3,3'-Dihydroxybenzidine
[CAS# 2373-98-0]

Identification

• Classification: Pharmaceutical intermediate >> Heterocyclic compound intermediate >> Thiophene compound
• Name: 3,3'-Dihydroxybenzidine
• Synonyms: 4,4'-Diaminobiphenyl-3,3'-diol
• Molecular Formula: C₁₂H₁₂N₂O₂
• Molecular Weight: 216.24
• CAS Registry Number: 2373-98-0
• EC Number: 679-800-2
• SMILES: C1=CC(=C(C=C1C2=CC(=C(C=C2)N)O)O)N

Properties

• Melting point: 292 °C

Safety Data

• Hazard Symbols: GHS08 Danger
• Risk Statements: H350
• Safety Statements: P203-P280-P318-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Carcinogenicity	Carc.	1B	H350
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Carcinogenicity	Carc.	2	H351
Specific target organ toxicity - repeated exposure	STOT RE	2	H373

Discovery and Applications

3,3'-Dihydroxybenzidine, also known as ortho-dihydroxybenzidine, is an aromatic diamine compound with two hydroxyl groups and two amine groups located symmetrically on the benzidine structure. This compound has been of interest in various industrial applications due to its chemical reactivity and ability to form stable bonds with other molecules. Its primary applications have been in the dye and pigment industry, particularly in the production of azo dyes.

The discovery of 3,3'-dihydroxybenzidine was driven by the need for intermediates that could be used in the synthesis of dyes with enhanced color properties and improved fastness to light, water, and chemicals. As an important building block in the production of azo dyes, 3,3'-dihydroxybenzidine contributes to the creation of vibrant and durable colors that are widely used in textiles, plastics, and printing inks. The presence of hydroxyl groups increases the compound’s ability to form strong bonds with fabric fibers, resulting in dyes that are resistant to washing and fading.

In addition to its use in dye manufacturing, 3,3'-dihydroxybenzidine has found applications in the field of organic electronics. Its electron-donating properties make it a useful component in the development of organic semiconductors and conductive polymers. These materials are essential for the production of flexible electronic devices, solar cells, and light-emitting diodes (LEDs). The ability of 3,3'-dihydroxybenzidine to undergo oxidation-reduction reactions also enables its use in electrochemical applications, including sensors and battery technologies.

Despite its industrial applications, 3,3'-dihydroxybenzidine is recognized for its potential health risks. Like many aromatic amines, it has been studied for its carcinogenic properties, particularly in relation to occupational exposure in industries that manufacture dyes. As a result, the handling and use of 3,3'-dihydroxybenzidine are subject to strict regulations in many countries, and safer alternatives are being developed for use in dye production.

The chemical versatility of 3,3'-dihydroxybenzidine ensures that it remains an important compound in various industrial processes, while ongoing research focuses on reducing its health risks and finding safer substitutes where necessary.

References

2018. Effects of Drawing and Heat-Treatment Conditions on the Structure and Mechanical Properties of Polyhydroxyamide and Polybenzoxazole Fibers. *Fibers and Polymers*, 19(8).
DOI: 10.1007/s12221-018-8241-9

2019. Preparation and Characterization of Polyhydroxyamide Hybrid Nanocomposite Films Containing MWCNTs and Clay as Reinforcing Materials. *Fibers and Polymers*, 20(4).
DOI: 10.1007/s12221-019-1034-y

2000. Thermal cyclodehydration of aromatic precursor polymers to polybenzoxazole and polyimide; their thermal and mechanical properties. *Polymer Bulletin*, 44(2).
DOI: 10.1007/s002890050574