Abstract: A lubricating composition comprising: (i) from 50% to 99% by weight of base oil; (ii) from 0.01% to 5% by weight of ionic liquid; and (iii) from 0.01% to 10% by weight of additive; wherein the lubricating composition has a pour point of at most ?54° C., a flashpoint of at least 246° C. and a kinematic viscosity at 100° C. in the range of from 4.9 to 5.4 mm2/s. The lubricating compositions according to the present invention are suitable for use in turbine engine oils and are useful for reducing the build up of sludge and for reducing coking in the lubricating composition.

Abstract: A functional fluid composition comprising: (a) from 70% to 99.99%, by weight of the fluid composition, of a base oil composition comprising: (i) from 50% to 95%, by weight of the base oil composition, of a naphthenic base oil; and (ii) from 5% to 50%, by weight of the base oil composition, of a Fischer-Tropsch derived base oil. The functional fluid compositions according to the present invention are suitable for use in hydraulic fluids and shock absorber fluids and are useful for reducing the volume swell of synthetic rubbers.