Process for preparing an extreme pressure lubricating oil additive

Claim 1

A process for making an extreme pressure lubricant additive comprising the steps of: (a) reacting sulfur monochloride with from about 1 to 2 moles of isobutylene per mole of sulfur monochloride at a temperature of from about 20° C. to about 80° C.; (b) reacting the product produced in step (a) with an alkali metal monosulfide and free sulfur in a ratio of moles of alkali metal monosulfide to gram-atoms of free sulfur from about 1.8 to about 2.2:1; (c) reacting the product produced in step (b) with an aqueous solution containing from about 5 to about 20 percent of an alkali metal hydroxide for a time sufficient to reduce the chlorine content below about 0.5 percent; and (d) reacting the sulfurized isobutylene produced in step (c) with a mild oxidizing agent in a mole ratio of oxidizing agent to sulfurized isobutylene of between about 0.5 and about 2.5 moles of equivalent oxygen to 1 mole of sulfurized isobutylene at a reaction temperature between about 20° C. and about 95° C. under conditions sufficient to effect the appearance of new infrared frequency bands at 1300 cm -1 and 1030 cm -1 indicative of the formation of sulfoxides and sulfones and recovering a liquid oxidized sulfurized isobutylene product which is soluble in a lubricating composition.