Tributylphosphane
[CAS# 998-40-3]

Identification

• Classification: Organic raw materials >> Organic phosphine compound
• Name: Tributylphosphane
• Synonyms: Tris(butyl)phosphine; Tri-n-butylphosphine; TBUP
• Molecular Formula: C₁₂H₂₇P
• Molecular Weight: 202.32
• CAS Registry Number: 998-40-3
• EC Number: 213-651-2
• SMILES: CCCCP(CCCC)CCCC

Properties

• Density: 0.82 g/mL (Expl.)
• Melting point: -65 °C (Expl.)
• Boiling point: 244.8 °C 760 mmHg (Calc.)^*, 257.9 °C (Expl.)
• Flash point: 112.2±25.0 °C (Calc.)^*, 37.2 °C (Expl.)
• Solubility: water: Insoluble (Expl.)
• Refraction index: 1.462 (Expl.)

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

Safety Data

• Hazard Symbols: GHS02;GHS05;GHS07;GHS09 Danger
• Risk Statements: H226-H250-H251-H302-H312-H314-H318-H411
• Safety Statements: P210-P222-P231-P233-P235-P240-P241-P242-P243-P260-P264-P264+P265-P270-P273-P280-P301+P317-P301+P330+P331-P302+P335+P334-P302+P352-P302+P361+P354-P303+P361+P353-P304+P340-P305+P354+P338-P316-P317-P321-P330-P362+P364-P363-P370+P378-P391-P403+P235-P405-P407-P410-P413-P420-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Pyrophoric liquids	Pyr. Liq.	1	H250
Acute toxicity	Acute Tox.	4	H302
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Acute toxicity	Acute Tox.	4	H312
Skin corrosion	Skin Corr.	1B	H314
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1A	H314
Flammable liquids	Flam. Liq.	3	H226
Self-heating substances or mixtures	Self-heat.	1	H251
Self-heating substances or mixtures	Self-heat.	2	H252
Flammable liquids	Flam. Liq.	2	H226

• Transport Information: UN 3254

Discovery and Applications

Tributylphosphane is an organophosphorus compound with the molecular formula C₁₂H₂₇P. Structurally, it consists of a phosphorus atom bonded to three n-butyl groups, giving a pyramidal geometry with a lone pair of electrons on the phosphorus center. This lone pair makes the compound a strong nucleophile and a good ligand for transition metals. Tributylphosphane is typically a colorless to pale yellow liquid with a characteristic fishy odor, soluble in organic solvents such as hexane, toluene, and dichloromethane, but insoluble in water.

The compound is primarily used as a ligand in coordination chemistry and homogeneous catalysis. Its nucleophilic phosphorus center readily coordinates to metals such as palladium, platinum, or rhodium, forming stable complexes that facilitate a variety of catalytic transformations, including hydrogenation, hydroformylation, and cross-coupling reactions. The flexible butyl substituents provide steric bulk that can influence the selectivity and activity of the catalytic complexes.

Tributylphosphane is also employed as a reducing agent and nucleophilic reagent in organic synthesis. It can reduce certain organohalides, sulfonyl compounds, and oxidized phosphorus species, and it is frequently used in the synthesis of phosphonium salts for use in Wittig reactions and other phosphorus-mediated transformations.

The compound is typically synthesized by the reaction of phosphorus trichloride with n-butyl magnesium halide or n-butyl lithium, followed by careful purification to remove unreacted starting materials and byproducts. Handling requires precautions due to its flammability, toxicity, and strong odor. It is also air-sensitive and may oxidize slowly upon prolonged exposure to oxygen, so it is often stored under inert atmosphere.

Overall, tributylphosphane is a versatile organophosphorus compound valued for its nucleophilic phosphorus center, ability to act as a ligand in catalysis, and utility as a reducing and functionalizing reagent in organic synthesis. Its combination of reactivity and steric properties makes it an essential tool in both academic and industrial chemical applications.

References

2011. Acute toxicity of nonylphenols and bisphenol A to the embryonic development of the abalone Haliotis diversicolor supertexta. Ecotoxicology, 20(6).
DOI: 10.1007/s10646-011-0672-7