Acetylene hydrochlorination over tin nitrogen based catalysts: effect of nitrogen carbondots as nitrogen precursor

Abstract

The catalysts comprising the main active compounds of $Sn-N_x$ were synthesized using trichlorophenylstannane $((C_6 H_5 )Cl_3 Sn)$, nitrogen carbon-dots (NCDs), and activated carbon (AC) as starting materials, and the activity and stability of catalysts was evaluated in the acetylene hydrochlorination. According to the results on the physical and chemical properties of catalysts (TEM, XRD, BET, XPS and TG), it is concluded that NCDs@AC can increase $(C_6 H_5 )Cl_3$ Sn dispersity, retard the coke deposition of $(C_6 H_5 )Cl_3$ Sn/AC and lessen the loss of (C6 H5 )Cl3 Sn, thereby further promoting the stability of $(C_6 H_5 )Cl_3$ Sn/AC. Based on the characterization results of $C_2 H_2$ - TPD and HCl adsorption experiments, we proposed that the existence of Sn-Nx can effectively strengthen the reactants adsorption of catalysts. By combing the FT-IR, C2 H2 -TPD and Rideal-Eley mechanism, the catalytic mechanism, in which $C_2 H_2$ is firstly adsorbed on $(C_6 H_5 )Cl_3$ Sn to form $(C_6 H_5 )Cl_3 Sn-C_2 H_2$ and then reacted with HCl to produce vinyl chloride, is proposed.