2-Ethylhexyl benzoate
[CAS 5444-75-7]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives >> Carboxylic esters and their derivatives
• Name: 2-Ethylhexyl benzoate
• Synonyms: Ethylhexyl benzoate; Finsolv EB; Hi-Ester B 508; NSC 19155
• Molecular Formula: C₁₅H₂₂O₂
• Molecular Weight: 234.33
• CAS Registry Number: 5444-75-7
• EC Number: 226-641-8
• SMILES: CCCCC(CC)COC(=O)C1=CC=CC=C1

Properties

• Solubility: Practically insoluble (0.014 g/L) (25 °C), Calc.^*
• Density: 1.0±0.1 g/cm³ Calc.^*, 0.9654 g/cm³ (20 °C)^**
• Boiling point: 313.1±10.0 °C 760 mmHg (Calc.)^*
• Flash point: 132.0±6.5 °C (Calc.)^*
• Index of refraction: 1.491 (Calc.)^*
• Refractive index: 1.4925 (589.3 nm 20 °C)^**

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software V11.02 (©1994-2015 ACD/Labs)

^** Matsuda, Sumio

Safety Data

• Hazard Symbols: GHS08 Danger
• Risk Statements: H360-H360F-H413
• Safety Statements: P203-P273-P280-P318-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Reproductive toxicity	Repr.	1B	H360F
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Reproductive toxicity	Repr.	1B	H360

Discovery and Applications

2-Ethylhexyl benzoate is an aromatic ester formed from benzoic acid and 2-ethylhexanol. It belongs to the benzoate ester family and is widely used as an emollient, solvent, plasticizer, and formulation component in cosmetics, personal care products, coatings, and industrial materials.

Structurally, the molecule consists of two main regions: a benzoate group (an aromatic phenyl ring attached to an ester carbonyl) and a branched 2-ethylhexyl chain. The ester linkage joins these components and strongly influences the compound's physical behavior. The aromatic portion contributes hydrophobicity and molecular stability, while the branched alkyl chain imparts flexibility and lowers crystallization tendency.

The ester carbonyl is the most polarized region of the molecule. Resonance stabilization between the carbonyl and ester oxygen creates a relatively stable functional group, although the ester bond can undergo hydrolysis under strongly acidic or strongly alkaline conditions. Under ordinary use conditions, however, 2-ethylhexyl benzoate is chemically stable.

The branched 2-ethylhexyl group has important effects on physicochemical properties. Branching reduces efficient molecular packing and therefore lowers melting behavior, helping maintain a liquid state over a broad temperature range. This property is useful in formulations where low viscosity and good spreadability are desired.

From a formulation standpoint, 2-ethylhexyl benzoate is valued for several properties:

* Low volatility compared with smaller esters
* Good compatibility with oils and hydrophobic ingredients
* Excellent spreading characteristics on surfaces and skin
* Ability to dissolve lipophilic compounds
* Softening and plasticizing effects in polymer systems

In cosmetic and personal-care applications, it frequently functions as an emollient. The hydrophobic alkyl chain helps create a smooth, non-greasy feel and can reduce moisture loss by forming a light film on the skin surface. It is also used as a solvent for active ingredients and fragrance components.

In materials chemistry, benzoate esters such as 2-ethylhexyl benzoate can serve as secondary plasticizers. Plasticizers reduce intermolecular attractions within polymers, increasing flexibility and improving processing behavior. Compared with lower molecular weight solvents, its relatively larger structure reduces volatility and migration.

Physicochemically, the compound is typically a colorless liquid with low water solubility because of its dominant hydrophobic character. Although the ester oxygen atoms contribute moderate polarity, the long branched hydrocarbon chain and aromatic ring largely determine its solubility profile, favoring compatibility with nonpolar and moderately polar organic systems.

Overall, 2-ethylhexyl benzoate is a branched aromatic ester characterized by a benzoate functionality and a hydrophobic alkyl chain. Its significance lies in its usefulness as an emollient, solvent, and plasticizing agent across cosmetic, pharmaceutical, and industrial formulations.

References

2011. Thermal conductivity and viscosity measurements of ethylene glycol-based Al2O3 nanofluids. Nanoscale Research Letters.
DOI: 10.1186/1556-276x-6-221