Petroleum Chemistry最新文献

The catalytic performance of iron-based nanodispersions in Fischer–Tropsch synthesis in two different slurry reactor types, specifically a continuous stirred-tank reactor (CSTR) and a slurry bubble column reactor (SBCR), was comparatively investigated. It was found that, at equal process temperatures, the CO conversion in the SBCR using a gas disperser with four equally spaced 1-mm holes was lower than that in the CSTR. However, this observation is inconsistent with other reports in the literature. Replacing this disperser with a plate with a single centered 2-mm hole enhanced the CO conversion up to values close to those obtained in the CSTR. The reaction rate constants were calculated for the different reactor types.

A Supported gold catalyst was prepared by reduction of HAuCl₄ with the Cacumen Platycladi extract. This catalyst was then used for oxidation of 2-phenylethyl alcohol in a model reaction. Our study evaluated the effect of various preparation conditions, including the Au loading ratio and calcination temperature. Additionally, we explored the influence of the reaction temperature and reaction time on the catalytic performance of a Au/TiO₂ catalyst. Our experimental findings revealed notable results for the Au/TiO₂ catalyst characterized by the Au loading of 1.3 wt % and calcinated at 400°C. Under specific reaction conditions (0.3 g catalyst, 220°C, 3.0 MPa, 2.5 h), the conversion of 2-phenylethyl alcohol reached 45.3 and a 59.6% selectivity and a 27.0% yield of the target product (phenylacetaldehyde). In addition, catalytic performance remained stable after 8 repeated uses.

The study investigates propane conversion in the presence of rare-earth metal zirconates Ln₂Zr₂O₇ (Ln = La, Gd, and Lu) prepared by high-temperature solid-phase synthesis at 500, 1000, and 1500°C. In the La₂Zr₂O₇ → Gd₂Zr₂O₇ → Lu₂Zr₂O₇ series, the phase transitions were found to follow the pyrochlore → defective fluorite → δ-phase route. This changed the parameters of the crystalline and local structures and, in particular, led to the appearance of oxygen vacancies in pyrochlore-based compounds. As a result of the structural changes, propane dehydrogenation prevailed over propane degradation. Therefore, the Lu₂Zr₂O₇ catalyst exhibited a higher propylene selectivity (up to 65%) than La₂Zr₂O₇, with 100% propane conversion being achieved.

In order to understand the structure of asphaltene after its disaggregating by chemical processing, a comprehensive study for exploring the structural changes of asphaltene after acylation as a case of chemical processing was conducted. Functional groups, crystal parameters, hydrogen types, and micromorphology of acylated asphaltenes were analyzed by FT-IR, XPS, XRD, ¹H NMR, SEM and IFM (inverted fluorescence microscope) methods. Additionally, fluorescence spectroscopy methods were performed to analyze the effect of acylation on the aggregation ability of asphaltene. Experimental results indicated that the C=O double bond was enhanced and the content of O–C=O was increased on the surface of acylated asphaltene. The number of stacking layers and the aggregate size of asphaltene decreased obviously after acylation. Fluorescence spectral analysis showed that the critical aggregation concentration of acylated asphaltenes increased compared to the raw asphaltenes. These results indicate that acylation reaction can disaggregate asphaltenes and hinder their re-aggregation in a solution. The disaggregation effect of asphaltene acylation can be attributed to the weakening of a hydrogen bonding and enhancement of a steric hindrance in the asphaltene molecule. This study provided the further understanding of the structural changes of asphaltene after the chemical treatment.

Published data on plasma-assisted carbon dioxide methane reforming using heterogeneous catalysts are analyzed. The pathways of the CH₄ and CO₂ transformation under the conditions of thermal catalysis, plasma action, and plasma-assisted catalysis are considered. Various types of plasma installations are described. The mechanisms of the formation of oxygenates under the conditions of plasma-assisted catalysis are presented. The process selectivity with respect to final products depends on the ratio of the gases and on the structure, dielectric properties, and composition of the catalysts. The important parameters influencing the oxygenate ratio are the metal oxidation state in the catalyst, kind of metal, and support acidity. The catalyst introduction into the plasma can also lead to negative phenomena, namely, to recombination of radicals into the starting compounds.

A novel catalyst was synthesized by immobilizing a MoO₂(acac)₂ complex on the surface of a porous aromatic framework functionalized with pyridine-2-carboxaldehyde (PAF-30-NPy). The immobilization was confirmed by IR spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis. The synthesized catalyst was tested in the epoxidation of cyclohexene, cycloheptene, 1-hexene, 1-octene, styrene, and trans-stilbene. The effects of the solvent type and the oxidant content on the olefin conversion were described. The catalyst reusability was further tested, and its activity was evaluated.

