Synthesis of Ricinoleate Anion based Ionic Liquids and their Application
as Green Lubricating oil Additives
Abstract
Ricinoleate anion based ionic liquids (ILs) were synthesized from four
different nitrogen containing cationic counterparts such as
tetrabutylammonium, tetrapropylammonium, cetyltrimethylammonium,
imidazolium and evaluated for tribological performance in two lubricant
base stocks. From the tribological tests it was found that the
synthesized ILs in base oil significantly reduced the wear scar diameter
by 17-25 % and a remarkable reduction in wear observed for all the
tested load and rotation speed at optimized concentration and also
improved the load carrying capacity by 25-43%. The results conclude
that the cation present in IL control the thermal stability, antiwear
and extreme pressure properties. The imidazolium cation containing IL
showed the better performance among all the ILs being studied.
Additionally, the morphology of worn surface and deposition of
elementals on rubbed surface lubricated with base oil and base oil
containing IL was studied by scanning electron microscope (SEM) and
Energy-dispersive X-ray spectroscopy (EDX). The fatty acid constituted
ILs are promising immense efficiency as environmentally friendly and
renewable lubricant additives since they are free from halide, sulphate
and phosphate ions.