Acetylene hydrochlorination is a major industrial technology for manufacturing vinyl chloride monomer in regions with abundant coal resources; however, it is plagued by the use of mercury(II) chloride catalyst. The development of a nonmercury catalyst has been extensively explored. Herein, we report a N-doped carbon catalyst derived from ZIF-8 with both high activity and quite good stability. The acetylene conversion reached 92% and decreased slightly during a 200 h test at 220 °C and atmospheric pressure. Experimental studies and theoretical calculations indicate that C atoms adjacent to the pyridinic N are the active sites, and coke deposition covering pyridinic N is the main reason for catalyst deactivation. The performance of those N-doped carbons makes it possible for practical applications with further effort. Furthermore, the result also provides guidance for designing metal-free catalysts for similar reactions.
Two 3D heterometal–organic frameworks based on infrequent trigonal bipyramidal Ln5 clusters as nodes were structurally and magnetically characterized (Ln=Gd (1), Dy (2)). The results indicate large MCE of up to 30.7 J kg−1 K−1 in 1 and slow magnetic relaxation behavior in 2. Expectedly, constructing 3D MOFs based on multinuclear clusters as nodes may will be a new strategy for achieving large −ΔSm. Additionally, compound 1 exhibits high thermal and solvent stabilities, providing a favorable foundation for realistic applications.
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