ASTM D974-07
(Test Method)Standard Test Method for Acid and Base Number by Color-Indicator Titration
Standard Test Method for Acid and Base Number by Color-Indicator Titration
SCOPE
1.1 This test method covers the determination of acidic or basic constituents (Note 1) 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.
Note 1—In new and used oils, the constituents considered to have acidic characteristics include organic and inorganic acids, esters, phenolic compounds, lactones, resins, salts of heavy metals, and addition agents such as inhibitors and detergents. Similarly, constituents considered to have basic properties include organic and inorganic bases, amino compounds, salts of weak acids (soaps), basic salts of polyacidic bases, salts of heavy metals, and addition agents such as inhibitors and detergents.
Note 2—This test method is not suitable for measuring the basic constituents of many basic additive-type lubricating oils. Test Method D 4739 can be used for this purpose.
1.2 This test method can be used to indicate relative changes 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 or basic property that can be used to predict performance of an oil under service conditions. No general relationship between bearing corrosion and acid or base numbers is known.
Note 3—Oils, such as many cutting oils, rustproofing oils, and similar compounded oils, or excessively dark-colored oils, that cannot be analyzed for acid number by this test method due to obscurity of the color-indicator end point, can be analyzed by Test Method D 664. The acid numbers obtained by this color-indicator test method need not be numerically the same as those obtained by Test Method D 664, the base numbers obtained by this color indicator test method need not be numerically the same as those obtained by Test Method D 4739, but they are generally of the same order of magnitude.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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.
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An American National Standard
Designation:D974–07
Designation: 139/98
Standard Test Method for
1
Acid and Base Number by Color-Indicator Titration
This standard is issued under the fixed designation D974; 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.
This standard has been approved for use by agencies of the Department of Defense.
numbers obtained by this color-indicator test method need not be
1. Scope*
numerically the same as those obtained by Test Method D664, the base
1.1 This test method covers the determination of acidic or
numbers obtained by this color indicator test method need not be
2
basic constituents (Note 1) in petroleum products and lubri-
numerically the same as those obtained by Test Method D4739, but they
cants soluble or nearly soluble in mixtures of toluene and
are generally of the same order of magnitude.
isopropylalcohol.Itisapplicableforthedeterminationofacids
1.3 The values stated in SI units are to be regarded as
or bases whose dissociation constants in water are larger than
standard. No other units of measurement are included in this
−9
10 ; extremely weak acids or bases whose dissociation
standard.
−9
constants are smaller than 10 do not interfere. Salts react if
1.4 This standard does not purport to address all of the
−9
their hydrolysis constants are larger than 10 .
safety concerns, if any, associated with its use. It is the
NOTE 1—In new and used oils, the constituents considered to have responsibility of the user of this standard to establish appro-
acidic characteristics include organic and inorganic acids, esters, phenolic
priate safety and health practices and determine the applica-
compounds, lactones, resins, salts of heavy metals, and addition agents
bility of regulatory limitations prior to use.
such as inhibitors and detergents. Similarly, constituents considered to
have basic properties include organic and inorganic bases, amino com-
2. Referenced Documents
pounds, salts of weak acids (soaps), basic salts of polyacidic bases, salts
3
2.1 ASTM Standards:
of heavy metals, and addition agents such as inhibitors and detergents.
D117 Guide for Sampling, Test Methods, and Specifica-
NOTE 2—This test method is not suitable for measuring the basic
constituents of many basic additive-type lubricating oils. Test Method tions for Electrical Insulating Oils of Petroleum Origin
D4739 can be used for this purpose.
D664 TestMethodforAcidNumberofPetroleumProducts
by Potentiometric Titration
1.2 Thistestmethodcanbeusedtoindicaterelativechanges
D1193 Specification for Reagent Water
that occur in an oil during use under oxidizing conditions.
D4175 Terminology Relating to Petroleum, Petroleum
Although the titration is made under definite equilibrium
Products, and Lubricants
conditions, the method does not measure an absolute acidic or
D4739 Test Method for Base Number Determination by
basicpropertythatcanbeusedtopredictperformanceofanoil
Potentiometric Titration
under service conditions. No general relationship between
bearing corrosion and acid or base numbers is known.
