What is Acetone?
Acetone is a powerful solvent that is used primarily in industrial and laboratory settings, but is safe enough for household applications such as removing nail polish. Acetone is currently produced from petrochemicals as a co-product of phenol, however there is a rich history of high purity acetone being made from the fermentation of sugars derived from corn and other agricultural products. Unlike alcohols such as ethanol, acetone is a ketone. Ketones are more oxidized (they have less energy content) than alcohols, so they are poor candidates for use in fuel, but this property allows them to dissolve both waterborne and oily residues, making for a more flexible cleaning agent. In addition to its use as a solvent and a cleaner, acetone is used as an intermediate chemical building block for valuable chemicals such as methyl methacrylate (MMA), a high value monomer used in acrylic plastics for applications such as plexiglass in aircraft windows, artificial joints, cement for total knee and total hip replacements, bathroom and kitchen fixtures, and even rocket fuel. Acetone is a global performance chemical with worldwide demand that exceeds 13 billion pounds and can be produced sustainably using renewable resources.
The first industrial production of acetone involved heating calcium acetate crystals to high temperatures until they decomposed. This process was inefficient and produced low purity acetone. In need of higher purity acetone to produce armaments during World War One, the Allies turned to a new technology called ABE (acetone, butanol and ethanol) developed in 1912 to produce high purity acetone from agricultural products using fermentation and clostridia bacteria. The technology played a key role on the battlefields of Europe. By 1927, the industry demand shifted to n-butanol production for use in nitro-cellulosic lacquers for the nascent automobile industry, and ABE technology shifted toward n-butanol production. By the 1940’s, with the advent of new, lower cost petrochemical processes, acetone production shifted to synthetic routes, co-produced with phenol through the cumene hydroperoxidation process. In 1954, the last ABE production facility in the U.S. shut down, and by 1985 the last operating units ceased operating in Russia and South Africa.
Advances in biotechnology, advanced fermentation technology, and separation sciences have made ABE fermentations competitive with large scale petrochemical processes both in terms of economics and feedstock flexibility. Scientific advances in microbiology have allowed for the selection of clostridia bacteria that are capable of using sugar from a wide variety of sources including agricultural and municipal waste more effectively than parent strains. Modern ABE fermentations also more economically produce high purity acetone with a carbon footprint that is a fraction of competing petrochemical methods.
Acetone is the workhorse solvent of manufacturing industries such as pharmaceuticals, rubber chemicals, electronics, and glass reinforcement plastics. In the North American market, acetone is primarily used as a building block for MMA and bisphenol A (BPA), two high value polymers that are used in many consumer products including safety glass, canned food liners, dentures, orthopedic and cosmetic implants, and acrylic paints. Other chemicals made from acetone include methyl isobutyl ketone (MIBK), another industrial solvent and synthetic rubber precursor. Acetone is also renowned for its nontoxic nature and presence in everyday products such as cleaning fluids, nail polish removers, spray paint, skin lighteners, hair spray, foot care, and wound treatments.
Unlike other solvents available to consumers such as toluene and turpentine, acetone is safe for environmental and human exposure. Acetone is a VOC-exempt solvent since it is produced by nearly all plants and animals and is completely biodegradable in the air, water, and soil. Health concerns with acetone exposure are almost negligible as its toxicity is on par with table salt. In fact, the human body produces acetone as a part of fat metabolism and detection of acetone on one’s breath can be an invaluable healthcare diagnostic tool.
Acetone’s immediate market is valued at over $7 billion dollars and downstream demand for derivative products such as MMA is strong. Using modern advances in process technology, existing ethanol plants can be repurposed to run ABE fermentations and produce acetone and n-butanol at a scale and cost that is directly competitive with large, fully integrated petrochemical plants in Houston. This enables the creation of high value jobs in clean renewable chemical manufacturing built upon the expertise of American farmers.