Bisphenol A ( CPA ) is an organic synthetic compound with the chemical formula (CH 3 ) 2 C (C 6 4 OH) 2 belongs to a diphenylmethane and bisphenol derivative group, with two hydroxyphenyl groups. It is a colorless solid that is soluble in organic solvents, but not soluble in water. It has been in commercial use since 1957.
BPA is the starting material for the synthesis of plastics, especially polycarbonates and certain epoxy resins, as well as certain polysulfones and niche materials. BPA-based plastics are clear and hard, and made into a variety of general consumer goods, such as plastic bottles including water bottles, sports equipment, CDs and DVDs. Epoxy resins containing BPA are used to coat a water pipe, as a coating on the inside of many food and beverage cans and in the manufacture of thermal paper as used in sales receipts. By 2015, an estimated 4 million tonnes of BPA chemicals are produced to produce polycarbonate plastic, making it one of the highest volumes of chemicals produced worldwide.
BPA is xenoestrogen, indicating the imitative properties of estrogen, which raises concerns about its suitability in some consumer products and food containers. Since 2008, several governments have been investigating its safety, prompting some retailers to withdraw polycarbonate products. The US Food and Drug Administration (FDA) has terminated the authorization of BPA use in baby bottles and baby formula packaging, based on market neglect rather than security. The EU and Canada have banned the use of BPA in baby bottles.
Video Bisphenol A
Production
The world production capacity of Bisphenol A was 1 million tons in the 1980s, and more than 2.2 million tons in 2009. This is a high volume of chemical production. In 2003, US consumption was 856,000 tons, 72% of which was used to make polycarbonate plastics and 21% went into epoxy resins. In the US, less than 5% of the resulting CPA is used in food contact applications, but still in the canned food industry and printing applications such as sales revenue.
Bisphenol A was first synthesized by the Russian chemist Alexander Dianin in 1891. This compound was synthesized by acetone condensation (hence the suffix A in the name) with two equivalents of phenol. The reaction is catalyzed by strong acids, such as hydrochloric acid (HCl) or sulphonated polystyrene resins. Industrially, large phenol excess is used to ensure full condensation; a mixture of products from the cumene process (acetone and phenol) can also be used as starting material:
A large number of ketones undergo an analog condensation reaction. Commercial production of BPA requires distillation - either BPA extraction from many resin byproducts under high vacuum or solvent based extraction using additional phenol followed by distillation.
Maps Bisphenol A
Usage
BPA is a precursor for other chemicals, especially polymers. Otherwise, BPA is rare in industry and in laboratories.
Polycarbonate
Bisphenol A is used primarily for making plastics, and products using bisphenol A-based plastics have been used commercially since 1957. These are the main ingredients in polymers used to make adhesives, containers, electronic coatings, hulls. In the case of consumer goods, reusable drink containers, food storage containers, canned food, toys, and even receipts from the store. At least 3.6 million tonnes (8 billion BPA) is used by the factory every year. However, it is estimated that the global annual output of CPA is 6.8 million tons. It is a key monomer in the production of epoxy resins Bisphenol A and phosgene reacts to provide polycarbonate under biphasic conditions; hydrochloric acid is scavenged with aqueous base:
In principle diphenyl carbonate may be used as a substitute for phosgene. Phenol is removed not hydrochloric acid. This transesterification process avoids toxicity and phosgene handling.
Epoxy resin and vinyl ester
Vinyl ester resins and some epoxy resins are produced using BPA
Other uses of CPA
BPA is also used in the synthesis of polysulfones and some Polyether ether ketones. It is an antioxidant in some plasticizers, and as a polymerization inhibitor in PVC.
Identify in plastic
Plastic packaging is divided into seven broad classes for recycling purposes with Plastic identification code. In 2014 there are no CPA labeling requirements for plastics in the US. "In general, plastics marked with Resin Identification Codes 1, 2, 4, 5, and 6 are highly unlikely to contain BPA Some, but not all, plastics marked with Resin 7 Identification Codes can be made with BPA." Type 7 is the "other" class, and some plastic types 7, such as polycarbonate (sometimes identified with the letters "PC" near the recycling symbol) and epoxy resins, made from bisphenol A. Type 3 (PVC) monomers may contain bisphenol A as an antioxidant "Flexible PVC" is softened by plasticizer, but not rigid PVC like pipe, window, and upholstery.
