4-Bromoaniline (C₆H₆BrN) Stability Study

Basic Information:

Alias: 4-Bromoaniline, p-Bromoaniline

CAS No: 106-40-1

Molecular Formula: C6H6BrN

Molecular Weight: 172.02

Physical State:White to light yellow to light orange solid

Melting Point:56-62°C (lit.)

Boiling Point:230-250°C

Uses:Used in the manufacturing of azo dyes and organic synthesis

Employed in the preparation of dihydroquinazoline

4-Bromoaniline, with the molecular formula C₆H₆BrN, is a crucial organic intermediate widely applied in dyes, pharmaceuticals, and pesticides. Understanding its chemical stability is essential for safe storage, transportation, and application. This study aims to investigate the stability of4-Bromoaniline under different conditions to provide a scientific basis for its safe use.

Physicochemical Properties 4-Bromoaniline appears as a white to light yellow crystalline powder, with a melting point of 63-67°C, a boiling point of 230°C, and a density of 1.617 g/cm³. It is relatively stable at room temperature and pressure, but may decompose or undergo other chemical reactions when exposed to high temperatures, light, or acidic and alkaline environments.

Thermal Stability Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to examine the thermal stability of 4-Bromoaniline. Results indicate that 4-bromoaniline is relatively stable below 200°C; however, as the temperature increases, its decomposition rate significantly accelerates. In air, the decomposition temperature is approximately 230°C, slightly higher in a nitrogen atmosphere.

Photostability 4-Bromoaniline is sensitive to light and can undergo photodegradation when exposed to UV light for extended periods. UV-Visible spectrophotometry (UV-Vis) tests reveal that 4-bromoaniline gradually decomposes under UV exposure, forming aniline and other by-products. Therefore, it should be stored in light-protected containers to avoid direct sunlight.

Chemical Stability The stability of 4-bromoaniline in acidic and alkaline environments was studied using titration and nuclear magnetic resonance (NMR) techniques. The results show that 4-bromoaniline is unstable in strong acid (such as hydrochloric and sulfuric acids) and strong alkaline solutions (like sodium hydroxide), where it can undergo hydrolysis and other chemical reactions. In neutral and mildly acidic or alkaline environments, it is relatively stable.

Storage and Usage Recommendations Based on the above findings, the following measures are recommended to ensure the stability of 4-Bromoaniline:

1、Storage Conditions: Store in a cool, dry, light-protected environment to avoid high temperatures and direct sunlight.

2、Packaging Requirements: Use well-sealed containers, such as glass bottles or plastic drums, and store in a shaded area.

3、Operating Environment: Handle in well-ventilated laboratories or production areas, with appropriate protective equipment to prevent skin contact and inhalation.

4、Waste Disposal: Dispose of4-Bromoaniline waste and solutions according to hazardous chemical disposal regulations to prevent environmental contamination.

4-Bromoaniline has a certain stability at room temperature and pressure but decomposes under high temperature, intense light, and strong acidic or alkaline conditions. Strict control over storage and handling conditions is essential for its safe use. This study provides a scientific basis for the safe application of 4-Bromoaniline across various fields.