Study On Catalytic Performance Of Copper - Based Catalysts For Synthesis Of O - Phenol

O-phenylpheol (OPP) is an important fine chemical engineering product. It has the wide spread use in heat stability solvent, medicine, dyeing auxiliary, biocide, etc. In industry, the noble metal as the active ingredient was used to transfer cyclohexanone dimer into o-phenylpheol, however the cost of production is high. In this work, we used the non-noble metal as the active metal to improve non-noble catalysts activity and stability.Firstly, the catalyst precursor was prepared via co-precipitation method with different Cu/Ni molar ratio, A series of catalysts were obtained by the calcilnation and reduction of the catalyst precursor. SEM images show that introduction of a small amount of Ni can optimize the hydrotalcite-like compound structure., the orginial OPP selectivity can be improved. The highest selectivity reaches up to 72.47% when Cu:Ni:Mg:Al molar ratio is 2:0.5:3.5:2. Further to introduce Ni, the catalysts stability is obviously enhanced., when Cu:Ni:Mg:Al molar ratio is 1.5:1:3.5:2, the stability isthe best after 6 h. The OPP selectivity can reach 59.37%.Then the catalyst precursor was prepared via co-precipitation method with different Al/Zr molar ratio,adopting co-precipitation method to prepare catalysts precursor, after calcination and reduction can obtain a series of catalysts. The experimental results show that introduction of Zr can control the size of copper nanoparticles, improve the Cu surface dispersibility. With the appropriate Zr content, the size of copper nanoparticle becomes smaller, and the corresponding catalytic performance is enhanced. When Cu:Mg:Al:Zr molar ratio is 2.5:3.5:1.5:0.5, the proportion of strong basic site reaches maximum, its OPP selectivity can reach up to 85.85%. However, there is no obvious enhancement for the stability. Cu nanoparticle is sintering after reaction, so reduce the aggregation of Cu is the essential part in next stage.Finally, the catalyst precursor was prepared impregation method, using CNTs as the carrier in order to loading metal solution inside and outside CNTs, respectively. A better OPP selectivity (the maximum value 51.89%) can be obtained with loading active metal on the outsides of CNTs, however, the catalytic stability become bad. For inside CNTs, its OPP selectivity is not perform well, but its stability perform good. The OPP selectivity can stabilize between 35% and 50%. There is an obvious difference for catalytic activity between the co-precipitation and impregation methods.