ASTM D2191-97

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: D 2191 – 97
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
1
Acetaldehyde Content of Vinyl Acetate
This standard is issued under the fixed designation D 2191; 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
1.1 This test method covers the determination of trace 7.1 Purity of Reagents—Unless otherwise indicated, it is
quantities of acetaldehyde, in the range from 0.00 to 0.05 %, intended that all reagents shall conform to the specifications of
contained in 99 % grade vinyl acetate. the Committee on Analytical Reagents of the American Chemi-
3
1.2 This standard does not purport to address all of the cal Society, where such specifications are available. Other
safety concerns, if any, associated with its use. It is the grades may be used provided that it is first ascertained that the
responsibility of the user of this standard to establish appro- reagent is of sufficiently high purity to permit its use without
priate safety and health practices and determine the applica- lessening the accuracy of the determination.
bility of regulatory limitations prior to use. For specific hazard 7.2 Purity of Water—Unless otherwise indicated, references
statements see Section 8. to water shall be understood to mean reagent water as defined
1.3 For hazard information and guidance, see the supplier’s by Type IV of Specification D 1193.
Material Safety Data Sheet. 7.3 Iodine, Standard Solution (0.1 N)—Dissolve 35.0 g of
potassium iodide (KI) and 13.0 g of resublimed iodine in water,
2. Referenced Documents
and dilute to 1 L with water. Store this solution in a dark bottle
2.1 ASTM Standards:
and standardize each day, as required, against a standard 0.1 N
2
D 1193 Specification for Reagent Water sodium thiosulfate (Na S O ) solution. (See standardization
2 2 3
procedure, 9.3 and 9.4.)
3. Summary of Test Method
7.4 Potassium Iodate (KIO ), primary standard.
3
3.1 The acetaldehyde present in the specimen is reacted
7.5 Sodium Bisulfite Solution (0.44 %)—Dissolve 4.4 g of
with a measured excess of sodium bisulfite. The amount of
sodium metabisulfite (Na S O ) in 1 L of water. This solution
2 2 5
sodium bisulfite consumed, determined by titrating the excess
should be prepared fresh daily or just before using.
with a standard iodine solution, is a measure of the acetalde-
7.6 Sodium Thiosulfate, Standard Solution (0.1 N)— Weigh
hyde present in the vinyl acetate.
to 0.1 g 24.8 g of sodium thiosulfate (Na S O ·5H O) crystals
2 2 3 2
and dissolve in 500 mL of water. Dilute this solution to 1 L
4. Significance and Use
with water. Add 0.5 mL of chloroform per litre of solution as
4.1 This test method provides a measurement of acetalde-
a preservative, and store in a clean dark bottle. This solution
hyde content in vinyl acetate. The results of these measure-
should be standardized weekly, as required, against potassium
ments can be used for specification acceptance.
iodate (KIO ). (See standardization procedure, 9.1 and 9.2.)
3
7.7 Starch Indicator—Make a paste of6gof powdered
5. Interference
soluble starch in water, and dilute to 1 L with water, stirring to
5.1 Ketones and other aldehydes, if present, cause a positive
produce a suspension. While stirring, add 20 g of potassium
interference.
hydroxide (KOH) pellets, and continue stirring until the KOH
is dissolved. Let stand for 2 h and add 27.5 mL of hydrochloric
6. Apparatus
acid (HCl). Adjust the mixture to a pH of 6.0 6 0.1 by adding
6.1 Buret, 50-mL capacity, graduated in 0.1-mL subdivi-
small increments of HCl or KOH as required. Add 6 mL of
sions, with a funnel or flared top and a ground-glass stopcock.
glacial acetic acid as a preservative.
6.2 Erlenmeyer Flask, 500-mL capacity, glass-stoppered.
7.8 Sulfuric Acid (1 N)—Place approximately 700 to 800
6.3 Pipet, 50-mL capacity.
mL of water in a 1-L volumetric flask. Add slowly and with
6.4 Pipet, 100-mL capacity.
constant stirring 27.2 mL of concentrated sulfuric acid (H SO ,
2 4
1 3
This test method is under the jurisdiction of ASTM Committee D-1 on Paint Reagent Chemicals, American Chemical Society Specifications, American
and Related Coatings, Materials, and Applications and is the direct responsibility of Chemical Society, Washington, DC. For suggestions on the testing of reagents not
Subcommittee D01.35 on Solvents, Plasticizers, and Chemical Intermediates. listed by the American Chemical Society, see Analar Standards for Laboratory
Current edition approved June 10,
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