2-(Cyclohexylthio)-1H-isoindole-1,3(2H)-dione

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.

LC50 Lepomis macrochirus (Bluegill sunfish, standard length 3.8 cm) 1.5 mg/L/24 hr; 1.2 mg/L/48 hr, 96 hr; static, temperature 22 °C, dissolved oxygen 0.4-8.3 mg/L, pH 6.8-7.3, water hardness (CaCO3) 255 ppm.

LC50 Oncorhynchus mykiss (Rainbow trout, standard length 2.7 cm) 0.47 mg/L/24 hr; 0.42 mg/L/48 hr; 0.41 mg/L/96 hr; static, temperature 12 °C, dissolved oxygen 5.2-9.8 mg/L, pH 7.2-7.6, water hardness (CaCO3) 255 ppm.

LC50 Pimephales promelas (Fathead minnow, standard weight 0.56 g, standard length 29.3 mm) 0.43 mg/L/24 hr; 0.42 mg/L/192 hr; 0.40 mg/L/240 hr; 0.39 mg/L/336 hr; flow-through, temperature 22 °C, dissolved oxygen 9.3 mg/L, pH 7.7, water hardness (CaCO3) 250 mg/L, alkalinity 360 mg/L

LC50 Paratanytarsus parthenogenetica (Midge, 3rd and 4th instar larvae, 8-10 days old) 130 mg/L/48 hr; static, temperature 20 °C, dissolved oxygen 8.9 to 7.9 mg/L, pH 7.9 to 8.3, water hardness (CaCO3) 255 ppm.

For more Ecotoxicity Values (Complete) data for N-(CYCLOHEXYLTHIO)PHTHALIMIDE (6 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 2,300(SRC), determined from a log Kow of 3.66(2) and a regression-derived equation(3), indicates that N-(cyclohexylthio)phthalimide is expected to have slight mobility in soil(SRC). Volatilization of N-(cyclohexylthio)phthalimide from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 6.4X10-8 atm-cu m/mole(SRC), determined using a fragment constant estimation method(4). N-(Cyclohexylthio)phthalimide would be expected to hydrolyze in moist soil(SRC), based on a reported hydrolysis half-life of 23.3 hours at pH 7 and 25 °C(2). N-(Cyclohexylthio)phthalimide is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 3.8X10-8 mm Hg(SRC), determined from a fragment constant method(5). Screening tests(2) suggest that biodegradation of N-(cyclohexylthio)phthalimide under environmental condition may be slow(SRC). Soil microorganisms were found to not colonize on N-(cyclohexylthio)phthalimide in experiments using soil burial techniques(6).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 2,300(SRC), determined from a log Kow of 3.66(2) and a regression-derived equation(3), indicates that N-(cyclohexylthio)phthalimide is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 6.4X10-8 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). According to a classification scheme(5), an estimated BCF of 130(SRC), from a log Kow of 3.66(2) and a regression-derived equation(6), suggests the potential for bioconcentration in aquatic organisms is high; however, N-(cyclohexylthio)phthalimide is expected to undergo rapid hydrolysis in aquatic environments(2). A hydrolysis half-life of 23.3 hours at pH 7 and 25 °C has been reported for N-(cyclohexylthio)phthalimide(2). Screening tests(2) suggest that biodegradation of N-(cyclohexylthio)phthalimide under environmental conditions may be slow(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), N-(cyclohexylthio)phthalimide, which has an estimated vapor pressure of 3.8X10-8 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase N-(cyclohexylthio)phthalimide may be removed from the air by wet and dry deposition(SRC).

The Koc of N-(cyclohexylthio)phthalimide is estimated as 2,300(SRC), using a log Kow of 3.66(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that N-(cyclohexylthio)phthalimide is expected to have slight mobility in soil. N-(Cyclohexylthio)phthalimide would be expected to hydrolyze in moist soil; a hydrolysis half-life of 23.3 hours at pH 7 and 25 °C has been reported for N-(cyclohexylthio)phthalimide(1).

