General Description
A clear colorless liquid, with a camphor-like odor. Less dense than water and insoluble in water. Boiling point 420°F. Flash point near 200°F. Contact irritates skin and eyes. Toxic by ingestion. Used as a solvent and in pesticides.
Reactivity Profile
Ketones, such as ISOPHORONE(78-59-1), are reactive with many acids and bases liberating heat and flammable gases (e.g., H2). The amount of heat may be sufficient to start a fire in the unreacted portion of the ketone. Ketones react with reducing agents such as hydrides, alkali metals, and nitrides to produce flammable gas (H2) and heat. Ketones are incompatible with isocyanates, aldehydes, cyanides, peroxides, and anhydrides. They react violently with aldehydes, HNO3, HNO3 + H2O2, and HClO4. Forms explosive peroxides
Air & Water Reactions
Insoluble in water.
Hazard
Irritant to skin and eyes. Possible carcinogen.
Health Hazard
LIQUID: Irritating to skin and eyes. Harmful if swallowed.
Physical properties
Clear, colorless liquid with a sharp peppermint or camphor-like odor. Experimentally determined
detection and recognition odor threshold concentrations were 1.1 mg/m3 (190 ppbv) and 3.0 μg/m3
(530 ppbv), respectively (Hellman and Small, 1974).
Occurrence
Reported found in Burley tobacco, cranberry, macadamia nuts, peas, roasted filbert, saffron, wine, osmanthus,
grapefruit juice, papaya, kohlrabi, Parmesan cheese, roast beef, black tea, oats, Japanese plum, prunes, plumcot, starfruit, mango,
rice, buckwheat, okra and sweet grass oil.
Uses
Isophorone is used as a solvent for vinylresins and cellulose esters, and in pesticides.
Uses
Solvent for lacquers, resins, and
plastics
Uses
Solvent in some printing inks, paints, lacquers and adhesives.
Definition
ChEBI: A cyclic ketone, the structure of which is that of cyclohex-2-en-1-one substituted by methyl groups at positions 3, 5 and 5.
Preparation
Isophorone is produced on a multi-thousand ton scale by the aldol condensation of acetone using KOH. Diacetone alcohol, mesityl oxide, and 3-hydroxy-3,5,5-trimethylcyclohexan-1-one are intermediates. A side product is beta-isophorone, where the C=C group is not conjugated with the ketone.
Aroma threshold values
Detection: 0.20 ppm; aroma characteristics at 1.0%: cooling, woody, camphoraceous, slightly green and
herbal
Taste threshold values
Taste characteristics at 30 ppm: sweet, green, waxy, pungent camphoreous, cooling minty
Flammability and Explosibility
Notclassified
Chemical Reactivity
Reactivity with Water No reaction; Reactivity with Common Materials: No reactions; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
Industrial uses
Isophorone is an excellent solvent for cellulose esters, nitrocellulose, natural and synthetic resins. Isophorone has a very high aromatic hydrocarbon dilution ratio in nitrocellulose formulations: 5.7 for toluene and 5.1 for xylene. The excellent solvency of isophorone allows the preparation of 45% solids nitrocellulose solutions at room temperatures.
Biochem/physiol Actions
Taste at 30 ppm
Synthesis
Isophorone is an intermediate in the synthesis of 3,5-xylenol, 3,3,5-trimethylcyclohexanol
Carcinogenicity
In a 2 year bioassay in rats and
mice (conducted by gavage on a 5- day/week treatment
schedule) at dose levels of 0, 250, and 500 mg/kg/day isophorone, there was decreased survival of male rats and
slight nephrotoxicity in female rats. There was no evidence
of carcinogenicity in female rats or mice. In male rats, there
was an increase in renal tumors in animals given either 250
or 500 mg/kg/day, and a low incidence of preputial gland
tumors at 500 mg/kg. Other proliferative lesions in male rats
included hyperplasia of the renal pelvis and tubular cell
hyperplasia.
Environmental Fate
Biological. The pure culture Aspergillus niger biodegraded isophorone to 3,5,5-trimethyl-2-
cyclo-hexene-1,4-dione, 3,5,5-trimethylcyclohexane-1,4-dione, (S)-4-hydroxy-3,5,5-trimethyl-2-
cyclohex-1-one, and 3-hydroxymethyl-5,5-dimethyl-2-cyclohexen-1-one (Mikami et al., 1981).
Chemical/Physical. At an influent concentration of 1,000 mg/L, treatment with GAC resulted in
an effluent concentration of 34 mg/L. The adsorbability of the carbon used was 193 mg/g carbon
(Guisti et al., 1974).
Isophorone will not hydrolyze in water.
At influent concentrations of 10, 1.0, 0.1, and 0.001 mg/L, the GAC adsorption capacities were
78.3, 32.0, 13.1, and 5.4 mg/g, respectively (Dobbs and Cohen, 1980).
Purification Methods
Wash isophorone with aqueous 5% Na2CO3 and then distil it under reduced pressure immediately before use. Alternatively, it can be purified via the semicarbazone. [Erskine & Waight J Chem Soc 3425 1960, Beilstein 7 IV 165.]
Toxicity evaluation
The toxicological mechanisms of isophorone are not well
characterized. Critical effects include irritation, narcosis,
malaise, fatigue, and CNS depression. Isophorone may induce
its neurological effects by interference with neuronal impulse
transmissions via physical interaction with nerve membrane
components. In animal models, isophorone may also act by
inducing neuropathy, involving binding to globulin proteins,
although this mechanism may not be relevant to humans.
Lesions of the liver have been observed after overexposure in
mouse models, although it is not clear whether isophorone
elicited the lesions directly or by enhancing an age-related
process. DNA-binding studies in mice have shown no significant
covalent binding of isophorone or its metabolites to DNA
from liver or kidney cells, supporting a potential nongenotoxic
mechanism of toxicity.
Toxics Screening Level
The initial threshold screening level (ITSL) for isophorone is 280 μg/m3 (1-hour average).
Waste Disposal
Incineration.