The paper describes an investigation into hydrogenation of furfural over ruthenium catalysts supported on porous aromatic frameworks. The supports were designated as PAF-30-SO₃H, PAF-30-NH₂, and PAF-30. The synthesized catalysts were tested in furfural hydrogenation carried out in water and in tetrahydrofuran (with a concentration of 10 wt %) at 90–250°C and a hydrogen pressure of 3 MPa. Although the highest furfural conversion (96%) was achieved in the case of its hydrogenation in water at 250°C over Ru-PAF-30, these conditions did not favor product selectivity. The reaction products mainly consisted of furfuryl alcohol, tetrahydrofurfuryl alcohol, and cyclopentanone. The highest yield of cyclopentanone, 71% (with 80% conversion and 89% selectivity) was observed in furfural hydrogenation over Ru-PAF-30 at 200°C, whereas the conditions optimal for selective hydrogenation of furfural into furfuryl alcohol were found to include either tetrahydrofuran as a solvent or water as a solvent and low temperatures (90–150°C).

One of the steps in scaling the technology for the synthesis of zeolite-containing catalysts from the laboratory to commercial level is support forming. In this study, halloysite nanotubes and aluminum oxide were used as binders for preparing a support based on MFI (ZSM-5) zeolite. The Pt catalysts (Pt/ZSM-5/Al₂O₃ and Pt/ZSM-5/Hall) were tested in isomerization of the aromatic C₈ fraction. The forming of supports influenced not only mechanical but also physicochemical properties of the catalysts. On introducing binders into the catalytic system, the fraction of mesopores in the total pore volume of the supports increased, the acidity of the samples decreased, and the ratio of the amounts of the weak and strong acid sites changed. The use of aluminum oxide and halloysite as binders leads to different pathways of the transformation of the aromatic feedstock. The main side reactions observed in the presence of Pt/ZSM-5/Al₂O₃ and Pt/ZSM-5/Hall catalysts are hydrocracking of alkylaromatic hydrocarbons and their transalkylation/disproportionation, respectively. The best results were obtained at 380°C and feed space velocity of 6 h^–1 with Pt/ZSM-5/Hall: p-/о-xylene ratio 1.05, loss of xylenes 4.31%, and ethylbenzene conversion 34%.

In this study, a non-catalytic process of oxidative coupling of methane (CH₄) and its conversion to ethane and propane in the presence of carbon dioxide (CO₂) was statistically studied. Fifteen experiments were conducted under different conditions, including determination of the CH₄/CO₂ ratio (1.5‒3), the total feed flow rate (22.5‒80 mL/min), argon flow rate (50‒100 mL/min), and voltage (6‒11 kV) under atmospheric conditions. The statistical analysis of the experiments showed that the model applied for evaluating the percentage of CH₄ conversion, Selective Internal Energy (SIE), and the reactor power was valid, and there was a good match between the experimental and predicted results. Based on the results, as the CH₄/CO₂ ratio increased, the selectivity of ethane and propane as well as the energy efficiency (EE) of a system increased, while CH₄ conversion decreased. In addition, increase in the Ar flow rate caused an increase in the CH₄ conversion and selectivity of ethane and propane. Moreover, CH₄ conversion, power, ethane selectivity and SIE increased as the voltage increased, though EE and propane selectivity decreased. Finally, the total feed flow rate caused increase in the CH₄ conversion and ethane selectivity, whereas propane selectivity and EE decreased.

The waxy oil-water interface has become a topic issue in the field of a two-phase oil-water pipe flow. Although some progress has been achieved in the understanding of interfacial rheological properties of the water-in-oil emulsion (W/O), the effect of surfactants (the main constituents of petroleum crude oil) still remains unclear. To test whether the structure of hydrophobic chains of surfactants influences the waxy oil-water interface, we monitored interfacial rheological parameters under different nonionic surfactants (Span80/60/65) using a DWR interfacial shear rheometer. Among these surfactants, the oil-water interface of Span65 characterized by multi-hydrophobic chains had the largest interfacial viscosity and critical storage modulus. A weak strain overshoot interface of Span65 suggested that sorbitan tristearate molecules provided a dominant contribution to the interfacial rheological properties of the waxy oil-water interface with much fewer effects of the interaction between wax molecules and surfactants. However, Span60/80 with a single hydrophobic chain was coupled to wax molecules and reshaped the waxy oil-water interface structure, which replaced the original wax crystal position (the interfacial viscosity and critical storage modulus decrease) and yielded an interfacial structure (the critical strain increase). The wax-surfactant interactions of Span60/80 with different hydrophobic chain saturation were discussed. These interfacial properties are of practical importance for the technological operations in oil production.