STOICHIOMETRIC ADSORPTION COMPLEXES OF BORON-TRICHLORIDE AND ANTIMONYPENTAFLUORIDE IN H-ZSM-5

This work demonstrates that inorganic metal halide compounds such as B Cl3 and SbF5 can be used to prepare adsorption complexes with a stoich iometry of one molecule per Bronsted acid site in the zeolite H-ZSM-5. BCl3-acid site complexes are prepared by saturating the zeolite with BCl3 and then evacuating. The BCl3 complex desorbs above 400 K, and si milar to 50% of the BCl3 remains adsorbed at temperatures above 750 K. SbF5-acid site complexes are prepared by saturating the zeolite, evac uating, and heating to 700 K in vacuum. The SbF5 complex is shown to p olarize coadsorbed acetone to the same degree as magic acid. The stabi lity of the metal halide complexes is further characterized with adsor ption and reaction of propene and ethene to form oligomers. Small amou nts (< 10%) of the metal halide desorb during the oligomer desorption experiment.