2-Butanol Dehydrogenation Over Copper-Based Catalysts

Since much is known that Methyl-ethyl-ketone (MEK) is widely used in oil refining, dope and medicine etc. with low boiling point as excellent organic solvent. Recently, Cu-Zn alloy, Zinc oxide and copper with promoter as catalysts have been widely applied in the dehydrogenation of 2-butanol to produce MEK. Copper with promoter catalysts is better than traditional solid catalysts in the high temperature reaction. The copper-based catalysts are now a mature technology and widely used in chemical industrial. So design and preparation of high active copper catalysts with low reaction temperature is an area of extensive research.In this paper, vapor-phase dehydrogenation of 2-butanol into MEK was examined over copper-based catalysts that were prepared by some methods such as impregnation and co-precipitation. The additive effects of promoter on copper-based catalysts were examined by XRD, TPD and TPR technique. Then we attempted to shape the high active copper catalysts and prepare the nanoparticle Cu-ZnO catalyst. The nano-Cu catalyst was prepared using the liquor phase precipitation method and nano-ZnO catalyst was prepared using the precipitation method. Then rubbing nano-Cu catalyst and nano-ZnO catalyst produced the nanoparticle Cu-ZnO catalyst.Cu-ZnO/Na-SiO2 catalyst was prepared via the incipient wetness impregnation method, and the catalytic activity of the catalyst in gas phase dehydrogenation of 2-butanol was studied at 543K and 3h-1. The results indicated that under the copper content was 8%, the ratio of Cu and Zn was controlled at 2/1 and Na content was 0.5%, the optimal conversion of 2-butanol was more than 93.6% and the selectivity to MEK was more than 98.0%. Na is an excellent pretreatment for both decrease the particle size of active Cu and strengthen the interaction between Cu and SiO2. The smaller Cu particle size can increase the activity of the catalysts and the more strongly interaction between Cu and SiO2 can promote the stability of the catalysts. In the end, the used time of Cu-ZnO/Na-SiO2 catalyst is shorter than the used time of commercial catalyst.Besides, a series of Cu-ZnO-MgO catalysts was prepared via the coprecipitation method, with various MgO content. The catalytic activity of Cu-ZnO-MgO catalyst in gas phase dehydrogenation of 2-butanol was studied at 543K and 3h-1. The results indicated that: the catalysts can obtained high catalytic activity by precipiting at 353K and calcining at 723K, the optimal conversion of 2-butanol was more than 93% and the selectivity to MEK was more than 99.0% under the ratio of Cu and Zn was controlled at 1/3 and MgO content was 0.3%. MgO is an excellent promoter for decrease the particle size of active Cu, and the smaller Cu particle size can increase the activity of the catalysts. In the end, the used time of Cu-ZnO catalyst is equal to or longer than commercial catalyst.In addition, nano-Cu, nano-ZnO and nanoparticle Cu-ZnO were respectively prepared as catalysts and the catalytic performance was investigated in gas phase dehyrogenation of 2-butanol. We found that the nanoparticle Cu-ZnO catalyst exhibited excellent catalytic activity and high stability. It because that the interaction between Cu and ZnO can decrease and stable the particle size of Cu. Among the additives, SiO2+C and Al2O3 are the best additives in shapping catalyst. The catalysts shapped by SiO2+C and Al2O3 can obtained high conversion of 2-butanol and high selectivity to MEK, and the intensity of the catalysts can be accomplished to industrialisation preliminary.