2-Isopropylthioxanthone is a sulfur-containing aromatic ketone that functions as a highly efficient Type II photoinitiator. The extended π-conjugation of the thioxanthone core gives strong UV-A absorption (λmax ≈ 250–400 nm) and excellent photochemical stability. ITX is practically insoluble in water (< 1 mg 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 ≥ 99 % purity and remains stable for ≥ 2 years when stored sealed at < 25 °C away from light .
Key Physicochemical Data:
Melting point: 76 °C
Boiling point: 399 °C / 760 mmHg (predicted)
Density: 1.20 g cm⁻³ (20 °C)
Flash point: 217 °C (closed cup, predicted)
Log P (octanol/water): 5.33 (predicted)
Vapour pressure: < 0.1 mmHg at 25 °C
Typical Uses:
High-performance Type II photoinitiator for UV-LED or mercury-lamp curing of clear and pigmented coatings, inks, adhesives and nail gels at 0.2–2 % w/w .
Photosensitiser for thick-section (> 4 mm) and highly coloured (black/red) formulations with low shrinkage and excellent through-cure .
Building block for thioxanthone-derived polymer research and optical materials .
Quality Specification (Commercial Grade):
Purity (HPLC): ≥ 99 %
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.
