Bis(2-ethylhexyl) phthalate

BEHP/DEHP/DOP
Chemical name	Bis(2-ethylhexyl)phthalate (BEHP)
Chemical formula	C₂₄H₃₈O₄
Molecular mass	390.56
Melting point	-50°C
Boiling point	385°C
Density	0.986 (Water=1)
CAS number	117-81-7
SMILES	O=C(OCC(CC)CCCC) C1=CC=CC=C1C (OCC(CC)CCCC)=O

Bis(2-ethylhexyl)phthalate (also BEHP, di-2-ethyl hexyl phthalate, DEHP, or dioctyl phthalate, DOP) is a phthalate , a branched-chain 2-ethylhexanol diester of phthalic acid. At normal temperature, it is a liquid with the viscosity similar to vegetable oil. It is soluble in oil, saliva, plasma, but not in water. It possesses good plasticizing efficiency, fusion rate and viscosity.

Trade names

DEHP comes under many trade names; several are Bisoflex 81, Bisoflex DOP, Compound 889, DAF 68, Eviplast 80, Eviplast 81, Fleximel, Flexol DOP, Hatcol DOP, Kodaflex DOP, Reomol DOP, Sicol 150, Staflex DOP, Truflex DOP, Union Carbide Flexol 380, Vestinol AH, Viniciser 80, Witcizer 312.

Use

Due to its low cost, DEHP is widely used as a plasticizer in manufacturing of PVC. 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.

Environmental exposure

DEHP is slowly released into the air from finished plastic, posing health risks (see outgassing). It can be absorbed form 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. It has low water solubility, therefore leaching from disposed plastics in landfills is generally slow.

The EPA limit for DEHP in drinking water is 6 ppb. OSHA limit for occupational exposure is 5 mg/m³ of air.

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. DEHP leaches out into the fluid or air and is transported into the patient. Certain populations seem to be particularly at risk for DEHP exposure, namely newborns in [[Neonatal intensive care unit| intensive care nursery]] settings, hemophiliacs, and kidney dialysis patients.

Metabolism

The metabolism of DEHP depends on several factors, including age, and route of absorption. Oral DEHP is preferentially hydrolyzed to MEHP (mono-ethylhexyl phthalate).

Toxicity

While DEPH has a low lethal toxicity, it affects certain organs at low concentration, specifically the reproductive organs (testis and ovary), lungs, kidney, and liver. Studies show that it crosses the placenta and is embryotoxic. DEHP can also be found in breast milk. DEHP does not absorb easily through skin, therefore contact with DEHP-containing products is not likely to be harmful.

DEHP is an peroxisome inducer and as such can lead to liver neoplasm in rodents, however there appear to be no data to link it to cancer in humans directly. DEHP in small amounts commonly present in environment is not considered harmful.

Risk Reduction and alternatives

The American Academy of Pediatrics has advocated not to use medical devices that can leach DEPH into patients and , instead, to resort to DEHP-free alternatives. A number of hospitals have taken a lead to reduce or eliminate DEHP containing medical devices.

The European Commission has banned the use of DEHP and other phthalates in PVC toys and indoor products.

References

External links

FDA Public Health Notification: PVC devices containing the plasticizer DEHP
ATSDR ToxFAQs
National Pollutant Inventory - Bis 2 ethylhexyl phthalate fact sheet
Eco-USA
DEHP Information Centre (pro-DEHP, industry-backed group)

Aromatic compounds | Carboxylate esters | Solvents | Plasticizers

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