Tributyl phosphate

Tributyl phosphate, known commonly as TBP, is an organophosphorus compound with the formula (CH₃CH₂CH₂CH₂O)₃PO. This colourless, odorless liquid finds some applications as an extractant and a plasticizer. It is an ester of orthophosphoric acid with "n"-butanol.

Production

Tributyl phosphate is manufactured by esterification of orthophosphoric acid with butyl alcohol. A laboratory synthesis proceeds with phosphorus oxychloride: [OrgSynth | author = G. R. Dutton and C. R. Noller | title = n-Butyl phosphate | collvol = 2 | collvolpages = 109| year = 1943 | prep = CV2P0109.pdf] : POCl₃ + 3 C₄H₉OH → PO(OC₄H₉)₃ + 3 HClProduction is estimated at 3,000 – 5,000 tonnes worldwide. [http://www.jetoc.or.jp/HP_SIDS/pdffiles/126-73-8.pdf]

Use

TBP is a solvent and plasticizer for cellulose esters such as nitrocellulose and cellulose acetate. It forms stable hydrophobic complexes with some metals; these complexes are soluble in organic solvents as well as supercritical CO₂. The major uses of TBP in industry are as a component of aircraft hydraulic fluid and as a solvent for extraction and purification of rare earth metals from their ores. [http://www.jetoc.or.jp/HP_SIDS/pdffiles/126-73-8.pdf]

TBP finds its use as a solvent in inks, synthetic resins, gums, adhesives (namely for veneer plywood) and herbicide and fungicide concentrates.

As it has no odour, it finds use as anti-foaming agent in detergent solutions, and in various emulsions, paints, and adhesives. It is also found as a defoamer in ethylene glycol-borax antifreze solutions.Fact|date=January 2008 In oil-based lubricants addition of TBP increases the oil film strength. It is used also in mercerizing liquids, where it improves their wetting properties. It is also used as a heat exchange medium. [http://www.greatvistachemicals.com/industrial_and_specialty_chemicals/tributyl_phosphate.html] TBP is used in some consumer products such as herbicides and water thinned paints and tinting bases. [http://www.scorecard.org/chemical-profiles/consumer-products.tcl?edf_substance_id=126%2d73%2d8]

Nuclear chemistry

A 15-40% (usually about 30%) solution of tributyl phosphate in kerosene or dodecane is used in the liquid-liquid extraction (solvent extraction) of uranium, plutonium, and thorium from spent uranium nuclear fuel rods dissolved in nitric acid, as part of a nuclear reprocessing process known as PUREX.

The shipment of 20 tons of tributyl phosphate to North Korea from China in 2002, coinciding with the resumption of activity at Yongbyon Nuclear Scientific Research Center, was seen by the United States and the International Atomic Energy Agency as cause for concern; that amount was considered sufficient to extract enough material for perhaps three to five potential nuclear weapons.Fact|date=January 2008

Hazards

Consult MSDS http://www.jtbaker.com/msds/englishhtml/t4706.htm. In contact with concentrated nitric acid the TBP-kerosene solution forms hazardous and explosive red oil.

References

External links