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 names m.p. °C b.p. °C Density g/cm3 Refractive Index1,2-Diethylbenzene, o-diethylbenzene 31.2 183.5 0.8800 1.50351,3-Diethylbenzene, m-diethylbenzene 83.9 181.1 0.8602 1.49551,4-Diethylbenzene, p-diethylbenzene 42.8 183.8 0.8620 1.4967
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.
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