Collection Scientific terms Electron microscopy
| Acetone[1] | |
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propanone
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other names
β-ketopropane, dimethyl ketone, dimethylformaldehyde, DMK, propanone, 2-propanone, propan-2-one
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| Identifiers | |
| CAS number | 67-64-1  |
| PubChem | 180 |
| ChemSpider | 175 |
| EC-number | 200-662-2 |
| RTECS number | AL31500000 |
| SMILES |
O=C(C)C
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| InChI |
1/C3H6O/c1-3(2)4/h1-2H3
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| InChI key | CSCPPACGZOOCGX-UHFFFAOYAF |
| Properties | |
| Molecular formula | C3H6O |
| Molar mass | 58.08 g mol−1 |
| Appearance | Colorless liquid (white snow-like form when solid) |
| Density | 0.7925 g/cm3 |
| Melting point |
-94.9 °C, 178 K, -139 °F |
| Boiling point |
56.53 °C, 330 K, 134 °F |
| Solubility in water | miscible |
| Acidity (pKa) | 24.2 |
| Refractive index (nD) | 1.35900 (20 °C) |
| Viscosity | 0.3075 cP |
| Structure | |
| Molecular shape | trigonal planar at C=O |
| Dipole moment | 2.91 D |
| Hazards | |
| MSDS | External MSDS |
| EU classification |  F Xi |
| R-phrases | R11, R36, R66, R67 |
| S-phrases | (S2), S9, S16, S26 |
| NFPA 704 |
 3
1
0
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| Flash point | -17 °C |
| Autoignition temperature |
465 °C |
| Explosive limits | 4.0–57.0 |
| Threshold Limit Value | 500 ppm (TWA), 750 ppm (STEL) |
| LD50 | >2000 mg/kg, oral (rat) |
| Related compounds | |
| Related solvents | Water Ethanol Isopropanol Toluene |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| (what is this?) (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Acetone is the organic compound with the formula OC(CH3)2. This colorless, mobile, flammable liquid is the simplest example of the ketones. Owing to the fact that acetone is miscible with water it serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory. More than 3 million tonnes are produced annually, mainly as a precursor to polymers.[2] Familiar household uses of acetone are as the active ingredient in nail polish remover and as paint thinner and sanitary cleaner/nail polish remover base. It is a common building block in organic chemistry. In addition to being manufactured, acetone also occurs naturally, even being biosynthesized in small amounts in the human body.
Contents |
Acetone is produced directly or indirectly from propene. Most commonly, in the cumene process, benzene is alkylated with propene and the resulting cumene (isopropylbenzene) is oxidized to give phenol and acetone:
This conversion entails the intermediacy of cumene hydroperoxide, C6H5C(OOH)(CH3)2.
Acetone is also produced by the direct oxidation of propene with a Pd(II)/Cu(II) catalyst, akin to the Wacker process.
Previously, acetone was produced by the dry distillation of acetates, for example calcium acetate. During World War I acetone was produced via bacterial fermentation, as developed by Chaim Weizmann (later the first president of Israel) in order to help the British war effort.[2] This Acetone Butanol Ethanol process was abandoned due to the small yields.[2]
Small amounts of acetone are produced in the body by the decarboxylation of ketone bodies.
About half of the world's production of acetone is consumed as a precursor to methyl methacrylate. This application begins with the initial conversion of acetone to its cyanohydrin:
In a subsequent step, the nitrile is hydrolyzed to the unsaturated amide, which is esterified:
The second major use of acetone entails its condensation with phenol to give bisphenol A:
Bisphenol-A is a component of many polymers such as polycarbonates, polyurethanes, and epoxy resins.
(CH3)2CO + 4O2 → 3CO2 + 3H2O
Acetone is a good solvent for most plastics and synthetic fibres including those used in laboratory bottles made of polystyrene, polycarbonate and some types of polypropylene.[3] It is ideal for thinning fiberglass resin, cleaning fiberglass tools and dissolving two-part epoxies and superglue before hardening. It is used as a volatile component of some paints and varnishes. As a heavy-duty degreaser, it is useful in the preparation of metal prior to painting; it also thins polyester resins, vinyl and adhesives.
