Acrylamide

Acrylamide (or acrylic amide) is an organic compound with the chemical formula CH2=CHC(O)NH2. It is a white odorless solid, soluble in water and several organic solvents. It is produced industrially as a precursor to polyacrylamides, which find many uses as water-soluble thickeners and flocculation agents. It is highly toxic, likely to be carcinogenic, and partly for that reason it is mainly handled as an aqueous solution. Acrylamide (or acrylic amide) is an organic compound with the chemical formula CH2=CHC(O)NH2. It is a white odorless solid, soluble in water and several organic solvents. It is produced industrially as a precursor to polyacrylamides, which find many uses as water-soluble thickeners and flocculation agents. It is highly toxic, likely to be carcinogenic, and partly for that reason it is mainly handled as an aqueous solution. The discovery that some cooked foods contain acrylamide in 2002 attracted significant attention to its possible biological effects. As of 2019 epidemiological studies suggest it is unlikely that acrylamide consumption increases people's risk of developing cancer. Acrylamide can be prepared by the hydrolysis of acrylonitrile. The reaction is catalyzed by sulfuric acid as well as various metal salts. It is also catalyzed by the enzyme nitrile hydratase. US demand for acrylamide was 253,000,000 pounds (115,000,000 kg) as of 2007, increased from 245,000,000 pounds (111,000,000 kg) in 2006. Acrylamide arises in some cooked foods via a series of steps initiated by the condensation of the amino acid asparagine and glucose. This condensation, one of the Maillard reactions followed by dehydrogenation produces N-(D-glucos-1-yl)-L-asparagine, which upon pyrolysis generates some acrylamide. The majority of acrylamide is used to manufacture various polymers, especially polyacrylamide used as a thickening agent and in water treatment. Acrylamide is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities. Acrylamide is considered a potential occupational carcinogen by U.S. government agencies and classified as a Group 2A carcinogen by the IARC. The Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health have set dermal occupational exposure limits at 0.03 mg/m3 over an eight-hour workday. In animal models, exposure to acrylamide causes tumors in the adrenal glands, thyroid, lungs, and testes. Acrylamide is easily absorbed by the skin and distributed throughout the organism; the highest levels of acrylamide post-exposure are found in the blood, non-exposed skin, kidneys, liver, testes, and spleen. Acrylamide can be metabolically-activated by cytochrome P450 to a genotoxic metabolite, glycidamide, which is considered to be a critical mode of action to the carcinogenesis of acrylamide. On the other hand, acrylamide and glycidamide can be detoxified via conjugation with glutathione to form acrylamide- and isomeric glycidamide-glutathione conjugates, subsequently metabolized to mercapturic acids and excreted in urine. Acrylamide has also been found to have neurotoxic effects in humans who have been exposed. Animal studies show neurotoxic effects as well as mutations in sperm. Acrylamide is also a skin irritant and may be a tumor initiator in the skin, potentially increasing risk for skin cancer. Symptoms of acrylamide exposure include dermatitis in the exposed area, and peripheral neuropathy. Laboratory research has found that some phytochemicals may have the potential to be developed into drugs which could alleviate the toxicity of acrylamide.