ASTM D8032-16

Standard Test Method for Acid Number of Terephthalic Acid by Color-Indicator Titration

SIGNIFICANCE AND USE
5.1 An estimate of TA purity can be determined by titrating with KOH. As an index of TA purity, the acid number can be used as a guide in the quality control of TA production.
SCOPE
1.1 This test method covers the determination of acid number of terephthalic acid (TA) by color-indicator titration. Acid number of TA product is usually within 674 to 676 mg KOH/g.  
1.2 In determining the conformance of the test results using this method, results shall be rounded off in accordance with the rounding-off method of Practice E29.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 29-Feb-2016
• ICS: 71.080.40 - Organic acids
• Technical Committee: D16 - Aromatic, Industrial, Specialty and Related Chemicals
• Drafting Committee: D16.02 - Oxygenated Aromatics

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D8032 − 16
Standard Test Method for
Acid Number of Terephthalic Acid by Color-Indicator
1
Titration
This standard is issued under the fixed designation D8032; 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 determination of acid
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number of terephthalic acid (TA) by color-indicator titration. 2.2 Other Document:
Acid number of TA product is usually within 674 to 676 mg
OSHA Regulations, 29 CFR paragraphs 1910.1000 and
KOH/g.
1910.1200
1.2 In determining the conformance of the test results using
3. Terminology
this method, results shall be rounded off in accordance with the
rounding-off method of Practice E29.
3.1 Definitions:
1.3 The values stated in SI units are to be regarded as 3.1.1 acid number, n—the quantity of base, expressed in
standard. No other units of measurement are included in this milligrams of potassium hydroxide per gram of sample that is
standard. required to titrate a sample in a specified solvent to a specified
end point.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4.1 A TA sample is dissolved in dimethyl sulfoxide and
bility of regulatory limitations prior to use.
titrated with standard sodium hydroxide solution to the end
pointindicatedbythecolorchangeoftheaddedphenolphtalein
2. Referenced Documents
solution (colorless in acid and pink in base). The acid number
2
2.1 ASTM Standards:
is calculated as milligrams of KOH per gram of TAsample. Its
D974 Test Method for Acid and Base Number by Color-
theoretical value of TA sample is 675.5 mg KOH/g.
Indicator Titration
D1193 Specification for Reagent Water
5. Significance and Use
D4790 Terminology ofAromatic Hydrocarbons and Related
5.1 An estimate of TApurity can be determined by titrating
Chemicals
with KOH. As an index of TA purity, the acid number can be
D6809 Guide for Quality Control and Quality Assurance
used as a guide in the quality control of TA production.
Procedures for Aromatic Hydrocarbons and Related Ma-
terials
6. Apparatus
E29 Practice for Using Significant Digits in Test Data to
Determine Conformance with Specifications
6.1 Analytical Balance, capable of weighing 60.0001 g.
E177 Practice for Use of the Terms Precision and Bias in
6.2 Burets, 50-mL with 0.1-mL graduations.
ASTM Test Methods
E300 Practice for Sampling Industrial Chemicals
7. Reagents
7.1 Purity of Reagents—Unless otherwise indicated, it is
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This test method is under the jurisdiction of ASTM Committee D16 on
intended that all reagents shall conform to the reagent grade
Aromatic Hydrocarbons and Related Chemicals and is the direct responsibility of
specification of the Analytical Reagents of the American
Subcommittee D16.02 on Oxygenated Aromatics.
Current edition approved March 1, 2016. Published June 2016. DOI: 10.1520/
D8032-16.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Available from U.S. Government Printing Office, Superintendent of
Standards volume information, refer to the standard’s Document Summary page on Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http://
the ASTM website. www.access.gpo.gov.
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D8032 − 16
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Chemical Society, where such specifications are available. 10.5 Calculate the molarity of the NaOH solution as fol-
Other grades may be used, provided it is first ascertained that lows:
the reagent is of sufficient high purity to permit its use without
m 3 1000
C 5 (1)
lessening the performance or accuracy of the determination.
M 3 ~V 2 V !
0
Reagent chemicals shall be used for all tests.
where:
7.2 Purity of Water—Unless otherwise indicated, references
C = molarity of NaOH solution, mol/L,
to water shall be understood to mean Type III of Specification
V = NaOH solution required for titration of the potassium
D1193. Boil the water gently for 5 to 10 min to remove any
hydrogen phthalate (10.3), mL,
CO and cool the water to room temperature.
2
V = NaOH solution required for titration of the potassium
0
7.3 Dimethyl Sulfoxide—(Warning—Flammable and harm-
hydrogen phthalate (10.4), mL,
fu
...