ASTM D8032-20

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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 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.

General Information

• Status: Published
• Publication Date: 31-Jul-2020
• ICS: 71.080.40 - Organic acids
• Technical Committee: D16 - Aromatic, Industrial, Specialty and Related Chemicals
• Drafting Committee: D16.02 - Oxygenated Aromatics

Standards Content (Sample)

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: D8032 − 20
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* Procedures for Aromatic Hydrocarbons and Related Ma-
terials
1.1 This test method covers the determination of acid
E29 Practice for Using Significant Digits in Test Data to
number of terephthalic acid (TA) by color-indicator titration.
Determine Conformance with Specifications
Acid number of TA product is usually within 674 to 676 mg
E177 Practice for Use of the Terms Precision and Bias in
KOH/g.
ASTM Test Methods
1.2 In determining the conformance of the test results using
E300 Practice for Sampling Industrial Chemicals
this method, results shall be rounded off in accordance with the
E691 Practice for Conducting an Interlaboratory Study to
rounding-off method of Practice E29.
Determine the Precision of a Test Method
3
1.3 The values stated in SI units are to be regarded as
2.2 Other Document:
standard. No other units of measurement are included in this
OSHA Regulations, 29 CFR paragraphs 1910.1000 and
standard.
1910.1200
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions:
priate safety, health, and environmental practices and deter-
3.1.1 acid number, n—the quantity of base, expressed in
mine the applicability of regulatory limitations prior to use.
milligrams of potassium hydroxide per gram of sample that is
1.5 This international standard was developed in accor-
required to titrate a sample in a specified solvent to a specified
dance with internationally recognized principles on standard-
end point.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4. Summary of Test Method
mendations issued by the World Trade Organization Technical
4.1 A TA sample is dissolved in dimethyl sulfoxide and
Barriers to Trade (TBT) Committee.
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.
6. Apparatus
1
This test method is under the jurisdiction of ASTM Committee D16 on
Aromatic, Industrial, Specialty and Related Chemicals and is the direct responsi-
6.1 Analytical Balance, capable of weighing 60.0001 g.
bility of Subcommittee D16.02 on Oxygenated Aromatics.
6.2 Burets, 50-mL with 0.1-mL graduations.
Current edition approved Aug. 1, 2020. Published September 2020. Originally
approved in 2016. Last previous edition approved in 2016 as D8032 – 16. DOI:
10.1520/D8032-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3
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.
*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
1

---------------------- Page: 1 ----------------------
D8032 − 20
7. Reagents 10.3 Add 3 drops of phenolphthalein indicator solution and
titrate with 0.5 M NaOH solution (7.4) until one drop of NaOH
7.1 Purity of Reagents—Unless otherwise indicated, it is
changes the color of the solution from colorless to pink.
intended that all reagents shall conform to the reagent grade
specification of the Analytical Reagents of the American
10.4 Perform a blank titration by repeating the ab
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D8032 − 16 D8032 − 20
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 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 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.
2. Referenced Documents
2
2.1 ASTM Standards:
D974 Test Method for Acid and Base Number by Color-Indicator Titration
D1193 Specification for Reagent Water
D4790 Terminology of Aromatic Hydrocarbons and Related Chemicals
D6809 Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Materials
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E300 Practice for Sampling Industrial Chemicals
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3
2.2 Other Document:
OSHA Regulations, 29 CFR paragraphs 1910.1000 and 1910.1200
1
This test method is under the jurisdiction of ASTM Committee D16 on Aromatic Hydrocarbons Aromatic, Industrial, Specialty and Related Chemicals and is the direct
responsibility of Subcommittee D16.02 on Oxygenated Aromatics.
Current edition approved March 1, 2016Aug. 1, 2020. Published June 2016September 2020. Originally approved in 2016. Last previous edition approved in 2016 as
D8032 – 16. DOI: 10.1520/D8032-16.10.1520/D8032-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from U.S. Government Printing Office, Superintendent of Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http://www.access.gpo.gov.
*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
1

---------------------- Page: 1 ----------------------
D8032 − 20
3. Terminology
3.1 Definitions:
3.1.1 acid number, n—the quantity of base, expressed in milligrams of potassium hydroxide per gram of sample that is required
to titrate a sample in a specified solvent to a specified end point.
4. Summary of Test Method
4.1 A TA sample is dissolved in dimethyl sulfoxide and titrated with standard sodium hydroxide solution to the end point indicated
by the color change of the added phenolphtalein solution (colorless in acid and pink in base). The acid number is calculated as
milligrams of KOH per gram of TA sample. Its theoretical value of TA sample is 675.5 mg KOH/g.
5. 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.
6. Apparatus
6.1 Analytical Balance, capable of weighing 60.0001 g.
6.2 Burets, 50-mL with 0.1-mL graduations.
7. Reagents
7.1 Purity of Reagents—Unless otherwise indicated, it is intended that all reagents shall conform to the reagent grade specification
4
of the Analytical Reagents of the American Chemical Society,
...