GB/T 4945-2002
Standard test method for acid and base number of petroleum products and lubricants by colour-indicator titration (English Version)
- Standard No.
- GB/T 4945-2002
- Language
- Chinese, Available in English version
- Release Date
- 2002
- Published By
- General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
- Latest
- GB/T 4945-2002
- Replace
- GB/T 4945-1985
- Scope
- 1.1 This standard is applicable to the determination of the acidic or alkaline components of petroleum products and lubricants that can be completely or almost completely soluble in a mixed solvent of toluene and isopropanol. It is suitable for the determination of acids with a dissociation constant greater than lo-9 in water Or base, very weak acid or base with dissociation constant less than 10-9 will not affect the determination, if the hydrolysis constant of salt is greater than 10-9, it will be affected. NOTE 1 In new and used oils, components considered acidic include organic acids, inorganic acids, esters, phenolic compounds, lactones, resins, heavy metal salts, and additives such as antioxidants and detergents . Likewise, components considered alkaline include organic bases, inorganic bases, amine compounds, salts of weak acids (soaps), basic salts of polybasic acids, heavy metal salts, and additives such as antioxidants and detergents . 2 This method is not suitable for determining the base number of lubricating oils containing various types of basic additives. The base number of such oils can be determined by the test method of SH/T 0688. 1.2 This standard can be used to indicate the relative change of oil products in service under oxidative conditions. Although the titration is carried out under specified conditions, this standard cannot determine the absolute acidity and alkalinity to predict the performance of the oil under the conditions of use. It is known that there is no necessary relationship between acid number or base number and bearing corrosion. Note: For some oil products, such as cutting oil, anti-rust oil and similar compound oil products, or dark oil products, the acid value cannot be determined by this method because the end point of the indicator is not obvious, and GB/T 7304 can be used determined by the test method. The acid value determined by the color indicator method is not necessarily equal to the result of GB/T 7304 in value. The base value determined by the color indicator method is not necessarily equal to the value of SH/T 0688, but the data has a certain correlation.
GB/T 4945-2002 history
- 2002 GB/T 4945-2002 Standard test method for acid and base number of petroleum products and lubricants by colour-indicator titration
- 0000 GB/T 4945-1985
