2-ETHYLHEXYL PHOSPHATE

2-ethylhexyl phosphate is a colorless, odorless, viscous liquid that is soluble in water. 
2-ethylhexyl phosphate is used as a plasticizer for polyvinyl chloride (PVC). 
2-ethylhexyl phosphate has been shown to have synergistic effects with hydrochloric acid and sodium carbonate, which can be used to extract it from PVC. 

CAS:    298-07-7
MF:    C16H35O4P
MW:    322.42
EINECS:    206-056-4

Synonyms
PHOSPHORIC ACID BIS (2-ETHYLHEXYL) ESTER;PHOSPHORIC ACID DI(2-ETHYLHEXYL) ESTER;PHOSPHORIC ACID DIOCTYL ESTER;Phosphorsurebis-(2-ethylhexyl)-ester;isooctanol, hydrogen phosphate;DIETHYLHEXYL PHOSPHATE;Bis(2-ethylhexyl) Hydrogen Phosphate [for Rare Metals Extraction];Dicapryl phosphate

The extraction process involves dissolution of the PVC in an acidic solution followed by neutralization with sodium carbonate. 
The monoclonal antibody is specific for 2-ethylhexyl phosphate and can be used to detect this chemical compound in human blood samples.
2-ethylhexyl phosphate could be used as a starting material to synthesize Bis(2-ethylhexyl) phosphate.
2-ethylhexyl phosphate is an organophosphate with the formula (C8H17O)2PO2H. 
The colorless liquid is a diester of phosphoric acid and 2-ethylhexyl phosphate. 
2-ethylhexyl phosphate is used in the solvent extraction of uranium, vanadium and the rare-earth metals.

2-ethylhexyl phosphate Chemical Properties
Melting point: −60 °C(lit.)
Boiling point: 48 °C (12 mmHg)
density: 0.965 g/mL at 25 °C(lit.)
vapor pressure: <0.1 hPa (20 °C)
refractive index: n20/D 1.443(lit.)
Fp: >230 °F
storage temp.: Store below +30°C.
solubility ethanol: soluble100mg/mL, clear
form: Liquid
pka: 1.47±0.50(Predicted)
Specific Gravity: 0.974
color: Colorless
PH: 3 (< 1g/l, H2O)
Water Solubility: slightly soluble
FreezingPoint: -60℃
BRN: 1712988
Henry's Law Constant: 2.4×102 mol/(m3Pa) at 25℃, HSDB (2015)
Stability: Moisture Sensitive
InChI: 1S/C16H35O4P/c1-5-9-11-15(7-3)13-19-21(17,18)20-14-16(8-4)12-10-6-2/h15-16H,5-14H2,1-4H3,(H,17,18)
InChIKey: SEGLCEQVOFDUPX-UHFFFAOYSA-N
LogP: 2.88 at 25℃
CAS DataBase Reference: 298-07-7(CAS DataBase Reference)
NIST Chemistry Reference: 2-ethylhexyl phosphate (298-07-7)
EPA Substance Registry System: 2-ethylhexyl phosphate (298-07-7)
ECETOC JACC REPORT: 2-ethylhexyl phosphate (298-07-7)

Uses    
Additive to lubrication oils, corrosion inhibitor, and antioxidant. 
Used as extractant in the hydrometallurgical separation of cobalt and nickel. 
Metal extraction and separation, intermediate for wetting agents and detergents. 
Feedstock for chemical synthesis; extraction fluid for metal salts; cation extracting agent.
2-ethylhexyl phosphate is used as a lubricant additive, corrosion inhibitor and a metal extractant. 
2-ethylhexyl phosphate is involved in the solvent extraction of uranium salts and rare earth metals. 
Iron(II) ions are extracted after reduction of Iron(III) ions. 
Further, 2-ethylhexyl phosphate is used as a plasticizer and as a solvent in the synthesis of plastic.

2-ethylhexyl phosphate can be used to extract lanthanides (rare earths) from aqueous solutions, it is commonly used in the lanthanide sector as an extraction agent. 
In general the distribution ratio of the lanthanides increase as their atomic number increases due to the lanthanide contraction. 
2-ethylhexyl phosphate is possible by bringing a mixture of lanthanides in a counter current mixer settler bank into contact with a suitable concentration of nitric acid to selectively strip (back extract) some of the lanthanides while leaving the others still in the 2-ethylhexyl phosphate based organic layer.
In this way selective stripping of the lanthanides can be used to make a separation of a mixture of the lanthanides into mixtures containing fewer lanthanides. 
Under ideal conditions this can be used to obtain a single lanthanide from a mixture of many lanthanides.

2-ethylhexyl phosphate is common to use DEHPA in an aliphatic kerosene which is best considered to be a mixture of long chain alkanes and cycloalkanes. 
When used in an aromatic hydrocarbon diluent the lanthanide distribution ratios are lower. 
2-ethylhexyl phosphate has been shown that it is possible to use a second generation biodiesel which was made by the hydrotreatment of vegetable oil. 
2-ethylhexyl phosphate has been reported that Neste's HVO100 is a suitable diluent for DEHPA when calcium, lanthanum and neodymium are extracted from aqueous nitric acid.

Production Methods    
Produced by chlorinating 2-ethylhexyl phosphate to give the phosphate diester chloride, followed by hydrolysis, or by saponification of tris(2-ethylhexyl) phosphate.

Reactivity Profile    
Organophosphates, such as 2-ethylhexyl phosphate, are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrides. 
Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides. 
Mildly corrosive to most metals; may form flammable hydrogen gas.

Health Hazard    
Contact with liquid irritates eyes and may cause serious injury; consult an eye specialist. 
Also causes skin irritation on contact. 
Ingestion produces irritation similar to that caused by strong vinegar.

Preparation
2-ethylhexyl phosphate is prepared through the reaction of phosphorus pentoxide and 2-ethylhexanol:

4 C8H17OH + P4O10 → 2 [(C8H17O)PO(OH)]2O
[(C8H17O)PO(OH)]2O + C8H17OH → (C8H17O)2PO(OH) + (C8H17O)PO(OH)2
These reaction produce a mixture of mono-, di-, and trisubstituted phosphates, from which DEHPA can be isolated based on solubility.