Triphenyl Phosphite (TPP) CAS 101-02-0

What Is Triphenyl Phosphite?

Triphenyl phosphite, commonly abbreviated as TPP, is an aromatic organophosphite with the formula C18H15O3P and CAS number 101-02-0.

It is used as a secondary antioxidant and processing stabilizer in selected polymers, resins, adhesives, coatings and lubricant formulations. It is also used as an organophosphorus intermediate and ligand in chemical synthesis.

Triphenyl phosphite is a low-melting material. Depending on temperature and thermal history, it may appear as a clear liquid, a low-melting solid, a solidified melt or a supercooled liquid. This physical variation does not by itself indicate a quality problem.

AOZUN supplies Triphenyl phosphite for industrial processing and international distribution. Product grade, impurity limits, packaging and documentation can be confirmed according to the customer’s application.

Triphenyl Phosphite Quick Facts

Physical-property values are reference data. The approved sales specification and batch-specific certificate of analysis govern commercial acceptance.

Is Triphenyl Phosphite a Liquid or a Solid?

Triphenyl phosphite has a melting or solidification range close to normal room temperature. As a result, the same material may arrive as:

• A clear liquid

• A partially crystallized liquid

• An off-white low-melting solid

• A solidified melt

• A supercooled liquid that remains fluid below its normal melting range

Crystallization during cool storage does not automatically mean the product has degraded.

If remelting is required, use controlled indirect heating according to the supplier’s SDS and handling instructions. Do not use direct flame or excessive temperature. The container should remain protected from water and humid air during conditioning.

Temperature-sensitive users should discuss winter transportation, heated unloading and transfer-line requirements before shipment.

Triphenyl Phosphite Specifications

The following table represents a typical industrial commercial profile. Exact AOZUN specifications must be confirmed in the quotation and batch COA.

Higher-purity, lower-color or tighter-phenol requirements may be considered after technical review. Buyers should define critical impurities before requesting a quotation.

Why Are Acid Value, Phenol and Moisture Important?

Acid Value

Acid value is one of the most useful indicators of Triphenyl phosphite condition.

An increased acid value may indicate:

• Moisture exposure

• Hydrolysis

• Improper storage

• Packaging leakage

• Extended storage under unsuitable conditions

• Formation of acidic degradation products

A low acid value is particularly important where TPP will be used in acid-sensitive catalysts, transparent polymers or formulations that require stable color.

Free Phenol

Phenol may be present as a manufacturing-related impurity or may form when Triphenyl phosphite undergoes hydrolysis.

Simplified hydrolysis can be represented as:

P(OC6H5)3 + water → phosphorus-containing acids + phenol

The actual hydrolysis pathway can involve intermediate products. The simplified equation should not be treated as a complete reaction mechanism.

Excess free phenol may affect:

• Odor

• Color

• Worker exposure controls

• Polymer processing

• Downstream reaction selectivity

• Regulatory assessment

• Final-product specifications

Buyers should specify a separate phenol limit rather than assuming that total assay fully represents product quality.

Moisture

Water can consume Triphenyl phosphite and generate acidic hydrolysis products. Moisture may therefore reduce effective stabilizer content even when the product still appears clear.

Moisture control should include:

• Dry storage

• Tightly closed containers

• Dry transfer systems

• Appropriate seals and hoses

• Inert-gas blanketing where required

• Limited exposure during sampling

• Prevention of humid-air backflow

Color

Low initial color is important for transparent, white and lightly pigmented polymers.

Color alone does not prove purity. A complete evaluation may require assay, acid value, free phenol, moisture and color results.

How Does Triphenyl Phosphite Work as a Polymer Stabilizer?

Triphenyl phosphite is generally classified as a secondary antioxidant or processing stabilizer.

