Effective Performance of the Cu/Zn/SiO2 Catalyst Applied in the Ethynylation of Formaldehyde for 1,4-Butynediol Synthesis

1,4-Butynediol synthesized from the ethynylation reaction of formaldehyde catalyzed by Cu-based catalysts has been of much concern. The stability of a Cu-based catalyst under a reducing atmosphere is still a serious challenge. Herein, a series of Cu/Zn/SiO2 catalysts were prepared by a deposition precipitation method and applied in the ethynylation of formaldehyde for 1,4-butynediol synthesis. The ethynylation of formaldehyde reaction conditions was optimized, and the activation energy was calculated. Compared with 30Cu/SiO2, 30Cu15Zn/SiO2 increases the yield of 1,4-butynediol from 27 to 72% and decreases the reaction activation energy from 28.02 to 15.86 kJ/mol, which improves the catalytic reaction efficiency. The experimental results also show that 30Cu15Zn/SiO2 and commercial catalysts are well-matched in activity and stability. All catalysts were carefully characterized by different techniques. The results show that ZnO in the Cu/Zn/SiO2 catalyst plays an important role in dispersing and decreasing the CuO particle size. Moreover, the strong Cu–Zn interaction in the CuO and ZnO interface is beneficial to stabilize the Cu2C2 intermediate, which effectively improves the catalyst performance. Additionally, the appropriate amounts of alkaline sites and oxygen vacancies brought from ZnO are also conducive to activating C2H2 to form Cu2C2.