Diisopropylbenzene

The diisopropylbenzenes (DIPB) are organic compounds with the formula C6H4(CH(CH3)2)2. Three isomers exist: 1,2- 1,3-, and 1,4-diisopropylbenzene. All are colorless liquids, immiscible in water, with similar boiling points. They are classified are aromatic hydrocarbons bearing a pair of isopropyl (CH(CH3)2) substituents. DIPB has been referred to as "a common diluent" alongside hexane.

Production and reactions
Diisopropylbenzenes typically arise by alkylation of benzene or isopropylbenzene with propylene:
 * C6H6 + CH3CH\dCH2  ->  C6H5CH(CH3)2
 * C6H5CH(CH3)2 + CH3CH\dCH2  ->  C6H4(CH(CH3)2)2

These alkylations are catalyzed by various Lewis acids, such as aluminium trichloride.

They can also be prepared and transformed by transalkylation reactions. In this way, triisopropylbenzenes are converted back to diisopropylbenzenes upon treatment with benzene or monoisopropylbenzene. As usual, these transformations are catalyzed by Lewis acids.
 * C6H4(CH(CH3)2)2 + C6H6  ->  2 C6H5CH(CH3)2

The 1,3- and 1,4- isomers are mainly of interest as precursors to the respective dihydroxylbenzene derivatives, which exploits the Hock rearrangements. All three isomers form hydroperoxides, as is implicit in the Hock rearrangement, which are of interest as radical initiators for polymerization.