During polymer processing, heat and oxygen may contribute to the formation of hydroperoxides. These unstable species can decompose into radicals that promote:

• Chain scission

• Crosslinking

• Yellowing

• Loss of mechanical properties

• Melt-viscosity change

• Surface defects

• Reduced processing stability

Phosphite antioxidants can react with hydroperoxides and convert them into less reactive products. During this process, the phosphorus(III) center is oxidized toward a phosphorus(V) form.

This mechanism can help reduce oxidative damage during high-temperature processing. Actual performance depends on the polymer, stabilizer package, processing temperature, residence time, oxygen exposure and additive concentration.

Primary and Secondary Antioxidant Synergy

Triphenyl phosphite may be used with selected primary antioxidants.

Primary antioxidants typically interrupt radical-chain reactions. Secondary phosphite antioxidants primarily address hydroperoxide decomposition. A properly designed combination may therefore provide better processing stability than either component alone.

Synergy must be confirmed experimentally. Compatibility, migration, color, hydrolysis resistance and regulatory status should all be evaluated in the finished formulation.

How Is Triphenyl Phosphite Used?

Triphenyl phosphite is selected for its phosphorus(III) reactivity, low initial color and compatibility with certain organic formulations.

PVC and Chlorinated Polymers

In selected PVC formulations, TPP may contribute to:

• Processing stability

• Color retention

• Transparency

• Metal-ion complexation

• Stabilizer-package performance

It is not a complete PVC stabilizer by itself. Performance depends on resin type, plasticizer, primary heat stabilizer, processing temperature and other additives.

Polyolefins

TPP may be used as a secondary antioxidant in selected polyethylene and polypropylene processing systems.

Before commercial use, formulators should evaluate:

• Melt-flow retention

• Color

• Odor

• Plate-out

• Hydrolytic stability

• Long-term aging

• Interaction with catalyst residues

• Regulatory requirements

Modern polymer systems may use more hydrolytically stable phosphites when severe moisture resistance or long service life is required.

Polyesters and Polyurethanes

Triphenyl phosphite may be evaluated in polyester, polyurethane and related resin systems as a processing stabilizer, color-control additive or chemical intermediate.

Water and acid value are especially relevant because these systems may contain moisture-sensitive components or catalysts.

Compatibility should be tested in the complete formulation.

Styrenics, ABS and Engineering Plastics

TPP may help reduce processing discoloration in selected styrenic, ABS and engineering-plastic systems.

The result depends on:

• Resin grade

• Processing temperature

• Number of heat histories

• Pigment package

• Residual catalyst

• Other stabilizers

• Required service life

A laboratory trial should reproduce the actual extrusion, molding or compounding conditions.

Adhesives, Coatings and Sealants

Triphenyl phosphite may function as a stabilizer or reactive intermediate in selected adhesive and coating formulations.

Formulators should evaluate:

• Storage stability

• Cure behavior

• Color

• Viscosity

• Adhesion

• Moisture sensitivity

• Emissions

• Compatibility with catalysts and curing agents

It should not be assumed that TPP is compatible with every coating or adhesive chemistry.

Lubricants and Greases

TPP has been evaluated as an auxiliary antioxidant or additive component in selected lubricant systems.

Performance depends on base oil, temperature, metal contact, water contamination and the complete additive package. Finished-lubricant testing is required.

Organic and Organophosphorus Synthesis

Triphenyl phosphite can act as:

• A phosphorus(III) reagent

• An organophosphorus intermediate

• A ligand in coordination chemistry

• A starting material for selected phosphorus compounds

Synthesis-grade requirements may place more emphasis on GC purity, water, phenol and related phosphorus impurities than polymer-grade applications.

Is Triphenyl Phosphite a Flame Retardant?

Triphenyl phosphite should not automatically be marketed as a stand-alone flame retardant.

Although it contains phosphorus and may be used as an intermediate in phosphorus chemistry, the flame-retardant performance of a finished material depends on:

• Polymer type

• Additive concentration

• Phosphorus content

• Decomposition pathway

• Char formation

• Dispersion

• Sample thickness

• Test method

A material should only be described as flame-retardant after the final formulation has passed an appropriate standard such as UL 94, limiting oxygen index or another relevant fire test.

