ASTM D2086-22

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D2086 − 22
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 E200 Practice for Preparation, Standardization, and Storage
of Standard and Reagent Solutions for ChemicalAnalysis
1.1 This test method covers the determination of total
acidity as acetic acid in refined vinyl acetate and acetaldehyde.
3. Summary of Test Method
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this 3.1 The specimen is mixed with either an equal volume of
standard.
chilled water or an equal volume of ethyl alcohol and titrated
at reduced temperature with aqueous sodium hydroxide solu-
1.3 For purposes of determining conformance of an ob-
tion to a phenolphthalein end point.
served value or a calculated value using this test method to
relevant specifications, test result(s) shall be rounded off “to
4. Significance and Use
the nearest unit” in the last right-hand digit used in expressing
the specification limit, in accordance with the rounding-off
4.1 Thistestmethodprovidesameasurementoftotalacidity
method of Practice E29.
in vinyl acetate and acetaldehyde. The results of these mea-
1.4 For hazard information and guidance, see the supplier’s
surements can be used for specification acceptance.
Material Safety Data Sheet.
1.5 This standard does not purport to address all of the 5. Interferences
safety concerns, if any, associated with its use. It is the
5.1 Any material or contaminant that will react with NaOH
responsibility of the user of this standard to establish appro-
under the test conditions will affect the results.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
5.2 Vinyl acetate will decompose on storage, typically by
For specific hazard statements, see Section 8.
way of hydrolysis, to form acetic acid.
1.6 This international standard was developed in accor-
5.3 Acetaldehydewillreactwithoxygen,eitherdissolvedor
dance with internationally recognized principles on standard-
in a storage container, to form acetic acid.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5.4 Various acids or other acidic materials may be present.
mendations issued by the World Trade Organization Technical
Common practice, including the method used here, calculates
Barriers to Trade (TBT) Committee.
these as acetic acid. The actual weight percent of acidic
materials may be different.
2. Referenced Documents
2.1 ASTM Standards:
6. Apparatus
D1193 Specification for Reagent Water
E29 Practice for Using Significant Digits in Test Data to
6.1 Buret, 10-mL, graduated in 0.05-mL subdivisions.
Determine Conformance with Specifications
6.2 Erlenmeyer Flask, 250-mL capacity.
6.3 Graduated Cylinder, 50 or 100-mL capacity.
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
6.4 Cold Bath, maintained at 0 °C or below.
Subcommittee D01.35 on Solvents, Plasticizers, and Chemical Intermediates.
Current edition approved Jan. 1, 2022. Published January 2022. Originally
approved in 1962. Last previous edition approved in 2012 as D2086 – 08 (2012) 7. Reagents
which was withdrawn January 2021 and reinstated in January 2022. DOI: 10.1520/
D2086-22. 7.1 Purity of Reagents—Reagent grade chemicals shall be
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
used in all tests. Unless otherwise indicated, it is intended that
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
all reagents shall conform to the specifications of the Commit-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. tee onAnalytical Reagents of theAmerican Chemical Society,
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2086 − 22
where such specifications are available. Other grades may be bromothymol blue indicator. The solution may be purged to
used, provided it is first ascertained that the reagent is of remove any absorbed carbon dioxide.
sufficiently high purity to permit its use without lessening the
9.4 Titrate with the 0.02 N NaOH solution to the blue color.
accuracy of the determination.
10. Procedure for Acetaldehyde (Warning—see Section 8)
7.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean reagent water as defined
10.1 Measure into a 250-mL Erlenmeyer flask 50 mL of
by Type IV or higher purity of Specification D1193.
water and add sufficient crushed ice (prepared from reagent
water) so that some ice will remain at the end of the
7.3 Ethyl Alcohol (Ethanol), 95 volume %, minimum.
determination.
NOTE1—DenaturedethylalcoholconformingtoFormulaNo.3Aofthe
NOTE 4—Titration at low temperature avoids interference and is
U.S. Bureau of Alcohol, Tobacco and Firearms is suitable for use as a
required because of the low boiling point of acetaldehyde.
solvent.
10.2 Add 0.5 mL of phenolphthalein indicator solution and
7.4 Phenolphthalein Indicator Solution (10 g/L)—Dissolve
titrate with 0.05 N NaOH solution to the first perceptible pink
1 g of phenolphthalein in 100 mL of methanol, ethanol, or
isopropanol. color.
10.3 By means of a graduated cylinder add 50 mL of the
7.5 Sodium Hydroxide, Standard Solution (0.05 N)—
Prepare and standardize a 0.05 N so
...