Bisphenol A

Bisphenol A (BPA) is an organic synthetic compound with the chemical formula (CH3)2C(C6H4OH)2 belonging to the group of diphenylmethane derivatives and bisphenols, with two hydroxyphenyl groups. It is a colorless solid that is soluble in organic solvents, but poorly soluble in water (0.344 wt % at 83 °C). BPA is a starting material for the synthesis of plastics, primarily certain polycarbonates and epoxy resins, as well as some polysulfones and certain niche materials. BPA-based plastic is clear and tough, and is made into a variety of common consumer goods, such as plastic bottles including water bottles, sports equipment, CDs, and DVDs. Epoxy resins containing BPA are used to line water pipes, as coatings on the inside of many food and beverage cans and in making thermal paper such as that used in sales receipts. In 2015, an estimated 4 million tonnes of BPA chemical were produced for manufacturing polycarbonate plastic, making it one of the highest volume of chemicals produced worldwide. BPA is a xenoestrogen, exhibiting estrogen-mimicking, hormone-like properties that raise concern about its suitability in some consumer products and food containers. Since 2008, several governments have investigated its safety, which prompted some retailers to withdraw polycarbonate products. The U.S. Food and Drug Administration (FDA) has ended its authorization of the use of BPA in baby bottles and infant formula packaging, based on market abandonment, not safety. The European Union and Canada have banned BPA use in baby bottles. World production capacity of BPA was 1 million tons in the 1980s, and more than 2.2 million tons in 2009. It is a high production volume chemical. This compound is synthesized by the condensation of acetone (hence the suffix A in the name) with two equivalents of phenol. The reaction is catalyzed by a strong acid, such as hydrochloric acid (HCl) or a sulfonated polystyrene resin. Industrially, a large excess of phenol is used to ensure full condensation; the product mixture of the cumene process (acetone and phenol) may also be used as starting material: Numerous ketones undergo analogous condensation reactions. In 2003, U.S. consumption was 856,000 tons, 72% of which used to make polycarbonate plastic and 21% going into epoxy resins. In the U.S., less than 5% of the BPA produced is used in food contact applications, but remains in the canned food industry and printing applications such as sales receipts. Bisphenol A and phosgene react to give polycarbonate. The reaction is conducted under biphasic conditions; the hydrochloric acid is scavenged with aqueous base: Million tonnes (8 billion pounds) of BPA are consumed for this purpose yearly.