Diethylbenzenes
 The three isomers of diethylbenzene:
ortho-, meta-, and para-diethylbenzene (left to right) | |
| Identifiers | |
|---|---|
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| ECHA InfoCard | 100.042.599 |
| EC Number |
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PubChem CID
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| RTECS number |
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| UNII |
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| UN number | 2049 |
CompTox Dashboard (EPA)
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| Properties | |
| C10H14 | |
| Molar mass | 134.22 |
| Density | 0.87 g/mL |
| Hazards | |
| Flash point | 134.6 °F / 57 °C |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Diethylbenzene (DEB) refers to any of three isomers with the formula C6H4(C2H5)2. Each consists of a benzene ring and two ethyl substituents. The meta and para have the greater commercial significance. All are colorless liquids.[1]
Nomenclature[edit]
- Ortho: known as 1,2-diethylbenzene and o-diethylbenzene.
- Meta: known as 1,3-diethylbenzene and m-diethylbenzene.
- Para: known as 1,4-diethylbenzene and p-diethylbenzene.
Production and applications[edit]
Diethylbenzenes arise as side-products of the alkylation of benzene with ethylene, which can be described as two steps. The first step is the industrial route to ethylbenzene, which is produced on a large scale as a precursor to styrene.
- C6H6 + C2H4 → C6H5C2H5
The diethylbenzene is an inadvertent side product.
- C6H5C2H5 + C2H4 → C6H4(C2H5)2
Using shape-selective zeolite catalysts, the para isomer can be produced in high selectivity.
Much diethylbenzene is recycled by transalkylation to give ethylbenzene:[1]
- C6H4(C2H5)2 + C6H6 → 2 C6H5C2H5
Uses[edit]
Diethylbenzene is used in a mixture with methyl and/or ethyl biphenyls as a low temperature heat transfer fluid.[2]
Diethylbenzene is dehydrogenated to give divinylbenzene (DVB):
- C6H4(C2H5)2 → C6H4(C2H3)2 + 2 H2
DVB is used in the production of crosslinked polystyrene.[3]
References[edit]
- ^ a b Karl Griesbaum; Arno Behr; Dieter Biedenkapp; Heinz-Werner Voges; Dorothea Garbe; Christian Paetz; Gerd Collin; Dieter Mayer; Hartmut Höke (2002). "Hydrocarbons". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a13_227. ISBN 3-527-30673-0.
- ^ Buske, Gary R.; Wenger, Terry L.; Beyrau, John A. (Nov 11, 1986), Heat-transfer fluid, retrieved 2016-06-30
- ^ Denis H. James William M. Castor, "Styrene" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a25_329.pub2.