/HUMAN EXPOSURE STUDIES/ Patches 1 inch square of /compounded, uncured rubber stock containing 2 pounds PVI per 100 pounds rubber (2 phr)/ were applied to the skin of 53 human volunteers and left in place for 24 hours. Readings were taken at the end of 24 hours, and the sites were rested for an additional 24 hours. Patches were reapplied and read again after 24 hours. Fifteen such applications were used. A 10-day rest period followed, and then the challenge application was applied for 24 hours. No positive reactions were observed following the initial application, any subsequent application or after the challenge application. Only mild cumulative irritation was observed in this study. The level used in this study, 2 parts per hundred rubber (2 phr) is about five times higher than what is normally used in compounded rubber stocks.

/HUMAN EXPOSURE STUDIES/ The test material was applied to an adhesive patch so as to cover approximately 1 square inch. The patch was applied to the upper arm or back of 55 human volunteers. After 24 hours, the patch was removed and the application site examined for reactions. After a 24-hr rest period, the patch was applied as before. When 8 such applications had been completed, a 2 wk rest period was allowed, after which a challenge application was made in the same manner as before. All applications were made to the same site. Evidence of primary irritation was observed in 10 of the 67 subjects following the initial application. During the subsequent serial applications, severe irritation was observed in 43 of the 67 subjects. Under the conditions of this test, Santogard PVI was considered to be a primary and cumulative skin irritant, as well as a sensitizer.

/HUMAN EXPOSURE STUDIES/ In a survey of 310 subjects patch tested with a series of 30 different rubber additives over a 4-yr period, 11 subjects (3.5%) showed an allergic reaction to CTP, N- (cyclohexylthio)phthalimide. Four of the CTP-sensitive patients reacted only to CTP, while the other seven reacted to other rubber chemicals as well. The authors concluded that CTP does not appear to cross-react with other rubber chemicals.

/OTHER TOXICITY INFORMATION/ Complaints of body odor following exposure have been received from production workers at two PVI manufacturing facilities. Workers reported the persistence of odor for several days after cessation of the exposure.

For more Human Toxicity Excerpts (Complete) data for N-(CYCLOHEXYLTHIO)PHTHALIMIDE (6 total), please visit the HSDB record page.

Soil microorganisms were found to not colonize on N-(cyclohexylthio)phthalimide in experiments using soil burial techniques(1). N-(Cyclohexylthio)phthalimide was found to degrade 99%+ after 160 hours in a semi-continuous activated sludge test (primary biodegradation) using adapted sewage(2). Ultimate biodegradation by a shake flask test showed 3.4% of the theoretical CO2 evolution after 32 days(2). N-(Cyclohexylthio)phthalimide was found to inhibit nitrification in wastewater(3).

An estimated BCF of 130 was calculated for N-(cyclohexylthio)phthalimide(SRC), using a log Kow of 3.66(4) 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, N-(cyclohexylthio)phthalimide is expected to undergo rapid hydrolysis in aquatic environments(4). A hydrolysis half-life of 23.3 hours at pH 7 and 25 °C has been reported for N-(cyclohexylthio)phthalimide(4).

The Henry's Law constant for N-(cyclohexylthio)phthalimide is estimated as 6.4X10-8 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that N-(cyclohexylthio)phthalimide is expected to be essentially nonvolatile from water surfaces(2). N-(Cyclohexylthio)phthalimide is not expected to volatilize from moist soil surfaces based on its estimated Henry's Law constant(SRC). N-(Cyclohexylthio)phthalimide would be expected to hydrolyze in moist soil and in water; a hydrolysis half-life of 23.3 hours at pH 7 and 25 °C has been reported for N-(cyclohexylthio)phthalimide(3). N-(Cyclohexylthio)phthalimide is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 3.8X10-8 mm Hg(SRC), determined from a fragment constant method(4).

/LABORATORY ANIMALS: Acute Exposure/ Four groups of male and female /Sprague-Dawley albino/ rats (5/sex/dose level) were fed a single oral dose of the test article as a 20% suspension in corn oil via oral gavage. /Doses administered were 1580, 2000, 2510 or 3160 mg/kg bw./ Male rats had initial body weights of 220-250 grams: females had initial body weights of 215-230 grams. Clinical signs of toxicity included reduced activity and appetite for 2-3 days for survivors, and increasing weakness, collapse and death for decedents in 1-3 days. Gross autopsy findings on decedents were hemorrhagic areas of the lungs, liver discoloration, and gastrointestinal inflammation. Survivors were sacrificed after a 14-day observation period. All viscera appeared normal in these animals.

