4-(4-Methylphenylthio)benzophenone (BMS) is a sulfur-containing aromatic ketone combining a benzophenone chromophore with a p-tolylthio ether. The extended conjugation provides strong UV-A absorption (λmax ≈ 310 nm, log ε ≈ 4.1) and excellent photochemical stability. It is practically insoluble in water (< 1 µg L⁻¹ at 25 °C), freely soluble in chloroform, acetone, toluene and most acrylic monomers, and can be recrystallised from ethanol. Commercial material is supplied at ≥ 98 % purity and remains stable for ≥ 2 years when stored sealed at < 30 °C away from light .
Key Physicochemical Data:
Melting point: 73–87 °C
Boiling point: 477.8 °C / 760 mmHg (predicted)
Density: ≈ 1.2 g cm⁻³ (20 °C)
Flash point: > 150 °C (closed cup, predicted)
Log P (octanol/water): 5.2 (predicted)
Thermal onset: > 230 °C
Typical Uses:
Type II photoinitiator for UV-LED or mercury-lamp curing of pigmented and clear coatings, inks, adhesives and nail gels at 0.5–3 % w/w .
Photosensitiser for thick-section (> 4 mm) and highly coloured (black/red) formulations with low shrinkage and excellent through-cure .
Building block for high-performance polymer research and optical materials .
Quality Specification (Commercial Grade):
Purity (HPLC): ≥ 98 %
Water content (KF): ≤ 0.3 %
Individual impurity (HPLC): ≤ 0.5 %
Total impurities (HPLC): ≤ 1.0 %
Heavy metals: ≤ 20 ppm
Hazard Statement:
Harmful to aquatic life with long-lasting effects (H413); causes skin and eye irritation (H315 + H319) . Avoid release to the environment; use gloves, goggles and adequate ventilation. Store in a cool, dry place away from oxidants and light. SDS available on request.
