Construction And Catalytic Properties Of Nano-copper Base Catalysts

Currently, the issue of resource shortage has been increasingly prominent, how to improve the utilization of limited resources, become the general attention of the researchers, efficient and rational utilization of catalyst has become more important. Now widely used catalyst are mainly gold, silver, palladium, platinum and other precious metal catalysts, but they have limited reserves and high price. And copper base catalyst is cheap, abundant, excellent in properties, is regarded as a kind of ideal catalyst instead of noble metal catalysts. The traditional homogeneous copper base catalysts mostly have the shortcomings of difficult to recycle, easy to reunite, easy to sinter, easy to oxidation. This paper aims to obtain a high stability, highly active, easy recycling of new copper base catalyst.In this paper, first of all, three kinds of external load type copper base catalysts were prepared based on the electrostatic spinning technology, combined with the gas phase(liquid phase) reduction method and high temperature carbonization technology, and theirs catalytic performance to Ullmann coupling reaction were explored; then 4A zeolite load copper catalyst was prepared by impregnation method and hydrogenation reduction method, and its catalytic performance to dimethyl oxalate gas phase hydrogenation to make ethylene glycol was explored. Concrete research content is as follows:1. The polymer fiber load copper catalyst was prepared by electrostatic spinning technology, impregnation method, gas phase reduction method(hydrogenation), then the carbon fiber load copper catalyst was prepared through high temperature carbonization technology, the catalysts were characterized by Fourier transform infrared spectrum(FT-IR), scanning electron microscopy(SEM), transmission electron microscope(TEM) and X-ray photoelectron spectroscopy(XPS) and their catalytic performance in Ullmann coupling reactions were inspected. The results showed that when the Ullmann coupling reactions were investigated under 82 ℃, acetonitrile as the solvent and cesium carbonate as alkali, the two kinds of catalysts have a certain catalytic activity to the reactions, but the catalyst performance needs to be improved.2. Combined with previous research content, to improve catalyst reduction method, the carbon fiber load copper catalyst was prepared by liquid phase reduction method(sodium borohydride and hydrazine hydrate) in combination with high temperature carbonization technology. The catalyst was characterized by Fourier transform infrared spectrum(FT-IR), scanning electron microscopy(SEM), transmission electron microscope(TEM), X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD) and proven the optimal reaction conditions to catalytic Ullmann coupling reactions:N, N-dimethyl acetamide as solvent, cesium carbonate as alkali, catalyst dosage is 0.09 g, reaction under 140 ℃ for 24 h; then, the expansion investigation of Ullmann coupling reaction substrates has confirmed that this catalyst has universality to the Ullmann coupling reaction. Finally the catalyst’s recycling performance were inspected, the results showed that the catalyst still has a certain catalytic activity after circulation use for five times.3. With 4A zeolite as the carrier, 4A zeolite load copper catalyst was prepared by impregnation method combined with hydrogenation reduction method. The catalyst was characterized by Field emission scanning electron microscope(FESEM), X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD) and proven the optimal reaction conditions to catalytic dimethyl oxalate gas phase hydrogenation to make ethylene glycol: When liquid hourly space velocity set as 0.1 h-1, H2/DMO is 200, reaction temperature is 220 ℃, pressure is 2.5 MPa, and on this condition, the catalyst can maintain its stability.In short, the nano-copper load on the surface of polymer fibers and carbon fibers, not only can improve the dispersion of nano-copper, effectively prevent the agglomeration of nano-copper, but also make the catalyst easy to recycle, improve the circulation use performance of catalyst. The 4A zeolite load nano-copper catalyst can also overcome the copper base catalyst’ shortcomings such as easy to sinter and easy to oxidation, has improved the stability of copper base catalyst. This will provide a new train of thought to prepare the new nano-copper base catalyst and the theoretical references for the industrial application of nano-copper base catalyst.