Diethylbenzenes

Diethylbenzenes
The three isomers of diethylbenzene:
ortho-, meta-, and para-diethylbenzene
(left to right)
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.042.599 Edit this at Wikidata
EC Number
  • 1,2: 205-170-1
  • 1,3: 205-511-4
  • 1,4: 203-265-2
RTECS number
  • CZ5600000
UNII
UN number 2049
  • 1,2: InChI=1S/C10H14/c1-3-9-7-5-6-8-10(9)4-2/h5-8H,3-4H2,1-2H3
    Key: KVNYFPKFSJIPBJ-UHFFFAOYSA-N
  • 1,3: InChI=1S/C10H14/c1-3-9-6-5-7-10(4-2)8-9/h5-8H,3-4H2,1-2H3
    Key: AFZZYIJIWUTJFO-UHFFFAOYSA-N
  • 1,4: InChI=1S/C10H14/c1-3-9-5-7-10(4-2)8-6-9/h5-8H,3-4H2,1-2H3
    Key: DSNHSQKRULAAEI-UHFFFAOYSA-N
  • 1,2: CCC1=CC=CC=C1CC
  • 1,3: CCC1=CC(=CC=C1)CC
  • 1,4: CCC1=CC=C(C=C1)CC
Properties
C10H14
Molar mass 134.222 g·mol−1
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).

Diethylbenzene (DEB) is 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 solids.

Physical Properties
Compound namesm.p. °Cb.p. °CDensity g/cm3Refractive Index
1,2-Diethylbenzene, o-diethylbenzene 31.2183.50.88001.5035
1,3-Diethylbenzene, m-diethylbenzene 83.9181.10.86021.4955
1,4-Diethylbenzene, p-diethylbenzene 42.8183.80.86201.4967


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 → 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:

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.

References

  1. 1 2 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.