ASTM D3339-04
(Test Method)Standard Test Method for Acid Number of Petroleum Products by Semi-Micro Color Indicator Titration
Standard Test Method for Acid Number of Petroleum Products by Semi-Micro Color Indicator Titration
SIGNIFICANCE AND USE
This test method measures the acid number of oils obtained from laboratory oxidation tests using smaller amounts of sample than Test Methods D 974 or D 664. It has specific application in Test Method D 943 in which small aliquots of oil are periodically removed for testing by Test Method D 3339. This test method, therefore, provides a means of monitoring the relative oxidation of oils, by measuring changes in acid number, at different time intervals and under the various oxidizing test conditions.
FIG. 1 Schematic Drawing of Typical Apparatus
SCOPE
1.1 This test method covers the determination of acidic constituents in new or used petroleum products and lubricants soluble or nearly soluble in mixtures of toluene, and isopropyl alcohol. The test method is especially intended for cases in which the amount of sample available to be analyzed is too small to allow accurate analysis by Test Methods D 974 or D 664. It is applicable for the determination of acids having dissociation constants in water larger than 109. Extremely weak acids having dissociation constants smaller than 109 do not interfere. Salts titrate if their hydrolysis constants are larger than 109.
1.2 This test method can be used to indicate relative changes in acid number that occur in an oil during use under oxidizing conditions. Although the titration is made under definite equilibrium conditions, the method does not measure an absolute acidic property that can be used to predict performance of an oil under service conditions. No general relationship between bearing corrosion and acid number is known.
1.3 Since this test method requires substantially less sample than Test Methods D 974 or D 664, it provides an advantageous means of monitoring an oxidation test by changes in acid number by (1) minimizing test sample depletion for acid number analyses and thus minimizing the disturbance of the test or (2) allowing additional acid number analyses to be made while maintaining the same test sample depletion and thus providing additional data. Note 1
Some oils, such as many cutting oils, rust-proofing oils, and similar compounded oils, or excessively dark-colored oils, may be more difficult to analyze by this test method due to obscurity of the color-indicator end point. These oils can be analyzed by Test Method D 664 provided sufficient sample is available. However, this situation is much less likely using Test Method D 3339 than using Test Method D 974 due to the use of a more highly dilute sample during the titration and due to the greater stability of the end point color change. The acid numbers obtained by Test Method D 3339 may or may not be numerically the same as those obtained by Test Method D 664 but they should be of the same order of magnitude.Note 2
The results obtained using this method have been found to be numerically the same as those obtained using Test Method D 974, within the precision of the two methods, for new or oxidized lubricants of the type primarily intended for hydraulic or steam turbine type service. The oxidized lubricants were obtained using the Test Method D 943 oxidation test. This correlation is shown by the correlation coefficient r = 0.989 with slope s = + 1.017 and intercept y = + 0.029, calculated using the acid numbers obtained using both titration methods for the samples used for the precision statement ().
1.4 The values stated in acceptable SI units are to be regarded as the standard. Values in inch-pound units are for information only.
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 warning statements, see Sections 7 and 9, A1.1.4, A2.3.1 and A2.10.1.
1.5 This test method is intended for determining the acceptability of p-naphtholbenze...
General Information
Relations
Standards Content (Sample)
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
An American National Standard
Designation:D3339–04
Standard Test Method for
Acid Number of Petroleum Products by Semi-Micro Color
1
Indicator Titration
This standard is issued under the fixed designation D3339; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
obtainedbyTestMethodD3339mayormaynotbenumericallythesame
1. Scope*
as those obtained by Test Method D664 but they should be of the same
1.1 This test method covers the determination of acidic
order of magnitude.
constituents in new or used petroleum products and lubricants
NOTE 2—Theresultsobtainedusingthismethodhavebeenfoundtobe
soluble or nearly soluble in mixtures of toluene, and isopropyl
numerically the same as those obtained using Test Method D974, within
alcohol. The test method is especially intended for cases in the precision of the two methods, for new or oxidized lubricants of the
type primarily intended for hydraulic or steam turbine type service. The
which the amount of sample available to be analyzed is too
oxidized lubricants were obtained using theTest Method D943 oxidation
small to allow accurate analysis by Test Methods D974 or
test.Thiscorrelationisshownbythecorrelationcoefficient r=0.989with
D664. It is applicable for the determination of acids having
slope s=+1.017 and intercept y=+0.029, calculated using the acid
−9
dissociation constants in water larger than 10 . Extremely
numbersobtainedusingbothtitrationmethodsforthesamplesusedforthe
−9
weak acids having dissociation constants smaller than 10 do 2
precision statement (12.2).
notinterfere.Saltstitrateiftheirhydrolysisconstantsarelarger
1.4 The values stated in acceptable SI units are to be
−9
than 10 .
regarded as the standard. Values in inch-pound units are for
1.2 Thistestmethodcanbeusedtoindicaterelativechanges
information only.
in acid number that occur in an oil during use under oxidizing
1.5 This standard does not purport to address all of the
conditions. Although the titration is made under definite
safety concerns, if any, associated with its use. It is the
equilibrium conditions, the method does not measure an
responsibility of the user of this standard to establish appro-
absolute acidic property that can be used to predict perfor-
priate safety and health practices and determine the applica-
mance of an oil under service conditions. No general relation-
bility of regulatory limitations prior to use. For specific
ship between bearing corrosion and acid number is known.
warning statements, see Sections 7 and 9,A1.1.4,A2.3.1, and
1.3 Sincethistestmethodrequiressubstantiallylesssample
A2.10.1.
than Test Methods D974 or D664, it provides an advanta-
geousmeansofmonitoringanoxidationtestbychangesinacid
2. Referenced Documents
number by (1) minimizing test sample depletion for acid
3
2.1 ASTM Standards:
number analyses and thus minimizing the disturbance of the
D664 TestMethodforAcidNumberofPetroleumProducts
testor(2)allowingadditionalacidnumberanalysestobemade
by Potentiometric Titration
while maintaining the same test sample depletion and thus
D943 Test Method for Oxidation Characteristics of Inhib-
providing additional data.
ited Mineral Oils
NOTE 1—Some oils, such as many cutting oils, rust-proofing oils, and D974 Test Method for Acid and Base Number by Color-
similar compounded oils, or excessively dark-colored oils, may be more
Indicator Titration
difficult to analyze by this test method due to obscurity of the color-
D1193 Specification for Reagent Water
indicator end point. These oils can be analyzed by Test Method D664
provided sufficient sample is available. However, this situation is much
3. Terminology
less likely using Test Method D3339 than using Test Method D974 due
3.1 Definitions:
to the use of a more highly dilute sample during the titration and due to
the greater stability of the end point color change. The acid numbers
2
Use of the correlation coefficient is given in Mack, C., Essentials of Statistics
for Scientists and Technologists, Plenum Press, New York, NY, 1967, or other
1
This test method is under the jurisdiction of ASTM Committee D02 on publications on statistics.
3
PetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommittee For referenced ASTM standards, visit the ASTM website, www.astm.org, or
D02.06 on Analysis of Lubricants. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Nov. 1, 2004. Published November 2004. Originally Standards volume information, refer to the standard’s Document Summary page on
approved in 1974. Last previous edition approved in 2002 as D3339–02. the ASTM we
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.