/LABORATORY ANIMALS: Acute Exposure/ 0.5 grams of the test substance (from five different lots manufactured over a two-month period) as a finely ground powder moistened with water, was applied to the shaved dorsal areas of 6 /New Zealand/ albino rabbits. The test material was applied to the skin under 1 inch square gauze patches and held in contact with the skin by means of an occlusive wrap of latex rubber secured by bandaging and elastic tape. The occlusive wrap and gauze patches were removed after 24 hours. Dermal irritation was scored by the Draize Method, and results were recorded 24, 48, 72 and 168 hours after topical application. The Primary Irritation Index was calculated by averaging the mean scores at 24 and 72 hours. The Primary Irritation Index ranged from 0.1-0.8 on a scale of 0.0-8.0. Non-irritating.

/LABORATORY ANIMALS: Acute Exposure/ 70-80 mg of the test substance (from five different lots manufactured over a two-month period) as a finely ground powder was applied to 1 eye of 6 /New Zealand/ albino rabbits. The other eye was not treated and served as a control. The cornea, iris and conjuntivea were examined immediately after treatment, and then at intervals of 10 minutes, 1 hr, and at 24, 48, 72 and 168 hours, and then again at 10 and 21 days. The Draize Method was used for scoring eye irritation. Findings: Immediate: Moderate discomfort, eyes tightly closed 10 minutes: Moderate erythema, very slight edema, copious discharge; 1 hr: Iris reaction to light sluggish, severe erythema, slight to moderate edema, copious discharge 24 hours: Areas of barely perceptible corneal dullness, iris reaction to light sluggish, severe erythema (necrosis), slight edema, copious discharge containing much whitish discharge (with blood); 48-168 hours: Gradual improvement. Very slight ulceration in some animals; 10 days: Slight ulceration in a few animals; 21 days: Slight ulceration in 1-2 animals, other scored "0". The average Draize score for 24, 48 and 72 hours was calculated for each animal and then averaged over the 6 animals. The Draize scores ranged from 22.3-24.6 on a scale from 0-110.0. Mildly irritating.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ In a 30-day range-finding study..., the test substance was administered orally, via dietary admixture, to groups of 6-wk old CD male and female rats (5/sex/group). /Doses administered were 0, 50, 150, 300, 600 or 1500 ppm./ Control animals received the standard laboratory diet. Physical observations, body weight and food consumption measurements were performed on all animals pretest and at selected intervals during the study. Hematology and chemistry determinations were performed on all animals at study termination. There were no mortalities during the course of the study. After four weeks of treatment, all animals were sacrificed, selected organs were weighed, and organ/body weight ratios were calculated. Complete postmortem examinations were conducted on all animals. ...Differences from control in mean body weights were statistically significant at 600 ppm and 1500 for both males and females. The reduced body weights were the only treatment-related effects observed.

A hydrolysis half-life of 23.3 hours at pH 7 and 25 °C has been reported for N-(cyclohexylthio)phthalimide(1). The primary hydrolysis product was identified as the carboxylic acid (ring-opened half-acid) derivative of the parent compound(1). N-(Cyclohexylthio)phthalimide is not expected to be susceptible to direct photolysis by sunlight, since a related compound, 1H-isoindole-1,3(2H)-dione, does not absorb light with wavelengths >290 nm(2).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 18,053 workers (3,410 of these are female) are potentially exposed to N-(cyclohexylthio)phthalimide in the US(1). Occupational exposure to N-(cyclohexylthio)phthalimide may occur through inhalation and dermal contact with this compound at workplaces where N-(cyclohexylthio)phthalimide is produced or used(SRC). Exposure of the general population to N-(cyclohexylthio)phthalimide is not expected, since during the rubber vulcanization process N-(cyclohexylthio)phthalimide reacts and becomes polymer bound(2). N-(Cyclohexylthio)phthalimide is not used in rubber gloves, food containers or other food-contact applications, children's toys, pacifiers, baby bottle nipples, elastic, adhesives or medicals device applications(2).