Triphenyl Phosphite vs Triphenyl Phosphate

Triphenyl phosphite and Triphenyl phosphate are different chemicals.

Because both names may be abbreviated as TPP, purchase orders should always include the full chemical name and CAS number.

Triphenyl Phosphite vs Triphenylphosphine

Triphenylphosphine is also a different compound.

• Triphenyl phosphite: P(OC6H5)3, CAS 101-02-0

• Triphenylphosphine: P(C6H5)3, CAS 603-35-0

Triphenyl phosphite contains three phosphorus–oxygen–phenyl groups. Triphenylphosphine contains direct phosphorus–carbon bonds.

They must not be substituted for one another without chemical-process validation.

How Should Buyers Select a Triphenyl Phosphite Grade?

For Transparent Polymers

Prioritize:

• Low color

• Low acid value

• Controlled phenol

• Consistent purity

• Clean packaging

For Moisture-Sensitive Processing

Prioritize:

• Moisture control

• Low acid value

• Inert-gas packaging

• Short exposure time during transfer

• Dry storage and dosing systems

For Chemical Synthesis

Prioritize:

• GC purity

• Identity confirmation

• Water

• Phenol

• Relevant phosphorus impurities

• Batch traceability

For Continuous Industrial Production

Prioritize:

• Batch consistency

• Reliable physical form

• Transfer temperature

• Drum or bulk-handling compatibility

• Lead time

• Change-notification procedure

• Retained samples

Quality Control for Triphenyl Phosphite

Gas Chromatography

GC is commonly used for assay and volatile or semi-volatile organic impurities.

The COA should clarify whether the result is GC area percentage or another calculation basis.

Acid-Value Testing

Acid value helps monitor hydrolysis and acidic degradation. Sampling equipment must be dry because moisture introduced during sampling can affect the result.

Free-Phenol Analysis

Free phenol should be measured separately when it is a critical parameter. Total assay cannot reliably replace a specific phenol test.

Color Measurement

APHA or platinum-cobalt color is useful for transparent and lightly colored applications. The agreed test method and temperature should be stated.

Density and Refractive Index

Density and refractive index support identity and batch-consistency checks. They do not replace chromatography or impurity testing.

Solidification-Point Testing

The solidification range helps explain handling behavior near room temperature. It can also support identity and purity assessment.

Why Choose AOZUN as Your Triphenyl Phosphite Supplier?

Application-Oriented Supply

AOZUN can review the intended polymer, resin or synthesis application before confirming the appropriate commercial specification.

Batch Documentation

Available documents can be confirmed during quotation and may include:

• Certificate of analysis

• Safety data sheet

• Technical data sheet

• Packing information

• Country-of-origin information

• Transport documents

• Regulatory statements where available

Industrial Packaging

Approved drums, IBCs or other industrial packaging may be available depending on quantity, destination and transport classification.

Exact packaging and net weight must be confirmed in the sales contract.

International Logistics Support

AOZUN can coordinate export documentation and shipment information with the customer and logistics provider.

Customers should disclose temperature-sensitive unloading requirements and destination regulations before shipment.

Packaging and Storage

Store Triphenyl phosphite in tightly closed, compatible containers in a cool, dry and well-ventilated location.

Recommended controls include:

• Protect from moisture and humid air

• Keep containers closed when not in use

• Use dry transfer equipment

• Consider inert-gas blanketing

• Protect from strong oxidizing agents

• Keep away from excessive heat

• Prevent direct sunlight exposure

• Use secondary containment

• Avoid contamination with acids or water

• Restrict handling to trained personnel

If the product solidifies during cool storage, follow the supplier-approved remelting procedure. Use controlled indirect heating and confirm that the packaging is suitable for warming.

