| Abstract: | Superacid polymers were prepared by bringing metal halides (AlCl3, SnCl4, TiCl4, BF3, or SbF5) in contact with macroporous sulfonic acid resins [sulfonated, crosslinked poly(styrene-divinylbenzene)]. The resulting solids were characterized by chemical analysis, temperature-programmed desorption, transmission electron microscopy, and X-ray photoelectron spectroscopy. They were also tested as catalysts for n-butane isomerization at 0.5 bar and 60 to 120°C. The polymers consist of supported metal oxyhalide particles, complexes of metal oxyhalides and sulfonate groups, and the remaining unreacted sulfonic acid groups. In the presence of HCl, these polymers were highly active catalysts for the butane isomerization reaction, the activity being a consequence of a high proton-donor strength inferred to be associated with H2Cl+ groups stabilized on the polymer surface by negative charge delocalization over sulfonate–metal oxyhalide sulfonate groups. |
