Alkylation of Other Polynuclear Hydrocarbons

The isopropylation of p-terphenyl (TP) was similar to the isopropylation of biphenyl.82 Over HM, the isomer compositions of 4-isopropyl-p-terphenyl (4-IPTP) and 4,4 -diisopropyl-p-terphenyl (4,4 -DIPT) at 175-200 °C are 78 and 75%, respectively. The selectivity for 4,4 -DITP was higher than that for 4,4 -DIPB under comparable reaction conditions. This difference is possibly caused by the differences in the steric restriction and the diffusion rates between both reactions. However, the isopropylation over SA was non-regioselective The selectivities were 35-50% and 10-20% for 4-IPTP and 4,4 -DIPT, respectively. 

The isopropylation of anthracene gave similar results to that of naphthalene.84 The selectivities for 2-isopropylanthracene (2-IPA) and 2,6-diisopropylanthra-cene (2,6-DIP A) over HM(25) were as high as 91% and 47%, respectively. On the other hand, the selectivities over HY were as low as 59% and 8% for both products. The Diels-Alder reaction of anthracene with propylene occurred at higher temperatures to yield large amounts of the adducts such as 11 -methyl-9, lO-dihydro-etano-anthracene. However, their formation was prevented by the addition of a small quantity of water. 

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