The typical physicochemical properties of these catalysts were characterized by X-Ray Diffraction (XRD), N 2 absorption-desorption, Pyridine-Fourier Transform Infrared (Py-FTIR), Transmission Electron Microscopy (TEM), X-Ray Fluorescence (XRF), Scanning Electron Microscopy (SEM) and NH 3-Temperature Programmed Desorption (NH 3-TPD), and the performance of these catalysts in n-dodecane hydroisomerization was evaluated in a continuous down-flow fixed bed with a stainless steel tubular reactor. The characterization results indicated that the intergrowth zeolite ZSM-22/ZSM-23 possessed the dual structure of ZSM-22 and ZSM-23, and the catalyst Pt/ZSM-22/ZSM-23 had similar pores and weak acidity to Pt/ZSM-22 and Pt/ZSM-23 catalysts. Moreover, Pt/ZSM-22/ZSM-23 catalyst showed a high selectivity in hydroisomerization of long chain n-alkanes to mono-branched isomers. The evaluation results for n-dodecane hydroisomerization indicated that the activity of Pt/ZSM-22/ZSM-23 was the lowest, while the hydroisomerization selectivity was the highest among the three catalysts. The maximum yield of i-dodecane product was 68.3% over Pt/ZSM-22/ZSM-23 at 320 ºC.

β/SBA-16 (BS) materials were fabricated using β-nanoclusters through self-assembly hydrothermal crystallization approach; subsequently, the corresponding NiMo/BS catalysts were synthesized. The influence of HCl concentration on the physicochemical properties of the composite support and the corresponding catalyst was investigated by a series of characterization methods. The hydrodesulfurization (HDS) performances were evaluated under the conditions of T = 340 °C, P H 2 = 4 MPa, and H 2 /oil (v/v) = 200 by adopting dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) as probe reactants. The results indicated that NiMo/BS-1.5 prepared under the HCl concentration of 1.5 mol L −1 exhibited the superior HDS performance due to its well-ordered shape and pore channel, high sulfidation degree, moderate acidity, and suitable metal−support interaction (MSI). In addition, the potential HDS reaction networks for DBT and 4,6-DMDBT of series NiMo/BS were presented.

No abstract

Hydrogenation of naphthalene can effectively reduce the content of aromatics in oil and generate high-value products. A series of Pt-based aluminum-modified core–shell-structured hierarchically periodic mesoporous organosilica@mesoporous silica nanoparticles (Pt/Al-x-PMOs@MSNs) were successfully synthesized and tested for the hydrogenation properties, with preferable mass transfer of macromolecular reactants in the pores and increasing the total acidity of the catalysts. Moreover, the physicochemical properties of the core–shell-structured Pt-based catalysts were systematically analyzed using various characterization techniques. At 300 °C, the naphthalene conversion on the Pt/Al-10-PMOs@MSNs catalyst reached up to 100%, the selectivity of trans-decalin reached 83.9%, and the rate constants (k 1, k2) and TOF were 13.2 × 10–6 mol·g–1·s–1, 1.7 × 10–7 mol·g–1·s–1, and 218.8 h–1, respectively. In the presence of sulfur, the naphthalene hydrogenation over the Pt/Al-10-PMOs@MSN catalyst first decreased to around 40% and then recovered to the original level, which originated from the synergistic effect of the texture and chemical properties over the Pt/Al-10-PMOs@MSNs with an excellent performance.

Nobel metallic Pt/ZSM-22 and Pt/ZSM-23 catalysts were prepared for hydroisomerization of normal dodecane and hydrodewaxing of heavy waxy lube base oil. The hydroisomerization performance of n-dodecane indicated that the Pt/ZSM-23 catalyst preferred to crack the C–C bond near the middle of n-dodecane chain, while the Pt/ZSM-22 catalyst was favorable for breaking the carbon chain near the end of n-dodecane. As a result, more than 2% of light products (gas plus naphtha) and 3% more of heavy lube base oil with low-pour point and high viscosity index were produced on Pt/ZSM-22 than those on Pt/ZSM-23 while using the heavy waxy vacuum distillate oil as feedstock.