[12] Furthermore, they could obtain styrene by dry-distilling "metastyrol". The dehydrogenation effluent is cooled and separated and the ethylene stream is recycled to the alkylation unit. [45][46], The neurotoxic[47] properties of styrene have also been studied and reported effects include effects on vision[48] (although unable to reproduce in a subsequent study[49]) and on hearing functions. Synonyms : Vinyl benzene; Stryrene; Cinnamenol; Cinnamol; Cinnamene; Cinnamenol; Ethenylbenzene; Phenethylene; Vinylbenzene; Vinylbenzol; Phenylethene; Styrolene; Styron; Styropol; Styropor; A brief history : Styrene was first isolated from styrax, the resin from a Turkish tree. Styrene occurs naturally in small quantities in some plants and foods (cinnamon, coffee beans, balsam trees[disambiguation needed] and peanuts)[7] and is also found in coal tar. Its glass transition temperature is approximately 105 °C (221 °F). [40] In 2012, the Danish EPA concluded that the styrene data do not support a cancer concern for styrene. Approximately 25 million tonnes of styrene were produced in 2010,[6] increasing to around 35 million tonnes by 2018. The vast majority of styrene is produced from ethylbenzene,[20] and almost all ethylbenzene produced worldwide is intended for styrene production. [33] The U.S. Environmental Protection Agency (EPA) has described styrene to be "a suspected toxin to the gastrointestinal tract, kidney, and respiratory system, among others". The material's properties are determined by short-range van der Waals attractions between polymers chains. Around 80% of styrene is produced by the dehydrogenation of ethylbenzene. The compound evaporates easily and has a sweet smell, although high concentrations have a less pleasant odor. It is reported[24] that an approximately 9:1 mixture of styrene and ethylbenzene is obtained, with a total styrene yield of over 60%. Please upgrade your Internet Explorer to a newer version. In 1845, French chemist Emil Kopp suggested that the two compounds were identical,[16] and in 1866, Erlenmeyer suggested that both "cinnamol" and styrene might be vinylbenzene. At 100 °C it will polymerise at a rate of ~2% per hour, and more rapidly than this at higher temperatures. Code: 2902.50 Chemical formula: H2C=C6H5CH Chemical Properties: Melting point: -30-31 C Boling point: 145-146 C Specific gravity: 0.91 Solubility in water: < 1% Vapour density: 3.60. [43] The National Toxicology Program of the U.S. Department of Health and Human Services has determined that styrene is "reasonably anticipated to be a human carcinogen". Styrene oxide is subsequently hydrolyzed in vivo to styrene glycol by the enzyme epoxide hydrolase.