alpha-Methylbenzyl isobutyrate (CAS 7775-39-5) — Sweet Top to Middle Note Fragrance Ingredient

Sweet · Floral

alpha-Methylbenzyl isobutyrate

CAS 7775-39-5

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

What Is alpha-Methylbenzyl isobutyrate?

alpha-Methylbenzyl isobutyrate is a synthetic fragrance ingredient used in perfumes and scented products. It provides a fruity, floral character with a sweet, rosy undertone. You’ll encounter it in fine fragrances, body care products, and home fragrances. This versatile material helps create complex floral bouquets and adds a touch of sophistication to fruity compositions. Its balanced profile makes it valuable for perfumers seeking to bridge floral and fruity accords seamlessly.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
No major restrictions in cosmetic use
Not classified as an allergen
CAS
7775-39-5
Formula
Mixture
MW
Variable
Odor Family
Sweet · Floral
Layer 1 · Enthusiast

What Does alpha-Methylbenzyl isobutyrate Smell Like?

alpha-Methylbenzyl isobutyrate opens with a burst of juicy pear and apple peel, like biting into a crisp Bartlett pear still warmed by the sun. This fruity intensity gradually softens into a heart of sugared rose petals and faint lily-of-the-valley, with a creamy undertone reminiscent of vanilla-scented lotion. The dry-down reveals a subtle woody-musky base that lingers close to the skin, leaving a clean, slightly powdery trail. Throughout its evolution, it maintains a radiant sweetness that never becomes cloying, making it ideal for modern floral-fruity compositions.

Scent Profile

In Famous Fragrances

Fragrance associations may not reflect actual formulations.

Chance Eau Tendre(Chanel, 2010)

Used here to enhance the quince-jasmine accord, adding a crisp, dewy fruitiness that prevents the white florals from becoming too heavy.

La Vie Est Belle(Lancôme, 2012)

Provides the initial juicy pear note that transitions into the gourmand heart, acting as a bridge between top and middle notes.

Daisy(Marc Jacobs, 2007)

Contributes to the sparkling fruity top that defines this youthful floral, complementing the strawberry and violet leaf notes.

Light Blue(Dolce & Gabbana, 2001)

Used sparingly to add dimension to the citrus opening, providing a subtle fruity counterpoint to the sharp lemon accord.

Idôle(Lancôme, 2019)

Helps create the modern rose accord by adding a contemporary fruity lift to the traditional floral heart.

Layer 2

2D Molecular Structure

Propanoic acid, 2-methyl-, 1-phenylethyl ester

SMILES: CC(C)C(=O)OC(C)C1=CC=CC=C1

Chemistry, Properties & Perfumer Guide

The Chemistry

alpha-Methylbenzyl isobutyrate is an ester formed by the reaction of alpha-methylbenzyl alcohol with isobutyric acid. As a synthetic material, it’s produced through acid-catalyzed esterification under controlled conditions. The molecule features a chiral center at the benzylic carbon, with the (R)-enantiomer typically exhibiting a more intense fruity character. Its chemical structure combines aromatic and aliphatic components, giving it both fruity and floral olfactory properties. The isobutyrate ester group contributes to its moderate volatility and good stability in various formulation matrices.

Physical & Chemical Properties

Boiling Point~230 °C (estimated)
Density~1.0 g/cm³ (estimated)
Vapor PressureLow (estimated)
SolubilitySoluble in alcohol, oils; insoluble in water

Perfumer Guide

Note Position
Top to Middle
Volatility
Medium (2-4 hours)
Blending
Very good
ApplicationTypical %RangeNotes
Fine Fragrance1-5%0.5-10%Fruity-floral modifier
Body Care0.5-3%0.1-5%Adds sophistication to fruity notes
Home Fragrance0.2-1%0.1-3%Used in floral-fruity diffuser blends
Functional Products0.1-0.5%0.05-1%Masking agent with pleasant character

Classic Accords

Tip: Use with hedione to extend the floral character and prevent the fruity top from fading too quickly.

Alternatives & Comparisons

1
Phenethyl isobutyrate CAS 103-48-0

More floral and less fruity, better for rose-heavy compositions where a honeyed character is desired.

2
Benzyl acetate CAS 140-11-4

Brighter and more jasmine-like, suitable when a cleaner floral effect is needed without fruity undertones.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

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

IFRA Status

Not restricted under current IFRA standards (as of 49th Amendment).

RIFM Assessment

Considered safe for use in fragrances based on RIFM’s evaluation of analogous esters.

Sustainability

As a synthetic material, alpha-Methylbenzyl isobutyrate has minimal environmental impact in production. It doesn’t require agricultural land or natural resources, and its synthesis can be optimized for atom efficiency. Being produced in controlled industrial settings allows for consistent quality and reduces batch-to-batch variation compared to natural materials.

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References

  1. Arctander, S. (1969). Perfume and Flavor Chemicals. Montclair, NJ.
  2. Bauer, K. et al. (2001). Common Fragrance and Flavor Materials. Wiley-VCH.

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

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Physicochemical Properties

DTXSID: DTXSID50864119

Physical Properties

Molecular Weight 192.258 g/mol🔬 EPA CompTox
Density 0.998 g/cm^3📊 OPERA
Boiling Point 244.923 °C📊 OPERA
Melting Point 23.814 °C📊 OPERA
Flash Point 93.477 °C📊 OPERA
Refractive Index 1.493 Dimensionless📊 OPERA
Molar Volume 192.885 cm^3/mol📊 OPERA

Partition & Solubility

LogP (Octanol-Water) 3.507 Log10 unitless📊 OPERA
LogD (pH 5.5) 3.507 Log10 unitless📊 OPERA
LogD (pH 7.4) 3.507 Log10 unitless📊 OPERA
LogKoa (Octanol-Air) 5.73 Log10 unitless📊 OPERA
Water Solubility 0.001 mol/L📊 OPERA
Henry's Law Constant 0 atm-m3/mole📊 OPERA

Transport Properties

Vapor Pressure 0.019 mmHg📊 OPERA
Viscosity 5.482 cP📊 OPERA
Surface Tension 33.351 dyn/cm📊 OPERA
Thermal Conductivity 131.053 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 3 count💻 Computed
Aromatic Rings 1 count💻 Computed
Molar Refractivity 56.07 cm^3/mol📊 OPERA
Polarizability 22.228 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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