Towards the development of a safe, metal-catalyzed aerobic oxidation of 2-acetyl thiophene

Thiophene-2-carbonyl chloride (TCC) is a key raw material in the manufacture of active ingredients for agriculture. A new 3-step process for preparing TCC from commercial thiophene was recently developed that featured a metal-catalyzed aerobic oxidation of 2-acetylthiopehene (AcT). That process utilized pure oxygen in a flammable solvent, acetic acid, at elevated temperatures, which represented a hazardous condition by operating above the limiting oxygen concentration for the solvent and at a temperature above the flashpoint for the solvent. More recently, the same oxidation reaction has been achieved in an autoclave using diluted oxygen. Described in this Letter are details of our progress towards the identification of safe operating conditions for the aerobic oxidation of AcT.