Active carbon supported S-promoted Bi catalysts for acetylene hydrochlorination reaction

In the present work, the sulfur doped bismuth-based catalysts were prepared by incipient wetness impregnation method and used for the hydrochlorination of acetylene to vinyl chloride monomer (VCM) in a fixed-bed reactor. The effect of introduction of S was characterized by N₂ adsorption-desorption, powder X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, temperature-programmed reduction and X-ray photoelectron spectroscopy. The characterization results indicated that the doping of S resulted in the increase of Brunauer-Emmett-Teller (BET) surface areas and decrease of active species particle size for the Bi-based catalysts, which led to more accessible active sites, and consequently boosted the catalytic hydrochlorination activity. The effect of H₂SO₄ concentration on the activity of this type catalyst was examined, and the results showed that there is an optimal loading of H₂SO₄ (S/Bi = 0.5 mol/mol), at which the conversion of C₂H₂ was enhanced to 81% under the reaction condition and coke deposition is a main reason for the deactivation of catalyst.