Isophorone
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| Names | |
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IUPAC name
3,5,5-Trimethyl-2-cyclohexene-1-one
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| Other names
1,1,3-Trimethyl-3-cyclohexene-5-one
Isoforone Isoacetophorone IP |
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| Identifiers | |
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3D model (Jmol)
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| ChemSpider | |
| ECHA InfoCard | 100.001.024 |
| EC Number | 201-126-0 |
| KEGG | |
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PubChem CID
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| Properties | |
| C9H14O | |
| Molar mass | 138.21 g·mol−1 |
| Appearance | Colorless to white liquid |
| Odor | Peppermint-like |
| Density | 0.9255 g/cm3 |
| Melting point | −8.1 °C (17.4 °F; 265.0 K) |
| Boiling point | 215.32 °C (419.58 °F; 488.47 K) |
| 1.2 g/100 mL | |
| Solubility | ether, acetone, hexane, dichloromethane, benzene, toluene, alcohol |
| Vapor pressure | 0.3 mmHg (20°C) |
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Refractive index (nD)
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1.4766 |
| Viscosity | 2.62 cP |
| Thermochemistry | |
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Std enthalpy of
formation (ΔfH |
43.4 kJ/mol |
| Hazards | |
| Flash point | 84 °C (183 °F; 357 K) |
| 460 °C (860 °F; 733 K) | |
| Explosive limits | 0.8%-3.8% |
| Lethal dose or concentration (LD, LC): | |
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LD50 (median dose)
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2280 mg/kg (rat, oral) 2330 mg/kg (rat, oral) 2690 mg/kg (mouse, oral) |
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LC50 (median concentration)
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4600 ppm (guinea pig, 8 hr) |
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LCLo (lowest published)
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885 ppm (rat, 6 hr) 1840 ppm (rat, 4 hr) |
| US health exposure limits (NIOSH): | |
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PEL (Permissible)
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TWA 25 ppm (140 mg/m3) |
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REL (Recommended)
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TWA 4 ppm (23 mg/m3) |
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IDLH (Immediate danger)
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200 ppm |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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 (what is   ?) |
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| Infobox references | |
Isophorone is an α,β-unsaturated cyclic ketone, a colorless to yellowish liquid with a characteristic peppermint-like smell. It is used as a solvent and as an intermediate in organic synthesis.
Isophorone is an α,β-unsaturated cyclic ketone (C9H14O). Isophorone can be degraded via a reaction with hydroxyl radicals which are formed via . The half-life of the reaction is about five hours.
Isophorone is not naturally available. Various techniques are available for obtaining isophorone. The most common and used method includes an self-condensation of acetone with KOH. For this reaction a dehydrogenated acetone allows one of the side faced carbon atoms to attack the central carbon atom (the carbonyl carbon) of another acetone molecule. Hereby a diacetone alcohol (4-hydroxy-4-methylpentan-2-one)(1) forms. A follow up dehydration reaction of diacetone alcohol yields (mesityl oxide)(2) and the rest product, water. Dehydrogenated acetone is then able to further react via an addition reaction with mesityl oxide (Michael reaction) to 4,4-dimethyl-2,6-dioxoheptan-1-ide (3), which successively attacks its own carbonyl carbon to form 3-hydroxy-3,5,5-trimethylcyclohexan-1-one(4). Finally a dehydration reaction of 3-hydroxy-3,5,5-trimethylcyclohexan-1-one forms isophorone.
For this reaction to occur in liquid phase mostly the catalyst magnesium aluminium double oxide is used. The magnesium aluminium double oxide has the following formula: Mg1-x Alx O1+x. Obtaining this molecule requires a, for example calcining hydrotalcites at temperatures lower than 800 °C. For the synthesis of isophorone to occur at vapor phase, the self-condensation reaction of acetone is carried out at temperatures above 200 °C.
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