ASTM D2896-98
(Test Method)Standard Test Method for Base Number of Petroleum Products by Potentiometric Perchloric Acid Titration
Standard Test Method for Base Number of Petroleum Products by Potentiometric Perchloric Acid Titration
SCOPE
1.1 This test method covers the determination of basic constituents in petroleum products by titration with perchloric acid in glacial acetic acid.
1.2 Procedures A and B use different titration solvent volumes and sample weights.
Note 1—A round robin on a series of new and used oils and additive concentrates has shown that the two procedures give statistically equivalent results.
1.3 Appendix A2 provides the use of an alternative solvent system which eliminates the use of chlorobenzene in this test method. The use of the alternative solvent gives statistically equivalent results; however, the precision is worse. Paragraph X2.5.5 provides guidance when comparing results using the two different solvents.
1.4 The constituents that may be considered to have basic characteristics include organic and inorganic bases, amino compounds, salts of weak acids (soaps), basic salts of polyacidic bases, and salts of heavy metals.
Note 2—This test method is applicable to both fresh oils and used oils as described in Sections 16, 17, and 19 and in the Appendix X1.
1.5 This test method can be used to determine base number >300 mg KOH/g. However, the precision statement in Section 19 has been obtained only on base number ≤300 mg KOH/g.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7, Section 10, and X2.2.
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NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn. Contact ASTM International (www.astm.org) for the latest information.
Designation: D 2896 – 98 An American National Standard
Designation: 276/95
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Base Number of Petroleum Products by Potentiometric
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Perchloric Acid Titration
This standard is issued under the fixed designation D 2896; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This test method has been approved by the sponsoring committees and accepted by the cooperating societies in accordance with
established procedures.
This standard has been approved for use by agencies of the Department of Defense.
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1. Scope D 1193 Specification for Reagent Water
1.1 This test method covers the determination of basic
3. Terminology
constituents in petroleum products by titration with perchloric
3.1 Definitions of Terms Specific to This Standard:
acid in glacial acetic acid.
3.1.1 base number—the quantity of perchloric acid ex-
1.2 Procedures A and B use different titration solvent
pressed in terms of the equivalent number of milligrams of
volumes and sample weights.
potassium hydroxide that are required to titrate1gofthe
NOTE 1—A round robin on a series of new and used oils and additive
sample dissolved in the specified solvent to a well-defined
concentrates has shown that the two procedures give statistically equiva-
inflection point as specified in this test method.
lent results.
4. Summary of Test Method
1.3 Appendix X2 provides the use of an alternative solvent
system which eliminates the use of chlorobenzene in this test
4.1 The sample is dissolved in an essentially anhydrous
method. The use of the alternative solvent gives statistically
mixture of chlorobenzene and glacial acetic acid and titrated
equivalent results; however, the precision is worse. Paragraph
with a solution of perchloric acid in glacial acetic acid using
X2.4.5 provides guidance when comparing results using the
potentiometric titrimeter. A glass indicating electrode and a
two different solvents.
calomel reference electrode are used, the latter being connected
1.4 The constituents that may be considered to have basic
with the sample solution by means of a salt bridge. The meter
characteristics include organic and inorganic bases, amino
readings are plotted against the respective volumes of titrating
compounds, salts of weak acids (soaps), basic salts of polya-
solution, and the end point is taken at the inflection in the
cidic bases, and salts of heavy metals.
resulting curve.
4.2 Procedure A uses 120 mL of titration solvent. Procedure
NOTE 2—This test method is applicable to both fresh oils and used oils
B uses 60 mL of titration solvent. In addition, the two
as described in Sections 16, 17, and 19 and in the Appendix X1.
procedures use different equations for the calculation of appro-
1.5 This standard does not purport to address all of the
priate sample weights. Since many portions of the test method
safety concerns, if any, associated with its use. It is the
are identical for procedures A and B, only the unique sections
responsibility of the user of this standard to establish appro-
will be described separately for the two versions of the test
priate safety and health practices and determine the applica-
method.
bility of regulatory limitations prior to use. For specific hazard
4.3 Occasionally certain used oils give no inflection in the
statements, see Note 6, Note 7, Note 9, Note 11, and Note 12.
forward titration mode, in which case a back titration modifi-
cation with sodium acetate titrant is employed.
2. Referenced Documents
2.1 ASTM Standards:
5. Significance and Use
5.1 New and used petroleum products can contain basic
constituents that are present as additives. The relative amounts
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This test method is under the jurisdiction of ASTM Committee D-2 on
of these materials can be determined by titration with acids.
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.06 on Analysis of Lubricants.
Current edition approved Aug. 10, 1998. Published November 1998. Originally
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published as D 2896 – 70 T. Last previous edition D 2896 – 96. Annual Book of ASTM Standards, Vol 11.01.
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D 2896
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The base number is a measure of the amount of basic substance where such specifications are available. Other grades may be
in the oil, always under the conditions of the test. It is used, provided it is first ascertained that the reagent is of
sometimes used as a measure of lubricant degradation in suff
...
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