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GB/T 30921.3-2016Test method of purified terephthalic acid (PTA) for industrial use - Part 3: Determination of water content (English PDF)

工业用精对苯二甲酸（PTA）试验方法第3部分：水含量的测定

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Issued by

SAMR; SAC

Level / Type

National · Recommended

Issue date

June 14, 2016

Implementation date

January 1, 2017

Scope

GB/T 30921.3-2016 is the English-translated version of 工业用精对苯二甲酸（PTA）试验方法第3部分：水含量的测定.

GB/T 30921.3-2016 is the Chinese standard "Test method of purified terephthalic acid (PTA) for industrial use - Part 3: Determination of water content". Its scope clause reads: This part of GB/T 30921 specifies the Karl Fischer volumetric method for the determination of water content in industrial terephthalic acid (PTA) and heat Weight loss method.

This part of the Karl Fischer volumetric method for industrial PTA content of not less than 0.010% (mass fraction) of the determination of moisture; heat Weight loss method for industrial PTA content of not less than 0.050% (mass fraction) of the determination of moisture.

Its clauses include normative reference documents; karl fischer volumetric method.

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Document preview — GB/T 30921.3-2016

National Standard of the People's Republic of China

ICS: 71.080.40
Classification: G 16

Issued by: State Administration for Market Regulation; Standardization Administration of the PRC

1 Scope
2 normative reference documents
3 Karl Fischer volumetric method
3.1 Method Summary
3.2 Reagents and Materials

1 Scope

This part of GB/T 30921 specifies the Karl Fischer volumetric method for the determination of water content in industrial terephthalic acid (PTA) and heat

Weight loss method.

This part of the Karl Fischer volumetric method for industrial PTA content of not less than 0.010% (mass fraction) of the determination of moisture; heat

Weight loss method for industrial PTA content of not less than 0.050% (mass fraction) of the determination of moisture.

2 normative reference documents

The following documents are indispensable for the application of this document. For dated references, only the dated edition applies to this article

Pieces. For undated references, the latest edition (including all modifications) applies to this document.

General rules for sampling safety of industrial chemical products GB/T 3723

GB/T 6283 Determination of moisture content in chemical products Karl Fischer method (general method)

General rules for sampling of solid chemical products GB/T GB/T 6682 Analytical laboratory water specifications and test methods

Representation and Judgment of Numerical Correction Rule and Limit Value of GB/T 8170

3 Karl Fischer volumetric method

3.1 Method Summary

The PTA sample was dissolved in pyridine, and the water present in the sample was mixed with a known titer of the Karl Fischer reagent (iodine, sulfur dioxide, pyridine

Pyridine and methanol) to calculate the water content of the sample based on the consumed Karl Fischer reagent.

The reaction is as follows.

H2O I2 SO2 3C5H5N -> 2C5H5N · HI C5H5N · SO3

C5H5N · SO3 CH3OH -> C5H5N · HSO4CH3

3.2 Reagents and Materials

3.2.1

Unless otherwise specified, the reagents used are analytical pure, experimental water in line with GB/T 6682 in the three water requirements.

3.2.2 Karl Fischer Reagent

commercially available (containing pyridine), titer of 1mg/mL ~ 3mg/mL or 3mg/mL ~ 6mg/mL;

GB/T 6283.

3.2.3 Pyridine

water content of less than 0.05% (mass fraction). If the water content is greater than 0.05%, add 500 points to 500 mL of pyridine

Sub-screen about 50g, plug the stopper, placed overnight, learn the use of supernatant.

Warning. Pyridine is toxic, has a strong irritant, can be inhaled, ingested, absorbed by the skin. Should be used in a fume hood and worn with a precaution

Pyridine infiltrated gloves.

......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 15 pages — is available in the English PDF.

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