Applications of Lewis Acidic [ZnCl2]2[ChCl] Deep Eutectic Solvents (DES) in the Synthesis of Unsymmetrical Ethers via Dehydrative Cross Etherification of Alcohols
Unsymmetrical ethers are generally synthesized via the Williamson ether method, but the unwanted formation of symmetrical ethers plus the basic and harsh conditions of the route pose a synthetic challenge. Other methods employed in the synthesis of unsymmetrical ether require the use of toxic mineral acids, and requires high catalyst loading which limits their large-scale application. Dehydration of alcohols in the presence of base-metal catalyst has, however, recently offered the greenest approach to synthesize unsymmetrical ethers, leaving water as by-product.