4,4'-Bis(diethylamino)benzophenone is a di-ortho-aminobenzophenone derivative carrying two strongly electron-donating diethylamino groups. The extended π-conjugation gives intense visible/UV-A absorption (λmax 374 nm in THF, log ε ≈ 4.3) and renders the compound an efficient Type II photoinitiator for visible-light or UV-LED curable systems. It is practically insoluble in water (< 1 µg L⁻¹ at 20 °C, pH 6.8–7), freely soluble in chloroform, acetone and acrylic monomers, and can be recrystallised from ethanol. Commercial material is supplied at ≥ 99 % purity and remains stable for ≥ 1 year when stored sealed at < 30 °C away from light .
Key Physicochemical Data:
Melting point: 93–97 °C
Density: 1.11 g cm⁻³ (20 °C)
Flash point: 151 °C
Log P (octanol/water): 5.2 (35 °C)
Thermal onset: > 230 °C
Typical Uses:
Type II photoinitiator for visible-light or UV-LED curing of pigmented and clear coatings, inks, adhesives and nail gels at 0.1–4 % w/w .
Photosensitiser for thick-section (> 4 mm) and highly pigmented (black/red) formulations with low shrinkage and excellent through-cure .
Building block for triarylmethane dyes (basic brilliant blue series) and optical materials .
Quality Specification (Commercial Grade):
Purity (HPLC): ≥ 99 %
Water content (KF): ≤ 0.3 %
Individual impurity (GC): ≤ 0.5 %
Total impurities (GC): ≤ 1.0 %
Heavy metals: ≤ 20 ppm
Hazard Statement:
Harmful to aquatic life with long-lasting effects (H411); causes skin and eye irritation (H315 + H319) . Avoid dust formation; use gloves, goggles and adequate ventilation. Store in a cool, dry place away from oxidants and light. SDS available on request.
