Physicochemical properties of amide–AlCl3 based ionic liquid analogues and their mixtures with copper salt

Abstract The physicochemical properties of three different amide–AlCl 3 based ionic liquid (IL) analogues and their mixtures with copper salt, such as conductivity, viscosity, density and isobutane solubility were determined over a wide range of temperatures. The effects of amide structure, amide/AlCl 3 molar ratio and CuCl modification on these physicochemical properties were investigated. Results showed that the conductivity of amide–AlCl 3 based IL analogues was much lower than that of traditional Et 3 NHCl–AlCl 3 IL with same ligand/AlCl 3 molar ratio due to incomplete splitting of AlCl 3 , whereas the density and viscosity of amide–AlCl 3 based IL analogues were slightly higher. The viscosity of amide–AlCl 3 based IL analogues was closely related to the amide structure, and followed the order of DMA–AlCl 3  > AA–AlCl 3  > NMA–AlCl 3 with same amide/AlCl 3 molar ratio. Meanwhile, the density of amide–AlCl 3 based IL analogues ranked in the following order: AA–AlCl 3  > NMA–AlCl 3  > DMA–AlCl 3 . Increasing the amide/AlCl 3 molar ratio decreased the conductivity and density, while increased the viscosity. The solubility experiment indicated that the isobutane solubility in NMA–AlCl 3 was highest than that in two other IL analogues. Under the modification of CuCl, the conductivity, viscosity and density of these IL analogues increased, whereas the isobutane solubility decreased. These results provide the foundation for the development of a suitable IL analogue catalyst for isobutane alkylation.