Diethylbenzenes

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]

Diethylbenzenes

The three isomers of diethylbenzene:
ortho-, meta-, and para-diethylbenzene
(left to right)
Identifiers
ECHA InfoCard 100.042.599
EC Number
  • 1,2: 205-170-1
    1,3: 205-511-4
    1,4: 203-265-2
RTECS number
  • CZ5600000
UNII
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).
Infobox references

Nomenclature
  • 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

Diethylbenzenes arise as side-products of the alkylation of benzene with ethylene, which can 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

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
  1. 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.
  2. Buske, Gary R.; Wenger, Terry L.; Beyrau, John A. (Nov 11, 1986), Heat-transfer fluid, retrieved 2016-06-30
  3. 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.
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