tributyl phosphate
{{Chembox
| Verifiedfields = changed
| verifiedrevid = 470613300
| ImageFile = Tributyl phosphate Structural Formula V1.svg
| ImageClass = skin-invert
| ImageFileL2 = Tributyl-phosphate-3D-vdW.png
| ImageNameL2 = Spacefill model of Tributyl phosphate
| ImageClassL2 = bg-transparent
| ImageFileR2 = Tributyl phosphate-3D-balls-by-AHRLS-2012.png
| ImageNameR2 = Ball and stick model of Tributyl phosphate
| ImageClassR2 = bg-transparent
| PIN = Tributyl phosphate
| OtherNames =
| Section1 = {{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 29090
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = C14439
| InChI = 1/C12H27O4P/c1-4-7-10-14-17(13,15-11-8-5-2)16-12-9-6-3/h4-12H2,1-3H3
| InChIKey = STCOOQWBFONSKY-UHFFFAOYAN
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C12H27O4P/c1-4-7-10-14-17(13,15-11-8-5-2)16-12-9-6-3/h4-12H2,1-3H3
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = STCOOQWBFONSKY-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 126-73-8
| CASNo2_Ref ={{fdacite|correct|FDA}}
| UNII = 95UAS8YAF5
| PubChem = 31357
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 35019
| SMILES = O=P(OCCCC)(OCCCC)OCCCC
}}
| Section2 = {{Chembox Properties
| C=12 | H=27 | O=4 | P=1
| MolarMass =
| Appearance = Colorless to pale-yellow liquid
| Density = 0.9727 g/mL
| MeltingPtC = -80
| BoilingPtC = 289
| VaporPressure = 0.004 mmHg (25°C)
| RefractIndex = 1.4231 (at 20 °C) {{cite journal|author1=Pabst, Florian|author2=Blochowicz, Thomas |title=On the intensity of light scattered by molecular liquids - Comparison of experiment and quantum chemical calculations|journal=The Journal of Chemical Physics|language=en|date=December 2022|volume=157|issue=24|pages=244501|doi=10.1063/5.0133511|pmid=36586992 |bibcode=2022JChPh.157x4501P |doi-access=free}}
}}
| Section3 = {{Chembox Hazards
| ExternalSDS = [http://hazard.com/msds/mf/baker/baker/files/t4706.htm External MSDS]
| NFPA-H = 2
| NFPA-R = 1
| NFPA-F = 1
| NFPA-S =
| HPhrases =
| PPhrases =
| GHS_ref =
| FlashPtC = 146.1
| AutoignitionPtC =
| PEL = TWA 5 mg/m3{{PGCH|0625}}
| REL = TWA 0.2 ppm (2.5 mg/m3)
| LC50 = 227 ppm (cat, 4–5 h)
123 ppm (rat, 6 h)
117 ppm (rat)
2529 ppm (rat, 1 h){{IDLH|126738|Tributyl phosphate}}
| LD50 = 1189 mg/kg (mouse, oral)
3000 mg/kg (rat, oral)
}}
}}
Tributyl phosphate, known commonly as TBP, is an organophosphorus compound with the chemical formula (CH3CH2CH2CH2O)3PO. This colourless, odorless liquid finds some applications as an extractant and a plasticizer. It is an ester of phosphoric acid with n-butanol.
Production
Tributyl phosphate is manufactured by reaction of phosphoryl chloride with n-butanol.{{OrgSynth | author = G. R. Dutton and C. R. Noller | title = n-Butyl phosphate | collvol = 2 | collvolpages = 109| year = 1943 | prep = CV2P0109}}
: POCl3 + 3 C4H9OH → PO(OC4H9)3 + 3 HCl
Use
TBP is a solvent and plasticizer for cellulose esters such as nitrocellulose and cellulose acetate, similarly to tricresyl phosphate. It is also used as a flame retardant for cellulose fabrics such as cotton.{{cite journal |last1=Alongi |first1=Jenny |last2=Malucelli |first2=Giulio |title=Cotton flame retardancy: state of the art and future perspectives |journal=RSC Advances |date=2015 |volume=5 |issue=31 |pages=24239–24263 |doi=10.1039/C5RA01176K|bibcode=2015RSCAd...524239A }}{{cite journal |last1=Gaan |first1=Sabyasachi |last2=Sun |first2=Gang |title=Effect of phosphorus flame retardants on thermo-oxidative decomposition of cotton |journal=Polymer Degradation and Stability |date=June 2007 |volume=92 |issue=6 |pages=968–974 |doi=10.1016/j.polymdegradstab.2007.03.009}} 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, brake fluid, and as a solvent for extraction and purification of rare-earth metals from their ores.{{cite web | publisher = Japan Chemical Industry Ecology-Toxicology & Information Center | title = Tributyl Phosphate | SIDS Initial Assessment Profile | url = http://www.jetoc.or.jp/HP_SIDS/pdffiles/126-73-8.pdf | url-status = dead | archiveurl = https://web.archive.org/web/20071011140920/http://www.jetoc.or.jp/HP_SIDS/pdffiles/126-73-8.pdf | archivedate = 2007-10-11 }}
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 is used as an anti-foaming agent in detergent solutions, and in various emulsions, paints, and adhesives. It is also found as a de-foamer in ethylene glycol-borax antifreeze solutions.{{Citation needed|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 can be used as a heat-exchange medium.{{cite web | publisher = Great Vista Chemicals | url = http://www.greatvistachemicals.com/industrial_and_specialty_chemicals/tributyl_phosphate.html | title = Tributyl Phosphate Product Information| date = 20 January 2023 }} TBP is used in some consumer products such as herbicides and water-thinned paints and tinting bases.{{cite web | title = Tributyl Phosphate | publisher = Scorecard | url = http://www.scorecard.org/chemical-profiles/consumer-products.tcl?edf_substance_id=126-73-8}}
= Nuclear chemistry =
Tributyl phosphate is used in combination with di(2-ethylhexyl)phosphoric acid for the solvent extraction of uranium, as part of the purification of natural ores.{{cite journal |last1=Kumar |first1=Jyothi Rajesh |last2=Kim |first2=Joon-Soo |last3=Lee |first3=Jin-Young |last4=Yoon |first4=Ho-Sung |title=A Brief Review on Solvent Extraction of Uranium from Acidic Solutions |journal=Separation & Purification Reviews |date=18 February 2011 |volume=40 |issue=2 |pages=77–125 |doi=10.1080/15422119.2010.549760|s2cid=95358600 }} It is also used in nuclear reprocessing as part of the PUREX process. 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. Liquid extraction can also be used for chemical uranium enrichment.{{cite book |edition=1. |publisher=Taylor |title=Nuclear energy and nuclear weapon proliferation |url=https://vufind.techlib.cz/Record/000148165}}
Hazards
In contact with concentrated nitric acid the TBP-kerosene solution forms hazardous and explosive red oil.