2. Acetone
2-propanone 67–64–1 CAS NUMBER C3H6O MOLECULAR FORMULA 58.1 g/mol MOLAR MASS C(62.0%) H(10.4%) O(27.6%) COMPOSITION –94.9°C MELTING POINT 56.3°C BOILING POINT DENSITY 0.79 g/cm3 CHEMICAL NAME
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Acetone is a flammable, colorless liquid with a pleasant odor. It is used widely as an organic solvent and in the chemical industry. It is the simplest ketone, which also goes by the name dimethyl ketone (DMK). Acetone was originally referred to as pyroacetic spirit because it was obtained from the destructive distillation of acetates and acetic acid. Its formula was correctly determined in 1832 by Justus von Liebig (1803–1873) and Jean-Baptiste Jean-Baptiste André Dumas (1800– 1884). In 1839, the name acetone began to be used. Acetone was derived by adding the ending “one” meaning “daughter of” to the root of acetum (acetic acid) to mean daughter of acetum because it was obtained from acetic acid. Te traditional method of producing acetone in the 19th century and the beginning of the 20th century was to distill acetates, particularly calcium acetate, Ca(C 2H3O2)2. World War I placed an increase demand on England to produce gunpowder, explosives, and propellants such as cordite. Cordite is a propellant made using nitroglycerin and nitrocellulose, and nitrocellulose is a principal component of smokeless gunpowder. gunpowder. Cordite is made by dissolving nitrocellulose in acetone, mixing it with nitroglycerin, then baking off the acetone. One of England’s suppliers of calcium acetate before the war was Germany, and the loss of this source and lack of other sources because of German blockades meant that it was imperative to find another source of acetone. One of these was from the fermentation of sugars. One of England’s leading scientists working on bacterial fermentation was Chaim Weizmann (1874–1952), a Russian-born Jew who was a professor at Manchester University. Weizmann had been working on methods to make butyl alcohol in order to produce synthetic rubber.
Acetone
Weizmann discovered a process to produce butyl alcohol and acetone from the bacterium Clostridium acetobutylicum in 1914. With England’s urgent demand for acetone, Winston Churchill (1874–1965) enlisted Weizmann to develop the Weizmann process for acetone production on an industrial scale. Large industrial plants were established in Canada, India, and the United States to provide the allies with acetone for munitions. Weizmann, who is considered the “father of industrial fermentation,” obtained significant status from his war contributions and used this to further his political mission of establishing a Jewish homeland. Weizmann was a leader of the Zionist movement and campaigned aggressively until the nation of Israel was established in 1948. He was the first president of Israel. Fermentation and distillation techniques for acetone production were replaced starting in the 1950s with the cumene oxidation process (Figure 2.1). In this process, cumene is oxidized to cumene hydroperoxide, which is then decomposed using acid to acetone and phenol. Tis is the primary method used to produce phenol, and acetone is produced as a co-product in the process, with a yield of about 0.6:1 of acetone to phenol.
Figure 2.1 Acetone production using cumene.
Acetone can also be produced from isopropanol using several methods, but the main method is by catalytic dehydrogenation:
Catalytic dehydrogenation
Acetone is used in the chemical industry in numerous applications. Its annual use in the United States approaches 2 million tons and worldwide its use is close to 5 million tons. Te primary use of acetone is to produce acetone cyanohydrin, which is then used in the production of methyl methacrylate (MMA). MMA polymerizes to polymethyl methacrylate. MMA is used in a variety of applications involving plastics and resins. It is used extensively in the production of skylights, Plexiglas, outdoor advertising signs, building panels, and light fixtures. It is also incorporated into paints, lacquers, enamels, and coatings. Another use of acetone in the chemical industry is for bisphenol A (BPA). BPA results form the condensation reaction of acetone and phenol in the presence of an appropriate catalyst. BPA is used in polycarbonate plastics, polyurethanes, and epoxy resins. Polycarbonate plastics are tough and durable and are often used as a glass substitute. Eyeglasses, safety glasses, and varieties of bullet-proof “glass” are made of polycarbonates. Additional
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Te 100 Most Important Chemical Compounds
uses include beverage and food containers, helmets (bicycle, motorcycle), compact discs, and DVDs.
In addition to its use as a chemical feedstock and intermediate, acetone is used extensively as an organic solvent in lacquers, varnishes, pharmaceuticals, and cosmetics. Nail polish remover is one of the most common products containing acetone. Acetone is used to stabilize acetylene for transport (see Acetylene). Acetone and several other ketones are produced naturally in the liver as a result of fat metabolism. Ketone blood levels are typically around 0.001%. Te lack of carbohydrates in a person’s diet results in greater fat metabolism, causing ketone levels in the blood to increase. Tis condition is called ketosis. People on low-carbohydrate diets and diabetics may have problems with ketosis because of a greater amount of fat in the diet. An indicator of ketosis is the smell of acetone on a person’s breath.
