2,2-Bis[4-(4-aminophenoxy)phenyl]hexafluoropropane
[CAS# 69563-88-8]

Identification

• Classification: Organic raw materials >> Organic fluorine compound >> Fluoropropane series
• Name: 2,2-Bis[4-(4-aminophenoxy)phenyl]hexafluoropropane
• Synonyms: 4-[4-[2-[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropan-2-yl]phenoxy]aniline
• Molecular Formula: C₂₇H₂₀F₆N₂O₂
• Molecular Weight: 518.45
• CAS Registry Number: 69563-88-8
• EC Number: 626-703-8
• SMILES: C1=CC(=CC=C1C(C2=CC=C(C=C2)OC3=CC=C(C=C3)N)(C(F)(F)F)C(F)(F)F)OC4=CC=C(C=C4)N

Properties

• Density: 1.4±0.1 g/cm³ Calc.^*
• Melting point: 159 - 163 °C (Expl.)
• Boiling point: 544.8±50.0 °C 760 mmHg (Calc.)^*
• Flash point: 283.3±30.1 °C (Calc.)^*
• Solubility: Soluble 100 mM (DMSO), 50 mM (ethanol) (Expl.)
• Index of refraction: 1.579 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P270-P271-P280-P301+P317-P302+P352-P304+P340-P305+P351+P338-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335

Discovery and Applications

2,2-Bis[4-(4-aminophenoxy)phenyl]hexafluoropropane is an aromatic diamine compound that is widely recognized for its application in high-performance polymer synthesis, particularly in the preparation of polyimides and polyamides. Its molecular formula is C₂₁H₁₆F₆N₂O₂. Structurally, the compound features a central hexafluoroisopropylidene group (–C(CF₃)₂–) flanked by two bisphenol-type aromatic rings, each bearing an aminophenoxy substituent. This configuration endows the molecule with both rigidity and flexibility, making it especially valuable in advanced materials science.

The hexafluoroisopropylidene unit plays a crucial role in enhancing the thermal and oxidative stability of the polymers derived from this compound. Fluorinated groups, such as –CF₃, lower the dielectric constant and increase hydrophobicity, which are desirable traits for polymers used in microelectronics, aerospace, and other demanding applications. The electron-withdrawing nature of the trifluoromethyl groups also improves chemical resistance, while the bulky nature of the group introduces free volume into polymer chains, contributing to solubility and processability.

2,2-Bis[4-(4-aminophenoxy)phenyl]hexafluoropropane is typically synthesized through multi-step organic synthesis. A common route involves nucleophilic aromatic substitution reactions where 4-nitrophenol reacts with hexafluoropropane-diol derivatives to yield dinitro precursors, which are then reduced using agents such as hydrogen over palladium on carbon to produce the diamine. The amine groups on the terminal phenyl rings are highly reactive towards diacid chlorides or dianhydrides, making the compound particularly suitable for condensation polymerizations.

In polymer chemistry, this compound is a key monomer in the formation of high-performance polyimides. These polymers are synthesized by reacting the diamine with tetracarboxylic dianhydrides under controlled conditions. The resulting polyimides exhibit exceptional thermal stability, mechanical strength, and chemical resistance. Applications for these polyimides include flexible printed circuit boards, insulating films, membranes, and aerospace coatings. The fluorinated core structure contributes to the formation of transparent films with low refractive indices and reduced water absorption.

In addition to polyimides, the compound is also employed in the synthesis of polyamides, epoxy resins, and other thermosetting systems. Its amine functionality allows for curing with epoxy resins to create thermally stable networks. These materials find use in structural composites, adhesives, and electronic packaging.

The analytical characterization of 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane involves various spectroscopic and chromatographic methods. Nuclear magnetic resonance (NMR) spectroscopy, especially ¹H and ¹⁹F NMR, is used to confirm the structure and purity of the compound. Infrared (IR) spectroscopy reveals characteristic bands corresponding to N–H stretching, C–F bonds, and aromatic C=C vibrations. High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) may also be used for purity and identification in complex mixtures.

The compound is typically a solid at room temperature, often appearing as a white or off-white powder. It is moderately soluble in polar aprotic solvents such as dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP), which are commonly used in polymer processing.

While the compound itself is not considered highly hazardous, standard laboratory safety precautions should be observed during handling. These include the use of gloves, eye protection, and adequate ventilation. The amine groups may cause irritation upon contact with skin or mucous membranes.

In summary, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane is a valuable aromatic diamine monomer used in the synthesis of high-performance fluorinated polymers. Its unique structural features provide enhanced thermal stability, chemical resistance, and processability, making it indispensable in the manufacture of advanced materials for electronics, aerospace, and industrial applications. The incorporation of fluorinated groups imparts low dielectric properties and improved environmental durability, which are critical for emerging technologies.

References

2009. 4,4'-[4,4'-(Perfluoro-propane-2,2-di-yl)bis-(4,1-phenyl-eneoxy)]dianiline. Acta crystallographica. Section E, Structure reports online, 65(6).
DOI: 10.1107/s1600536809020121

2009. Optically transparent and colorless poly(ether-imide)s derived from a phenylhydroquinone bis(ether anhydride) and various trifluoromethyl-substituted bis(ether amine)s. Journal of Polymer Research, 16(12).
DOI: 10.1007/s10965-009-9369-5

2011. Comparative Kinetic Study and Microwaves Non-Thermal Effects on the Formation of Poly(amic acid) 4,4′-(Hexafluoroisopropylidene)diphthalic Anhydride (6FDA) and 4,4′-(Hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline (BAPHF). Reaction Activated by Microwave, Ultrasound and Conventional Heating. International Journal of Molecular Sciences, 12(10).
DOI: 10.3390/ijms12106703