Synthesis of Tertiary Fatty Amines in Water: The Dual Role of Dimethylamine as Reagent and Phase Mediator in the Homogeneously Catalyzed Fatty Alcohol Amination

The amination of long-chain fatty alcohols with dimethylamine to the desired tertiary amines proceeds in water as the solvent with unprecedented conversions and selectivities exceeding 99%. Key to success was the combination of a water-soluble ruthenium-based catalyst and the unique phase-mediating properties of the cosubstrate dimethylamine. After the reaction, the homogeneous mixture split into a pure product phase and catalyst-containing aqueous phase upon reducing the pressure, enabling the straightforward isolation of high-purity products. Several fatty alcohols were successfully transformed into the respective tertiary fatty dimethyl alkyl amines under these unique conditions.