A New Family of Zwitterionic Liquids Arising from a Phase Transition of Ammonium Inner Salts Containing an Ether Bond

Aliphatic and alicyclic ammonium inner salts containing an ether bond were prepared as a new family of zwitterionic liquids. Ether bond is not only effective for lowering melting points of ammonium-type zwitterions but also interesting to realize unique solid–solid transition.