ASTM D2086-08(2012)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D2086 − 08 (Reapproved 2012)
Standard Test Method for
Acidity in Vinyl Acetate and Acetaldehyde
This standard is issued under the fixed designation D2086; 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.
1. Scope* at reduced temperature with aqueous sodium hydroxide solu-
tion to a phenolphthalein end point.
1.1 This test method covers the determination of total
acidity as acetic acid in refined vinyl acetate and acetaldehyde.
4. Significance and Use
1.2 The values stated in SI units are to be regarded as
4.1 Thistestmethodprovidesameasurementoftotalacidity
standard. No other units of measurement are included in this
in vinyl acetate and acetaldehyde. The results of these mea-
standard.
surements can be used for specification acceptance.
1.3 For purposes of determining conformance of an ob-
5. Interferences
served value or a calculated value using this test method to
relevant specifications, test result(s) shall be rounded off “to
5.1 Any material or contaminant that will react with NaOH
the nearest unit” in the last right-hand digit used in expressing
under the test conditions will affect the results.
the specification limit, in accordance with the rounding-off
5.2 Vinyl acetate will decompose on storage, typically by
method of Practice E29.
way of hydrolysis, to form acetic acid.
1.4 For hazard information and guidance, see the supplier’s
5.3 Acetaldehydewillreactwithoxygen,eitherdissolvedor
Material Safety Data Sheet.
in a storage container, to form acetic acid.
1.5 This standard does not purport to address all of the
5.4 Various acids or other acidic materials may be present.
safety concerns, if any, associated with its use. It is the
Common practice, including the method used here, calculates
responsibility of the user of this standard to establish appro-
these as acetic acid. The actual weight percent of acidic
priate safety and health practices and determine the applica-
materials may be different.
bility of regulatory limitations prior to use. For specific hazard
statements, see Section 8.
6. Apparatus
6.1 Buret, 10-mL, graduated in 0.05-mL subdivisions.
2. Referenced Documents
6.2 Erlenmeyer Flask, 250-mL capacity.
2.1 ASTM Standards:
D1193 Specification for Reagent Water
6.3 Graduated Cylinder, 50 or 100-mL capacity.
E29 Practice for Using Significant Digits in Test Data to
6.4 Cold Bath, maintained at 0°C or below.
Determine Conformance with Specifications
E200 Practice for Preparation, Standardization, and Storage
7. Reagents
of Standard and Reagent Solutions for ChemicalAnalysis
7.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
3. Summary of Test Method
all reagents shall conform to the specifications of the Commit-
3.1 The specimen is mixed with either an equal volume of
tee onAnalytical Reagents of theAmerican Chemical Society,
chilled water or an equal volume of ethyl alcohol and titrated
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
This test method is under the jurisdiction of ASTM Committee D01 on Paint
accuracy of the determination.
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.35 on Solvents, Plasticizers, and Chemical Intermediates.
Current edition approved Nov. 1, 2012. Published November 2012. Originally
approved in 1962. Last previous edition approved in 2008 as D2086 – 08. DOI: Reagent Chemicals, American Chemical Society Specifications, American
10.1520/D2086-08R12. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Analar Standards for Laboratory
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Standards volume information, refer to the standard’s Document Summary page on and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
the ASTM website. MD.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2086 − 08 (2012)
NOTE 4—Titration at low temperature avoids interference and is
7.2 Purity of Water—Unless otherwise indicated, references
required because of the low boiling point of acetaldehyde.
to water shall be understood to mean reagent water as defined
by Type IV or higher purity of Specification D1193.
10.2 Add 0.5 mL of phenolphthalein indicator solution and
titrate with 0.05 N NaOH solution to the first perceptible pink
7.3 Ethyl Alcohol (Ethanol), 95 volume %, minimum.
color.
NOTE1—DenaturedethylalcoholconformingtoFormulaNo.3Aofthe
10.3 By means of a graduated cylinder add 50 mL of the
U.S. Bureau of Alcohol, Tobacco and Firearms is suitable for use as a
acetaldehyde specimen that previously has been chilled to 0 to
solvent.
5°C.
7.4 Phenolphthalein Indicator Solution (10 g/L)—Dissolve
1 g of phenolphthalein in 100 mL of methanol, ethanol, or 10.4 Titrate immediately with the 0.05 N NaOH solution to
isopropanol.
thesamefirstperceptiblepinkcolororiginallyobtainedin10.2.
7.5 Sodium Hydroxide, Standard Solution (0.05 N)—
11. Calculation
Prepare and standardize a 0.05 N sodium hydroxide (NaOH)
solution (Note 2) in accordance with the Sodium Hydroxide
11.1 Calculat
...