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Phthalate

Phthalates (US: /ˈθæleɪts/, UK: /ˈθɑːleɪts/), or phthalate esters, are esters of phthalic acid. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used primarily to soften polyvinyl chloride (PVC). Lower-molecular-weight phthalates, those derived from C3-C6 alcohols, are being gradually replaced in many products in the United States, Canada, and European Union over health concerns. They are replaced by high-molecular-weight phthalates (those with more than 6 carbons in their backbone, which gives them increased permanency and durability). In 2010, the market was still dominated by high-phthalate plasticizers; however, due to legal provisions and growing environmental awareness and perceptions, producers are increasingly forced to use non-phthalate plasticizers. Due to the ubiquity of plasticized plastics, the majority of people are exposed to some level of phthalates. For example, most Americans tested by the Centers for Disease Control and Prevention have metabolites of multiple phthalates in their urine. In studies of rodents exposed to certain phthalates, high doses have been shown to change hormone levels and cause birth defects. Phthalates are used in a large variety of products, from enteric coatings of pharmaceutical pills and nutritional supplements to viscosity control agents, gelling agents, film formers, stabilizers, dispersants, lubricants, binders, emulsifying agents, and suspending agents. End-applications include adhesives and glues, agricultural adjuvants, building materials, personal-care products, medical devices, detergents and surfactants, packaging, children's toys, modelling clay, waxes, paints, printing inks and coatings, pharmaceuticals, food products, and textiles. Phthalates are also frequently used in soft plastic fishing lures, caulk, paint pigments, and sex toys made of so-called 'jelly rubber'. Phthalates are used in a variety of household applications such as shower curtains, vinyl upholstery, adhesives, floor tiles, food containers and wrappers, and cleaning materials. Personal-care items containing phthalates include perfume, eye shadow, moisturizer, nail polish, liquid soap, and hair spray. Phthalates are also found in modern electronics and medical applications such as catheters and blood transfusion devices. The most widely used phthalates are di(2-ethylhexyl) phthalate (DEHP), diisodecyl phthalate (DIDP), and diisononyl phthalate (DINP). DEHP was the dominant plasticizer used globally in PVC due to its low cost. Benzylbutylphthalate (BBP) is used in the manufacture of foamed PVC, which is used mostly as a flooring material, although its use is decreasing rapidly in the Western countries. Phthalates with small R and R' groups are used as solvents in perfumes and pesticides. Approximately 8.4 million tonnes of plasticizers are produced globally every year, of which European produced accounts for approximately 1.5 million metric tonnes. Approximately 70% of those totals are phthalates, down from about 88% in 2005. The remaining 30% are alternative chemistries. Plasticizers contribute 10-60% of total weight of plasticized products. More recently in Europe and the US, regulatory developments have resulted in a change in phthalate consumption, with the higher phthalates (DINP and DIDP) replacing DEHP as the general purpose plasticizer of choice because DIDP and DINP were not classified as hazardous. All of these mentioned phthalates are now regulated and restricted in many products. DEHP, although most applications are shown to pose no risk when studied using recognized methods of risk assessment, has been classified as a Category 1B reprotoxin, and is now on the Annex XIV of the European Union's REACH legislation. DEHP has been phased out in Europe under REACH and can only be used in specific cases if an authorisation has been granted. Authorisations are granted by the European Commission, after obtaining the opinion of the Committee for Risk Assessment (RAC) and the Committee for Socio-economic Analysis (SEAC) of the European Chemicals Agency (ECHA). The development of cellulose nitrate plastic in 1846 led to the patent of castor oil in 1856 for use as the first plasticizer. In 1870, camphor became the more favored plasticizer for cellulose nitrate. Phthalates were first introduced in the 1920s and quickly replaced the volatile and odorous camphor. In 1931, the commercial availability of polyvinyl chloride (PVC) and the development of di(2-ethylhexyl) phthalate (DEHP) began the boom of the plasticizer PVC industry. Phthalate esters are the dialkyl or alkyl aryl esters of phthalic acid (also called 1,2-benzenedicarboxylic acid, not be confused with the structurally isomeric terephthalic or isophthalic acids ); the name 'phthalate' derives from phthalic acid, which itself is derived from the word 'naphthalene'. When added to plastics, phthalates allow the long polyvinyl molecules to slide against one another. The phthalates have a clear syrupy liquid consistency and show low water solubility, high oil solubility, and low volatility. The polar carboxyl group contributes little to the physical properties of the phthalates, except when R and R' are very small (such as ethyl or methyl groups). Phthalates are colorless, odorless liquids produced by reacting phthalic anhydride with an appropriate alcohol (usually 6- to 13-carbon).

[ "Chemical engineering", "Chromatography", "Composite material", "Organic chemistry", "Dimethyl phthalate", "Diheptyl phthalate", "Di-sec-octyl phthalate", "di n butyl phthalate", "Mono(2-ethyl-5-oxohexyl)phthalate" ]
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