Ethylbenzene

Ethylbenzene occurs naturally in coal tar and petroleum. Used in the recovery of natural gas, ethylbenzene may be injected into the ground. ==Production==

Ethylbenzene is produced on a large scale by combining benzene and ethene in an acid-catalyzed chemical reaction: : In 2012, more than 99% of ethylbenzene was produced in this way. Small amounts of ethylbenzene are recovered from the mix of xylenes by superfractioning, an extension of the distillation process. In the 1980s a zeolite-based process using vapor phase alkylation offered a higher purity and yield. Then a liquid phase process was introduced using zeolite catalysts. This offers low benzene-to-ethylene ratios, reducing the size of the required equipment and lowering byproduct production. Industrial accidents On June 3, 2014, an explosion occurred in the Dutch Moerdijk industrial area. This happened in a chemical reactor operated by Shell which overheated due to an exothermal runaway reaction between the metal oxide catalyst and ethylbenzene. ==Health effects==

The acute toxicity of ethylbenzene is low, with an LD50 of about 4 grams per kilogram of body weight. The longer term toxicity and carcinogenicity is ambiguous. Eye and throat sensitivity can occur when high level exposure to ethylbenzene in the air occurs. At higher level exposure, ethylbenzene can cause dizziness. A study conducted in 2012 found that in country air the median concentration was found to be 0.01 ppb and indoors the median concentration was 1.0 ppb. It can also be released into the air through the burning of coal, gas, and oil. The use of ethylbenzene in the industry contributes to ethylbenzene vapor in the air. After about three days in the air with the help of sunlight, other chemicals break down ethylbenzene into chemicals that can be found in smog. Generally, ethylbenzene is not found in drinking water, however it can be found in residential drinking water wells if the wells are near waste sites, underground fuel storage tanks that are leaking, or landfills. Biodegradation Certain strains of the fungus Cladophialophora can grow on ethylbenzene. The bacterium Aromatoleum aromaticum EbN1 was discovered due to its ability to grow on ethylbenzene.{{Cite journal | last1 = Rabus | first1 = R. | last2 = Widdel | first2 = F. ==References==