2-イソプロピルナフタレン

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.

The following wastewater treatment technology has been investigated for naphthalene: Biological treatment. /Naphthalene/

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 9,000(SRC), determined from a structure estimation method(2), indicates that 2-isopropylnaphthalene is expected to be immobile in soil(SRC). Volatilization of 2-isopropylnaphthalene from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 8.5X10-4 atm-cu m/mole(SRC), using a fragment constant estimation method(3). However, adsorption to soil is expected to attenuate volatilization(SRC). 2-Isopropylnaphthalene is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 5.18X10-3 mm Hg(4). 2-Isopropylnaphthalene may degrade in the soil environment based on MITI test data using analogous 1- and 2-methylnaphthalenes(5).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 9,000(SRC), determined from a structure estimation method(2), indicates that 2-isopropylnaphthalene 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 8.5X10-4 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 5 hrs and 5 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 78 days if adsorption is considered(5). According to a classification scheme(6), an estimated BCF of 730(SRC), from an estimated log Kow of 4.6(7) and a regression-derived equation(8), suggests the potential for bioconcentration in aquatic organisms is high(SRC). Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions(9). 2-Isopropylnaphthalene may degrade in the aquatic environment based on MITI test data using analogous 1- and 2-methylnaphthalenes; using a freshwater inoculum, 49% and 72% for 1- and 2-methylnaphthalene, respectively, was lost in 28 days under aerobic conditions at 25 °C(10).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2-isopropylnaphthalene, which has a vapor pressure of 5.18X10-3 mm Hg at 25 °C(2), is expected to exist primarily as a vapor in the ambient atmosphere. Vapor-phase 2-isopropylnaphthalene 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 7 hrs(SRC), calculated from its rate constant of 5.4X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Based upon aqueous photolysis data(4), 2-isopropylnaphthalene may undergo direct photolysis in the atmosphere.

Using a structure estimation method based on molecular connectivity indices(1), the Koc for 2-isopropylnaphthalene can be estimated to be 9,000(SRC). According to a classification scheme(2), this estimated Koc value suggests that 2-isopropylnaphthalene is expected to be immobile in soil.

AEROBIC: 2-Isopropylnaphthalene may degrade in the environment based on data from analogous 1- and 2-methylnaphthalenes(1). Less than 5% and 5% degradation of 1- and 2-methylnaphthalene, respectively, occurred in 28 days using the Japanese MITI I procedure; however, for the MITI II test with a freshwater inoculum, 49% and 72% for 1- and 2-methylnaphthalene, respectively, was lost in 28 days under aerobic conditions at 25 °C(1).

SEDIMENT: 2-Isopropylnaphthalene was detected in sediment samples at a concn of 50 ng/g dry wt(1) 400 m downstream from a discharge of produced water at midchannel at Pass Fourchon, LA(1). Produced water is a complex chemical mixture that can contain petroleum organics, heavy metals, radionuclides, treating chemicals, salts, and dissolved nonvolatile organic matter of unknown chemical composition at concns as high as 750 mg C/L, and is generated as a result of petroleum production(2).

An estimated BCF of 730 was calculated for 2-isopropylnaphthalene(SRC), using an estimated log Kow of 4.6(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is high(SRC). However, using a bioaccumulation study, 2-isopropylnaphthalene was not detected in oyster tissue samples following a 14 day exposure to 2-isopropylnaphthalene-contaminated sediment (concn of <10 ng/g dry wt) collected near Port Lachon, LA(4).

The Henry's Law constant for 2-isopropylnaphthalene is estimated as 8.5X10-4 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that 2-isopropylnaphthalene 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 5 hours(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 5 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 78 days when adsorption is considered(3). 2-Isopropylnaphthalene is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 5.18X10-3 mm Hg(4).

