Patent ID: 6642187
Filing Date: 2003-11-04
Classification: C10M,C10N,F02B

Abstract:
A method of preparing a lubricating oil composition, comprising:(1) preparing an intermediate product by reacting isobutylene, or a dimer, trimer or tetramer of isobutylene, or a mixture thereof, with sulfur and hydrogen sulfide; (2) fractionating the intermediate product from step (1) at a subatmospheric pressure in the range of about 1 to about 250 mmHg and a reflux ratio in the range of about 1:1 to about 15:1 to provide a dihydrocarbyl polysulfide mixture comprising at least about 90% dihydrocarbyl trisulfide, from about 0.1 to about 8% dihydrocarbyl disulfide, and less than about 5% dihydrocarbyl higher polysulfides; and (3) blending a mixture comprising a major amount of an oil of lubricating viscosity, (A) the product from step (2), and (B) at least one overbased metal composition or a phosphorus or boron compound, or mixtures thereof.