Benzophenone is the simplest aromatic ketone, consisting of two phenyl rings linked by a carbonyl group. It exhibits strong UV-A/UV-B absorption (λmax ≈ 330 nm, log ε 3.9), is practically insoluble in water (< 0.1 g/100 mL at 25 °C) and readily soluble in ethanol, ether, chloroform and most organic monomers. The compound is thermally stable up to ≈ 305 °C and functions as both a UV absorber and a Type II photoinitiator. Commercial material is supplied at ≥ 99 % purity and remains stable for ≥ 2 years when stored below 30 °C in tightly closed containers away from light .
Key Physicochemical Data:
Melting point: 47–49 °C
Boiling point: 305 °C
Density: 1.11 g cm⁻³ (50 °C)
Flash point: > 110 °C (closed cup)
Log P (octanol/water): 3.18 (25 °C)
Vapour pressure: 1 mmHg at 108 °C
Typical Uses:
Type II photoinitiator for UV-LED or mercury-lamp curing of clear coatings, inks, adhesives and 3-D printing resins at 1–5 % w/w .
UV-absorbing additive in food-contact packaging, cosmetic containers and optical-grade polymers .
Fragrance fixative and UV stabiliser in perfumes, soaps and sun-care formulations .
Quality Specification (Commercial Grade):
Purity (GC): ≥ 99 %
Water content (KF): ≤ 0.3 %
Free acid (as benzoic acid): ≤ 0.2 %
Residue on ignition: ≤ 0.1 %
Heavy metals: ≤ 20 ppm
Hazard Statement:
Combustible solid; 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 strong acids. SDS available on request.
