Petroleum Chemistry最新文献

For the first time, the study systematically investigates, the effects of the partial pressures of CO and H₂ on Fischer–Tropsch performance in a slurry bubble column reactor (SBCR) over an iron-based nanodispersion. It is shown that, over the tested temperature range, both decreasing CO partial pressure and increasing H₂ partial pressure enhance CO conversion. At CO/H₂ molar ratios of 1 : 1.5 to 1 : 2, reactor pressures of 1.9–2.2 MPa, and temperatures of 240–300°C, methane and C₂–C₄ hydrocarbons are selectively produced. On the other hand, at CO/H₂ = 1 : 1, 1.5–2.0 MPa, and 280–300°C, the predominant products were C₅₊ hydrocarbons. The CO/H₂ molar ratios of 1 : 1 to 1 : 2, 1.5–2.2 MPa, and 240–260°C are the optimal reaction conditions to maximize the selectivity towards oxygenates. The XRD data for the spent catalysts corroborate the correlations identified during the catalytic test.

This study proposes a method for selectively producing diesel-range hydrocarbons by combining Fischer–Tropsch synthesis (FTS) over a zeolite-supported catalyst with the oligomerization of C₅–C₁₀ alkenes over an H-Beta zeolite. FTS was carried out under gas recirculation conditions (H₂/CO = 1.85, 2.0 MPa). At a recirculation ratio of 16, the diesel content in the product increased to 54.6 wt %, compared to 38.7 wt % under flow-through conditions. Finally, by oligomerizing the alkene-enriched gasoline fraction from the FTS over H-Beta-18, the overall diesel fuel content was enhanced to 69%.

This study presents the first investigation into the hydrodeoxygenation (HDO) of syringol (2,6-dimethoxyphenol) and 2-methoxyhydroquinone—model compounds for lignin depolymerization products—using in situ synthesized NiMoS nanocatalysts. The catalysts were formed from oil-soluble precursors (Mo(CO)₆ and Ni(II) 2-ethylhexanoate) and elemental sulfur. By varying the reaction conditions (300–350°C, 1–7 MPa H₂, 15–300 min, and substrate-to-Mo molar ratios of 10.5 : 1 to 105.3 : 1), product distribution can be controlled to achieve 100% conversion and high yields of deoxygenated products, primarily cyclohexane. Characterization by XRD, HR-TEM, and XPS revealed that the catalyst formed during syringol conversion consisted of highly dispersed three-layer nanoparticles (average length: 4.3 nm), dominated by MoS₂ (81.5%) and a Ni–Mo–S active mixed phase (80.4%). The proposed HDO pathway for syringol proceeds through initial demethoxylation to guaiacol and phenol, followed by their subsequent deoxygenation and hydrogenation.

This study investigates the synthesis and performance of iron–polymer composite catalysts for the conversion of syngas to higher alcohols. A promoted Fe–polyvinyl alcohol (PVA) composite catalyst, with a formulation denoted as 20Fe/2Al–2Mn–2K–2V/PVA, was synthesized via the organic matrix method. Its physicochemical properties and catalytic performance were evaluated. X-ray diffraction (XRD) analysis and Fourier transform infrared (FTIR) spectroscopy revealed that heat treatment facilitated the formation of active phases (Fe₃O₄, χ-Fe₅C₂, and Fe₇C₃), which were stabilized within a carbon matrix featuring a polyconjugated bond network. The resulting composite exhibited high catalytic activity in CO hydrogenation following hydrogen pre-reduction. The reduced catalyst achieved 82% CO conversion at 320°C, and the content of higher alcohols in the hydrocarbon phase reached 27 wt % with a marked predominance of heavy alcohols (C₈₊/C₄–C₇ ratio ≈ 2.1).

Tandem reactions based on hydroformylation are an alternative route from olefins to the products of high value, whose classical synthesis procedures involve several steps. Reduction of the number of synthesis steps, equipment required, separation and purification procedures make tandem reactions promising for the development of less power- and resource-consuming procedures for producing a wide range of demanded compounds. Search for effective heterogeneous multifunctional catalysts for tandem reactions based on hydroformylation allows solving problems associated with the catalyst separation and recycling. The most important examples of using heterogeneous catalytic systems for reductive hydroformylation, hydroaminomethylation, hydroformylation– acetalization, and hydroformylation–aldol condensation are considered in this review. Key advantages in this field, operating principles of multifunctional catalysts, and the existing drawbacks that presently restrict the use of such catalysts are discussed.

