From pollutant to painkiller: hazardous halogenated wastes become a safe chlorine source

Persistent halogenated pollutants can be repurposed to act as effective chlorinating agents, simultaneously reducing their toxic impact on the environment. The team in China used environmental contaminants including the banned insecticide DDT and flame-retardant insulator hexabromocyclododecane (HBCD) to chlorinate a variety of ketone and alkene substrates, ultimately incorporating a pollutant-mediated step into the syntheses of several non-steroidal anti-inflammatory drugs.

Organic halides are a versatile class of compounds. The polar C–X bond is a convenient functional handle in synthetic organic chemistry but also confers a number of useful properties including flame retardance, lipophilicity and chemical resistance, making these compounds excellent for diverse applications such as building materials, plastics and pesticides. However, while the strength of this bond makes these materials physically tough and resistant to chemical degradation, it has also led to the problem of persistent halogenated compounds in the environment. In particular, their lipophilicity has had a devastating cumulative impact on food chains and strategies to safely process and dispose of these substances are now an important part of environmental policy.