ASTM D2031-97

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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Designation: D 2031 – 97
Standard Test Method for
Reducing Substances in Refined Pyridine
This standard is issued under the fixed designation D 2031; 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 where such specifications are available. Other grades may be
used, provided it is first ascertained that the reagent is of
1.1 This test method covers the qualitative determination of
sufficiently high purity to permit its use without lessening the
reducing substances in refined pyridine.
accuracy of the determination.
1.2 This standard does not purport to address all of the
5.2 Purity of Water—Unless otherwise indicated, references
safety concerns, if any, associated with its use. It is the
to water shall be understood to mean reagent water conforming
responsibility of the user of this standard to establish appro-
to Types I to IV of Specification D 1193.
priate safety and health practices and determine the applica-
5.3 Potassium Permanganate Solution (3.2 g/L)—Dissolve
bility of regulatory limitations prior to use. For specific hazard
3.2 g of potassium permanganate (KMnO ) in water and dilute
statements, see Section 6. 4
to 1 L in a volumetric flask. Standardization of the solution is
2. Referenced Documents not required. Store the permanganate solution in a brown bottle
and prepare fresh every 30 days.
2.1 ASTM Standards:
5.4 Hydrochloric Acid, concentrated (HCl, sp gr 1.19).
D 1193 Specification for Reagent Water
D 3437 Practice for Sampling and Handling Liquid Cyclic
NOTE 1—Clean all equipment used to store and handle the permanga-
Products
nate solution with concentrated hydrochloric acid (HCl, sp gr 1.19) and
2.2 Other Document: rinse thoroughly with water. Continuous use of such equipment without
cleaning results in a deposition of manganese dioxide (MnO ) which
OSHA Regulations, 29 CFR, paragraphs 1910.1000 and 2
catalyzes reduction of the permanganate.
1910.1200.
6. Hazards
3. Summary of Test Method
6.1 Consult current OSHA regulations, supplier’s Material
3.1 Specified volumes of pyridine and potassium perman-
Safety Data Sheets, and local regulations for all materials used
ganate are mixed, allowed to stand for 30 min at room
in this test method.
temperature, and the color of the solution noted.
7. Sampling and Handling
4. Significance and Use
7.1 Sample the material in accordance with practice D 3437.
4.1 This test method gives a qualitative means of detection
of reducing substances in pyridine.
8. Procedure
8.1 Pipet 5 mL of pyridine specimen and 0.5 mL of KMnO
5. Reagents
solution into a 25 by 150-mm test tube. Mix thoroughly by
5.1 Purity of Reagents—Reagent grade chemicals shall be
shaking, stopper, and let stand for 30 min at room temperature.
used in all tests. Unless otherwise indicated, it is intended that
8.2 Note the color of the specimen solution. If a brown color
all reagents shall conform to the specifications of the Commit-
or precipitate interfer
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