Bisphenol A
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Bisphenol A, commonly abbreviated as BPA, is an organic compound with two phenol functional groups. It is a difunctional building block of several important plasticsand plastic additives.
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 containing it from their shelves. A 2010 report from theFDA raised further concerns regarding exposure of fetuses, infants, and young children.[1]Bisphenol A, commonly abbreviated as BPA, is an organic compound with two phenol functional groups. It is a difunctional building block of several important plasticsand plastic additives.
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 containing it from their shelves. A 2010 report from theFDA raised further concerns regarding exposure of fetuses, infants, and young children.[1]Bisphenol A, commonly abbreviated as BPA, is an organic compound with two phenol functional groups. It is a difunctional building block of several important plasticsand plastic additives.
Synthesis
It is prepared by the condensation of acetone (hence the suffix A in the name)[4] with two equivalents of phenol. The reaction is catalyzed by an acid, such as hydrochloric acid (HCl) or a sulfonated polystyrene resin. Typically, a large excess of phenol is used to ensure full condensation:
- (CH3)2CO + 2 C6H5OH → (CH3)2C(C6H4OH)2 + H2O
A large number of ketones undergo analogous condensation reactions. The method is efficient and the only by-product is water.[5]
[edit]Use
Further information: Polycarbonate
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 a key monomer in production of epoxy resins[6][7] and in the most common form of polycarbonate plastic.[5][8][9] 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 fillingsand sealants, eyeglass lenses, CDs and DVDs, and household electronics.[10] BPA is also used in the synthesis of polysulfones and polyether ketones, as an antioxidant in some plasticizers, and as a polymerization inhibitor in PVC. Epoxy resins containing bisphenol A are used as coatings on the inside of almost all food and beverage cans,[11] however, due to BPA health concerns, in Japan epoxy coating was mostly replaced by PET film.[12] Bisphenol A is also a precursor to the flame retardant, tetrabromobisphenol A, and was formerly used as a fungicide.[13] Bisphenol A is a preferred color developer in thermal paper[14] and in carbonless copy paper.[15]
Global production of bisphenol A in 2003 was estimated to be over 2 million tonnes.[16] In the U.S., it is manufactured by Bayer MaterialScience, Dow Chemical Company, SABIC Innovative Plastics (formerly GE Plastics), Hexion Specialty Chemicals, and Sunoco Chemicals. In 2004, these companies produced just over 1 million t of bisphenol A, up from just 7,260 t in 1991. In 2003, annual U.S. consumption was 856,000 t, 72% of which was used to make polycarbonate plastic and 21% going into epoxy resins.[10]
[edit]Identification in plastics
Main article: Resin identification code
There are seven classes of plastics used in packaging applications. Type 7 is the catch-all "other" class, and some type 7 plastics, such as polycarbonate (sometimes identified with the letters "PC" near the recycling symbol) and epoxy resins, are made from bisphenol A monomer.[5][17]
Types 1 (PET), 2 (HDPE), 4 (LDPE), 5 (polypropylene), and 6 (polystyrene) do not use bisphenol A during polymerization or package forming.[citation needed] [18]
[edit]Health effects
Bisphenol A is an endocrine disruptor, which can mimic the body's own hormones and may lead to negative health effects.[19][20][21][22] Early development appears to be the period of greatest sensitivity to its effects.[23] Regulatory bodies have determined safety levels for humans, but those safety levels are currently being questioned or under review as a result of new scientific studies.[24][25]
In 2009 the The Endocrine Society released a scientific statement expressing concern over current human exposure to BPA.[26]
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