Ethyl 9-oxo-9H-thioxanthene-2-carboxylate is a sulfur-containing fused-aromatic ester that combines a thioxanthone core with an ethyl carboxylate group at the 2-position. The compound is essentially odourless, light-stable, freely soluble in dichloromethane, chloroform, ethyl acetate and hot ethanol, but almost insoluble in water (< 0.1 mg mL⁻¹ at 25 °C) .
Key physicochemical data:
Melting point: 103–105 °C
Boiling point: 373–381 °C @ 101.3 kPa
Density: 1.433 g cm⁻³ (20 °C)
Vapour pressure: < 0.001 Pa (20 °C)
Log P (octanol/water): 4.97 (20 °C)
Flash point: > 200 °C (closed cup, estimated)
Typical uses:
Photo-initiator for UV-curable inks, coatings and dental formulations; exhibits strong absorption at 365–405 nm and efficient triplet-state electron transfer .
Building block for organic electronic materials (OLED hole-transport layers, organic photovoltaics) and fluorescent probes that require a thioxanthone chromophore .
Synthetic intermediate for thioxanthone-2-carboxylic acid derivatives used as herbicide safeners and antimicrobial agents .
Quality specification (commercial grade):
Purity (HPLC): ≥98 %
Water content (KF): ≤0.3 %
Residue on ignition: ≤0.1 %
Heavy metals: ≤20 ppm
Hazard statement:
Causes skin and eye irritation (R36/37/38). Avoid inhalation of dust; use gloves, goggles and adequate ventilation. SDS available on request.
