Formation Of Active Copper Species And Ethynylation Performance On Copper-based Catalyst Of Formaldehyde Ethynylation

1,4-butynediol is an important organic chemical raw material, which can be extended downstream to obtain 1,4-butanediol and a series of important high value-added chemicals.1,4-butynediol is produced industrially by formaldehyde ethynylation process. Although several sets of 1,4-butynediol devices were built in China, the ethynylation catalyst, the core of the technology, has been monopolized by foreigner. The research and development of ethynylation catalyst are widely concerned by industry and academia.In this thesis, CuO-Bi2O3/SiO2-MgO catalyst was prepared by the coprecipitation method. The effects of different activation process on formation and ethynylation performance of active copper species on CuO-Bi2O3/SiO2-MgO catalyst were studied comparatively. On this basis, the effects of CuO grain size and interaction between CuO and Bi2O3 species on formation and ethynylation performance of active copper species in the CuO-Bi2O3 catalyst activation process were further studied. The inherent correlation of the presence state of copper species and the role of Bi2O3 species and ethynylation performance of the catalyst were explored. The main results of this thesis were as follows:1. CuO-Bi2O3/SiO2-MgO catalyst was prepared by the coprecipitation method. The transformation of copper species in two different activation processes was studied comparatively. The results showed that the catalyst activated in the presence of formaldehyde and acetylene exhibited high ethynylation performance, while the catalyst activated in the presence of acetylene after reduced firstly by formaldehyde to Cu2O showed poor ethynylation performance. The characterization of the status of intermediate species Cu2O showed the cause of this result is probably the growth of Cu2O grain size during the formaldehyde reduction, which resulted in the decrease of the number of cuprous acetylide activity center.2. Besides the grain size of the copper species, interaction between CuO and Bi2O3 species may also be an important factor affecting the ethynylation performance of the catalyst. Refering the results and methods of the first part, CuO-Bi2O3 unsupported catalyst was prepared by coprecipitation. Formation and ethynylation performance of active copper species on CuO-Bi2O3 unsupported catalyst with different CuO grain sizes and CuO-Bi2O3 interaction in the presence of formaldehyde and acetylene were studied. The effects of the CuO grain size and the interaction between CuO and Bi2O3 species on ethynylation performance of the catalyst were discussed. The results showed that, besides the CuO grain size, the interaction between CuO and Bi2O3 species was also an important factor affecting the catalytic activity. When the CuO crystallite size is less than 36 nm and the interaction between CuO and Bi2O3 species is appropriate, CuO is effectively converted to the active species of cuprous acetylide in the presence of formaldehyde and acetylene. When the grain size of CuO was further increased, CuBi2O4 solid solution was formed and CuO and Bi2O3 species exhibited strong interactions, the transformation of CuO to cuprous acetylide species was hindered and the ethynylation performance of the catalyst was reduced.