CHARACTERIZATION AND IMPROVEMENTS IN THE SYNTHESIS OF THE NOVEL SOLIDSUPERACID ALCL2(SG)(N)

The preparation of the novel solid acid catalyst AlCl2(SG)(n), previou sly synthesized in CCl4, has been accomplished with a sealed-tube gas- phase reaction using an extended contact time. Reactivity studies and spectroscopic investigations indicate the similarity in the catalysts prepared via the two different methods. The hydration level of the sil ica support, prior to use in catalyst synthesis, is examined in this w ork. Excessively dry silica is deficient in surface silanol (Si-OH) mo ieties and yields an ineffective catalyst. Exposure of this dry silica to humid air allows sufficient hydration for the preparation of an ac tive catalyst. Calorimetric titration and spectral studies-show that t he Bronsted acidity of the solid gives rise to its strong acidity.