Triphenyl phosphite
[CAS# 101-02-0]

Identification

• Classification: Organic raw materials >> Inorganic acid ester
• Name: Triphenyl phosphite
• Synonyms: Phosphorous acid triphenyl ester
• Molecular Formula: C₁₈H₁₅O₃P
• Molecular Weight: 310.29
• CAS Registry Number: 101-02-0
• EC Number: 202-908-4
• SMILES: C1=CC=C(C=C1)OP(OC2=CC=CC=C2)OC3=CC=CC=C3

Properties

• Density: 1.184
• Melting point: 22-24 ºC
• Boiling point: 360 ºC
• Refractive index: 1.5893-1.5913
• Flash point: 218 ºC
• Water solubility: insoluble

Safety Data

• Hazard Symbols: GHS07;GHS09 Warning
• Hazard Statements: H315-H319-H400-H410
• Precautionary Statements: P260-P261-P264-P264+P265-P270-P272-P273-P280-P301+P317-P302+P352-P305+P351+P338-P319-P321-P330-P332+P317-P333+P317-P337+P317-P362+P364-P391-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Skin irritation	Skin Irrit.	2	H315
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Acute toxicity	Acute Tox.	4	H302
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Skin sensitization	Skin Sens.	1	H317
Skin sensitization	Skin Sens.	1B	H317
Skin sensitization	Skin Sens.	1A	H317
Specific target organ toxicity - single exposure	STOT SE	2	H371
Acute toxicity	Acute Tox.	4	H332
Skin corrosion	Skin Corr.	1B	H314

• Transport Information: UN 3077

Discovory and Applicatios

Triphenyl phosphite is an organophosphorus compound with the chemical formula P(OC₆H₅)₃. It consists of a central phosphorus atom bonded to three phenoxy groups (OC₆H₅), forming a structure that is widely used in both industrial applications and organic synthesis. The compound is a clear, colorless liquid at room temperature and has gained importance due to its role as a ligand in coordination chemistry and its use as a stabilizer in polymer processing.

The discovery of triphenyl phosphite dates back to the early 20th century when phosphorus-based compounds were being investigated for their potential in both organic and inorganic chemistry. The synthesis of triphenyl phosphite typically involves the reaction of phosphorus trichloride (PCl₃) with phenol (C₆H₅OH). This process results in the substitution of chlorine atoms in phosphorus trichloride with phenoxy groups, yielding triphenyl phosphite. The synthesis is relatively straightforward and can be performed under controlled laboratory conditions, making it accessible for various research and industrial uses.

One of the primary applications of triphenyl phosphite is as a ligand in coordination chemistry. Its phosphorus atom can coordinate with metal centers, forming complexes that are useful in catalysis. Triphenyl phosphite’s ability to donate lone pairs of electrons from its phosphorus atom allows it to stabilize metal centers in various catalytic systems. This feature is particularly valuable in transition metal-catalyzed reactions, such as hydroformylation, hydrogenation, and carbonylation. The presence of bulky phenyl groups around the phosphorus atom in triphenyl phosphite often enhances the selectivity of these reactions by controlling the steric environment around the metal center.

In addition to its role in catalysis, triphenyl phosphite is also used as a stabilizer in polymer processing. Polymers, particularly those used in plastics and rubber manufacturing, are often susceptible to degradation when exposed to heat and oxygen during processing. Triphenyl phosphite acts as an antioxidant, preventing the breakdown of polymer chains and extending the material's lifespan. It is commonly added to polyvinyl chloride (PVC) and other thermoplastic materials to enhance their thermal stability. By inhibiting oxidative degradation, triphenyl phosphite helps maintain the mechanical properties of these materials, making them more durable and resistant to aging.

Another significant application of triphenyl phosphite is in organic synthesis, where it is used as a reagent in various chemical reactions. One well-known reaction involving triphenyl phosphite is the Arbuzov reaction, in which phosphonate esters are formed. This reaction is widely employed in the synthesis of compounds that are used in agriculture, medicine, and materials science. Phosphonate esters, which are derived from triphenyl phosphite, play a critical role in the production of herbicides, insecticides, and flame retardants.

Triphenyl phosphite also finds application in the pharmaceutical industry. Its role as a reagent and intermediate in the synthesis of bioactive molecules has been explored in the production of drugs and other therapeutic agents. The compound’s phosphorus-based structure can be incorporated into various pharmaceutical compounds, contributing to the development of new medicines with unique modes of action.

Beyond its applications in catalysis, polymer stabilization, and organic synthesis, triphenyl phosphite has been used in research to study the reactivity of phosphorus-containing compounds. Its relatively simple structure makes it a useful model compound for investigating the behavior of organophosphorus compounds in different chemical environments. Researchers have explored its electronic properties, reactivity patterns, and coordination behavior with metals, contributing to a deeper understanding of phosphorus chemistry.

Although triphenyl phosphite is generally considered safe for industrial use, its handling requires precautions. It is known to be sensitive to moisture, and exposure to water can lead to hydrolysis, producing phenol and other byproducts. Additionally, in high concentrations, triphenyl phosphite can cause irritation to the skin, eyes, and respiratory system. Therefore, proper protective equipment and ventilation are recommended when working with the compound in laboratory or industrial settings.

In conclusion, triphenyl phosphite is a versatile organophosphorus compound with wide-ranging applications in catalysis, polymer processing, organic synthesis, and pharmaceutical development. Its ability to act as a ligand in metal complexes, combined with its stabilizing effects in polymer systems, makes it a valuable chemical in both academic research and industrial production. Ongoing research into its properties and potential new applications ensures that triphenyl phosphite will remain an important substance in various fields of chemistry.

References

1. Synthesis: Kosolapoff, G. M. (1947). "Synthesis of triphenyl phosphite from phenol and phosphorus trichloride." Journal of the American Chemical Society, 69(8), 2020�2022.
DOI: 10.1021/ja01200a048

2. Applications: Walsh, R. A. (1985). "Triphenyl phosphite as a stabilizer in polymers." Polymer Engineering & Science, 25(12), 765�770.
DOI: 10.1002/pen.760251205

3. Review: Allen, D. W. (2006). "Phosphorus esters: Triphenyl phosphite." Phosphorus, Sulfur, and Silicon and the Related Elements, 181(9), 1987�2001.
DOI: 10.1080/10426500600614892