Corrosion behaviour of aluminum and copper in dimethyl- and diethyl phosphate ionic liquids

Abstract

The effect of phosphonium—based ionic liquids (ILs): 1,3-dimethyl-imidazolium dimethyl phosphate, [C₁C₁IM][DMP], 1-ethyl-1-methylpyrrolidinium dimethyl phosphate, [C₁C₂PYR][DMP], 1-hydroxyethyl-1-methylpyrrolidinium dimethyl phosphate, [C₁C_2OHPYR][DMP], 1-methylpyridinium dimethyl phosphate, [C₁Py][DMP], 1-ethyl-1-methylmorpholinium dimethyl phosphate, [C₁C₂MOR][DMP], 1-ethyl-1-methylpiperidinium dimethyl phosphate, [C₁C₂PIP][DMP], N,N,N-trimethyl-N-methylammonium dimethyl phosphate, [N_1,2,2,2][DMP], 1-ethyl-3-methylimidazolium diethyl phosphate, [C₁C₂IM][DEP], 1-ethyl-1-methylpyrrolidinium diethyl phosphate, [C₁C₂PYR][DEP], 1-ethyl-1-methyl-morpholinium diethyl phosphate, [C₁C₂MOR][DEP] and tri(butyl)ethylphosphonium diethyl phosphate, [P_2,4,4,4][DEP] on the corrosion of aluminium and copper were investigated using potentiodynamic polarization. All tested ionic liquids formed a passivation layer on the surface of the tested metals and due to their low affinity to promote corrosion of Cu and Al, can be used in refrigeration technology.