4431-89-4Relevant academic research and scientific papers
Promising Ni/Al-SBA-15 catalysts for hydrodeoxygenation of dibenzofuran into fuel grade hydrocarbons: Synergetic effect of Ni and Al-SBA-15 support
Gbadamasi, Sharafadeen,Ali, Tammar Hussein,Voon, Lee Hwei,Atta, Abdulazeez Yusuf,Sudarsanam, Putla,Bhargava, Suresh K.,Abd Hamid, Sharifah Bee
, p. 25992 - 26002 (2016/03/25)
This work has been undertaken with the aim of designing promising noble-metal-free catalysts for efficient hydrodeoxygenation (HDO) of dibenzofuran (DBF) into fuel grade hydrocarbons. For this, various Ni/Al-SBA-15 catalysts with different Si/Al (50, 60, 70 and 80) mole ratios were synthesized and their catalytic performance was tested for HDO of DBF in a batch reactor. The catalysts were systematically characterized using XRD, N2-adsorption-desorption, Raman, H2-TPR, NH3-TPD, XRF, and FESEM techniques. The activity results showed that the HDO of DBF proceeds via hydrogenation of benzene on the Ni sites followed by cleavage of C-O bonds on the acidic sites of the catalyst to yield unsaturated hydrocarbons. Further hydrogenation of unsaturated hydrocarbons on the Ni sites gives bicyclohexane as the major product. Remarkably, a 100% DBF conversion was found for all the catalysts except for Ni/SBA-15 and Ni/Al-SBA-15(80) (Si/Al mole ratio = 80) catalysts, which showed 97.97 and 99.31%, respectively. A significant observation noticed in this study is that the incorporation of Al into Ni/SBA-15 results in an outstanding improvement in the selectivity of the bicyclohexane product. Among the catalysts tested, the Ni/Al-SBA-15(50) (Si/Al mole ratio = 50) catalyst showed the highest efficiency, with superior selectivity of ～87% for bicyclohexane and ～96% degree of deoxygenation at 10 MPa, 260 °C and 5 h. The obtained structure-activity results reveal the synergetic effect of Ni and support in HDO of DBF reaction: the concentration of acidic sites has a significant effect on the selectivity of the desired products.
Nickel and cobalt phosphides as effective catalysts for oxygen removal of dibenzofuran: Role of contact time, hydrogen pressure and hydrogen/feed molar ratio
Infantes-Molina,Gralberg,Cecilia,Finocchio, Elisabetta,Rodríguez-Castellón
, p. 3403 - 3415 (2015/06/08)
The catalytic activity of nickel and cobalt phosphides, with a metal loading of 5 wt.%, supported on silica was investigated in the hydrodeoxygenation reaction (HDO) of dibenzofuran (DBF) as a model oxygenated compound at different contact times, H2 pressures and H2/DBF molar ratios. The aim of the study was to understand the mechanism of the reaction and to study the impact of H2 pressure and H2/DBF molar ratio on the reaction. The catalysts were characterized by N2 adsorption-desorption isotherm measurement at -196°C, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), CO chemisorption, NH3 Temperature-Programmed Desorption (NH3-TPD), IR spectroscopy and H2 Temperature-Programmed Desorption (H2-TPD). The prepared catalysts were tested in the HDO reaction of DBF in a continuous-flow fixed-bed stainless steel catalytic reactor at pressures ranging from 1-30 bar at 275°C. The results obtained indicate that the Ni2P catalyst is more active than the CoP catalyst, converting more than 90% of DBF at the highest contact time into oxygen-free products. The activity of both catalysts increases with increased contact time. At low contact times, the intermediates tetrahydrodibenzofuran (THDBF) and hexahydrodibenzofuran (HHDBF) are observed as products, while an increment in the contact time led to the transformation of THDBF and HHDBF into O-free compounds, mainly bicyclohexane (BCH), indicating that the HDO of DBF follows the path: DBF → HHDBF → THDBF → 2-CHP → BCH. Further, both Ni2P and CoP catalysts are active at medium pressures with HDO degrees similar to those obtained at 30 bar. Ni2P is less affected by the changes in H2/DBF ratio than CoP and the catalysts are more active at high H2/DBF molar ratios.
Highly selective self-condensation of cyclic ketones using MOF-encapsulating phosphotungstic acid for renewable high-density fuel
Deng, Qiang,Nie, Genkuo,Pan, Lun,Zou, Ji-Jun,Zhang, Xiangwen,Wang, Li
, p. 4473 - 4481 (2015/08/11)
Transferring biomass-derived cyclic ketones such as cyclopentanone and cyclohexanone to a mono-condensed product through aldol self-condensation has great potential for the synthesis of a renewable high-density fuel. However, the selectivity is low for numerous catalysts due to the rapid formation of di-condensed by products. Herein, MIL-101-encapsulating phosphotungstic acid is synthesized to catalyze the self-condensation with selectivity of more than 95%. PTA clusters are uniformly dispersed in MOF cages and decrease the empty space (pore size), which provides both acidic sites and shape-selective capability. The optimal PTA amount decreases corresponding to the increase of reactant size. The shape-selectivity is also realized by changing the pore size of MOF such as from MIL-101 to MIL-100. Moreover, the catalyst is resistant to PTA leaching and performs stably after 5 runs. After hydrodeoxygenation of the mono-condensed product, high-density biofuels with densities of 0.867 g ml-1 and 0.887 g ml-1 were obtained from cyclopentanone and cyclohexanone, respectively. This study not only provides a promising route for the production of high-density biofuel but also suggests the advantage of MOF-based catalysts for shape-selective catalysis involving large molecular size.
Hydrodesulfurization of dibenzothiophene, 4,6-dimethyldibenzothiophene, and their hydrogenated intermediates over bulk tungsten phosphide
Yang, Lei,Li, Xiang,Wang, Anjie,Prins, Roel,Chen, Yongying,Duan, Xinping
, p. 330 - 343 (2015/09/01)
The kinetics of the hydrodesulfurization (HDS) of dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), and their hydrogenated intermediates over bulk tungsten phosphide (WP) was studied. WP possessed high hydrogenation/dehydrogenation activity but was highly sensitive to piperidine inhibition. 4,6-DMDBT reacted faster than DBT, and both DBT and 4,6-DMDBT reacted mainly through the hydrogenation pathway. The methyl groups suppressed the direct desulfurization of 4,6-DMDBT but significantly promoted the hydrogenation of 4,6-DMDBT and the dehydrogenation of 1,2,3,4-tetrahydro-4,6-dimethyldibenzothiophene (TH-4,6-DMDBT) and 1,2,3,4,4a,9b-hexahydro-4,6-dimethyldibenzothiophene, but decreased the rate of hydrogenation of TH-4,6-DMDBT. Piperidine inhibited the HDS of 4,6-DMDBT much more strongly than that of DBT. Substantial dehydrogenation of TH-4,6-DMDBT to 4,6-DMDBT and two of its isomers occurred. The formation of these 4,6-DMDBT isomers in the dehydrogenation of TH-4,6-DMDBT and the hydrocracking of 1-methyl-4-(3-methylcyclohexyl)-benzene, as well as the formation of cyclopentylphenylmethane and (cyclopentylmethyl)cyclohexane, is ascribed to the metallic character of WP.
