Test method for acid number of petroleum products by potentiometric titration (First revision)
This Malaysian Standard covers procedures for the determination of acidic constituents in petroleum products, lubricants, biodiesel and blends of biodiesel.
Test Method A—For petroleum products and lubricants soluble or nearly soluble in mixtures of toluene and propan-2-ol. It is applicable for the determination of acids whose dissociation constants in water are larger than 10(superscript-9); extremely weak acids whose dissociation constants are smaller than 10-9 do not interfere. Salts react if their hydrolysis constants are larger than 10(superscript-9). The range of acid numbers included in the precision statement is 0.1 mg/g KOH to 150 mg/g KOH.
Test Method B—Developed specifically for biodiesel and biodiesel blends with low acidity and slightly different solubility. This test method requires the use of an automatic titrator with automatic endpoint seeking capability.
NOTE 1—In new and used oils, the constituents that may be considered to have acidic characteristics include o
