Promotion of Cu-based catalyst by supported ionic liquid for efficient acetylene hydrochlorination

• A non-precious metal catalyst was prepared for acetylene hydrogenation: an ionic liquid modified Cu based catalyst (Cu-[Hnmpo] H 2 PO 4 /AC). • Under reaction conditions close to industrialization, the catalyst achieved a conversion of 89.16 % for acetylene and a selectivity of over 99 % for vinyl chloride. • The ionic liquid coordinated with Cu through P atoms, which not only enhanced the stability of Cu, but also modulated its electronic properties, made it more electropositive, and stabilized Cu (II) active species. Therefore, the ability of Cu to activate acetylene and HCl was enhanced. The Cu-based catalyst is a highly promising non-precious metal catalyst for acetylene hydrochlorination. Its activity and stability need to be improved. A specific ionic liquid, [Hnmpo]H 2 PO 4 , was developed to modulate the activated carbon-supported Cu (Cu/AC), and a supported ionic liquid-metal catalyst (Cu-[Hnmpo] H 2 PO 4 /AC) was prepared. With a n (Cu): n (N) molar ratio of 2:1, the catalyst achieved 89.16 % acetylene conversion and >99 % vinyl chloride selectivity under near-industrial conditions (150 °C, GHSV(C 2 H 2 )=50 h⁻¹, HCl/C 2 H 2 =1.0). Characterizations and theoretical calculations revealed that ionic liquids increased the stability and anti-carbon-deposition ability of Cu. Ionic liquids modulate the electronic properties of Cu through H 2 PO 4 - anion. The active species in Cu (II) valence state were stably maintained, thereby promoting the activation of acetylene and HCl.