ASTM D974

ASTM D974 Acid Number

ACID NUMBER, PETROLEUM PRODUCTS

This test method covers the determination of acidic or basic constituents in petroleum products and lubricants soluble or nearly soluble in mixtures of toluene and isopropyl alcohol. It is applicable for the determination of acids or bases whose dissociation constants in water are larger than 10−9; extremely weak acids or bases whose dissociation constants are smaller than 10−9 do not interfere. Salts react if their hydrolysis constants are larger than 10−9.
Source: www.astm.org