This study investigates ammonia decomposition over a series of cobalt/silica gel catalysts with the loading of active metal varying from 2.1 to 32.4 wt %. The reaction was conducted in a continuous-flow reactor at temperatures between 400 and 550°C and a weight hour space velocity (WHSV) of 3000 h^–1. The catalysts were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X–ray diffraction analysis (XRD), multimolecular Brunauer–Emmett–Teller (BET) adsorption, and hydrogen temperature-programmed reduction (H₂-TPR). The results demonstrate that catalytic activity is dependent on cobalt content, with an optimal loading of 15–20 wt % providing the highest catalytic performance.

The composition of gaseous products formed during hydroupgrading of a model feedstock containing benzothiophene and 2-methylnaphthalene over unsupported (dispersed) Ni–Mo sulfide catalysts under the water gas shift reaction conditions (reaction of carbon monoxide with water) was studied. The influence of the reaction conditions (Т = 340–400°C, Р = 5 MPa (at 25°C), t = 4–10 h) on the conversion of individual feed components and composition of gaseous products was examined. The process conditions ensure in situ hydrogen generation (Н₂ content 25–30 vol %) and formation of hydrocarbon gases by methanation and hydrogenation of CO and СО₂ (СН₄ content up to 50 vol %, content of С₂–С₄ hydrocarbons 23–30 vol %). For the model feedstock with equimolar component ratio, at 360–380°C, CO pressure of 5 MPa (at 25°C), and water content of 10 wt %, the 2-methylnaphthalene conversion in 8–10 h does not exceed 30–34%, whereas for the benzothiophene it reaches 100% already in 4 h.

The research is interested in producing metakaolin by heat treatment (calcination) of kaolin at different temperatures (550, 600, 650, and 700°C) for 30, 60, 120, and 180 min and calculating the degree of the dehydroxylation. The results show that the dehydroxylation level remains more stable at 700°C, 120 min. An X-ray diffraction (XRD) analysis is used to assay kaoline before and after heat treatment. Taguchi’s statistical method utilized the optimal conditions; the design summary is L16 (4²) with 16 runs and 2 factors. Metakaolin produced was used with ratios of 0, 1, 1.5, 3, 5, and 6%) to prepare epoxy-metakaolin composite. The mechanical properties of the composite material were studied. Scanning electron microscopy (SEM) is used to assay the fracture surface morphology of composite material. At 5% the highest value of impact strength and hardness were 4.63 kJ/m^2, and 80.35 respectively.

In this work, a novel approach has been implemented to effectively enhance the performance of the CO gas sensor utilizing a bifacial porous silicon layer (B-PSi) with tri-metallic nanoparticles. The B-PSi was synthesized by double beam laser-induced etching (D-LIE) of the n-type silicon substrate by two like diode laser beams with a laser wavelength of 533 nm and a power of 30 mW. The tri-metallic, core/shell Au, Ag and Pd nanoparticles were incorporated on B-PSi through a dipping process in a solution of 1 : 1 : 1 mixing volumetric ratio of HAuC_l4, AgNO₃ and PdC_l2 with concentrations of 2 mM for 4 min. The performance of the B-PSi sensor was investigated using effective and non-poisonous measuring techniques involving the resonance frequency shift as a function of CO gas concentrations. The two structures with and without tri-metallic nanoparticles involving Al/(Ag : Au : Pd-NPs)/PSi/c-Si/PSi/(Ag : Au : Pd-NPs)/Al and Al/PSi/c-Si/PSi/Al were synthesised and tested at room temperature. Current-frequency properties are a function of CO gas concentrations presented an outstanding response of the B-PSi sensor with tri-metallic compared to the bare B-PSi sensor. A significant improvement in terms of gas sensitivity which is about 180.3%, is achieved at a gas concentration of 0.8 ppm. Further, the stability of the B-PSi sensor with tri-metallic has trebled over compared with the bare B-PSi gas sensor. The substantial enhancement of the B-PSi gas sensor with tri-metallic performance is attributable to the incorporated tri-metallic nanoparticles.

Metal oxide catalysts capable of competing with commercial platinum and chromium catalysts for non-oxidative propane dehydrogenation (PDH) are of increasing research and practical interest. In this study, the catalytic activity of bulk gallium oxide promoted by La, Y, V, Fe, Co, Ni, W, Mo, Cu, Ce, Mn, In, and Sn has been screened in PDH resulting in the selection of La, Y, Mo, Cu, Ce, and Ni as the most promising additives. The subsequent screening of the catalytic performance of alumina-supported gallium oxide promoted by Y, Mo, Cu, Ce, and Ni has indicated Mo as the most preferred dopant. The catalysts have been characterized using low-temperature nitrogen adsorption, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and transmission electron microscopy. PDH reaction catalyzed by Mo-Ga/Al₂O₃ at 600°C and tested in a fixed-bed flow-type reactor at a gas hourly space velocity (GHSV) of 7500 mL h^–1 g_cat^–1 (propane/N₂ = 1/10) provides ca. 32% propane conversion with the propylene selectivity of 96%.