ASTM D5984-97

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact
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Designation: D 5984 – 97 An American National Standard
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
Semi-Quantitative Field Test Method for Base Number in
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New and Used Lubricants by Color-Indicator Titration
This standard is issued under the fixed designation D 5984; 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.
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1. Scope Potentiometric Titration
1.1 This test method covers a procedure for determining the
3. Terminology
basic constituents in petroleum products in the field or labora-
3.1 Definitions:
tory using a pre-packaged test kit. The test uses a micro-
3.1.1 base number, n—the quantity of an acid, expressed in
titration resulting in a visual end point facilitated by a color
terms of the equivalent number of milligrams of potassium
indicator.
hydroxide per gram of sample, that is required to titrate a
1.1.1 This test method covers base numbers from 0 to 20. It
sample dissolved in the specified solvent to a specified end
can be extended to higher ranges by diluting the sample or by
point (for example, Test Method D 4739).
using a smaller sample size; however, the precision data were
3.1.1.1 Discussion—This test method uses fixed amounts of
obtained for base numbers up to 20.
isooctane and alcoholic hydrochloric acid as the sample solvent
1.2 This test method can be used to indicate relative changes
and the end point is defined as the amount of titrant required to
that occur in an oil during use under oxidizing conditions.
reach a yellow end-point with a methyl red indicator solution.
Although the test is performed under closely specified condi-
tions with standardized reagents, the test method does not
4. Summary of Test Method
measure an absolute basic property that can be used to predict
4.1 To determine the base number of an oil sample, the
performance of an oil under service conditions. No general
sample is dissolved in a fixed amount of isooctane and
relationship between bearing corrosion and base number is
alcoholic hydrochloric acid. The solution is mixed well with 7
known.
mL of sodium chloride solution and the aqueous and organic
1.3 The values stated in SI units are to be regarded as the
phases are allowed to separate. The aqueous phase is then
standard. The values given in parentheses are for information
decanted off and a small amount of methyl red indicator is
only.
added. The solution is titrated with a solution of sodium
1.4 This standard does not purport to address all of the
hydroxide contained in a calibrated 1 mL micro-burette. When
safety concerns, if any, associated with its use. It is the
the solution changes from magenta to yellow, the titration is
responsibility of the user of this standard to establish appro-
stopped and the base number is read off the side of the titration
priate safety and health practices and determine the applica-
burette.
bility of regulatory limitations prior to use.
5. Significance and Use
2. Referenced Documents
5.1 New and used petroleum products can contain basic
2.1 ASTM Standards:
constituents that are present as additives or as degradation
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D 1193 Specification for Reagent Water
products formed during service. The amount of these additives
D 2896 Test Method for Base Number of Petroleum Prod-
in an oil can be determined by titrating against an acid. The
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ucts by Potentiometric Perchloric Acid Titration
base number is a measure of the amount of basic substance in
D 4057 Practice for Manual Sampling of Petroleum and
the oil, always under the conditions of the test. A decrease in
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Petroleum Products
base number is often used as a measure of lubricant degrada-
D 4177 Practice for Automatic Sampling of Petroleum and
tion, but any condemning limits must be empirically estab-
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Petroleum Products
lished.
D 4739 Test Method for Base Number Determination by
5.2 This test method uses reagents that are considered less
hazardous than most reagents used in alternate base number
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methods. It uses pre-packaged reagents to facilitate base
This test method is under the jurisdiction of ASTM Committee D-2 on
Petroleum Products and Lubricantsand is the direct responsibility of Subcommittee
number determinations in the field where scientific equipment
D02.06 on Analysis of Lubricants.
is unavailable and quick results are at a premium.
Current edition approved Nov. 10, 1997. Published June 1998. Originally
published as D 5984 96. Last previous edition D 5984 96
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Annual Book of ASTM Standards, Vol 11.01.
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Annual Book of ASTM
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