Reagents & Standards
Total Base Number (TBN)
The constituents of oils and lubricants that may be considered to have basic characteristiscs include organic bases, inorganic bases, amino compounds, salts of weak acids (soap), basic salts of polyacidic bases and salts of heavy metals. The test method involves dissolving the sample in an anhydrous mixture of chlorobenzene/glacial acetic acid and titrating potentiometerically with a solution of perchloric acid in glacial acetic acid. Both new and used petroleum products can contain basic constituents that are present as additives. The test is sometimes used as a measure of lubricants degradation but any condemning limits based on the test must be established on an individual bais.