This is an old revision of this page, as edited by 192.203.205.129 (talk) at 02:45, 17 May 2005. The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Revision as of 02:45, 17 May 2005 by 192.203.205.129 (talk)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)| Bisphenol A | |
|---|---|
| Chemical name | 4,4'-(propan-2-ylidene)diphenol Bisphenol A |
 | |
| Chemical formula | C15H16O2 |
| Molecular Weight | 228.2902 |
| Melting point | 153°C |
| Boiling point | 220°C at 4 mm Hg 222°C at 3 mm Hg |
| Flashpoint | 227°C |
| CAS number | 80-05-7 |
Bisphenol A is a chemical compound that is prepared by reaction of two equivalents of phenol with one equivalent of acetone. Bisphenol A belongs to the phenol class of aromatic organic compounds; it has two phenol functional groups in its molecule. Bisphenol A was first synthesized by Dianin in 1891.
Bisphenol A was investigated in the 1930s during the search for synthetic estrogens. At that time, another synthesized compound, diethylstilbestrol, turned out to be more powerful as an estrogen, so bisphenol A was shelved until polymer chemists discovered that it could be polymerized to form polycarbonate plastic. Its current main use is in the manufacture of polycarbonate polymers and epoxy glues.
Polycarbonates are widely used in all sorts of consumer products, from sunglasses and CDs to water and food containers and shatter-resistant baby bottles. Some polymers used in dental fillings also contain bisphenol A, while epoxy resins containing bisphenol A are popular coatings for the inside of cans used for canning food.
Possible Health Risks
BPA has been known to leach from plastics which are cleaned with harsh detergents or used to contain acidic or high temperature liquids. The chemical has been found in nearly every human tested in the United States.
The first evidence of bisphenol A's estrogenicity came from experiments in the 1930's feeding BPA to ovariectomised rats (Dodds and Lawson 1936, 1938). Some hormone disrupting effects in studies on animals and human cancer cells have been shown to occur at levels as low as 2-5 ppb (parts per billion).
The plastics industry has long claimed that bisphenol A is safe at typical levels of human exposure, minimizing or discounting all tests to the contrary. Eleven industry-funded studies found no risk from bisphenol A, while 90% of 104 independent studies showed possible risks, says a December 2004 report from scientists Frederick vom Saal and Claude Hughes
A previous report, released by the Harvard Center for Risk Analysis and funded by the American Plastics Council, called the evidence for risks "weak" and "inconsistent".
References
- Dianin, Zhurnal russkogo fiziko-khimicheskogo obshchestva, 23 (1891), pp. 492 ff.
- Mittheilungen aus dem chemischen Laboratorium der Universität Marburg, T. Zincke, Justus Leibigs Annals Chemie, 343 (1905), pp. 75-99.
- Handbook of Chemistry and Physics, CRC Press, 76th edition (1995-1996).
External Links
"Study Cites Risk of Compound in Plastic Bottles" - LA Times
Plastics Industry Bisphenol A information site
Bisphenol Info page of a site about dangers of endocrine disruptors