GB/T 25789-2023
p-Phenylenediamine (English Version)

Standard No.

GB/T 25789-2023

Language

Chinese, Available in English version

Release Date

2023

Published By

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China  CN  /  GB

Latest

GB/T 25789-2023

Replace

GB/T 25789-2010

Introduction

Interpretation of the National Standard of the People's Republic of China GB/T 25789-2023

Standard Overview

GB/T 25789-2023 "p-Phenylenediamine" is the national standard of the People's Republic of China, which is used to regulate the quality requirements, safety information, sampling, test methods, packaging and storage of p-Phenylenediamine products. This standard replaces the old version GB/T 25789-2010. The main updates include:

• Changes to the quality requirements for p-phenylenediamine (Chapter 4)
• Adjustments to the sampling volume regulations (Chapter 6)
• Optimization of appearance evaluation method (7.2)
• Addition of capillary melting point method (7.3.2)
• Improvement of chromatographic operating conditions (7.4.4)

Quality Requirements Comparison Table

Serial number	Item	Indicator			Test method chapter number
		Superior product	First-class product	Qualified products
1	Appearance	White to light red crystals	Off-white to gray-brown crystals	Yellow-brown to gray-brown crystals	7.2
2	Initial melting point	≥139.0 °C	≥139.0 °C	≥137.0 °C	7.3

Analysis of test methods

The standard specifies a variety of test methods, including:

• Capillary liquid bath method (arbitration method): used to determine the initial melting point.
• Gas chromatography: used for quantitative analysis of the purity of p-phenylenediamine and organic impurities.

Among them, the specific operating conditions of gas chromatography are shown in Table 2:

Control parameters	Operating conditions
Carrier gas	High purity nitrogen
Detector temperature/°C	300

Safety Information and Protection Recommendations

According to GB12268-2012, p-phenylenediamine is a Class 6.1 toxic substance, and the dangerous goods number is UN:1673. When using and handling:

• Wear protective equipment
• Avoid direct contact
• Strictly abide by storage regulations

Implementation recommendations

To ensure the effective implementation of the standard, it is recommended to:

• Strictly follow the sampling regulations
• Use capillary melting point instrument to perform initial melting point detection
• Standardize the calibration and maintenance of gas chromatographs
• Strengthen employee safety training

GB/T 25789-2023 Referenced Document

• GB 12268-2012 List of dangerous goods
• GB 12463 General specifications for transport packages of dangerous goods
• GB 15258 General rules for preparation of precautionary label for chemicals
• GB 15603 General rules for the hazardous chemicals warehouse storage
• GB/T 16483 Safety data sheet for chemical products.Content and order of sections
• GB/T 8170-2008 Rules of rounding off for numerical values & expression and judgement of limiting values
• GB/T 9722-2006 Chemical reagent.General rules for the gas chromatography

GB/T 25789-2023 history

• 2023 GB/T 25789-2023 p-Phenylenediamine
• 2010 GB/T 25789-2010 ρ-Phenylenediamine

Topics on standards and specifications

Standard and Specification