High-frequency microtitrimetric determination of acidic and basic constituents in lubricating oils. Part II. Determination of total base number

Abstract

A high-frequency microtitration method is described for the determination of total base number in new and used lubricating oils. The sample, dissolved in toluene-propan-2-ol-water (5 + 4.95 + 0.05), is titrated with standard alcoholic hydrochloric acid solution. A study of solvents, titrants, sample size and other experimental parameters is reported. This method provides sharp breaks at the end-points of the titration graphs and more repeatable and faster results than those obtained with the standard potentiometric method. The method can also be used for macrotitrations, with a commercially available oscillator, and can be suggested as an alternative to ASTM and IP methods for the determination of total base number.