Nitrogen‐Doped Pitch‐Based Spherical Active Carbon as a Nonmetal Catalyst for Acetylene Hydrochlorination

Abstract A highly active nitrogen‐doped pitch‐based spherical activated carbon catalyst (PSAC‐N) is synthesized through a nitrogen‐doping treatment and used as a nonmetal catalyst for acetylene hydrochlorination. The conversion of acetylene on PSAC‐N exceeds 68 % and the selectivity of vinyl chloride is over 99 % at a temperature of 250 °C, an acetylene gas hourly space velocity of 120 h −1 , and a feed volume ratio V (HCl)/ V (C 2 H 2 ) of 1.15. DFT calculations performed with Gaussian 09 program package reveal that the active site of PSAC‐N has a N‐6v (quaternary nitrogen bonded between two 6‐membered rings) structure. A seven benzene ring unit model is used in the DFT study. In addition, the reason for inactivation for PSAC‐N catalysts is discussed. Of all the adsorption energies obtained, the adsorption capacity of hydrogen chloride on PSAC‐N is the highest, which indicates strong ability for acetylene hydrochlorination. The reaction mechanism is determined, and the reaction energy of N‐6v(7) calculated as 236.2 kJ mol −1 .