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Tributyl phosphate

Tributyl phosphate

Chemical formula (CH3CH2CH2CH2O)3PO
Appearance colorless to yellowish liquid
CAS number 126-73-8 (anhydrous)
6131-90-4 (trihydrate)
Molar mass 266.32 g/mol
Melting point 193K
(-80°C; -112°F)
Boiling point 562K
(289°C; 552°F)
Density 0.9727 g/cm3
Crystal structure FIXME orthorhombic
Solubility 1 mL /165 mL of water
ΔfH0gas -?
ΔfH0liquid  ?
ΔfH0solid  ?
S0gas, 1 bar  ?
S0liquid, 1 bar  ?
S0solid  ?
Ingestion "May cause abdominal pain, vomiting. Other symptoms parallel inhalation." [1]
Inhalation "Causes irritation to the respiratory tract. Symptoms may include coughing, shortness of breath. May cause headache. May also mildly affect blood cholinesterase levels, which will affect central nervous system operation." [1]
Skin "Causes irritation to skin. Symptoms include redness, itching, and pain. May be absorbed through the skin with possible systemic effects." [1]
Eyes "Causes irritation, redness, and pain." [1]
Firefighting Data
Flash point 120C (248°F)
Extingushing Media "Water spray, dry chemical, alcohol foam, or carbon dioxide. Water or foam may cause frothing."[1]

SI units and standard conditions used unless otherwise stated.
Disclaimer and references

Tributyl phosphate (TBP), n-tributyl phosphate, or tri-n-butyl phosphate, is an odorless liquid, colorless to pale yellow in appearance, with applications in industrial and nuclear chemistry. It is slightly flammable and moderately dangerous to humans. It is an ester of orthophosphoric acid and n-butanol. It is a very good solvent.

Additional recommended knowledge



Section pending.


Tributyl phosphate is manufactured by esterification of orthophosphoric acid with butyl alcohol.

This is a high volume chemical with production estimated at 3,000 – 5,000 tonnes worldwide. [1]



TBP is a solvent and plasticizer for cellulose esters (eg. nitrocellulose and cellulose acetate). It forms stable hydrophobic complexes with some metals; these complex are soluble in organic solvents and in 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. [2]

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, together with a large amount of eg. isopropyl alcohol it finds use as anti-foaming agent in most detergent solutions, and in various emulsions, paints, and adhesives. It is also found as a defoamer in ethylene glycol-borax antifreze solutions.

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. [3]

Consumer Products

TBP is used in some consumer products such as herbicides and water thinned paints and tinting bases. [4]

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.

Because of this, 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.


The material will burn, but (in the absence of significant vaporization) should not pose a particular explosive hazard. Inhalation and ingestion should be avoided due to possible central nervous system effects. A lab coat and safety glasses should be worn; a tributyl phosphate is not presently known to be, or suspected of being, a carcinogen, but may be mutagenic or have reproductive effects; consult the substance's MSDS for full details (see link at bottom).

In contact with concentrated nitric acid the TBP-kerosene solution forms hazardous and explosive red oil.


Material Safety Data Sheet (MSDS) for tributyl phosphate

See also

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Tributyl_phosphate". A list of authors is available in Wikipedia.
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