420090772

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

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Physicochemical Properties

DTXSID: DTXSID7041702

Physical Properties

Molecular Weight 144.214 g/mol🔬 EPA CompTox
Density 0.87 g/cm^3🔬 EPA CTX
Boiling Point 166.342 °C🔬 EPA CTX
Melting Point -91.759 °C🔬 EPA CTX
Flash Point 52.045 °C🔬 EPA CTX
Refractive Index 1.413 Dimensionless📊 OPERA
Molar Volume 164.072 cm^3/mol📊 OPERA

Partition & Solubility

LogP (Octanol-Water) 2.16 Log10 unitless🔬 EPA CTX
LogD (pH 5.5) 2.56 Log10 unitless📊 OPERA
LogD (pH 7.4) 2.56 Log10 unitless📊 OPERA
LogKoa (Octanol-Air) 4.58 Log10 unitless📊 OPERA
Water Solubility 0.004 mol/L🔬 EPA CTX
Henry's Law Constant 0.001 atm-m3/mole🔬 EPA CTX

Transport Properties

Vapor Pressure 3.788 mmHg🔬 EPA CTX
Viscosity 0.977 cP📊 OPERA
Surface Tension 26.365 dyn/cm📊 OPERA
Thermal Conductivity 137.337 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 5 count💻 Computed
Aromatic Rings 0 count💻 Computed
Molar Refractivity 40.887 cm^3/mol📊 OPERA
Polarizability 16.209 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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