Butyl-2-ethylhexylphthalat

Phthalate esters are soluble to various extents in many common organic solvents and oils, but have a relatively low solubility in water. /Phthalate esters/

Slightly soluble in water

0.0000236 [mmHg]

Vapor pressures for phthalate esters are extremely low, contributing much to their thermal stability in plastics. /Phthalate esters/

Phthalate esters would be expected to have UV maxima in the 230 nm and 270 nm regions. /Phthalate esters/

... Resistance to migration from polymers, low temperature flexibility ... compatibility with polar polymers and additives over a wide range of compositions. /Phthalate esters/

Nat'l Research Council Canada; Phthalate Esters in the Aquatic Environment (1980) NRCC No. 17583

USEPA; Ambient Water Quality Criteria Doc: Phthalate Esters (1980) EPA 440/5-80-067

Woodward KN (ed); Phthalate Esters: Toxicity and Metabolism (1988).

Phthalate Esters; Environ Health Perspect 45: 1-210 (1982)

USEPA/ECAO; Atlas Document for: Phthalate Esters (1980)

Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. 1,2-Benzenedicarboxylic acid, butyl 2-ethylhexyl ester is included on this list. Effective date: 10/4/82; Sunset date: 10/4/92.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

Increased/room/ ventilation and aspiration of vapors and dusts. /Phthalic esters/

SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning.

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1.6X10+4(SRC), determined from a structure estimation method(2), indicates that 2-ethylhexyl butyl phthalate is expected to be immobile in soil(SRC). Volatilization of 2-ethylhexyl butyl phthalate from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 2.1X10-6 atm-cu m/mole(SRC), using a fragment constant estimation method(3). Adsorption to soil is expected to attenuate volatilization(SRC). 2-Ethylhexyl butyl phthalate is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.4X10-6 mm Hg(SRC), determined from a fragment constant method(4). Using an inoculum obtained from soil and sewage sludge, 2-ethylhexyl butyl phthalate underwent >99% primary biodegradation under aerobic conditions in 28 days, and 87% mineralization to CO2 during the same time period(5).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 1.6X10+4(SRC), determined from a structure estimation method(2), indicates that 2-ethylhexyl butyl phthalate is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 2.1X10-6 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 32 and 240 days, respectively(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 50 years if adsorption is considered(5). According to a classification scheme(6), an estimated BCF of 640(SRC), from an estimated log Kow of 6.5(7) and a regression-derived equation(8), suggests the potential for bioconcentration in aquatic organisms is very high(SRC). However, bioconcentration studies on compounds that are structurally similar suggest that bioconcentration may be lower than that indicated by the regression-derived equations due to the ability of aquatic organisms to readily metabolize this class of compounds(9). Hydrolysis is not expected to be an important process(SRC) based on estimated hydrolysis half-lives of 4.2 years and 150 days at pHs 7 and 8, respectively(10). 2-Ethylhexyl butyl phthalate underwent 84.5% biodegradation in a semi-continuous activated sludge test under aerobic conditions in 24 hrs; complete degradation was observed in three days during an activated sludge die-away test under aerobic conditions(11).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2-ethylhexyl butyl phthalate, which has an estimated vapor pressure of 2.4X10-5 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 2-ethylhexyl butyl phthalate is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 25 hours(SRC), calculated from its rate constant of 1.6X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase 2-ethylhexyl butyl phthalate may be removed from the air by wet or dry deposition(SRC). 2-Ethylhexyl butyl phthalate does contain chromophores that absorb at wavelengths >290 nm(4) and therefore may be susceptible to direct photolysis by sunlight(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of 2-ethylhexyl butyl phthalate can be estimated to be 1.6X10+4(SRC). According to a classification scheme(2), this estimated Koc value suggests that 2-ethylhexyl butyl phthalate is expected be immobile in soil.

/SIGNS AND SYMPTOMS/ Since phthalates ... are of very low /acute oral/ toxicity, only hazard of importance in handling ... consists of possible eye, skin and/or mucous membrane irritation from phthalic anhydride, which may occur during synthesis of phthalates. /Phthalates/

AEROBIC: Using an inoculum obtained from soil and sewage sludge, 2-ethylhexyl butyl phthalate underwent >99% primary biodegradation under aerobic conditions in 28 days, and 87% mineralization to CO2 during the same time period(1). 2-Ethylhexyl butyl phthalate underwent 84.5% biodegradation in a semi-continuous activated sludge test under aerobic conditions in 24 hrs, and complete degradation was observed in three days during an activated sludge die-away test under aerobic conditions(2).

An estimated BCF of 640 was calculated in fish for 2-ethylhexyl butyl phthalate(SRC), using an estimated log Kow of 6.5(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is very high(SRC). However, bioconcentration studies on compounds which are structurally similar suggest that bioconcentration may be lower than that indicated by the regression-derived equations due to the ability of aquatic organisms to readily metabolize this class of compounds(4).

