ASTM D3634-99(2015)

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of the standard as published by ASTM is to be considered the official document.
Designation: D3634 − 99 (Reapproved 2009) D3634 − 99 (Reapproved 2015)
Standard Test Method for
Trace Chloride Ion in Engine Coolants
This standard is issued under the fixed designation D3634; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This test method covers the determination of chloride ion in engine coolants in the range from 5 to 200 ppm in the presence
of up to 0.6 weight % mercaptobenzothiazole.
1.2 Other materials that react with silver ion will interfere.
1.3 Chloride in engine coolants containing an aryltriazole instead of mercaptobenzothiazole can be determined directly by this
test method without pretreatment with hydrogen peroxide.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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. Specific hazards statements are given in Section 7.
2. Referenced Documents
2.1 ASTM Standards:
D1176 Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
D1193 Specification for Reagent Water
E200 Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis
2.2 Manufacturing Chemists Association Document:
MCA Chemical Safety Data Sheet SD-53
3. Summary of Test Method
3.1 The sample is first treated at a pH of 12 to 13 with aqueous hydrogen peroxide to oxidize the mercaptobenzothiazole to
soluble, noninterfering sulfonate. The treated sample is dissolved in glacial acetic acid and titrated potentiometrically with dilute
standard silver nitrate solution. Since the solubility of silver chloride in this system is sufficient to prevent obtaining a suitable
inflection at the very low limit of the test method, some chloride is deliberately added to the glacial acetic acid solvent and then
corrected for by a blank titration.
4. Significance and Use
4.1 This test method permits the determination of very low levels of chloride ion in engine coolants containing the common
corrosion inhibitor, mercaptobenzothiazole, or related mercaptans, which would normally interfere with the titration by also
forming insoluble silver salts with silver nitrate.
5. Apparatus
5.1 Manual Titrations:
This test method is under the jurisidictionjurisdiction of ASTM Committee D15 on Engine Coolants and Related Fluids and is the direct responsibility of Subcommittee
D15.04 on Chemical Properties.
Current edition approved Nov. 1, 2009May 1, 2015. Published December 2009June 2015. Originally approved in 1977. Last previous edition approved in 20052009 as
ε1
D3634 – 99(2005)(2009). . DOI: 10.1520/D3634-99R09.10.1520/D3634-99R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
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Available from the Manufacturing ChemistsChemists’ Association, 1825 Connecticut Ave., Washington, DC 20009.
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D3634 − 99 (2015)
5.1.1 pH Meter—An expanded scale pH meter which can be read to 1 or 2 mV is desirable but not required. A silver billet
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indicator electrode and glass reference electrode are used for the chloride titration. The silver electrode should be polished
occasionally with fine steel wool or scouring powder and thoroughly rinsed.
5.1.2 Buret, 10-mL, micro, Class A, calibrated in 0.02-mL divisions.
5.1.3 Beakers, electrolytic, 250-mL tall form.
5.2 Automatic Titrators are satisfactory for this test method, provided they exhibit resolution and accuracy equivalent to that
specified for manual titrations.
5.3 Pipets, 10, 20, and 100-mL, Class A.
5.4 Flask, Erlenmeyer, 250 mL, with a 24/40 standard taper, female ground glass joint.
5.5 Condenser—The condenser shall be of the water-cooled, reflux, glass-tube type, having a condenser jacket approximately
200 mm in length. The bottom end of the condenser shall have a 24/40 male ground glass joint to match the Erlenmeyer flask.
5.6 Flask, volumetric, 200 mL, Class A.
NOTE 1—All glassware should be thoroughly cleaned and reserved for use in this test method. Great care must be exercised to avoid contamination.
Glassware should be cleaned with chromic acid (Warning —See 7.1.) cleaning solution, then thoroughly rinsed with water, then with acetone
(Warning—See 7.2.), and dried.
6. Reagents and Materials
6.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
6.2 Purity of Water—References to water shall be understood to mean Type IV reagent water conforming to Specification
D1193: total particulate and dissolved matter, 2.0 mg/L maximum; pH at 25°C, 5.0 to 8.0; electrical conductivity at 25°C, 5.0
μmho/cm maximum; minimum color retention time of potassium permanganate, 10 min.
6.3 Acetic Acid, Glacial (Warning—See 7.3.).
6.4 Hydrogen Peroxide Solution—(Warning—See 7.4.) Use 30 mass % hydrogen peroxide (H O ), reagent grade. Aged or
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contaminated H O can undergo considerable decomposition and cause incomplete oxidation of the sulfur compounds with
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subsequent high apparent chloride values; therefore, fresh reagent should be used.
6.5 Potassium Chloride Solution—Dissolve 0.20 6 0.02 g of potassium chloride (KCl) in 100 mL of water. The solution will
contain 1 mg of chloride per mL solution.
6.6 Silver Nitrate Solution—(Warning—See 7.5.) Prepare a standard 0.01 N
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