Catalytic activity of HAlBEA and NixHAlBEA zeolites in hydrogen-assisted dehydrochlorination of 1,2-dichloroethane into vinyl chloride monomer

• Ni(II) was incorporated in HAlBEA zeolite by conventional postsynthesis impregnation.
• NixHAlBEA were active in dehydrochlorination of 1,2-dichloroethane.
• NixHAlBEA showed an excellent selectivity toward vinyl chloride (∼100%).
• Dehydrochlorination of 1,2-dichloroethane on NixHAlBEA was depended on its acidity.
• The small Ni particles favor the dehydrochlorination to vinyl chloride.

HAlBEA zeolite is prepared by calcination of parent TEABEA zeolite at 823 K for 3 h in air following ionic exchange with NH4NO3 solution. NixHAlBEA zeolites are prepared by impregnation of HAlBEA with an aqueous solution of Ni(NO3)2, following a drying at 333 K to obtain NixHAlBEA. The calcination of HAlBEA and NixHAlBEA at 773 K for 3 h in air leads to the formation of C-HAlBEA and C–NixHAlBEA with appeared, for the latter, an octahedral and tetrahedral Ni(II) species incorporated in BEA framework as evidenced by XRD, DR UV–vis and XPS. Red-C-HAlBEA and red-C–NixHAlBEA are investigated as the catalysts in dehydrochlorination of 1,2-dichloroethane into vinyl chloride monomer in the presence of hydrogen at 503–523 K. Red-C-HAlBEA and red-C–Ni1.0HAlBEA show an excellent selectivity toward vinyl chloride (∼100%). Activity of HAlBEA and NixHAlBEA in the catalytic conversion of 1,2-dichloroethane strongly depends on the acidic properties of these materials and for the latter the catalytic activity depend on metal dispersion. The small Ni particles favor the dehydrochlorination of 1,2-dichloroethane to vinyl chloride. With increasing nickel particles size decreases activity of the red-C–NixHAlBEA catalysts. For these catalysts after kinetic run sintering of nickel phase is observed. Besides of carburization the nickel sintering is the main cause of red-C–NixHAlBEA deactivation. It is stronger for spent-red-C–Ni2.0HAlBEA with larger nickel particles than for red-C–Ni1.0HAlBEA containing smaller nickel particles (smaller than 5 nm).

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