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CAS NUMBER: 298-07-7
MOLECULAR WEIGHT: 210.21
EC NUMBER: 206-056-4
Di ethylhexyl phosphate is an organophosphorus compound with the formula (C8H17O)2PO2H.
The colorless liquid is a diester of phosphoric acid and 2-ethylhexanol.
Di ethylhexyl phosphate is used in the solvent extraction of uranium, as well as the rare-earth metals.
Di ethylhexyl phosphate is a clear colorless to pale yellow liquid with a slight sharp odor.
Di ethylhexyl phosphate has been widely used as a plasticizer, fire retardant and solvent.
As a plasticizer, Di ethylhexyl phosphate is used as a component of vinyl stabilizers, grease additives and flame-proofing compositions for vinyl plastic and synthetic rubber compounds.
As a fire retardant, Di ethylhexyl phosphate is used in consumer products, such as clothing.
As a solvent, it is used as a co-solvent to produce hydrogen peroxide.
The world production of TEHP was estimated to be between 1000 to 5000 tons per year (IPCS, 2000).
Occupational exposure may occur through inhalation and dermal contact with TEHP at workplaces (HSDB, 2010).
The general population may be exposed to TEHP via ingestion of contaminated food and drinking water (HSDB, 2010) or via dermal contact with TEHP-treated clothing.
USES:
Di ethylhexyl phosphate is used in the solvent extraction of uranium salts from solutions containing the sulfate, chloride, or perchlorate anions.
This extraction is known as the “Dapex procedure.”
Reminiscent of the behaviors of carboxylic acids, Di ethylhexyl phosphate generally exists as a hydrogen-bonded dimer in the non-polar organic solvents.
For practical applications, the solvent, often called a diluent, is typically kerosene.
A complex is formed from two equivalents of the conjugate base of DEHPA and one uranyl ion.
Complexes of the formula (UO2)2[(O2P(OR)2]4 also form, and at high concentrations of uranium, polymeric complexes may form.
The extractability of Fe3+ is similar to that of uranium, so Di ethylhexyl phosphate must be reduced to Fe2+ before the extraction.
The uranium is then stripped from the Di ethylhexyl phosphate/kerosene solution with hydrochloric acid, hydrofluoric acid, or carbonate solutions.
Sodium carbonate solutions effectively strip uranium from the organic layer, but the sodium salt of Di ethylhexyl phosphate is somewhat soluble in water, which can lead to loss of the extractant.
The extractive capabilities of Di ethylhexyl phosphate can be increased through synergistic effects by the addition of other organophosphorus compounds.
Di ethylhexyl phosphate is often used, as well as dibutyl-, diamyl-, and dihexylphosphonates.
The synergistic effects are thought to occur by the addition of the trialkylphosphate to the uranyl-Di ethylhexyl phosphate complex by hydrogen bonding.
The synergistic additive may also react with the Di ethylhexyl phosphate, competing with the uranyl extraction, resulting in a decrease in extraction efficiency past a concentration specific to the compound.
Secondary, tertiary, and quaternary amines have also been used for some uranium extractions as an alternative to Di ethylhexyl phosphate.
Compared to phosphate extractants, amines are more selective for uranium, extract the uranium faster, and are easily stripped with a wider variety of reagents.
However, the phosphates are more tolerant of solids in the feed solution and show faster phase separation.
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.
APPLICATION:
Di ethylhexyl phosphate is used as a lubricant additive, corrosion inhibitor and a metal extractant.
Di 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, it is used as a plasticizer and as a solvent in the synthesis of plastic.
Di ethylhexyl phosphate is a reagent used in a veriety of processes, from the synthesis of vesicles that are amino acid based to nutritive sweeteners.
APPLICATION GROUPS:
-Foams:
Rubbers/elastomers
PVC/nitrile foam
-Textiles/Paints/Adhesives:
Latex/adhesives
-Wire and cables:
EPDM
PVC flexible & rigid
PRODUCTION METHOD:
Produced by chlorinating bis(2-ethylhexyl) phosphonate to give the phosphate diester chloride, followed by hydrolysis, or by saponification of tris(2-ethylhexyl) phosphate.
PURIFICATION METHOD:
Contaminants of commercial samples include the monoester, polyphosphates, pyrophosphate, 2-ethylhexanol and metal impurities.
Dissolve the acid in n-hexane to give an 0.8M solution.
Wash this with an equal volume of M HNO3, then with saturated (NH4)2CO3 solution, with 3M HNO3, and twice with water.
PHYSICAL AND CHEMICAL PROPETIES:
-Physical state: liquid
-Color: colorless
-Odor: ester like
-PH: 2.3
-Initial Boiling point/boiling range: > 180 °C
-Flash point: 100 °C
-Flash Point: 171°C (340°F)
-Density: 0.965 g/mL
-Refractive Index: 1.442
-pH: 2 to 3
-Melting Point: -50°C
-Boiling Point: 48°C (12mmHg)
-Quantity: 100g
-Assay Percent Range: 95%
CHEMICAL DANGERS:
Decomposes at 240°C.
This produces toxic fumes of phosphorus oxides.
Attacks many metals.
This produces flammable/explosive gas
STORAGE:
Separated from metals.
PACKAGING:
Separated from metals.
SYNONYM:
Tris(2-ethylhexyl)phosphate
Disflamoll TOF
Phosphoric acid, tris(2-ethylhexyl) ester
Flexol TOF
Kronitex TOF
Flexol plasticizer TOF
2-Ethyl-1-hexanol phosphate
Tris(ethylhexyl) phosphate
Tri(2-ethylhexyl)phosphate
Tri(2-ethylhexyl) phosphate