Shelf life depends on product grade, packaging and storage conditions. Refer to the commercial documents supplied with the order.

Safety and Environmental Handling

Triphenyl phosphite may be harmful if swallowed and may irritate the skin and eyes. It may cause skin sensitization and may affect organs after prolonged or repeated exposure. It is also hazardous to aquatic life.

Consult the current SDS before handling.

Appropriate controls may include:

• Closed transfer

• Local exhaust ventilation

• Chemical-resistant gloves

• Protective clothing

• Eye or face protection

• Emergency washing facilities

• Spill containment

• Controlled waste collection

Do not release Triphenyl phosphite, contaminated water or cleaning residues into drains or the environment.

Burning or severe overheating may generate irritating or toxic phosphorus-containing fumes. Fire response must follow the current SDS and site emergency plan.

Transport and Regulatory Considerations

Transport classification may vary with purity, composition, jurisdiction and applicable regulations. Do not assign a UN number or packing group from a generic online source alone.

Before shipment, verify:

• Current supplier SDS

• Proper shipping name

• UN number, if applicable

• Hazard class

• Packing group

• Marine-pollutant status

• Approved packaging

• Temperature controls

• Import requirements

Buyers should also confirm REACH, TSCA, local inventory, food-contact, automotive, electrical or other end-use requirements where applicable.

General chemical availability does not establish approval for a regulated final product.

Information to Include in Your Inquiry

For a more accurate quotation, provide:

• Product: Triphenyl phosphite

• CAS number: 101-02-0

• Required assay

• Maximum acid value

• Maximum free phenol

• Maximum color

• Moisture requirement

• Required quantity

• Preferred packaging

• Destination

• Intended application

• Required documents

• Delivery schedule

• Special winter-handling requirements

Frequently Asked Questions

What is the CAS number of Triphenyl phosphite?

The CAS number is 101-02-0.

Is Triphenyl phosphite solid or liquid?

It can be either. Its melting range is close to room temperature, so it may be supplied as a liquid, low-melting solid, partially crystallized material or supercooled liquid.

Why did Triphenyl phosphite crystallize in the drum?

Crystallization can occur when the storage temperature falls near or below its solidification range. Crystallization alone does not demonstrate degradation.

Can solidified Triphenyl phosphite be remelted?

It may generally be conditioned using controlled indirect heating, but the supplier’s approved procedure and SDS must be followed. Avoid direct flame, water contamination and excessive heat.

Is Triphenyl phosphite moisture-sensitive?

Yes. Moisture can cause hydrolysis and generate phenol and acidic phosphorus-containing products.

What does acid value indicate?

Acid value helps monitor acidic impurities, moisture-related hydrolysis and storage condition.

Is Triphenyl phosphite a primary antioxidant?

It is normally described as a secondary antioxidant or processing stabilizer. It may be combined with suitable primary antioxidants.

Is Triphenyl phosphite the same as Triphenyl phosphate?

No. Triphenyl phosphite is CAS 101-02-0, while Triphenyl phosphate is CAS 115-86-6.

Is TPP a flame retardant?

It should not automatically be described as a stand-alone flame retardant. Flame performance must be verified in the final polymer using an applicable fire test.

Can TPP be used in food-contact polymers?

Only when the specific grade, use level, formulation and destination-market regulations permit it. Standard industrial grade should not be assumed to be food-contact compliant.

Which specification is most important?

That depends on the application. Assay, acid value, free phenol, moisture and color are commonly important.

What documents can AOZUN provide?

Available documents may include a batch COA, SDS, TDS, packaging information and transport documentation. Confirm requirements before ordering.

Request a Triphenyl Phosphite Quote

AOZUN supplies Triphenyl phosphite CAS 101-02-0 for polymer processing, chemical synthesis and international industrial distribution.

Send us your required assay, acid value, phenol limit, color, quantity, packaging and destination. AOZUN will review product availability, documentation and shipping requirements before providing a quotation.