Modification Of Amorphous Ni-B Catalyst And Its Catalytic Synthesis Of Furfural Hydrogenation

Cyclopentanone is a kind of important fine chemical intermediates. It is also drugs, pesticides, herbicides and perfume raw materials. Cyclopentanone has good solubility to resin in the electronics industry, so it is widely used as solvent. In addition, cyclopentanone is also used to synthesis of long chain alkane by condensation and hydrogenation. Furfural derives from biomass resources. Furfural synthesizes cyclopentanone by hydrogenating is a sustainable production line, so this research has important academic value and profound social significance.Furfural synthesizes cyclopentanone by hydrogenating has high pressure, low selectivity, poor stability and so on. The key to solving the problem is to develop a high performance catalyst of hydrogenation.In this paper, a series of Ni-B and Ni-M-B(M = Cu、Co、Zn、Cr、Mo、Fe、Mg and Al) amorphous alloy catalysts were prepared by chemical reduction method and used in furfural hydrogenation to cyclopentanone.By surveying the effect of nickel source and boride nickel molar ratio on the structure and catalytic hydrogenation properties of amorphous Ni-B catalyst, we could understand that suitable nickel source was nickel chloride, the best boride nickel molar ratio was 4 : 1. The catalyst had good particle dispersion and uniform particle size under the optimum preparation conditions. The catalyst prepared by nickel nitrate was not an amorphous structure, and the catalyst prepared under the other conditions presented an amorphous structure. The TG curve of the catalyst prepared by nickel nitrate was not weight gain phenomenon, and the TG curve of the catalyst prepared under other conditions showed a significant weight gain.The effect of different metals on the catalytic performance of Ni-B catalyst for hydrogenation of furfural was investigated. Adding a small amount of metal did not change the amorphous structure of the Ni-B catalyst. Amorphous Ni-B catalyst modified with different metal activity results for hydrogenation of furfural showed that adding the appropriate amount of Cu and Co would help to improve the catalytic hydrogenation properties of amorphous Ni-B catalyst for hydrogenation of furfural(Cu(xCu = 5%) > Co(xCo = 3%)) and adding Zn, Cr, Mo, Fe, Mg and Al had adverse effects on th e catalytic hydrogenation properties of amorphous Ni-B catalyst for hydrogenation of furfural.The amorphous Ni-B catalysts modified with Cu were characterized by means of XRD, nitrogen adsorption, SEM, H2-TPD and XPS, and the modification mechanism of Cu on amorphous Ni-B catalysts was studied. XRD results showed that the addition of Cu did not change the amorphous structure of Ni-B catalyst. SEM results showed that when xCu = 5%, spherical particles of the catalyst was more complete, better dispersion, more uniform particle size, no agglomeration, the surface area of the catalyst and hydrogenation activity center increased, which greatly promoted the reactant adsorption and reaction on the catalyst surface, and product desorption process. H2-TPD results showed that Ni-B and Ni-Cu-B amorphous catalysts had two desorption peak, which indicated that there were two kinds of hydrogen adsorption centers, and two high temperature desorption peaks were attributed to the chemisorption desorption of H2. The area of desorption peak was obviously increased when xCu = 5%, which showed the interaction between Cu and Ni, leaded to the degree of adsorption of hydrogen changed, the number of active centers increased, so that the adsorption of hydrogen species was more easy to flow on the catalyst surface and participate in the reaction, it was helpful to improve the activity of the catalyst. XPS results showed that the chemical environment of the catalyst was changed after the addition of Cu promoter, partial electron transfered from alloying B to metallic Ni, making Ni electron-rich.The optimal reaction conditions of amorphous Ni-Cu-B catalyst for furfural hydrogenation to cyclopentanone were obtained by using the single factor optimization method. The optimum reaction temperature, hydrogen pressure, reaction time and solvent ratio were 160 ℃, 0.8 Mpa, 6 h and 5 : 1, respectively. Under these conditions, the conversion of furfural was 100%, the selectivity and yield of the cyclopentone were 52.9% and 52.9%, respectively. Through the investigation of the active stability of amorphous Ni-Cu-B catalyst, it was found that the catalyst still keeps the activity after 5 times, indicated that the catalyst has better activity stability. By characterization and analysis of the catalyst after using 5 times, we could found that the specific surface area and pore volume of catalyst reduces, and agglomeration or unknown blobs were produced. But its amorphous structure unchanged, which indicates that the active center of catalysts may appear deactivation because of the agglomeration or unknown block coverage.