Trioctylphosphine oxide

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Trioctylphosphine oxide
Structural formula of trioctylphosphine oxide
IUPAC name
Other names
Tri-n-octylphosphine oxide
3D model (JSmol)
Abbreviations TOPO
ECHA InfoCard 100.001.020
EC Number 201-121-3
MeSH Trioctyl+phosphine+oxide
RTECS number SZ1662500
UN number 3077
Molar mass 386.64 g·mol−1
Appearance White, opaque crystals
Melting point 50 to 54 °C (122 to 129 °F; 323 to 327 K)
Boiling point 411.2 °C (772.2 °F; 684.3 K) at 760 mmHg[1]
Irritant Xi
R-phrases (outdated) R38, R41
S-phrases (outdated) S26, S39
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oilHealth code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gasReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
Flash point 110 °C (230 °F; 383 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☑Y verify (what is ☑Y☒N ?)
Infobox references

Trioctylphosphine oxide (TOPO) is an organophosphorus compound with the formula OP(C8H17)3. Frequently referred to as TOPO, this compound is used as an extraction or stabilizing agent. It is an air-stable white solid at room temperature.

Preparation and use[edit]

TOPO is usually prepared by oxidation of trioctylphosphine, which in turn is produced by alkylation of phosphorus trichloride.

The main use of TOPO is in solvent extraction of metals, especially uranium. The high lipophilicity and high polarity are properties key to this application. Its high polarity, which results from the dipolar phosphorus-oxygen bond, allows this compound to bind to metal ions. The octyl groups confer solubility in low polarity solvents such as kerosene.[2]

In the research laboratory, both trioctylphosphine and TOPO are frequently useful as a capping ligand for the production of quantum dots such as those consisting of CdSe. In these cases, TOPO serves as solvent for the synthesis and solubilizes the growing nanoparticles. TOPO-coated quantum dots are typically soluble in chloroform, toluene, and (to a lesser extent) hexane. These quantum dots are also used in biological applications as part of the protective barrier to prevent degradation as it travels through the harsh climate of the body.


  1. ^ Nakhutin, I. E. (1971). Zhurnal Obshchei Khimii. 41 (5): 940–943. Missing or empty |title= (help)
  2. ^ Watson, E. K.; Rickelton, W. A. "A review of the industrial and recent potential applications of trioctylphosphine oxide" Solvent Extraction and Ion Exchange 1992, volume 10, pp. 879-89. doi:10.1080/07366299208918141