ASTM D4755-95(2000)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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Designation: D 4755 – 95 (Reapproved 2000)
Standard Test Method for
Free Halogens in Halogenated Organic Solvents and Their
Admixtures
This standard is issued under the fixed designation D 4755; 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.
1. Scope 7. Reagents
7.1 Purity of Reagents—Reagent grade chemicals shall be
1.1 This test method covers the evaluation of free halogens
in halogenated organic solvents and their admixtures. used in all tests. Unless otherwise indicated, it is intended that
1.2 This standard does not purport to address all of the all reagents shall conform to the specifications of the Commit-
safety concerns, if any, associated with its use. It is the tee on Analytical Reagents of the American Chemical Society,
responsibility of the user of this standard to establish appro- where such specifications are available. Other grades may be
priate safety and health practices and determine the applica- used, provided it is first ascertained that the reagent is of
bility of regulatory limitations prior to use. sufficiently high purity to permit its use without lessening the
accuracy of the determination.
2. Referenced Documents
7.2 Purity of Water— Unless otherwise indicated, refer-
2.1 ASTM Standards:
ences to water shall be understood to mean reagent water
D 1193 Specification for Reagent Water conforming to Type III of Specification D 1193.
7.3 Potassium Iodide (KI) Test Solution—Dissolve 16.5 g of
3. Summary of Test Method
potassium iodide in water to make 100 mL. Store in light-
3.1 Any free halogens present in the halogenated solvent are
resistant containers.
extracted with water and reacted with potassium iodide test
7.4 Starch Test Solution—Mix1gof soluble starch with 10
solution containing starch indicator. A blue color indicates that
mg of red mercuric iodide and sufficient cold water to make a
presence of free halogens.
thin paste. Add 200 mL of boiling water, and boil for 1 min
with continuous stirring. Cool, and use only the clear solution.
4. Significance and Use
8. Procedure
4.1 Free halogens will react with any residual moisture in a
solvent to form acid. These acids can cause corrosion to
8.1 Transfer 10 mL of sample to a glass-stoppered graduate
process and storage equipment used for halogenated solvents.
and add 10 mL of potassium iodide test solution and 1 mL of
4.2 The presence of free halogens in halogenated solvents is
starch indicator solution. Shake vigorously for 2 min and
often an indication that the stabilizers in the solvent system are
observe color of the aqueous layer. The presence of free
breaking down.
halogens is indicated by a blue coloration.
4.3 This test method provides a means of detecting the
NOTE 1—The potassium iodide solution can generate free iodine via air
presence of free halogens in halogenated solvents and their
oxidation. For this reason, the test procedure should first be performed on
admixtures.
a reagent blank (10 mL of potassium iodide and 1 mL of starch). If a faint
blue color is observed in the blank, a fresh potas
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