Superacid polymers: Paraffin isomerization and cracking in the presence of AlCl3-sulfonic acid resin complexes

Polymers were prepared by the reaction of anhydrous AlCl3 vapors with macroporous sulfonic acid resin. HCl was evolved, and a bound complex was formed which incorporated S, Al, and Cl in the ratio 2:1:2. The resin was similar to HSO4AlCl2, initially converting n-butane into isobutane and n-hexane into isomerization and cracking products at temperatures near 100 °C. Like HSO4AlCl2, the polymer was unstable, rapidly losing Cl during operation. Olefin addition to the paraffin reactants did not significantly affect rates of cracking and isomerization, and this result stands in contrast to those of Pines and Wackher, who used n-butane and AlCl3HCl mixtures. It is suggested that the polymer was capable of protonating paraffins and had a proton-donor strength comparable to that of a superacid solution like SbF5 + HF.