History
Bisphenol A was discovered in 1891 by Russian chemist Aleksandr Dianin.
Based on research by the chemists at Bayer and General Electric, BPA has been used since 1950 to harden polycarbonate plastics, and make epoxy resins, contained in layers of food and beverage containers.
In the early 1930s, the English biochemist Edward Charles Dodds tested BPA as an artificial estrogen, but found it to be 37,000 times more effective than estradiol. Dodds eventually developed a structurally similar compound, diethylstilbestrol (DES), which is used as a synthetic estrogen drug in women and animals until it is prohibited because of the risk of causing cancer; the ban on the use of DES in humans came in 1971 and in animals, in 1979. BPA was never used as a drug. The ability of BPA to mimic the effects of natural estrogen stems from the similarity of phenol groups in both BPA and estradiol, which allows these synthetic molecules to trigger the path of estrogen in the body. Usually a phenol-containing molecule similar to BPA is known to have weak estrogenic activity, so it is also regarded as an endocrine disrupter (ED) and estrogenic chemistry. Xenoestrogens is another category that chemical BPA fits under because of its ability to disrupt the tissues that regulate signals that control reproductive development in humans and animals.
BPA has been found to bind both nuclear estrogen receptor (ER), ER? and ER? This is 1000 to 2000 times less powerful than estradiol. Both BPAs can mimic estrogen and estrogen antagonist action, suggesting that it is a selective estrogen receptor modulator (SERM) or a partial ER agonist. At high concentrations, BPA also binds and acts as an antagonist of the androgen receptor (AR). In addition to the receptor binding, such compounds have been found to affect the steroidogenesis of Leydig cells, including those affecting 17? -hydroxylase/17,20 lyase and aromatase expression and disrupt the lig-receptor lH binding.
In 1997, adverse effects of low-dose BPA exposure in laboratory animals were first proposed. Modern studies are beginning to find possible connections to health problems caused by BPA exposure during pregnancy and during development. See the history of US public health settings and Chemical manufacturers' reactions to the ban. In 2014, research and debate are underway as to whether or not BPA should be banned.
A 2007 study investigated the interactions between bisphenol A and estrogen receptors? (ERR-?). These orphan receptors (unknown endogenous ligands) behave as constitutive activators of transcription. CPA seems strongly bound to ERR-? (dissociation constant = 5.5 nM), but only weak in ER. CPA binding ERR-? maintaining its constitutive basal activity. It can also protect it from deactivation of SERM 4-hydroxytamoxifen (afimoxifene). This may be the mechanism by which BPA acts as an xenoestrogen. Different ERR-Expressions? in different parts of the body can cause variations in the bisphenol effect A. BPA has also been found to act as a GET agonist (GPR30).
Health effects
According to the European Food Safety Authority "BPA poses no health risk to consumers of all age groups (including unborn children, infants and teenagers) at current exposure levels". But by 2017 the European Chemical Agency concluded that BPA should be listed as a substance that is very concerned because of its nature as an endocrine disrupter.
In 2012, the United States Food and Drug Administration (FDA) prohibits the use of BPA in baby bottles.
The Environmental Protection Agency (EPA) also holds the position that BPA is not a health issue. In 2011, Andrew Wadge, chief scientist at the UK Food Standards Agency, commented on a 2011 US study on adult human exposure to BPA, saying, "This corroborates other independent studies and adds to the evidence that BPA is rapidly absorbed, detoxified, and removed from humans - because it's not a health issue. "
The Endocrine Society said in 2015 that ongoing laboratory research results provide a reason for concerns about the potential dangers of endocrine disrupting chemicals - including BPA - in the environment, and that on the basis of prudential principles, these substances must continue to be assessed. and strictly regulated. A 2016 literature review says that the potential harm caused by BPA is a topic of scientific debate and that further investigation is a priority because of the relationship between BPA exposure and adverse human health effects including reproductive and developmental effects and metabolic diseases.
