Phthalates

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R, R' =CnH2n+1; n = 4-15

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Phthalates are a group of chemical compounds that are mainly used as plasticizers -- substances added to plastics to increase their flexibility. They are chiefly used to turn polyvinyl chloride from a hard plastic into a flexible plastic.

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Phthalates, also known as phthalate esters, are the dialkyl or alkyl aryl esters of 1,2-benzenedicarboxylic acid. The name phthalate is derived from phthalic acid + -ate. When added to plastics, they allow the long polyvinyl molecules to slide against one another. The phthalates 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). They are colorless, odorless liquids produced by reacting phthalic anhydride with an appropriate alcohol (usually 6 to 13 carbon).

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As of 2004, about 400,000 tons (one billion pounds) of them are produced each year. They were first produced during the 1920s, and have been produced in large quantities since the 1950s, when PVC was introduced. The most widely used phthalates are di-2-ethyl hexyl phthalate (DEHP), diisodecyl phthalate (DIDP) and diisononyl phthalate (DINP). DEHP is the dominant plasticizer used in PVC, due to its low cost. Benzylbutylphthalate is used in the manufacture of foamed PVC, which is mostly used as a flooring material. Phthalates with small R and R' groups are used as solvents in perfumes and pesticides.

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Phthalates are also frequently used in nail polish, adhesives, caulk, paint pigments, and sex toys made of so-called "jelly rubber." Some vendors of jelly rubber sex toys advise covering them in condoms when used internally, due to the possible health risks.

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Plastic: Plastic is a term that covers a range of synthetic or semisynthetic polymerization products. They are composed of organic condensation or addition polymers and may (often) contain other substances to improve performance or economics. There are few natural polymers generally considered to be "pla...

Polyvinyl chloride: Polyvinyl chloride (PVC) is a widely-used plastic. In terms of revenue generated, it is one of the most valuable products of the chemical industry. Globally, over 50% of PVC manufactured is used in construction. As a building material, PVC is cheap and easy to assemble. In recent years, PVC has bee...

Alkyl: An Alkyl is a univalent radical containing only carbon and hydrogen atoms arranged in a chain. The alkyls form a homologous series with the general formula CnH2n+1. Examples include methyl, CH3· (derived from methane) and butyl C4H9· (derived from butane). They are normally not found o...