ASTM D7704-16

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: D7704 − 16
Standard Test Method for
Total Aldehydes in Styrene Monomer by Potentiometric
1
Titration
This standard is issued under the fixed designation D7704; 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* E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 This test method covers the wet chemical determination
2.2 Other Documents:
of total aldehydes in styrene monomer. Total aldehydes are
OSHA Regulations, 29 CFR paragraphs 1910.1000 and
calculated and reported as benzaldehyde. The Range of Con-
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1910.1200
centration for this test method is 0.004 weight % to 0.013
weight %.
3. Summary of Test Method
1.2 Limit of Detection (LOD) and Limit of Quantification
3.1 An alcoholic solution of hydroxylamine hydrochloride
(LOQ) is 0.0006 and 0.0020 weight %, respectively
is added to a specimen of styrene monomer. Active aldehydes
1.3 In determining conformance of the test results using this present react in accordance with Eq 1:
methodtoapplicablespecifications,resultsshallberoundedoff
RCHO1NH OH·HCl→RCHNOH1H O1HCl (1)
2 2
in accordance with the rounding-off method of Practice E29.
The amount of hydrochloric acid released, which is equiva-
1.4 The values stated in SI units are to be regarded as
lent to the aldehyde present in the sample, is titrated with
standard. No other units of measurement are included in this
standard alcoholic potassium hydroxide solution.
standard with the exception: weight % should be used rather
than mass %.
4. Significance and Use
1.5 This standard does not purport to address all of the
4.1 This test method is suitable for determining the quantity
safety concerns, if any, associated with its use. It is the
of aldehydes, both for quality control and quality assurance of
responsibility of the user of this standard to establish appro-
the product.
priate safety and health practices and determine the applica-
5. Interferences
bility of regulatory limitations prior to use.
5.1 Ketones, if present, interfere by partially reacting with
2. Referenced Documents
the reagent.
2
2.1 ASTM Standards:
5.2 Methanolusedinthisproceduremaypartiallyreactwith
D1193 Specification for Reagent Water
aldehydes to form (hemi)acetals.
D3437 Practice for Sampling and Handling Liquid Cyclic
Products
6. Apparatus
D6809 Guide for Quality Control and Quality Assurance
6.1 Titration Vessel, 150 mL.
Procedures for Aromatic Hydrocarbons and Related Ma-
terials 6.2 Combined pH – Glass Electrode, dedicated for non-
E29 Practice for Using Significant Digits in Test Data to aqueous liquids.
Determine Conformance with Specifications
6.3 Stirring Bar, 30 mm.
6.4 Titration Stand with stirrer.
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This test method is under the jurisdiction of ASTM Committee D16 on
6.5 Pipets, 25 mL.
Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of
Subcommittee D16.07 on Styrene, Ethylbenzene and C9 and C10 Aromatic
6.6 Volumetric Flasks, 100 mL.
Hydrocarbons.
Current edition approved June 1, 2016. Published October 2016. Originally
6.7 Burets, 5 mL. (Microburets are preferred.)
approved in 2011. Last previous edition approved in 2012 as D7704 – 12. DOI:
10.1520/D7704-16. 6.8 Exchange Unit, 5 mL.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on Available from DLA Document Services, Building 4/D, 700 Robbins Ave.,
the ASTM website. Philadelphia, PA 19111-5094, http://quicksearch.dla.mil.
*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
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D7704 − 16
6.9 Thermometers, capable of differentiating 1°C at ambi- 10.2 Pipet 25.0 mL of the sample (Warning—see 8.2) and
ent. 25 mL of methanol (7.4) into a 150-mL titration vessel with
stirringbar.Add0.2mLofwater.Add25mLoftheneutralized
7. Reagents and Materials
hydroxylamine hydrochloride solution and allow to stand 0.5 h
7.1 Purity of Reagents—Reagent grade chemicals shall be while stirring. Titrate with the 0.02 N KOH/methanol solution,
used in all tests. Unless otherwise indicated, it is intended that dispensed from a 5-mL buret, until the first equivalence point,
all reagents conform t
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