ASTM D1386-98(2004)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D1386–98(Reapproved 2004)
Standard Test Method for
Acid Number (Empirical) of Synthetic and Natural Waxes
This standard is issued under the fixed designation D1386; 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 Department of Defense.
1. Scope 5. Apparatus
1.1 This test method covers the determination of the acid 5.1 Analytical Balance.
number of synthetic waxes and natural waxes. The number is 5.2 Buret, 50-mL, with 0.1-mL graduations.
obtained by direct titration of the material and indicates the 5.3 Flasks, acid value, 250-mL.
amount of free acid present.
6. Reagents and Materials
1.2 This test method, using an ethanol-xylene mixture, is
6.1 Purity of Reagents—Reagent-grade chemicals or
applicable to all natural waxes, including carnauba. The test
method is also applicable to oxidized microcrystalline waxes, equivalent, as specified in Practice E200, shall be used in all
tests.
oxidized Fischer-Tropsch, oxidized polyethylene, and montan
esters. 6.2 Ethanolic Potassium Hydroxide, Standard Solution (0.1
N)—Dissolve 6.6 g of potassium hydroxide in 5.6 g of distilled
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the water. Dilute with USSD3Adenatured ethanol or 95 % ethanol
to 1000 mL. Standardize with 0.1 N hydrochloric acid.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 6.3 Phenolphthalein Indicator Solution (10 g/litre)—
Dissolve1gof phenolphthalein in 100 mL of USSD3A,
bility of regulatory limitations prior to use.
denatured ethanol or 95 % ethanol.
2. Referenced Document
6.4 Xylene.
2.1 ASTM Standards:
7. Procedure
E200 Practice for Preparation, Standardization, and Storage
of Standard and Reagent Solutions for Chemical Analysis 7.1 Transfer 1 to2gofthe sample, weighed to the nearest
0.001 g, to a 250-mL acid-value flask. Add 40 mL of xylene.
3. Terminology
Heat on a hot plate or water bath to put the sample into
3.1 Definition: solution. Occasional swirling may be necessary.
3.1.1 acid number or acid value—the number of milligrams 7.2 Add 3 to 5 drops of phenolphthalein indicator solution
of potassium hydroxide necessary to neutralize1gofthe and titrate the hot solution to the first persistent pink color.The
sample. end point is taken when the pink color remains for at least 10
s.Swirltheflaskvigorouslyduringthetitration.Ifprecipitation
4. Significance and Use
of waxes occurs during titration, reheat the sample. The
4.1 This test method is used to determine the property of titrati
...