LUBE OIL COMPOSITION, OVERBASED ALKALINE EARTH METAL SULFIDE PHENEATE CONCENTRATE USED FOR PREPARING THE SAME, AND PROCESS FOR PREPARING THE CONCENTRATE

摘要

A lube oil composition having a high base value and an excellent high-temperature cleanness and containing an overbased alkaline earth metal sulfide phenate, and a process for preparing an overbased alkaline earth metal sulfide phenate concentrate having a high base value, a viscosity of not more than 1000 cSt at 100 DEG C, and excellent hydrolysis stability and oil solubility. The concentrate can be prepared by feeding an alkaline earth metal reagent, and a phenol compound and sulfur each in an amount of 1 to 100 equivalents per mole of the metal reagent, optionally together with water, into a reactor, adding a dihydric alcohol to the mixture at an internal pressure of the reactor of 10 to 250 kPa-G, allowing a reaction to proceed, removing excess dihydric alcohol and water at least in its excess portion by distillation, treating the distillation bottom with carbon dioxide in the presence of water in an amount of 0.3 to 0.8 mol per mole of the metal reagent, allowing a fatty acid compound in an amount of 0.001 to 0.3 mol per mole of the metal reagent to exist until the carbon dioxide treatment at the latest, and removing the excess phenolic compound in the product of carbon dioxide treatment by distillation.