Bis(2-ethylhexyl) phthalate

Description

Bis(2-ethylhexyl) phthalate, known by a variety of other names and usually abbreviated DEHP, was patented in 1950 and first used as vacuum pump oil. But since then, it has become the most widely used plasticizer for poly(vinyl chloride) (PVC) and other plastics. Recently, relatively high levels of DEHP have been found in foods, especially foods high in oils and fats. The U.S. Food and Drug Administration now restricts its use in packaging materials to water-based foods. The European Commission has banned the use of DEHP and other phthalates in PVC toys.

Chemical properties

Bis(2-ethylhexyl)phthalate is a colorless liquid with a slight odor. It is miscible with mineral oil and hexane, and soluble in most organic solvents. Bis(2-ethylhexyl)phthalate is insoluble in water (NTP, 1994a).

The Uses of Bis(2-ethylhexyl) phthalate

Bis(2-ethylhexyl) phthalate (DEHP) is a benzenedicarboxilate ester which is the most widely used plasticizer to soften resins. The U.S. Food and Drug Administration now restricts its use in packaging materials to water-based foods. The European Commission has banned the use of DEHP and other phthalates in PVC toys.

Production Methods

DEHP is commercially produced via esterification of phthalic acid anhydride and 2-ethylhexanol. Esterification is completed with an acid or metal catalyst or with no catalyst at high temperature.

Reactivity Profile

Bis(2-ethylhexyl) phthalate reacts with acids to liberate heat along with alcohols and acids. Strong oxidizing acids may cause a vigorous reaction that is sufficiently exothermic to ignite the reaction products. Heat is also generated by the interaction of esters with caustic solutions. Flammable hydrogen is generated by mixing with alkali metals and hydrides. Incompatible with nitrates .

Health Hazard

The acute oral toxicity is of extremelylow order. The oral LD50 value in miceis in the range 30,000 mg/kg. Ingestion ofabout 10 mL of the liquid may produce gas trointestinal pain, hypermotility, and diar rhea in humans. Chronic administration byoral route did not produce any adverseeffect in animals.

Flammability and Explosibility

Not classified

Chemical Reactivity

Reactivity with Water No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.

Potential Exposure

Bis(2-ethylhexyl)phthalate is primarily used as one of several plasticizers in polyvinyl chloride resins used for fabricating flexible vinyl products. It has also been reported as being used as a replacement for polychlorinated biphenyls (PCBs) in dielectric fluids for electric capacitors and in vacuum pumps (NTP, 1994a; Merck, 1989). The primary stationary sources that have reported emissions of bis(2-ethylhexyl)phthalate in California are furniture and fixtures manufacturing, and lumber and wood products manufacturing (ARB, 1997b).

Carcinogenicity

Bis(2-ethylhexyl) phthalate (DEHP) is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals.

Metabolism

Bis(2-ethylhexyl) phthalate is metabolized in fish by enzymatic hydrolysis to mono-2-ethylhexyl phthalate, phthalic acid, and glucuronides of these compounds (Stalling et al., 1973).

Storage

Bis (2-ethylhexyl)phthalate must be stored to avoid contact with oxidizing materials, such as permanganates, nitrates, peroxides,chlorates, and perchlorates, since violent reactions occur.Store in tightly closed containers in a cool, well-ventilatedarea away from heat.

Shipping

The name of this material is not on the DOT listof materials for label and packaging standards. However,based on regulations, it may be classified as anEnvironmentally hazardous substances, liquid, n.o.s. It fallsin Hazard Class 9 and Packing Group III.[20,21]

Purification Methods

Wash the ester with Na2CO3 solution, then shake it with water. After the resulting emulsion has been broken by adding ether, the ethereal solution is washed twice with water, dried (CaCl2), and evaporated. The residual liquid is distilled several times under reduced pressure, then stored in a vacuum desiccator over P2O5.

Incompatibilities

Nitrates, strong oxidizers, strong acids,strong alkalis.