3. Terminology
NOTE 3—Oils, such as many cutting oils, rustproofing oils, and similar
3.1 Definitions:
compounded oils, or excessively dark-colored oils, that cannot be ana-
3.1.1 acid number, n—the quantity of base, expressed in
lyzed for acid number by this test method due to obscurity of the
milligrams of potassium hydroxide per gram of sample that is
color-indicatorendpoint,canbeanalyzedbyTestMethodD664.Theacid
required to titrate a sample to a specified end point.
3.1.1.1 Discussion—In this test method, the indicator is
1
This test method is under the jurisdiction of ASTM Committee D02 on
p-naphtholbenzeintitratedtoagreen/green-brownendpointin
PetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommittee
a toluene-water-isopropanol solvent.
D02.06 on Analysis of Lubricants.
In the IP, this test method is under the jurisdiction of the Standardization
Committee. This test method was adopted as a joint ASTM-IP standard in 1965.
3
Current edition approved Nov. 1, 2007. Published November 2007. Originally For referenced ASTM standards, visit the ASTM website, www.astm.org, or
approved in 1948. Last previous edition approved in 2006 as D974–06. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
2
Statementsdefiningthistestmethod,itsmodification,anditssignificancewhen Standards volume information, refer to the standard’s Document Summary page on
applied to electrical insulating oils of mineral origin will be found in GuideD117. the ASTM website.
*A Summary of Changes section appears at t
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
An American National Standard
Designation:D974–06 Designation:D974–07
Designation: 139/98
Standard Test Method for
1
Acid and Base Number by Color-Indicator Titration
This standard is issued under the fixed designation D974; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope*
2
1.1 This test method covers the determination of acidic or basic constituents (Note 1) in petroleum products and lubricants
solubleornearlysolubleinmixturesoftolueneandisopropylalcohol.Itisapplicableforthedeterminationofacidsorbaseswhose
−9
dissociation constants in water are larger than 10 ; extremely weak acids or bases whose dissociation constants are smaller than
−9 −9
10 do not interfere. Salts react if their hydrolysis constants are larger than 10 .
NOTE 1—In new and used oils, the constituents considered to have acidic characteristics include organic and inorganic acids, esters, phenolic
compounds, lactones, resins, salts of heavy metals, and addition agents such as inhibitors and detergents. Similarly, constituents considered to have basic
properties include organic and inorganic bases, amino compounds, salts of weak acids (soaps), basic salts of polyacidic bases, salts of heavy metals, and
addition agents such as inhibitors and detergents.
NOTE 2—This test method is not suitable for measuring the basic constituents of many basic additive-type lubricating oils. Test Method D4739 can
be used for this purpose.
1.2 This test method can be used to indicate relative changes 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 or basic
property that can be used to predict performance of an oil under service conditions. No general relationship between bearing
corrosion and acid or base numbers is known.
NOTE 3—Oils, such as many cutting oils, rustproofing oils, and similar compounded oils, or excessively dark-colored oils, that cannot be analyzed for
acid number by this test method due to obscurity of the color-indicator end point, can be analyzed by Test Method D664. The acid numbers obtained
by this color-indicator test method need not be numerically the same as those obtained by Test Method D664, the base numbers obtained by this color
indicatortestmethodneednotbenumericallythesameasthoseobtainedbyTestMethodD4739,buttheyaregenerallyofthesameorderofmagnitude.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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.
2. Referenced Documents
3
2.1 ASTM Standards:
D117 Guide for Sampling, Test Methods, and Specifications for Electrical Insulating Oils of Petroleum Origin
D664 Test Method for Acid Number of Petroleum Products by Potentiometric Titration
D1193 Specification for Reagent Water
D4175 Terminology Relating to Petroleum, Petroleum Products, and Lubricants
D4739 Test Method for Base Number Determination by Potentiometric Titration
1
This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.06 on
Analysis of Lubricants.
In the IP, this test method is under the jurisdiction of the Standardization Committee. This test method was adopted as a joint ASTM-IP standard in 1965.
Current edition approved Nov. 1, 2006.2007. Published November 2006.2007. Originally approved in 1948. Last previous edition approved in 20042006 as
D974–04.D974–06.
2
Statements defining this test method, its modification, and its significance when applied to electrical insulating oils of mineral origin will be found in Guide D117.
3
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard.
Copyright © AST
...
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