4,4'-Biphenol
[CAS# 92-88-6]

Identification

• Classification: Organic raw materials >> Hydrocarbon compounds and their derivatives >> Aromatic hydrocarbon
• Name: 4,4'-Biphenol
• Synonyms: Biphenyl-4,4'-diol; 4,4'-Dihydroxybiphenyl; PPDP
• Molecular Formula: C₁₂H₁₀O₂
• Molecular Weight: 186.21
• CAS Registry Number: 92-88-6
• EC Number: 202-200-5
• SMILES: C1=CC(=CC=C1C2=CC=C(C=C2)O)O

Properties

• Density: 1.2±0.1 g/cm³ Calc.^*, 1.22 g/mL (Expl.)
• Melting point: 280 - 282 ºC (Expl.)
• Boiling point: 355.2±17.0 ºC 760 mmHg (Calc.)^*
• Flash point: 176.1±15.5 ºC (Calc.)^*
• Solubility: water: sparingly soluble (Expl.)
• Index of refraction: 1.64 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07;GHS09 Warning
• Hazard Statements: H312-H315-H317-H319-H335-H411-H412
• Precautionary Statements: P261-P264-P264+P265-P271-P272-P273-P280-P302+P352-P304+P340-P305+P351+P338-P317-P319-P321-P332+P317-P333+P317-P337+P317-P362+P364-P391-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin sensitization	Skin Sens.	1	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Acute toxicity	Acute Tox.	4	H312
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Self-heating substances or mixtures	Self-heat.	2	H252
Serious eye damage	Eye Dam.	1	H318

Discovory and Applicatios

4,4'-Biphenol is an aromatic diol with the molecular formula C₁₂H₁₀O₂. Structurally, it consists of two phenol rings connected at the 1-position, with each ring bearing a hydroxyl group at the para (4) position. This symmetrical arrangement imparts both rigidity and planarity to the molecule, as well as two highly reactive phenolic hydroxyl groups. 4,4'-Biphenol typically appears as a white to light beige crystalline solid, soluble in polar organic solvents such as ethanol, acetone, and dimethylformamide, but only sparingly soluble in water.

The compound is primarily used as a monomer and building block in polymer synthesis. Its phenolic groups readily react with epoxides, formaldehyde, or acid chlorides to form high-performance polymers, including polycarbonates, polyarylethers, and phenolic resins. The rigid biphenyl backbone contributes to high thermal stability, mechanical strength, and chemical resistance, making it valuable in the production of engineering plastics, adhesives, and coatings.

4,4'-Biphenol also serves as a ligand precursor in coordination chemistry and catalysis. Its hydroxyl groups can be functionalized or converted into chelating ligands for transition metals, enabling applications in asymmetric catalysis and organometallic chemistry. The planar, conjugated structure of 4,4'-biphenol further facilitates electronic communication between metal centers in complex structures.

Synthetically, 4,4'-biphenol can be prepared by the oxidative coupling of phenol derivatives using oxidizing agents such as copper(II) salts or enzymatic catalysts. Purification is typically achieved through recrystallization to obtain material suitable for polymerization or further chemical modifications. Handling requires standard precautions for phenolic compounds, as they can be corrosive and irritant to skin and eyes.

Overall, 4,4'-biphenol is a versatile aromatic diol with reactive hydroxyl groups and a rigid biphenyl framework. Its combination of chemical reactivity, structural rigidity, and thermal stability makes it an important intermediate for high-performance polymers, functional materials, and catalytic ligand development.

References

2025. π-Conjugated Ionic Crystals for Materials Toward Electronics and Photonics Applications. Advances in Organic Crystal Chemistry.
DOI: 10.1007/978-981-96-5984-5_15

2024. Depolymerization and Functionalization of Super Engineering Plastics. Chinese Journal of Polymer Science.
DOI: 10.1007/s10118-024-3226-1