Many millions of kilograms of acetone are consumed in the production of the solvents methyl isobutyl alcohol and methyl isobutyl ketone. These products arise via an initial aldol condensation to give diacetone alcohol.[2]
Acetone is used as a solvent by the pharmaceutical industry and as a denaturation agent in denatured alcohol.[4] Acetone is also present as an excipient in some pharmaceutical products.[5]
Although flammable itself, acetone is also used extensively as a solvent for the safe transporting and storing of acetylene, which cannot be safely pressurized as a pure compound. Vessels containing a porous material are first filled with acetone followed by acetylene, which dissolves into the acetone. One liter of acetone can dissolve around 250 liters of acetylene.[6][7]
In the laboratory, acetone is used as a polar aprotic solvent in a variety of organic reactions, such as SN2 reactions. The use of acetone solvent is also critical for the Jones oxidation. It is a common solvent for rinsing laboratory glassware because of its low cost, volatility, and ability to form a low boiling temperature azeotrope with water[citation needed]. For similar reasons, acetone is also used as a drying agent. Acetone can be cooled with dry ice to -78 °C without freezing; acetone/dry ice baths are commonly used to conduct reactions at low temperatures. Acetone is fluorescent under ultraviolet light, and its vapor may be used as a fluorescent tracer in fluid flow experiments.[8]
Acetone is often the primary component in cleaning agents such as nail polish remover. Ethyl acetate, another organic solvent, is sometimes used as well. Acetone is a component of superglue remover and it easily removes residues from glass and porcelain.
It can be used as an artistic agent; when rubbed on the back of a laser print or photocopy placed face-down on another surface and burnished firmly, the toner of the image transfers to the destination surface.
Some automotive enthusiasts add acetone at around 1 part in 500 to their fuel, following claims of improvement in fuel economy and engine life.[9] Systematic testing has determined that acetone has no measurable effect on fuel economy or may in fact reduce engine life by adversely affecting fuel system parts.[10][11] The effect of acetone on fuel economy was addressed on the popular American TV show MythBusters in 2006, in which they observed a decrease on fuel economy.[12]
The most common hazard associated with acetone is its extreme flammability. It auto-ignites at a temperature of 465 °C (869 °F). At temperatures greater than acetone's flash point of −20 °C (−4 °F), air mixtures of between 2.5% and 12.8% acetone, by volume, may explode or cause a flash fire. Vapors can flow along surfaces to distant ignition sources and flash back. Static discharge may also ignite acetone vapors.[13]
When oxidized, acetone forms acetone peroxide as a byproduct, which is a highly unstable compound. It may be formed accidentally, e.g. when waste hydrogen peroxide is poured into waste solvent containing acetone. Acetone peroxide is more than ten times as friction and shock sensitive as nitroglycerin. Due to its instability, it is rarely used, despite its easy chemical synthesis.
Acetone is believed to exhibit only slight toxicity in normal use, and there is no strong evidence of chronic health effects if basic precautions are followed.[14]
At very high vapor concentrations, acetone is irritating and, like many other solvents, may depress the central nervous system. It is also a severe irritant on contact with eyes, and a potential pulmonary aspiration risk. In one documented case, ingestion of a substantial amount of acetone led to systemic toxicity, although the patient eventually fully recovered.[15] Some sources estimate LD50 for human ingestion at 1.159 g/kg; LD50 inhalation by mice is given as 44 g per cubic meter, over 4 hours.[16]
Acetone has been shown to have anticonvulsant effects in animal models of epilepsy, in the absence of toxicity, when administered in millimolar concentrations.[17] It has been hypothesized that the high-fat low-carbohydrate ketogenic diet used clinically to control drug-resistant epilepsy in children works by elevating acetone in the brain.[17]
Acetone evaporates rapidly, even from water and soil. Once in the atmosphere, it is degraded by UV light with a 22-day half-life. Acetone dissipates slowly in soil, animals, or waterways since it is sometimes consumed by microorganisms,[18] but it is a significant groundwater contaminant due to its high solubility in water. The LD50 of acetone for fish is 8.3 g/l of water (or about 0.8%) over 96 hours, and its environmental half-life is about 1 to 10 days. Acetone may pose a significant risk of oxygen depletion in aquatic systems due to the microbial activity consuming it.[19]
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