| Abstract: | Cationic oligomerizations of styrene by a solid acid poly(styrenesulfonic acid) resin, Amberlyst 15] and by the corresponding soluble catalyst (p-toluenesulfonic acid) were compared with respect to their reactivity and the molecular weight distribution of products. The feature of Amberlyst 15 as oligomerization catalyst, in addition to its easy separation from products, was found to be was follows: The activity of Amberlyst 15 was 10 times larger than that of p-toluenesulfonic acid in benzene, although catalyst deactivation at high conversions was observed for Amberlyst 15 at high monomer concentrations. Styrene trimer and tetramer were dominantly produced by Amberlyst 15 at low monomer concentrations, whereas a linear dimer was obtained in 85% yield with p-toluenesulfonic acid. Characteristically, solvent polarity had almost no effect on the reaction rate and product composition in the Amberlyst 15-catalyzed oligomerization. These facts were discussed in relation to differences between the heterogeneous and homogeneous catalyses. |
