Abstract
Catalytic systems consisting of copper oxide and bismuth oxide are commonly employed for the industrial production of 1,4-butynediol (BD) through ethynylation. However, few studies have investigated the influence mechanism of Bi for these Cu-based catalysts. Herein, a series of nanostructured CuO-Bi2O3 catalysts were prepared by co-precipitation followed by calcination at different temperatures. The obtained catalysts were applied to the ethynylation reaction. The textural and crystal properties of the catalysts, their reduction behavior, and the interactions between copper and bismuth species, were found to strongly depend on temperature. When calcined at 600 °C, strong interactions between Cu and Bi in the CuO phase facilitated the formation of highly dispersed active cuprous sites and stabilized the Cu+ valency, resulting in the highest BD yield. Bi2O3 was completely absent when calcined at 700 °C, having been converted into the spinel CuBi2O4 phase. Spinel Cu2+ was released gradually to form active Cu+ species over eight catalytic cycles, which continuously replenished the decreasing activity resulting from the formation of metallic Cu and enhanced catalytic stability. Moreover, the positive correlation between the in-situ-formed surface Cu+ ions and BD yield suggests that the amount of Cu+ ions is the key factor for ethynylation of formaldehyde to BD on the as prepared CuO-Bi2O3 catalysts. Based on these results and the literature, we propose an ethynylation reaction mechanism for CuO-based catalysts and provide a simple design strategy for highly efficient catalytic CuO-Bi2O3 systems, which has considerable potential for industrial applications.
Highlights
In the early 1900s, Alexei Favorskii first reported the addition of alkynes to carbonyl compounds in basic media to form alkinols, which was further developed into a known reaction process by Reppe [1]
Due to the numerous applications of chemicals derived from BD, such as 1,4-butanediol (BDO), 3-butene-1-ol (BTO), tetrahydrofuran (THF), poly(tetramethylene ether) glycol (PTMEG), γ-butyrolactone (GBL), and poly(butylene succinate) (PBS), among others [4,5,6], which are in high demand in the chemical, polymer, pharmaceuticals, and textiles industries [7,8,9,10,11], the design of highly efficient ethynylation catalysts for the synthesis of BD is of great significance
A series of nanostructured CuO-Bi2 O3 catalysts was prepared using simple coprecipitation methods followed by calcination at different temperatures, after which they were applied to the ethynylation of formaldehyde to produce BD
Summary
In the early 1900s, Alexei Favorskii first reported the addition of alkynes to carbonyl compounds in basic media to form alkinols, which was further developed into a known reaction process by Reppe [1]. The phase transformation from CuO to the active cuprous species involves reduction and carbonization processes [14,15]. The preparation process, especially calcination temperature, has been shown to greatly impact particle size, the crystalline phase, and the interactions between different components in the catalyst, which can substantially affect catalytic performance [25,26,27,28]. The results revealed that there are various degrees of interaction between the copper and bismuth species among catalysts calcined at different temperatures, and the formation of a spinel CuBi2 O4 phase was observed, which greatly influences catalytic activity and stability, and supplements the theoretical basis for the development of highly efficient ethynylation catalysts
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