Environmental effects
In 2010, the US Environmental Protection Agency reported that more than a million pounds of BPA are released into the environment each year. BPA can be released into the environment by pre-consumer and post-consumer washes. Common introduction route from a pre-consumer perspective to the environment directly from plastic producers, coats and dyes, foundry using CPA in sand casting, or transporting products containing CPA and CPA. Post-consumer CPA waste comes from effluent removal from municipal wastewater treatment plants, irrigation pipes used in agriculture, ocean-borne plastic debris, indirect leaching of plastics, paper and waste metal in landfills, and paper recycling companies or materials. Although the soil is fast and water is half the age of 4.5 days, and the air beak is less than a day, the existence of BPA makes it an important pollutant. BPA has a low evaporation rate from water and soil, which presents a problem, despite biodegradability and low attention to bio-accumulation. BPA has low volatility in the atmosphere and low vapor pressure between 5.00 and 5.32 Pascals. BPA has a high water solubility of about 120 mg/L and most of its reaction in the aqueous environment. An interesting fact is that BPA dust is flammable if ignited, but has minimal explosive concentrations in the air. Also, in aqueous solutions, BPA absorbs at wavelengths greater than 250 nm.
The general nature of CPA makes the pollutant compounds important for study because it has been shown to interfere with nitrogen fixation at the legume roots associated with the bacterial symbology of Sinorhizobium meliloti. A 2013 study also observed changes. in plant health due to BPA exposure. This study exposed soybean seeds to various BPA concentrations and saw changes in root growth, nitrate production, ammonium production, and changes in nitrate reductase and reductase nitrite activity. At low doses of BPA, root growth is increased, the amount of nitrate in the roots increases, the amount of ammonium in the roots decreases, and the activity of nitrate and nitrite reductase remains unchanged. However, at much higher concentrations of BPA, the opposite effect was seen for all but increased nitrate concentrations and decreased activity of nitrite and nitrate reductase. Nitrogen is a plant nutrient, but also the basis of growth and development of plants. Changing the concentration of BPA can be harmful to the ecosystem ecosystem, also to humans if the plant is produced for consumption.
The amount of BPA absorbed in the sediments also appears to decrease with increasing temperatures, as demonstrated by a 2006 study with various plants from the Xiangjiang River in Central-South China. In general, when the temperature increases, the solubility of a compound increases. Therefore, the amount of sorbate entering the solid phase will be lower at the equilibrium point. It was also observed that the BPA adsorption process in the sediments is exothermic, the enthalpy of molar formation, H HÃ, Â °, negative, GGÃ, Â ° negative energy, and molar entropy, SSÃ, Â °, positive. This shows that BPA adsorption is driven by enthalpy. Adsorption of BPA has also been observed to decrease with increasing pH.
A 2005 study conducted in the US has found that 91-98% BPA can be removed from water during treatment at municipal water treatment plants. A more detailed explanation of the aqueous BPA reaction can be observed in the Degradation of BPA sections below. Nevertheless, 2009 CPA meta-analysis in surface water systems shows BPA present in surface water and sediments in the US and Europe. According to Environment Canada 2011, "Current BPA can be found in urban wastewater [...] Initial assessment indicates that at low levels, bisphenol A may harm fish and organisms over time."
BPA affects growth, reproduction, and development in aquatic organisms. Among freshwater organisms, fish seem to be the most sensitive species. Evidence of endocrine-related effects on fish, aquatic invertebrates, amphibians, and reptiles has been reported at an environmentally relevant level of exposure lower than that required for acute toxicity. There is wide variation in reported values ​​for endocrine-related effects, but many fall within the range of 1? G/L up to 1 mg/L.
The 2009 review of the biological impact of plasticists on wildlife published by the Royal Society with a focus on water and terrestrial annelids, molluscs, crustaceans, insects, fish and amphibians concluded that BPA affects reproduction in all animal groups studied, damaging development in crustaceans and amphibians and induce genetic aberrations.
References
Further reading
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