Diethylenetriamine

The three amine groups in diethylenetriamine (DETA) make it water-soluble and basic enough to extract acids from gases and hydrocarbon mixtures. Like most organic amines, it has an ammonia-like odor. Its profound toxicity is illustrated by all the category 1 ratings shown in the hazard information table.

The three nitrogen atoms make DETA an excellent complexing agent for metals such as cobalt, copper, and platinum. Some DETA-based metal complexes can be used to catalyze organic reactions; examples are the oxidation of phenol with hydrogen peroxide and Heck cross-coupling reactions.

Recently, Julien Leclaire at the University of Lyon (France) and colleagues there and at the University of Turin (Italy) showed that the cost of carbon dioxide capture with DETA can be offset by another environmentally beneficial process. The chemists devised a way to selectively remove metal contaminants from water by adding DETA to the aqueous solutions, then bubbling CO₂ through the mixture. A series of ligand exchange reactions results in the formation of an insoluble carbonate of the target metal.

The authors demonstrated their technique by removing lanthanum as La₂(CO₃)₃ from a La–Ni mixture and by separating the solubilized metals from a La–Co–Ni battery anode alloy into the individual components with 97% or greater purity. Their aim is to collaborate with metal recyclers to develop and commercialize their technology.