Adipic Acid, or hexanedioic acid, is a white crystalline solid with the chemical formula C6H10O4. Its molecular structure, featuring two carboxylic acid groups separated by a flexible six-carbon aliphatic chain, dictates its reactivity and broad applicability in industrial chemistry. For researchers and product developers, a thorough understanding of its properties is fundamental when considering it as a raw material for new formulations or improved manufacturing processes.

Key Chemical Properties:

  • Acidity: As a dicarboxylic acid, Adipic Acid exhibits acidic properties with two dissociation constants (pKa values). This acidity is leveraged in its use as an acidulant in food products and as a pH regulator.
  • Solubility: Adipic Acid is soluble in water and common organic solvents like alcohol and acetone, but sparingly soluble in cyclohexane and virtually insoluble in benzene and petroleum ether. This solubility profile influences its use in various reaction media and formulations.
  • Melting Point: It has a melting point of approximately 151-154 °C, indicating its stability at typical ambient temperatures. This property is essential for its handling and storage.
  • Reactivity: The two terminal carboxylic acid groups readily participate in esterification and amidation reactions. This is the basis for its critical role in forming polyesters and polyamides (like Nylon 66) through polycondensation reactions. It can also undergo ketonization to form cyclopentanone under specific conditions.

Safety and Handling:

Like many organic acids, Adipic Acid is generally considered to have a low order of toxicity. However, it can be a mild irritant to skin and eyes upon prolonged contact. Standard industrial hygiene practices should be followed when handling it. This includes wearing appropriate personal protective equipment (PPE) such as gloves, safety glasses, and protective clothing. Good ventilation in work areas is also recommended to minimize dust inhalation.

The median lethal dose (LD50) for oral ingestion in rats is around 3600 mg/kg, which is considered moderately low in toxicity. Environmental considerations primarily relate to its production process, which can emit nitrous oxide (N2O), a greenhouse gas. Responsible manufacturers are implementing technologies to mitigate these emissions.

When considering purchasing Adipic Acid, it is vital to obtain a current Safety Data Sheet (SDS) from the supplier. This document provides comprehensive information on hazards, safe handling, storage, and emergency procedures. For businesses seeking a reliable supplier for high-quality Adipic Acid, understanding these chemical properties and safety aspects ensures informed decision-making and safe integration into their processes.