Diethylbenzenes Explained

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]

2

Nomenclature

Production and applications

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 → C6H5C2H5The diethylbenzene is an inadvertent side product.

C6H5C2H5 + C2H4 → C6H4(C2H5)2Using 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

Diethylbenzene is used in a mixture with methyl and/or ethyl biphenyls as a low temperature heat transfer fluid.

Diethylbenzene is dehydrogenated to give divinylbenzene (DVB):

C6H4(C2H5)2 → C6H4(C2H3)2 + 2 H2

DVB is used in the production of crosslinked polystyrene.[2]

Notes and References

  1. Encyclopedia: Karl Griesbaum . Arno Behr . Dieter Biedenkapp . Heinz-Werner Voges . Dorothea Garbe . Christian Paetz . Gerd Collin . Dieter Mayer . Hartmut Höke . Hydrocarbons. Ullmann's Encyclopedia of Industrial Chemistry. 2002. Wiley-VCH. Weinheim. 10.1002/14356007.a13_227. 3-527-30673-0.
  2. Book: Denis H. James William M. Castor, "Styrene" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.. 10.1002/14356007.a25_329.pub2.