Research Phenylphenol Catalytic Synthesis Of Copper-based Neighbors

O-phenylphenol (OPP), as an important fine chemical product, is widely used in antiseptics, plastic heat stabilizers and new flame retardants. With the development and application of new flame retardants DOPO, the demand for OPP is remarkably increased in both domestic and foreign markets. The process for the preparation of OPP uses cyclohexanone as the raw material, which comprises condensation of cyclohexanone to cyclohexanone dimmer and then dehydrogenation of cyclohexanone dimmer. For this process, dehydrogenation catalysts are the key factor. The catalyst usually uses Pt as active metal and γ-Al2O3catalyst, alkali metals as promoters. However, the noble metal platinum is expensive resulting in the cost of the catalyst is very high. In order to further reduce production costs, we take non-precious metals copper as the active component, so copper-based catalyst is prepared by a coprecipitation method and add Mn as the promoter in order to improve the catalytic activity and heat resistance.In this paper, Cu as the active component, MgO as the catalysis support, the Cu-based catalyst prepared by the coprecipitation method.The effects of CuO loading, calcination temperatures, reaction conditions on the catalytic activity of Cu-based catalysts were studied. These catalysts were characterized by XRD, BET, H2-TPR and TG-DTG techniques. The results showed that:(1) Cu-based catalysts prepared by the coprecipitation method had smaller crystallines of Cu and MgO, higher dispersion of Cu and larger dehydrogenation activity. When the CuO loading was35%, the Cu-based catalyst had a high conversion rate up to99.6%and the selectivity of OPP about90%when the reaction temperature at330℃, the feed speed for3mL/h, H2flow rate of20mL/min;(2) The calcination temperature was a significant factor. When Cu-based catalysts were calcinated at300℃, the catalyst precursors were decomposed incompletely, which would lead to the decrease of active sites, surface area and catalytic activity. When the calcination temperature increased to350℃, the copper precursor decomposed completely. The catalysts with sufficient active sites and surface area can satisfy the demand of dehydrogenation. However, the crystallines became larger and the dispersion of Cu became poorer when the calcination temperature was further increased, which would lead to the decrease of catalytic activity.(3) The addition of promoter of Mn on catalytic activity and selectivity is significant, the results show that the addition of Mn improves the dispersibility of the active ingredient, improve the activity and selectivity of the catalyst, but the obvious improvement in heat resistance of the catalyst;(4) Cu/MgO Catalyst stability of performance, using XRD, SEM, BET and other characterization methods for catalyst deactivation a preliminary exploration, the results show that the active component Cu sintered at high temperatures to cause grain aggregation and growth, the specific surface area decreased Cu dispersion, and therefore the active ingredient under high temperature sintering of Cu is the main reason for the decline of the activity of the catalyst dehydrogenation.