Physicochemical Properties

4-Hexadecylaniline (C₂₂H₃₉N, MW 321.55 g/mol) is a primary aromatic amine in which a hexadecyl (C16) alkyl chain is attached at the para position of the aniline ring. This amphiphilic architecture gives the molecule a hydrophilic amino head group and a hydrophobic aliphatic tail, a combination that underpins its utility across multiple research domains.

The compound is typically a waxy solid or low-melting crystalline material at room temperature, consistent with other long-chain fatty anilines. Its solubility profile reflects its amphiphilic nature: it dissolves readily in non-polar and moderately polar organic solvents such as chloroform, dichloromethane, toluene, and ethanol, while being essentially insoluble in water. The aromatic amine group is weakly basic (pK_a of the conjugate acid typically in the range of 4–5 for para-substituted anilines) and can be protonated by mineral or organic acids to form salts that modify solubility and self-assembly behavior.

The long alkyl chain promotes ordered packing through van der Waals interactions, enabling formation of lamellar or columnar mesophases under appropriate conditions. Researchers should note that, like all primary arylamines, 4-Hexadecylaniline may undergo oxidation on prolonged exposure to air and light, generating colored impurities; therefore, storage under inert atmosphere or in amber containers is advisable.

Safe Handling and Storage Guidelines

As a primary aromatic amine, 4-Hexadecylaniline should be handled with appropriate precautions. Aromatic amines as a chemical class are associated with potential health hazards including skin and eye irritation, and some members of this class are known or suspected sensitizers or carcinogens; users should consult the current Safety Data Sheet (SDS) for H195075 before use.

Personal Protective Equipment (PPE): Wear chemical-resistant gloves (e.g., nitrile), safety goggles or face shield, and a laboratory coat when handling the bulk material or concentrated solutions. Work in a well-ventilated area or under a fume hood, particularly when heating the compound or working with solutions in volatile solvents.

Storage: Store in a tightly sealed container in a cool (below 25 °C), dry location away from direct sunlight, oxidizing agents, strong acids, and ignition sources. An inert atmosphere (nitrogen or argon) blanketing is recommended for long-term storage to minimize oxidative degradation. Keep containers closed when not in use.

Waste Disposal: Dispose of waste material and contaminated items in accordance with local, regional, and national regulations governing aromatic amine-containing waste. Do not pour into drains or waterways.

First Aid: In case of skin contact, wash thoroughly with soap and water. For eye contact, flush with copious water for at least 15 minutes and seek medical attention. If inhaled, move to fresh air and consult a physician if symptoms persist.

Research Applications

The unique amphiphilic structure of 4-Hexadecylaniline, combining a reactive primary amine with a long hydrophobic alkyl chain, makes it valuable across several cutting-edge research disciplines.

Self-Assembled Monolayers (SAMs) and Supramolecular Chemistry: The compound's tendency to form ordered lamellar assemblies is exploited in the construction of self-assembled monolayers on solid substrates and in the design of supramolecular architectures. The free amine group provides a handle for further covalent functionalization or hydrogen-bond-driven organization.

Surfactant and Amphiphile Synthesis: 4-Hexadecylaniline serves as a building block for cationic and zwitterionic surfactants. Protonation or quaternization of the amine yields surfactants with potential applications in emulsification, phase-transfer catalysis, and antibacterial formulations.

Nanoparticle Functionalization: The amine head group coordinates effectively to metal nanoparticle surfaces (e.g., gold, silver, quantum dots), enabling surface passivation and providing a platform for subsequent bioconjugation or ligand-exchange reactions. The C16 chain contributes steric stabilization.

Organic Electronics and Thin Films: Long-chain arylamines are used as hole-transport or interfacial layer materials in organic field-effect transistors (OFETs) and perovskite solar cells. Their ability to form ordered thin films with favorable molecular orientation makes them attractive candidates for device engineering.

Polymer and Epoxy Curing: As a primary amine, 4-Hexadecylaniline can act as a curing agent for epoxy resins, imparting flexibility and hydrophobicity from the long alkyl chain to the cross-linked network.

Quality, Purity and Procurement Guidance

When selecting 4-Hexadecylaniline for research use, reagent purity is a critical parameter. For most synthetic and materials-science applications, high-purity grades (≥97% or ≥98% by GC or HPLC) are recommended to avoid side reactions or inconsistent self-assembly behavior arising from amine or alkyl-chain impurities.

Analytical Verification: Researchers are encouraged to verify identity and purity upon receipt using techniques such as ¹H NMR (confirm aromatic protons, NH₂, and the alkyl chain methylene/methyl pattern), GC or HPLC purity assessment, and melting point determination. Any deviation from the expected physicochemical profile should be reported to the supplier.

Lot-to-Lot Consistency: For reproducible results in device fabrication or biological assays, request a Certificate of Analysis (CoA) for each lot. Aladdin Scientific provides CoA documentation for SKU H195075 upon request, detailing purity, appearance, and other quality parameters.

Packaging and Quantities: Contact Aladdin Scientific for available pack sizes and custom quantities suited to your project scale. Proper secondary containment during shipping ensures the compound arrives in optimal condition.