Preparation Of Difunctional Nickel-Supported Catalyst And Its Application For Hydroconversion Of Arenes And Aryl Ethers

Hydrogenation of aromatic hydrocarbons and aromatic ethers is a key issue in the utilization of heavy carbon resources. The development of highly active supported metal catalysts is the key technology for the hydroconversion of aromatics. Nickel is the main component of the catalyst for the hydrogenation of aromatic compounds; Ni(CO)4 decomposited at low temperature directly to generate nickel particles, but the nickel carbonyl volatilization temperature is low, so it is extremely difficult to decompose on the carrier stability. In this paper, Ni(CO)4 was used as the precursor for nickel and then it was dissolved into diethyl ether mixed with zeolitre 5A(Z5A) in an zutoclave by the method of in-situ decomposition. The catalyst was charactered by transmission electron microscopy transmission electron microscope(TEM), energy dispersive spectrometer(EDS), X-ray diffraction(XRD), H2 temperature programmed reduction(H2-TPR), NH3-temperature-programmed desorption(NH3-TPD), X-ray photoelectron spectroscopic spectrum(XPS) and Fourier transform infrared(FTIR). The results showed that the metal load was lower, which dispersion in molecular sieve even in the form of noncrystalline state, metal nickel and support with strong interaction.Through the hydrogenation of 9-phenylanthracene and benzyl phenyl ether on Ni/Z5 A, we find Ni/Z5 A has good hydrotreating effect on 9-phenylanthracene and benzyl phenyl ether at 200 oC and the main products are 9-cyclohexyltetradecahydroanthracene and methylcyclohexane. Ni/Z5 A proved to have difunctions, which includes activating H2 to biatomic active hydrogen and heterolytically splitting H2 to H+ relatively free from Ni/Z5 A and H- adsorbed on Ni/Z5 A. We further research the catalytic hydrogenation products and its variation of naphtha-1-ol and oxybis(methylene)dibenzene(OBMDB) at 200 oC. Over Ni/Z5 A, the catalytic hydroconversion of naphtha-1-ol and OBMDB proceed via biatomic active hydrogen and H+ transfer to mainly produce tetralin and decalin from naphtha-1-ol and methylcyclohexane and toluene from OBMDB. Ni/Z5 A could be recycled for several times and it was passivated due to the agglomeration of supported nickel caused by long-time catalyzing reaction.In order to explore the industrial application value of the catalyst, the Ni/Z5 A was used to catalyze the hydrogenation conversion of low temperature coal tar(LTCT), high temperature coal tar(HTCT) and pitch volatile(PV). As detected by gas chromatography/mass spectrometry(GC/MS), the industrial oil were excellent hydrogenation upgrading, aromatic depth or even completely hydrogenation and heteroatoms especially oxygen were removed in LTCT.We adapt the methanol-soluble portion(MSP) at 300 oC for 3 h from Xiaolongtan lignite(XL) as the inferior oil for the hydrogenation at 200 oC to afford catalytically hydrogenated MSP(HMSP). XL and its residue(RXL) were analyzed with XPS and thermogravimetry analysis(TA). We used FTIR to the functional groups in XL, RXL, MSP and HMSP to study the change of the functional groups in the samples. Detailed molecular compositions of MSP and HMSP were characterized with GC/MS, positive- and negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometer(ESI FT-ICR MS). According to analysis with GC/MS, MSP is rich in aromatic ring- and heteroatom-containing compounds, while most of the compounds analyzed by GC/MS in HMSP are chain alkanes and cyclane. The analysis with ESI FT-ICR MS shows that the oxygen- and nitrogen-containing species in MSP were obviously reduced after hydrogenation.