Chemical Properties, Uses, & Production of Antioxidant 168

Posted on: January 15, 2024

Antioxidant 168 is a chemical compound commonly used as an antioxidant in various industries. Its primary function is to inhibit the oxidation of substances, particularly polymers and plastics, by neutralizing free radicals and preventing chain reactions that can lead to degradation.  

Chemical Structure: 

Antioxidant 168 belongs to the class of phenolic antioxidants. Its chemical structure includes a 3,5-di-tert-butyl-4-hydroxybenzyl group. The IUPAC name for Antioxidant 168 is Tris(2,4-di-tert-butylphenyl) phosphite. 

Physical Properties: 

  • Molecular Formula: C42H63O3P 
  • Molecular Weight: Approximately 646.93 g/mol 
  • Appearance: Antioxidant 168 is typically a white crystalline powder. 
  • Melting Point: The compound has a melting point of around 182-185°C. 


  1. Free Radical Scavenging
     The reaction involves the antioxidant breaking the chain reaction by neutralizing free radicals and preventing them from propagating further. 
  2. Hydrogen Atom Transfer (HAT) Mechanism
     Antioxidant 168 can undergo hydrogen atom transfer reactions, granting a hydrogen atom to a radical species, forming a stable product and breaking the chain reaction. 
  3. Phosphite Oxidation
     The phosphite group in Antioxidant 168 is susceptible to oxidation. These phosphite antioxidants act as sacrificial agents, undergoing oxidation to protect the polymer or material from oxidative degradation. 
  4. Synergistic Effects with Other Antioxidants
     Antioxidant 168 is often used with other antioxidants, such as hindered phenols, to achieve synergistic effects. The combined action enhances the overall antioxidant capacity, providing a more comprehensive protection against oxidation. 
  5. Metal Deactivation
     Antioxidant 168 can also act as a metal deactivator by chelating metal ions that might otherwise catalyze oxidation reactions. Chelation helps prevent metal-catalyzed oxidation processes. 
  6. Prevention of Peroxide Formation
     Antioxidant 168 can interfere with forming peroxides during the initial stages of oxidation, disrupting the chain reaction and protecting the material from further degradation. 
  7. Stabilization of Polymer Chains
     The antioxidant stabilizes polymer chains by inhibiting reactions that lead to the cleavage of molecular bonds. It helps maintain the integrity of the polymer structure. 



Antioxidant 168 is generally soluble in organic solvents, such as acetone, benzene, chloroform, and ethyl acetate. However, it has limited solubility in water. 


The primary function of Antioxidant 168 is to protect materials from oxidative degradation. It acts as a stabilizer for polymers and plastics, preventing the formation of free radicals and the subsequent deterioration of the material due to exposure to oxygen, heat, and light. 


Antioxidant 168 is commonly used to produce plastics, rubber, synthetic fibers, and other polymer-based materials. These plastic antioxidants are particularly effective in preventing the degradation of these materials during processing, storage, and use. 


This antioxidant is often used with other stabilizers to enhance its effectiveness. It is compatible with various polymers, including polyethene, polypropylene, and polyvinyl chloride (PVC). 


Antioxidant 168 generally has low toxicity. However, like any chemical substance, it must be handled carefully by following the appropriate safety precautions.  



  1. Oxidation Inhibition:

Antioxidant 168 is a highly efficient phenolic antioxidant that effectively inhibits the oxidation of materials. 

It scavenges free radicals formed during oxidation, preventing chain reactions and material degradation. 

  1. Thermal Stabilization:

The antioxidant provides thermal stabilization to polymers and plastics, protecting them from the harmful effects of heat exposure during processing and use. 

  1. Light Stabilization:

Antioxidant 168 helps protect materials from the damaging effects of ultraviolet (UV) radiation and light exposure, contributing to the material’s longevity. 

  1. Extended Service Life:

Antioxidant 168 contributes to extending the service life of polymers and plastic products by preventing oxidation and degradation. 

  1. Processing Stability:

It enhances the stability of materials during processing, preventing unwanted changes in physical and mechanical properties. 

  1. Compatibility:

Antioxidant 168 is compatible with many polymers, including polyethene, polypropylene, and polyvinyl chloride (PVC). Its adaptability makes it appropriate for a range of uses. 

  1. Synergistic Effects:

Often used in combination with other stabilizers, Antioxidant 168 exhibits synergistic effects, enhancing overall antioxidant performance. 

  1. Low Volatility:

The compound has low volatility, minimizing the risk of evaporating during processing or use. 

  1. Cost-Effective:

Antioxidant 168 is known for its cost-effectiveness, providing adequate protection against oxidation at a relatively low cost. 

  1. Low Toxicity:

It generally exhibits low toxicity, making it safer for handling and use. 

  1. Wide Industrial Applications:

Antioxidant 168 finds applications in various industries, including producing plastics, rubber, synthetic fibers, and other polymer-based materials. 

  1. Improved Physical Properties:

Antioxidant 168 helps maintain materials’ physical and mechanical properties, such as flexibility, tensile strength, and impact resistance, by preventing oxidation-induced degradation. 

  1. Shelf-Life Extension:

The use of Antioxidant 168 in manufacturing contributes to extending the shelf life of end products by protecting them from environmental factors. 


It’s important to note that the information provided here is a general characterization of Antioxidant 168, and specific properties may vary depending on the manufacturer and formulation. Refer to our product specifications and safety data sheets at Vinati Organics for accurate and detailed information. Vinati Organics, driven by a dedication to excellence and ongoing innovation, plays a substantial role in various global chemical applications through the significant contributions of its antioxidants and plastic antioxidants. Contact us to know more about our plastic antioxidant blends.