Isoamyl 4-(dimethylamino)benzoate is a lipophilic ester of 4-dimethylaminobenzoic acid and isoamyl alcohol. The molecule combines a strong electron-donating dimethylamino group with a conjugated benzoate chromophore, giving it an intense UV-A absorption (λmax ≈ 310 nm, ε ≈ 2.7×10⁴ L mol⁻¹ cm⁻¹) and making it an efficient UV-A filter. It is miscible with most cosmetic oils, fatty alcohols and ethanol, and practically insoluble in water (< 0.5 g L⁻¹ at 25 °C). Commercial material is supplied at ≥ 98 % purity and remains stable for ≥ 2 years when stored at room temperature in tightly closed containers away from light.
Key Physicochemical Data:
Boiling point: 150–155 °C / 2.5 mmHg (lit.)
Density: 1.02 g cm⁻³ (25 °C)
Refractive index: n²⁰/D 1.553
Flash point: 185 °F (85 °C) (closed cup)
Log P (octanol/water): 4.3 (predicted)
Melting point: 31–36 °C (lit.)
Typical Uses:
High-performance UV-A filter in sun-care formulations (EU, US, ASEAN) providing broad-spectrum protection when combined with UV-B filters.
Photoinitiator synergist for UV-curable nail gels, dental resins and cosmetic coatings.
Building block for preparing lipophilic UV-absorbing polymers and fragrance encapsulation systems.
Quality Specification (Commercial Grade):
Purity (GC): ≥ 98 %
Water content (KF): ≤ 0.3 %
Free acid (as 4-dimethylaminobenzoic acid): ≤ 0.2 %
Residue on ignition: ≤ 0.1 %
Heavy metals: ≤ 20 ppm
Hazard Statement:
Causes skin and eye irritation (H315 + H319). Avoid inhalation of vapour; use gloves, goggles and adequate ventilation. Store in a cool, dry place away from oxidants and strong acids. SDS available on request.
