IARC Cancer Review: Group 2B IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 ,1987,p. 345.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Animal Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 19 ,1979,p. 231.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Human Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 19 ,1979,p. 231.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . NCI Carcinogenesis Bioassay (gavage); Inadequate Studies: mouse, rat NCITR*    National Cancer Institute Carcinogenesis Technical Report Series. (Bethesda, MD 20014) No. NCI-CG-TR-170 ,1979. (gavage). Reported in EPA TSCA Inventory. EPA Genetic Toxicology Program. Community Right-To-Know List.

OSHA PEL: TWA 50 ppm; STEL 100 ppm
ACGIH TLV: TWA 20 ppm; STEL 40 ppm; Not Classifiable as a Human Carcinogen; BEI: 800 mg(mandelic acid)/L in urine at end of shift; 0.55 mg/L styrene in blood at end of shift; 0.02 mg/L styrene in blood prior to next shift
DFG MAK: 20 ppm (86 mg/m³); BAT: 2 g/L of mandelic acid in urine at end of shift
NIOSH REL: (Styrene) TWA 50 ppm; CL 100 ppm
DOT Classification:  3; Label: Flammable Liquid

For occupational chemical analysis use OSHA: #09 or NIOSH: Hydrocarbons, Aromatic, 1501.

Styrene, also called vinyl benzene, is colorless, oily, highly flammable liquid that evaporates easily and has a aroma odour. It is an organic compound formed by vinyl instead of one hydrogen atom of benzene. Styrene is insoluble in water, soluble in alcohol and ether. When exposure to air it can gradually polymerize. So people should increase polymerization inhibitor [hydroquinone or tert-butyl catechol (0.0002% ~ 0.002%) as stabilizing agent to keep in storage. In industry, styrene is an important monomer for synthetic resin, ion exchange resin and synthetic rubber.

Preparation: Now, people mainly get the styrene by ethylbenzene from heat insulation or isothermal furnace catalytic dehydrogenation. In the presence of catalytic agent, heat ethylbenzene to 600 °C to get crude product. After distillation, the end product is obtained.
C₆H₅CH₂CH₃ → C₆H₅CH=CH₂ + H₂

Technological process: Ethylbenzene which is heated in the evaporator by the flue gas evaporates into the preheater. With the reaction gas preheated to 400 °C, heat it in the furnace to 560 °C or more. Then mix the steam and ethylbenzene (the amount of 1.5-2) and heat it to 560 °C or more into the tube reactor. The reactor contains 100mm diameter chrome tube. There is catalyst in tube. And the external of tube is heated by flue gas to maintain bed temperature at 580-610 °C. After condensation and separation of water layer, people can get crude styrene. Finally, the end product is obtained by distillation and vacuum distillation. The purity is 99.5% and the yield is 92% -94%. This method is mainly used active zinc oxide as catalyst.

There is also other methods to produce styrene. Such as, it can be synthesized from toluene and methanol, which are cheaper raw materials than those in the conventional process.

Uses: The most important use is as monomer for synthetic rubber and plastic which are used for the production of styrene butadiene rubber, polystyrene and polystyrene foam. Styrene is also used in copolymerization with other monomers to manufacture different uses of engineering plastics. For example: SAN, the copolymer of styrene and acrylonitrile, is resin with bright color and resistant to shock. Moreover, styrene is widely used in various household appliances and industry. In addition, a small amount of styrene is used as intermediate of spices. Styrene is also used as original drug of expectorant eprazinone and anticholinergics glycopyrrolate.

Safty: Styrene is toxic by inhalation, in contact with skin and if swallowed. It is also irritating to eyes AND respiratory system. If you want to contact this product, you must Wear suitable protective clothing and gloves. In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) People should not breathe vapour of styrene. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.

Structure Descriptors:
1. Smiles:c1(ccccc1)C=C
2. InChI:InChI=1/C8H8/c1-2-8-6-4-3-5-7-8/h2-7H,1H2

Toxicity: