1,5-Bis(p-aminophenoxy)pentane
[CAS# 2391-56-2]

Identification

• Classification: Pharmaceutical intermediate >> Heterocyclic compound intermediate >> Pyrimidine compound >> Amine
• Name: 1,5-Bis(p-aminophenoxy)pentane
• Synonyms: 4-[5-(4-aminophenoxy)pentoxy]aniline
• Molecular Formula: C₁₇H₂₂N₂O₂
• Molecular Weight: 286.37
• CAS Registry Number: 2391-56-2
• EC Number: 678-856-5
• SMILES: C1=CC(=CC=C1N)OCCCCCOC2=CC=C(C=C2)N

Properties

• Density: 1.1±0.1 g/cm³ Calc.^*
• Boiling point: 510.1±35.0 ºC 760 mmHg (Calc.)^*
• Flash point: 286.5±19.6 ºC (Calc.)^*
• Index of refraction: 1.599 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H302-H312-H315-H319-H332-H335
• Precautionary Statements: P261-P264-P264+P265-P270-P271-P280-P301+P317-P302+P352-P304+P340-P305+P351+P338-P317-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Discovory and Applicatios

1,5‑Bis(p‑aminophenoxy)pentane is an aromatic diamine monomer with the molecular formula C₁₇H₂₂N₂O₂. Chemically, it consists of a pentane (five‑carbon) aliphatic spacer linking two para‑aminophenoxy groups, each carrying a primary amino (–NH₂) functionality at the para position of a benzene ring. The two aromatic amine groups make the molecule bifunctional, able to participate in step‑growth polymerization reactions, while the central aliphatic pentamethylene segment imparts flexibility relative to entirely rigid aromatic diamines. Its CAS Registry Number is 2391‑56‑2 and it is also known by synonyms such as 4,4′‑(pentane‑1,5‑diylbis(oxy))dianiline and 1,5‑di(p‑aminophenoxy)pentane.

Aromatic diamines such as 1,5‑Bis(p‑aminophenoxy)pentane belong to a class of primary diamines that are widely used as monomers in step‑growth polymerizations to produce high-performance polymers such as polyimides, polyamides, and poly(ether imide)s. In these reactions, the diamine condenses with diacid chlorides, dianhydrides, or diisocyanates to form long polymer chains with amide, imide, or urea linkages. The combination of aromatic rings for rigidity, ether linkages, and a flexible aliphatic spacer allows precise tuning of polymer properties including solubility, thermal stability, and mechanical strength.

The two primary amino groups make 1,5‑Bis(p‑aminophenoxy)pentane a reactive bifunctional monomer suitable for synthesizing polyimides and related polymers. The aromatic rings contribute to rigidity and thermal resistance, while the pentane spacer and ether linkages increase chain flexibility and solubility in organic solvents. Incorporation of this monomer into polymer backbones allows modulation of polymer chain packing, mechanical behavior, and thermal transitions. Such structural modifications are particularly relevant in designing polymers with lower glass transition temperatures and improved processability compared with polymers made from entirely rigid aromatic diamines.

Typical synthetic strategies for this compound involve formation of the ether bridges, commonly via nucleophilic aromatic substitution or Williamson ether synthesis, followed by reduction of nitro precursors to produce the diamine. For example, a dinitro intermediate such as 1,5‑bis(4‑nitrophenoxy)pentane can be reduced through catalytic hydrogenation to yield the corresponding diamine. These multi-step synthetic approaches are standard for producing aromatic ether-linked diamines with high purity, and the final product is typically characterized by nuclear magnetic resonance spectroscopy and elemental analysis.

Applications of 1,5‑Bis(p‑aminophenoxy)pentane are primarily in research and materials science. It is employed as a monomer for specialty polyimides, polyamides, and poly(ether imide)s, allowing researchers to tailor polymer chain architecture and properties. Its bifunctional nature and flexible linker make it suitable for modifying mechanical flexibility, thermal stability, and solubility of resulting polymers. Beyond polymer synthesis, the primary amino groups can also be derivatized to produce imines, amides, or other functional molecules for chemical research and materials development.

Overall, 1,5‑Bis(p‑aminophenoxy)pentane is a difunctional aromatic diamine monomer whose structural features — primary amines, aromatic rings, and flexible ether-linked spacers — make it a valuable building block for high-performance polymer synthesis and advanced materials research. Its combination of rigidity, flexibility, and chemical reactivity allows precise control over polymer properties and supports exploratory studies in polymer chemistry and material science.

References

2016. Emergence of new red-shifted carbon nanotube photoluminescence based on proximal doped-site design. Scientific Reports, 6.
DOI: 10.1038/srep28393

2013. Spacer effect on nanostructures and self-assembly in organogels via some bolaform cholesteryl imide derivatives with different spacers. Nanoscale Research Letters, 8(1).
DOI: 10.1186/1556-276x-8-160

1986. Short-circuiting the visual cycle with retinotoxic aromatic amines. Proceedings of the National Academy of Sciences of the United States of America, 83(6).
DOI: 10.1073/pnas.83.6.1632