The Henry's Law constant for 2-ethylhexyl butyl phthalate is estimated as 2.1X10-6 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that 2-ethylhexyl butyl phthalate is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 32 days(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 240 days(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The volatilization half-life from a model pond is about 50 years when adsorption is considered(3). 2-Ethylhexyl butyl phthalate's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). 2-Ethylhexyl butyl phthalate is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 2.4X10-5 mm Hg(SRC), determined from a fragment constant method(4).

/LABORATORY ANIMALS: Acute Exposure/ Generally, the oral acute toxicity of the phthalates decreases with increasing molecular weight. /Alkyl phthalates/

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ ...The esters may /also/ bring about biochemical and pathological changes in the liver of rats when repeatedly administered orally or by ip. /Phthalic acid esters/

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ ... At high doses when injected ip, the esters can act as teratogenic agents ... in rats. These esters also have an effect upon gonads in rats. /Phthalic acid esters/

/ALTERNATIVE and IN VITRO TESTS/ Primary rat hepatocyte cultures were used to compare the effects of some alkylphthalate esters on peroxisomal enzyme activities and morphology. Linear diesters from methyl to n-octyl and their constituent monoesters, and alcohols were compared with the branched chain 2-ethylhexyl derivatives. Studies with diesters indicated that induction of carnitine acetyltransferase required hydrolysis of the diester. The straight chain phthalates had little effect on hepatic peroxisomes compared with the 2-ethylhexyl ester, and hepatocyte cultures provided a rapid means of comparing the peroxisomal effects of different phthalates. /Alkyl phthalate esters/

The rate constant for the vapor-phase reaction of 2-ethylhexyl butyl phthalate with photochemically-produced hydroxyl radicals has been estimated as 1.6X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 25 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). A base-catalyzed second-order hydrolysis rate constant of 0.053 L/mole-sec(SRC) was estimated using a structure estimation method(2); this corresponds to half-lives of 4.2 years and 150 days at pH values of 7 and 8, respectively(2). 2-Ethylhexyl butyl phthalate does contain chromophores that absorb at wavelengths >290 nm(3) and therefore may be susceptible to direct photolysis by sunlight(SRC).

Occupational exposure to 2-ethylhexyl butyl phthalate may occur through inhalation of aerosols and dermal contact with this compound at workplaces where 2-ethylhexyl butyl phthalate is produced or used. Use data indicate that the general population may be exposed to 2-ethylhexyl butyl phthalate via dermal contact with products containing this compound. (SRC)

Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. 1,2-Benzenedicarboxylic acid, butyl 2-ethylhexyl ester is included on this list. Effective date: 10/4/82; Sunset date: 10/4/92.

The phthalate diesters are rapidly metabolized to the monoester both in the intestine and following absorption. The rate of hydrolysis is greater for the lower molecular weight esters. The monoester may undergo further oxidation of the alcohol side chain, but further hydrolysis is minimal. Suggest that the half hydrolysis of diester substrates is due to the anionic charge of the free carbonyl group inhibiting formation of the enzyme-substrate complex. /Phthalate diesters/

The phthalic acid esters and/or their metabolites are readily absorbed from the intestinal tract, the intraperitoneal cavity, and the lung. There is also evidence indicating that these esters can be absorbed through the skin. The vehicle can play an important role in the absorption, distribution, and elimination of the ester. /Phthalic acid esters/

Absorbed esters of phthalic acid esters (or their metabolites) distribute quite rapidly to various organs and tissues both in animals and humans, especially the liver, kidney, and bile. /Phthalic acid esters/

Pharmacokinetic studies have been performed using ingestion, absorption through skin, and injection. Phthalates were readily taken up, distributed, metabolized, and excreted by all three routes of exposure. /Phthalates/

Used as a plasticizer; [HSDB]

Plasticizer.

1,2-Benzenedicarboxylic acid, butyl 2-ethylhexyl ester is listed as a High Production Volume (HPV) chemical (65FR81686). Chemicals listed as HPV were produced in or imported into the U.S. in >1 million pounds in 1990 and/or 1994. The HPV list is based on the 1990 Inventory Update Rule. (IUR) (40 CFR part 710 subpart B; 51FR21438).

Production volumes for non-confidential chemicals reported under the Inventory Update Rule. [Table#5312]

1,2-Benzenedicarboxylic acid, 1-butyl 2-(2-ethylhexyl) ester: ACTIVE

The alcohol (butyl, octyl, etc) esterified with phthalic anhydride in the presence of a catalyst (sulfuric acid or p-toluenesulfonic acid) or non-catalytically at high temp. The esterification is carried out at ordinary pressure or in a vacuum, the water formed during the reaction being eliminated as it is formed by entrainment by a third component (hydrocarbon or usually the alcohol used in the esterification). The hydrocarbon may be benzene, toluene, or cyclohexane. The reaction can be carried out discontinuously or by a continuous method. /Phthalic esters/