Bis(2-ethylhexyl) phthalate

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Bis(2-ethylhexyl) phthalate
Bis(2-ethylhexyl) phthalate
IUPAC name Bis(2-ethylhexyl)phthalate (BEHP)
Identifiers
CAS number [117-81-7]
SMILES O=C(OCC(CC)CCCC)
C1=CC=CC=C1C(OCC(CC)CCCC)=O
Properties
Molecular formula C24H38O4
Molar mass 390.56
Melting point

-50°C
Boiling point

385°C
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Bis(2-ethylhexyl)phthalate, commonly abbreviated DEHP, is an organic compound with the formula C6H4(CO2C8H17)2. It is the most important "phthalate," being the diester of phthalic acid and the branched-chain 2-ethylhexanol. This colourless viscous liquid is soluble in oil, but not in water. It possesses good plasticizing properties. Being produced on a massive scale by many companies, it has acquired many names and acronymns, including BEHP, di-2-ethyl hexyl phthalate, as well as dioctyl phthalate (DOP).

Contents

[edit] Production

The process entails the reaction of phthalic anhydride with 2-ethylhexanol:

C6H4(CO)2O + 2 C8H17OH → C6H4(CO2 C8H17)2 + H2O

Approximately three billion kilograms are produced annually.[1]

[edit] Use

Due to its suitable properties and the low cost, DEHP is widely used as a plasticizer in manufacturing of articles made of PVC.[1] Plastics may contain 1% to 40% of DEHP. It is also used as a hydraulic fluid and as a dielectric fluid in capacitors. DEHP also finds use as a solvent in lightsticks.

[edit] Environmental exposure

DEHP has a low vapor pressure, but the temperatures for processing PVC articles are often high, leading to release of elevated levels, raising concerns about health risks (see outgassing). It can be absorbed from food and water. Higher levels have been found in milk and cheese. It can also leach into a liquid that comes in contact with the plastic; it extracts faster into nonpolar solvents (eg. oils and fats in foods packed in PVC). Food and Drug Administration (FDA) therefore permits use of DEHP-containing packaging only for foods that primarily contain water. In soil, DEHP contamination moves very slowly because of its low solubility in water. Therefore, leaching from disposed plastics in landfills is generally slow. The US EPA limits for DEHP in drinking water is 6 ppb. The U.S. agency OSHA's limit for occupational exposure is 5 mg/m3 of air.

[edit] Use in medical devices

DEHP has been used as a plasticiser in medical devices such as intravenous tubing and bags, catheters, nasogastric tubes, dialysis bags and tubing, and blood bags and transfusion tubing, and air tubes. For this reason, concern has been expressed about leachates transported into the patient, especially for those requiring extensive infusions, e.g. newborns in intensive care nursery settings, hemophiliacs, and kidney dialysis patients. The American Academy of Pediatrics has advocated not to use medical devices that can leach DEHP into patients and , instead, to resort to DEHP-free alternatives.[citation needed] In July 2002, the U.S. FDA issued a Public Health Notification on DEHP, stating in part, "We recommend considering such alternatives when these high-risk procedures are to be performed on male neonates, pregnant women who are carrying male fetuses, and peripubertal males" noting that the alternatives were to look for non-DEHP exposure solutions.

[edit] Metabolism

DEHP hydrolyzes to MEHP (mono-ethylhexyl phthalate) and subsequently to phthalate salts. The released alcohol is susceptible to oxidation to the aldehyde and carboxylic acid.[1]

[edit] Toxicity

The acute toxicity of DEHP is 30g/kg in rats (oral) and 24g/kg in rabbits (dermal).[1] Concerns instead focus on its potential as an endocrine disruptor. The European Commission has banned the use of DEHP and some other phthalates in PVC toys.

[edit] References

  1. ^ a b c d Peter M. Lorz, Friedrich K. Towae, Walter Enke, Rudolf Jäckh, Naresh Bhargava, Wolfgang Hillesheim "Phthalic Acid and Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH: Weinheim, 2002.


[edit] External links