Evaluating water miscible deep eutectic solvents (DESs) and ionic liquids as potential lubricants

Abstract

Although mineral oils are commonly used as lubricants their emission particularly in marine environments can cause significant impact. In the current study the properties of water miscible deep eutectic solvents and ionic liquids are compared with a typical mineral base oil to ascertain their efficacy for potential marine lubricants. The environmental compatibility of some of the liquids, particularly choline chloride and glycerol, makes it an interesting potential base lubricant. Surprisingly some DESs showed very low corrosion rates with steel, nickel and aluminium even when the liquids contained water. This is a surprising result given that the chloride ion concentration is approximately 5 mol dm⁻³.