Bisphenol A (Molecule of the Month for October 2009)
Bisphenol A, commonly abbreviated as BPA, is an organic compound with two phenol functional groups. It is a difunctional building block of several important plastics and plastic additives. With an annual production of 2–3 million tonnes, it is an important monomer in the production of polycarbonate. It is prepared by the condensation of acetone (hence the suffix A in the name) with two equivalents of phenol. The reaction is catalyzed by an acid, such as hydrochloric acid (HCl) or a sulfonated polystyrene resin.
Bisphenol A is used primarily to make plastics, and products containing bisphenol A-based plastics have been in commerce for more than 50 years. It is used in the synthesis of polyesters, polysulfones, and polyether ketones, as an antioxidant in some plasticizers, and as a polymerization inhibitor in PVC. It is a key monomer in production of epoxy resins and in the most common form of polycarbonate plastic. Polycarbonate plastic, which is clear and nearly shatter-proof, is used to make a variety of common products including baby and water bottles, sports equipment, medical and dental devices, dental fillings and sealants, eyeglass lenses, CDs and DVDs, and household electronics. Epoxy resins containing bisphenol A are used as coatings on the inside of almost all food and beverage cans.] Bisphenol A is also a precursor to the flame retardant, tetrabromobisphenol A, and was formerly used as a fungicide.
Suspected of being hazardous to humans since the 1930s, concerns about the use of bisphenol A in consumer products were regularly reported in the news media in 2008 after several governments issued reports questioning its safety, and some retailers have removed products made of it from their shelves. Bisphenol A is an endocrine disruptor, which can mimic the body's own hormones and may lead to negative health effects. In 2007, a consensus statement by 38 experts on bisphenol A concluded that average levels in people are above those that cause harm to animals in laboratory experiments. A panel convened by the U.S. National Institutes of Health determined that there was "some concern" about BPA's effects on fetal and infant brain development and behavior. A 2008 report by the U.S. National Toxicology Program (NTP) later agreed with the panel, expressing "some concern for effects on the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to bisphenol A," and "minimal concern for effects on the mammary gland and an earlier age for puberty for females in fetuses, infants, and children at current human exposures to bisphenol A."
Update by Karl Harrison
(Molecule of the Month for October 2009 )