Tris(nonylphenyl) Phosphate: Properties & Lab Uses

Tris(nonylphenyl) phosphate is a triaryl phosphate ester valued in research and industry for its dual function as a plasticizer and antioxidant co-stabilizer in polymer systems.

Chemical Name

Tris(nonylphenyl) phosphate (TNPP)

CAS Number

26523-78-4

Molecular Formula

C₄₅H₆₉O₄P

Compound Class

Triaryl phosphate ester

Primary Functions

Plasticizer; antioxidant co-stabilizer; flame-retardant auxiliary

Typical Physical State

Viscous liquid or low-melting solid at room temperature

Aladdin SKU

P951399

Chemical Identity and Physical Properties

Tris(nonylphenyl) phosphate (TNPP), CAS 26523-78-4, is a triaryl organophosphorus ester in which three nonylphenyl groups are esterified to a central phosphate. Its molecular formula is C₄₅H₆₉O₄P, giving a relatively high molecular weight that contributes to low volatility—an important practical advantage in long-term polymer stabilization applications.

At room temperature TNPP typically appears as a pale yellow viscous liquid or a low-melting-point solid, depending on the isomeric composition of the nonylphenyl substituents (predominantly para-nonylphenyl). It is soluble in common organic solvents such as toluene, acetone, and chloroform, but is essentially insoluble in water. Its lipophilic character (high log P) means care must be taken when working near aquatic systems.

The phosphate ester linkage confers moderate thermal stability, allowing TNPP to function effectively at the processing temperatures typical of commodity plastics without significant decomposition.

Applications in Research and Industry

Plasticizer: TNPP is widely employed as a secondary or primary plasticizer in PVC and other polymer formulations. By intercalating between polymer chains, it reduces intermolecular forces, lowering the glass-transition temperature and improving flexibility and processability of the final material. Researchers investigating structure–property relationships in plasticized polymers frequently use TNPP as a reference compound.

Antioxidant co-stabilizer: One of the most significant research applications of TNPP is as a hydroperoxide decomposer. In combination with hindered phenol primary antioxidants, TNPP acts synergistically to interrupt oxidative degradation cycles in polyolefins, elastomers, and lubricant formulations. This secondary antioxidant function—operating via a phosphite/phosphate mechanism to reduce hydroperoxides to alcohols—makes it a benchmark material in antioxidant screening studies.

Flame-retardant auxiliary: The phosphorus content of TNPP contributes a degree of flame retardancy in certain polymer matrices, making it of interest in materials science research focused on halogen-free flame retardant systems.

Analytical reference standard: Because TNPP and its degradation products (notably nonylphenol) are monitored environmental contaminants, the compound also serves as an analytical reference standard in environmental chemistry and ecotoxicology research.

Safety, Handling, and Storage

Hazard profile: TNPP is classified as an environmental hazard, primarily due to its potential to degrade to nonylphenol—a substance of very high concern (SVHC) under REACH regulation because of its endocrine-disrupting properties. Researchers should consult the current Safety Data Sheet (SDS) for up-to-date hazard classifications before use.

Personal protective equipment (PPE): Standard laboratory PPE—including nitrile gloves, safety goggles, and a laboratory coat—is recommended when handling TNPP. Work in a well-ventilated area or fume hood, particularly when heating the material, to minimize inhalation of vapors.

Storage: Store TNPP in a tightly sealed container away from heat, direct sunlight, and strong oxidizing agents. Cool, dry storage conditions help prevent hydrolysis of the phosphate ester linkage and maintain reagent integrity over time. Check the product specification sheet for the recommended storage temperature range.

Waste disposal: Dispose of TNPP and contaminated materials in accordance with local environmental regulations. Because of concerns about nonylphenol contamination of water systems, avoid releasing TNPP or its solutions down drains.

Reagent Specification and Quality Considerations

When selecting TNPP for research applications, purity grade is a critical parameter. For use as an analytical reference standard or in mechanistic antioxidant studies, high-purity material (≥95% or better) minimizes interference from isomeric impurities or residual free nonylphenol. Procurement teams should request a Certificate of Analysis (CoA) confirming identity (typically by GC or ¹H NMR), purity, and water content.

Commercial TNPP is frequently a mixture of isomers arising from the branched structure of the nonyl group. The isomeric distribution can influence physical properties such as melting point and viscosity, as well as biological activity. For applications where isomeric composition matters, suppliers should provide detailed analytical data.

Aladdin Scientific offers Tris(nonylphenyl) phosphate under SKU P951399. Researchers are encouraged to review the product page for current specifications, available pack sizes, and pricing. Contact technical support for custom purity or bulk requirements.

Frequently asked questions

What is Tris(nonylphenyl) phosphate primarily used for in a laboratory setting?

TNPP is primarily used as a secondary antioxidant (hydroperoxide decomposer) in combination with hindered phenol antioxidants for polymer stabilization studies, and as a plasticizer in PVC and polyolefin research. It also serves as an analytical reference standard in environmental chemistry when monitoring nonylphenol contamination.

Is Tris(nonylphenyl) phosphate hazardous to the environment?

Yes. TNPP can degrade to nonylphenol, which is listed as a Substance of Very High Concern (SVHC) under the EU REACH regulation due to its endocrine-disrupting properties and aquatic toxicity. Researchers should follow local regulations for proper waste disposal and avoid releasing TNPP into water systems.

How should Tris(nonylphenyl) phosphate be stored to maintain reagent quality?

TNPP should be stored in a tightly sealed container under cool, dry conditions, away from heat sources, direct sunlight, and strong oxidizing agents. These conditions minimize hydrolysis of the phosphate ester bond and prevent degradation over time. Always consult the product's Certificate of Analysis or SDS for specific recommended storage temperatures.

What purity grade of TNPP should I select for antioxidant mechanism studies?

For mechanistic studies where impurities could confound results, a high-purity grade (≥95%, confirmed by GC or NMR) is recommended. Request a Certificate of Analysis from the supplier to verify identity, purity, and the absence of significant free nonylphenol before use.

References

1. PubChem. Tris(nonylphenyl) phosphate. National Library of Medicine. CID 16213. Retrieved 2024.
2. European Chemicals Agency (ECHA). Nonylphenol – Substance of Very High Concern (SVHC). REACH Regulation.
3. Zweifel H, Maier RD, Schiller M. Plastics Additives Handbook. 6th ed. Hanser; 2009.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.