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
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
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]