Catalytic hydrogen-assisted dehydrochlorination of 1,2-dichloroethane over cobalt-containing beta zeolite
Résumé
HAlBEA zeolite obtained by calcination of parent TEABEA zeolite at 823 K for 3 h in air following ion exchange with NH4NO3 solution and calcination at 773 K for 3 h was used for synthesis of cobalt containing zeolite by conventional wet impregnation with an aqueous solution of Co(NO3)2. The calcination of as-prepared Co2.0HAlBEA at 773 K in air led to the formation of C-Co2.0HAlBEA with isolated mononuclear Co(II) and polynuclear Co(II) and Co(III) species as evidenced by XRD, FTIR, DR UV–Vis and XPS. C-HAlBEA and C-Co2.0HAlBEA treated up to 1200 K in flowing 10% H2/Ar were investigated as the catalysts in hydrogen-assisted dehydrochlorination of 1,2-dichloroethane. Both C-HAlBEA and C-Co2.0HAlBEA catalysts were given 100% of selectivity toward vinyl chloride monomer in the presence of hydrogen at rather low reaction temperature (i.e. 523 K). Specific balance between amounts of Brønsted and Lewis acidic related, respectively, to Si–O(H)–Al and unsaturated Al(III), Co(II) and/or Co(III) species had a beneficial impact on the activity and stability of C-Co2.0HAlBEA catalyst.