/LABORATORY ANIMALS: Acute Exposure/ Pulmonary toxicity of 2-isopropylnaphthalene (2-IPN) and its photoproducts was studied in mice. Twenty-four hr after the intraperitoneal injection of 2-IPN or its photoproducts, 2-isopropenylnaphthalene (2-IPeN) (1000 mg/kg), 2-acetonaphthone (2-AN) (700 mg/kg), beta-naphthol (BN) (50 mg/kg), phthalide (PH) (500 mg/kg) and phthalic acid (PA) (100 mg/kg) produced pulmonary damage, but 2-IPN (3000 mg/kg) and 2-(2-naphthyl)-2-propanol (2-NP) (100 mg/kg) did not produce pulmonary damage. The maximum levels of 2-IPN in the lung, liver and kidney were observed 6 hr after the administration, and then the levels decreased with time. The concentrations of 2-IPeN, 2-NP, 2-AN, BN, PH and PA in the tissues, reached the maximum levels within 1 or 2 hr, and then rapidly decreased with time. The binding of both 2-AN and BN to lung slices was greater than that of other compounds. The injections of 2-IPN, 2-IPeN, BN and PH caused considerable depletion of pulmonary GSH (reduced glutathione).

/LABORATORY ANIMALS: Acute Exposure/ Pulmonary toxicity of naphthalene (NAP), 2-methylnaphthalene (2-MN), 2-isopropylnaphthalene (2-IPN) and 2,6-diisopropylnaphthalene (2,6-DIPN) was studied in mice. Twenty four hr after the intraperitoneal (i.p.) administration of NAP (200 mg/kg (1.6 mmol] or 2-MN (400 mg/kg (2.8 mmol], pulmonary damage was detected. Prior treatment with diethyl maleate resulted in enhancement of NAP and 2-MN-induced bronchiolar damage. In contrast to the effects of NAP and 2-MN, injections of 2-IPN (3000 mg (17.6 mmol)/kg) and 2,6-DIPN (3000 mg (14.2 mmol)/kg) did not cause detectable pulmonary damage. Injections of NAP and 2-MN caused considerable depletion of pulmonary reduced glutathione (GSH), while injections of 2-IPN and 2,6-DIPN caused only a slight depletion. There were general decreases in the binding of the compounds to lung slices with increasing number of carbons of the alkyl substituent. Pretreatment with a cytochrome P-450 inducer (beta-naphthoflavone) increased the binding of NAP, 2-MN, and 2-IPN to lung slices. Treatments with NAP, 2-MN, 2-IPN and 2,6-DIPN did not affect the lipid peroxidation or phospholipid contents in the lung. These results suggest that the difference in pulmonary toxicity among NAP, 2-MN, 2-IPN, and 2,6-DIPN may be dependent on the ability of these compounds to irreversibly bind to lung tissue.

The rate constant for the vapor-phase reaction of 2-isopropylnaphthalene with photochemically-produced hydroxyl radicals has been estimated as 5.3X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 7 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions(2). The rate constant for the direct photolysis of 2-isopropylnaphthalene in a pyrex beaker of distilled water maintained at 20 °C and exposed to a 100W mercury lamp for 96 hours was measured to be 0.31 hr-1; which corresponds to a half-life of about 22.3 hours(3).

Occupational exposure to 2-isopropylnaphthalene may occur through inhalation and dermal contact with this compound at workplaces where 2-isopropylnaphthalene is produced or used. Monitoring data indicate that the general population may be exposed to 2-isopropylnaphthalene via ingestion of contaminated drinking water and recreational activities on contaminated waterways. (SRC)

This action promulgates standards of performance for equipment leaks of Volatile Organic Compounds (VOC) in the Synthetic Organic Chemical Manufacturing Industry (SOCMI). The intended effect of these standards is to require all newly constructed, modified, and reconstructed SOCMI process units to use the best demonstrated system of continuous emission reduction for equipment leaks of VOC, considering costs, non air quality health and environmental impact and energy requirements. Alkyl naphthalenes is produced, as an intermediate or a final product, by process units covered under this subpart. /Alkyl Naphthalenes/

Used in solvents and as an organic intermediate; [HSDB]

Organic intermediate.

2-Isopropylnaphthalene is contained in solvents and used as a chemical intermediate.