SPECTRUM

Chemical Fact Sheet

Chemical Abstract Number (CAS #) 78591
CASRN 78-59-1
SynonymsIsophorone
3,5,5-Trimethyl-2-cyclohexenone
Analytical Methods EPA Method 609
EPA Method 625
EPA Method 8270
Molecular FormulaC9H14O

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use SOLVENT FOR LACQUERS & PLASTICS SOLVENT FOR MANY OILS, FATS, GUMS, RESINS, NITROCELLULOSE, & VINYL-RESIN COPOLYMERS CHEM INT FOR 3,3,5-TRIMETHYLCYCLOHEXANOL, & 3,5-XYLENOL; SPECIALTY SOLVENT IN PESTICIDES; STOVING LACQUERS SOLVENT IN ACRYLIC, EPOXY, POLYESTER AND SILICONE RESIN SYSTEMS
Apparent Color WATER-CLEAR LIQ
Odor PEPPERMINT-LIKE ; Camphor-like
Boiling Point 214 DEG C @ 754 MM HG; 99 DEG C @ 18 MM HG
Melting Point -8.1 DEG C
Molecular Weight 138.2
Density 0.9229 AT 20 DEG C
Odor Threshold Concentration Odor detection in air= 2.00 ppm. Purity not specified. Odor recognition in air= 5.40 ppm. Purity not specified. 1 mg/cu m (odor low); 50 mg/cu m (odor high)
Sensitivity Data MEN EXPOSED AT 40, 85, 200 & 400 PPM ISOPHORONE EXPERIENCED EYE, NOSE, AND THROAT IRRITATION.
Environmental Impact Isophorone is used as a solvent for a large number of natural and synthetic polymers, resins, waxes, fats, oils, and pesticides, in addition to being used as a chemical intermediate. As a result this compound may be released to the environment from a wide variety of industries, from the disposal of many different products and during the application of some pesticides. If released to soil or water, isophorone is predicted to be removed partially by volatilization (half-life 7.5 days from a model river) and partially by biodegradation. Potential biodegradation products include: 3,5,5-trimethyl-2-cyclohexene-1,4-dione, 3,5,5-trimethylcyclohexane-1,4-dione, (S)-4-hydroxy-3,5,5-trimethyl-2-cyclohexen-1-one, and 3-hydroxymethyl-5,5-dimethyl-2-cyclhexen-1-one. Potential exists for contamination of groundwater by leaching through soil. Isophorone is not expected to sorb significantly to suspended solids and sediments in water, bioaccumulate significantly in aquatic organisms, photolyze, oxidize by reaction with singlet oxygen or alkyperoxy radicals in water, or undergo chemical hydrolysis. If released to air, isophorone is expected to exist primarily in the vapor phase. Reaction with ozone is expected to be the dominant removal process and reaction with photochemically generated hydroxyl radicals is expected to be of minor importance (overall half-life 32 min). Isophorone emitted to the atmosphere in particulate form may be removed by wet or dry deposition. The most probable route of human exposure to isophorone in the ambient environment is by ingestion of drinking water contaminated with this compound. Worker exposure may occur by inhalation or dermal contact.
Environmental Fate TERRESTRIAL FATE: If released to soil, isophorone may be removed partially by volatilization and partially by biodegradation. AQUATIC FATE: If released to water, isophorone may biodegrade or it may volatilize (half-life 7.5 days from a model river(1,SRC). Results of biodegradation screening studies are conflicting: However, it has been shown that mixed microbial populations are capable of degrading isophorone fairly rapidly. Potential biodegradation products include 3,5,5-trimethyl-2-cyclohexane-1,4-dione, 3,5,5-trimethylcyclohexane-1,4-dione, (S)-4-hydroxyl-3,5,5-trimethyl-2-cyclohexen-1-one and 3-hydroxymethyl-5,5-dimethyl-2-cyclohexen-1-one . Adsorption to suspended solids and sediments, bioacculmulation in aquatic organisms, photolysis, oxidation by reaction with singlet oxygen or alkylperoxy radicals and chemical hydrolysis are not expected to be important fate process in water. ATMOSPHERIC FATE: Based on a vapor pressure of 0.38 mm Hg at 20 deg C, isophorone is expected to exist primarily in the vapor phase in the atmosphere(1,2). Isophorone is predicted to be removed from the atmosphere by reaction with ozone (t/2 39 minutes) and reaction with photochemically generated hydroxyl radicals (t/2 3 hours). The overall half-life for isophorone has been estimated to be 32 minutes . Direct photolysis is not expected to occur. Isophorone emitted to the atmosphere in particulate form may be removed by wet or dry deposition.
Drinking Water Impact SURFACE WATER: USEPA STORET Data Base - 795 water samples, 1% pos., median concn <10.00 ug/l . During Aug 1977 in Delaware River at river mile 106, 108, and 110 isophorone concentration was found to be 3, 0.6 and <0.01 ug/l, respectively . Isophorone was detected in the St. Joseph River and not detected in the Cuyahoga River . USEPA National Urban Runoff Program (NURP) results as of July 1982 indicate that isophorone was found in runoff in 1/19 cities across USA . 10 ug/l was detected in urban runoff of Washington DC . DRINKING WATER: Isophorone identified in finished drinking water from: Cincinnati, OH - Oct 1978 and Jan 1980; Philadelphia, PA - Feb 1976; Ottumwa, IA - Sept 1976; and Seattle, WA - Nov 1976 . During the USEPA 1974 National Organics Reconnaissance Survey (NORS) isophorone was detected in 1/10 finished drinking water supplies . Approximately 0.02 ug/l was found in drinking water from Cincinnati, OH . Trace levels detected in Philadelpha, PA drinking water during Aug 1977 . Detected in drinking water from New Orleans, LA during 1974, max concn 2.9 ug/l . GROUNDWATER: Identified in groundwater in the Netherlands, max concn 10 ug/l . EPA maintains an inventory of organic compounds that have been isolated and identified in drinking water in the USA. Isophorone was detected at concentrations as high as 9.5 ug/l. EFFL: USEPA STORET Data Base - 1272 effluent samples, 1.6% pos, median concn <10.0 ug/l . Isophorone has been found in the treated wastewater from the following industries: iron and steel mfg, 1/5 samples pos, concn 170 ug/l; Coil coating, 5/31 samples pos, max concn 560 ug/l, mean concn 120 ug/l; Foundries, 7/7 samples pos, max concn 28 ug/l, mean concn 12 ug/l; photographic equipment and supplies, 2/4 samples pos, max concn 10 ug/l, mean concn 10 ug/l; paint and ink formulation, 1/1 samples pos, concn <7 ug/l; automobile tire plant, 40 ug/l; and oil shale retorting, 340-5800 ug/l(2,3,4). The influent and effluent of the Philadelphia (PA) Northeast Sewage Treatment plant during Aug 1977 was 100 and 10 ug/l, respectively . Isophorone was also identified as a contaminant (approximate concn, 0.04 mg/l) in the waste water from a tire manufacturing plant. Isophorone has been detected in the effluents from latex and chemical plants in Alabama, but no levels were reported.

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