Sn(II)/PN@AC catalysts: synthesis, physical-chemical characterization, and applications.

Abstract

In this study, the novel tin-based catalysts (Sn(II)/PN@AC) were prepared using the phosphorus and nitrogen dual-modified activated carbon as support and SnCl2 as active compounds, as well as then evaluated in acetylene hydrochlorination. Under the reaction temperature of 180 °C and an acetylene gas hourly space velocity (GHSV-C2H2) of 30 h–1, the 15%Sn(II)/PN@AC-550 showed the initial acetylene conversion of 100% and vinyl chloride selectivity over 98.5%. Additionally, the deactivation rate of 15%Sn(II)/PN@AC-550 reached 0.47% h–1, which was lower than that of 15%Sn(II)/AC-550 (1.02% h–1), suggesting that PN@AC-550 as novel support can retarded the deactivation of Sn(II)/AC-550 catalysts during acetylene hydrochlorination. Based on the catalytic tests and characterization results (XRD, Raman, BET surface area, TEM, C2H2-TPD, H2-TPR, XPS, FT-IR, TGA, and ICP), it demonstrated that PN@AC-550 as support could effectively improve the dispersion of tin species, retard the formation of coke deposition, lessen the oxidation of SnCl2 during the preparation process, as well as relatively inhibit the leach of tin species during the reaction. By combing the FTIR results and Rideal–Eley mechanism, we proposed that that HSnCl3 was transition state of SnCl2 in catalysis acetylene hydrochlorination and then adsorbed the acetylene to produce the vinyl chloride.