ASTM D7881-13
Standard Test Method for Determination of 4-Carboxybenzaldehyde and p-Toluic Acid in Purified Terephthalic Acid by Capillary Electrophoresis with Reverse Voltage Mode

Standard No.

ASTM D7881-13

Release Date

2013

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM D7881-19

Latest

ASTM D7881-20e1

Scope

5.1 The presence of 4-CBA and p-TOL in PTA used for the production of polyester is undesirable because they can slow down the polymerization process; and 4-CBA is also imparting coloration to the polymer due to thermal instability.

5.2 Determining the amount of 4-CBA and p-TOL remaining from the manufacture of PTA is often required. This test method is suitable for setting specifications and for use as an internal quality control where these products are produced or used.

5.3 This test method is intended as an alternative to the HPLC method for the determination of 4-CBA and p-TOL in PTA. The major benefits of CE are speed, simplicity, reduced reagent consumption, and operating costs.

1.1 This test method² covers the determination of 4-carboxybenzaldehyde (4-CBA) and p-toluic acid (p-TOL) in purified terephthalic acid (PTA) by capillary electrophoresis (CE) with reverse voltage mode and UV detection. It is applicable for 4-CBA from 3 to 400 mg/kg and for p-TOL from 8 to 400 mg/kg, respectively.

1.2 In determining the conformance of the test results using this method to applicable specification, 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.

ASTM D7881-13 Referenced Document

• ASTM D1193 Standard Specification for Reagent Water
• ASTM D4790 Standard Terminology of Aromatic Hydrocarbons and Related Chemicals
• ASTM D6809 Standard Guide for Quality Control and Quality Assurance Procedures for Aromatic Hydrocarbons and Related Materials
• ASTM E177 Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• ASTM E29 Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
• ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

ASTM D7881-13 history

• 2020 ASTM D7881-20e1 Standard Test Method for Determination of 4-Carboxybenzaldehyde and p-Toluic Acid in Purified Terephthalic Acid by Capillary Electrophoresis with Reverse Voltage Mode
• 2020 ASTM D7881-20 Standard Test Method for Determination of 4-Carboxybenzaldehyde and p-Toluic Acid in Purified Terephthalic Acid by Capillary Electrophoresis with Reverse Voltage Mode
• 2019 ASTM D7881-19 Standard Test Method for Determination of 4-Carboxybenzaldehyde and p-Toluic Acid in Purified Terephthalic Acid by Capillary Electrophoresis with Reverse Voltage Mode
• 2013 ASTM D7881-13 Standard Test Method for Determination of 4-Carboxybenzaldehyde and p-Toluic Acid in Purified Terephthalic Acid by Capillary Electrophoresis with Reverse Voltage Mode