Bis(2,6-di-ter-butyl-4-methylphenyl)pentaerythritol-diphosphite
[CAS# 80693-00-1]

Identification

• Classification: Catalysts and additives >> Antioxidant
• Name: Bis(2,6-di-ter-butyl-4-methylphenyl)pentaerythritol-diphosphite
• Synonyms: 3,9-Bis[2,6-bis(1,1-dimethylethyl)-4-methylphenoxy]-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane; ADK Stab PEP 36
• Molecular Formula: C₃₅H₅₄O₆P₂
• Molecular Weight: 632.75
• CAS Registry Number: 80693-00-1
• EC Number: 410-290-4
• SMILES: CC1=CC(=C(C(=C1)C(C)(C)C)OP2OCC3(CO2)COP(OC3)OC4=C(C=C(C=C4C(C)(C)C)C)C(C)(C)C)C(C)(C)C

Properties

• Melting point: 235-240 °C
• Boiling Point: 577.0±50.0 °C (760 mmHg), Calc.^*
• Flash Point: 380.5±30.4 °C, Calc.^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H412
• Safety Statements: P501-P273-P264-P280-P302+P352-P337+P313-P305+P351+P338-P362+P364-P332+P313

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413

Discovery and Applications

Bis(2,6-di-ter-butyl-4-methylphenyl)pentaerythritol-diphosphite, often abbreviated as P-PEP, was developed in the mid-20th century during advancements in polymer science. Researchers were exploring stabilizers that could enhance the thermal stability and longevity of polymers. The discovery of P-PEP, with its unique phosphite structure and antioxidant properties, marked a significant breakthrough in the development of effective polymer stabilizers.

One of the primary applications of P-PEP is in the stabilization of polymers, particularly polyolefins like polyethylene and polypropylene. It acts as a secondary antioxidant, working synergistically with primary antioxidants to protect polymers from thermal and oxidative degradation during processing and in end-use applications.

In the plastic manufacturing industry, P-PEP is added during the compounding process to improve the thermal stability of the material. It helps prevent discoloration and brittleness caused by heat and light exposure.

P-PEP is also used in the rubber industry to enhance the stability of synthetic rubbers. By protecting against oxidative degradation, it extends the lifespan of rubber products, such as tires and industrial rubber goods.

In the production of adhesives and sealants, P-PEP is incorporated to improve the thermal and oxidative stability of the formulations.

P-PEP is used in the coatings and inks industry to prevent the degradation of organic pigments and binders. It enhances the stability of coatings and inks, ensuring that they maintain their color and consistency during storage and application.

P-PEP is employed as an antioxidant in the formulation of lubricants and greases. It helps to prevent the oxidation of oils, maintaining their viscosity and performance characteristics.

References

2009. Suzuki-Miyaura Coupling Reactions Using Phosphite Ligands. Synthesis, 2009(9).
DOI: 10.1055/s-0029-1216822

2010. Aryl Bromides in Hiyama Cross-Coupling Reactions. Science of Synthesis.
URL: https://science-of-synthesis.thieme.com/app/text/?id=SD-045-00539