The goal of our study is the synthesis and evaluation of new additives to increase the dropping point and improving the extreme pressure (EP) properties of prepared Lithium 12-hydroxy stearate grease samples. High dropping point, extreme pressure properties (EP) and low oil separation are often the most important factors. The target additive, polyethylene glycol borate esters were synthesized via the stoichiometric reaction of poly ethylene glycol 400 and boric acid to give polyethylene glycol borate ester (PB) which reacted with the linear alkyl benzene sulfonate (1:1) in the presence of toluene as azeotrope to give the target sulfonate ester (SPB). The structure of the new synthesized polyethylene glycol borate esters (PB) and (SPB) were confirmed by using FT-IR. High performance liquid chromatography technique was used to confirm the purity and reactivity of the borate ester (PB) as a precursor for the synthesis of the target additive (SPB). The two new synthesized additives showed the ability to improve some properties of the prepared grease samples such as grease consistency ASTM D-217, dropping point ASTM D-2265 and oil separation ASTM D-6184. Four–Ball test ASTM D-2783 showed better capacities of (SPB) may due to the presence of the sulfonate group.