What Is Acetone?
Acetone is a ketone of the simplest structure, an amphiphilic liquid that is both hydrophilic and hydrophobic.
It is also called dimethyl ketone or 2-propanone. Acetone is classified as a “Class 4 Hazardous Substance, Petroleum No. 1, Water Soluble Liquid” under the Fire Service Law, and is extremely flammable.
It is also classified under the Industrial Safety and Health Law as a “hazardous and noxious substance that should be labeled or notified” and requires the wearing of appropriate protective equipment when handled.
Uses of Acetone
Acetone dissolves a wide variety of organic compounds, and because it is highly volatile and dries easily at room temperature, it is used as a solvent for resins, rubber, fats, paints, dyes, adhesives, acetyl cellulose, nitrocellulose, and many other applications.
Another application that takes advantage of its property of dissolving organic compounds well is the removal of dirt from laboratory equipment. Nail polish remover is another application. Because of its high volatility, acetone is sometimes used to remove water from laboratory equipment after it has been cleaned with water.
Acetone can also be used as a raw material for synthesizing acetic anhydride, methyl methacrylate, bisphenol A, ascorbic acid (vitamin C), chloroform, iodoform, and sulfonal, as well as a stabilizer for acetylene gas.
Properties of Acetone
Acetone is a clear, colorless, volatile liquid with the molecular formula CH3COCH3 and molecular weight of 58.08. It is light, with a specific gravity of 0.791, and can be mixed with water, ethanol, and ether in any proportion. Acetone also has an ethereal odor and an anesthetic effect.
Acetone has a flash point of -21°C and will ignite at room temperature. Its melting point is -93.9°C, boiling point 56.1°C, and ignition point 465~560°C. Due to its high volatility, it is necessary to ventilate the room and be careful of fire when using it.
It has a high affinity for many substances, whether hydrophilic or hydrophobic and dissolves well. Plastics, jewelry, and synthetic fibers may be attacked or discolored if they adhere to surfaces, so care should be taken to protect them beforehand, and if they do adhere, wipe them off immediately.
In addition, when acetone is thermally decomposed at high temperatures, ketene and methane are formed.
Other Information on Acetone
How Acetone Is Produced
Acetone is industrially produced by the Hoechst-Wacker method, which partially oxidizes propylene, or by the Cumene method, which simultaneously synthesizes phenol and acetone from benzene and propylene.
1. Hoechst-Wacker Method
Propylene, air as an oxygen source, and a palladium chloride-copper chloride catalyst solution are mixed in a reaction column and reacted. Propylene is directly oxidized to produce acetone.
The acetone produced is separated from the catalyst solution in the separation column, and then purified and dehydrated in the rectification column to produce the product. The catalyst solution is reduced during the reaction in the reaction column but is sent to the oxidation column where it is reacted with air, oxidized again, and returned to the reaction column.
Oxidation Reaction of Propylene in the Reaction Column and Catalyst Reduction Reaction
CH3CH = CH2 + PdCl2 + H2O → CH3COCH3 + Pd + 2HCl
Pd + 2CuCl2 → PdCl2 + 2CuCl
Catalyst Recycling
2CuCl + 1/2O2 + 2HCl → 2CuCl2 + H2O
2. Cumene Method
Propylene is reacted with benzene using zeolite or phosphoric acid as a catalyst to produce cumene (isopropylbenzene). Cumene is oxidized to yield (cumene hydroperoxide), which is decomposed to yield acetone and Phenol.
Formation of Cumene
CH3CH = CH2 + C6H6 → C6H5-CH(CH3)2
Oxidation of Cumene
C6H5-CH(CH3)2 + O2 → C6H5-C(CH3)2COOH
Decomposition of Cumene Hydroperoxide
C6H5-C(CH3)2COOH → C6H5OH + CH3COCH3