ISOMERIZATION OF GAS GASOLINE IN THE PARTICIPATION OF COMPOSITE CATALYSTS

New multicomponent catalytic systems synthesized by modifying zeolites (НМOR17 and HZSM-5) and γ-Al2O3 with metals (Co, Ni), zirconium dioxide and subsequent sulfation and tungestation of the obtained samples. It was shown that the introduction of zirconia into the M/MOR (where M = Co, Ni) system allows one to lower the isomerization temperature by 140-160°С, turning the medium-temperature skeletal-isomerisation catalyst M/MOR into a low-temperature M/MOR/ZrO2. It was found that sulfated Co/MOR/ZrO2/SO42- and Co/HZSM-5/ZrO2/SO42- have a higher isomerization activity, which makes it possible to increase the content of isomeric C5-C6 components with high octane numbers in gas gasoline from 43 to 66%. It was found that upon contacting the gas gasoline with the Co/MOR/ZrO2/SO42- or Co/HZSM-5/ZrO2/SO42- catalytic systems, efficient processing of higher molecular weight C7+ alkanes occurs not only into iso-C5 and C6, but also into n-pentane whose content in contact products rises from 19 to 40%. For the first time it was found that at temperatures of 160-200 °C, impurity gaseous C4- alkanes in the gas gasoline are consumed of when contacted with synthesized catalysts, turning into liquid alkanes. It was established that sulfated catalysts have more isomerizing activity in the low-temperature isomerization conversion of gas gasoline than volframated ones. The effect of the concentration of SO42- ions on the activity of the catalysts was studied and it was found that 2 wt.% is satisfactory for the studied catalysts. The temperature dependence of the activity of the most active of the synthesized catalysts in this process – Co/HZSM-5/ZrO2/SO42-, was studied. The results showed that the optimum temperature for the isomerization functioning of the selected catalyst is 180 oC. The change in the activity of the optimal catalyst (Co/HZSM-5/ZrO2/SO42-) depending on the reaction period was also studied. It was established that with the course of the process, the activity of the catalyst increases and reaches a maximum of 30 minutes work. After this, the activity of the catalyst gradually decreases. In this case, the total concentration of iso-C5 and iso-C6 increases by 22.9% and reaches 66.1%, and the conversion of C7+ components of gas gasoline is 69.2%.

Production of high octane gasoline components by hydroprocessing of coal-derived aromatic hydrocarbons

Comparison of the promotion effects on sulfated mesoporous zirconia catalysts achieved by alumina and gallium

Mesoporous zirconia, hydrothermally synthesized from surfactant templating, was directly impregnated with aluminum sulfate to give the acidic Al-promoted sulfated mesoporous zirconia (AS/MP-ZrO2). A series of AS/MP-ZrO2 catalysts were characterized by Brunauer−Emmett−Teller and X-ray diffraction for their texture properties and crystalline phases. The catalytic behavior for n-butane isomerization was found to be strongly promoted at relatively low temperature by the addition of a proper amount of alumina as a promoter. 27Al S.S. magic-angle spinning nuclear magnetic resonance results indicated that Zr atoms were partially substituted by Al, giving a considerable increased concentration of Brønsted acids. X-ray photoelectron spectroscopy and diffuse-reflectance infrared Fourier-transformed spectra (DRIFT) analysis were then employed to identify and relatively quantify properties of acid sites on catalyst surface. A balanced distribution of acid sites strength was proven to prevent a catalyst from deactivating rapidly due to coke formation on the catalyst surface. A small concentration of olefins formed by oxidation of n-butane and proven to be key intermediates during n-butane isomerization on sulfated zirconia was found by the Baeyer test. Electron paramagnetic resonance and in situ DRIFT results show that this occurs via oxidative dehydrogenation of butane by the sulfate groups to form butene which leads to butyl carbenium species for skeleton isomerization. A modified biomolecular mechanism for the isomerization of butane is examined to explain the catalysis results.

The nitration reaction of aromatic compounds is one of the extensively studied chemical reactions that result in the manufacturing of various industrial products applied in pharmaceuticals, dyes, perfumes, and explosives. A series of modified sulfated zirconia (SZ) catalysts SO42-/ZrO2-MxOy (M=Ce, Co, Mn, Zn, and M/SZ) doped with different metal elements by a coprecipitation method were investigated in the toluene nitration reaction. Various characterization techniques (X-ray diffraction, Brunauer-Emmett-Teller, thermogravimetric analysis, X-ray photoelectron spectroscopy, and temperature-programmed desorption of ammonia) indicated that doping metal elements in SZ led to excellent catalytic properties, increasing the specific surface area of the catalyst and facilitating the formation of a stable tetragonal zirconia phase. Doping zinc and cobalt in SZ enhanced the acidity of the catalyst and formed stronger acidic sites, promoting the generation of nitronium ions and providing more active sites for the toluene nitration reaction. Additionally, it reduced the loss of sulfate ions in the catalytic system that helped in improving the stability of the catalyst. Under the same conditions, the catalytic activity of toluene nitration reaction demonstrated the following order: Zn/SZ > Ce/SZ > Co/SZ > Mn/SZ > SZ, with the zinc-doped SZ catalyst exhibiting the best catalytic performance, achieving a toluene conversion rate of 78.58% and a para/ortho nitrotoluene ratio of 0.67.

High-entropy perovskite oxides (HEPOs) are attracting significant attention due to their unique structures, unprecedented properties and great application potential in many fields, while available synthetic methods have many shortcomings; so it is still a challenge to develop a simple, low-cost and environment-friendly synthetic strategy for HEPOs. Herein, a novel synthetic strategy is reported for HEPOs using an ionic liquid (IL)-hydroxide-mediated technique at a low temperature and normal atmospheric pressure. The synthesized HEPOs, including Ba(FeNbTiZrTa)O3, Ba(MnNbTiZrTa)O3, Ba(FeSnTiZrTa)O3 and Ba(FeVTiZrTa)O3, exhibit a cubic structure and a dispersed nanoparticle morphology (particle size of 20-60 nm). The formation process of HEPOs in an IL-KOH system can be described as follows: first, B-site metal source compounds are dissolved in IL-KOH medium to form hydroxyl complexes; second, the complexes further dehydrate, condensate and react with Ba2+ ions to form the crystal nuclei of HEPOs under the synergistic effect of reaction temperature and basicity; third, the growth of HEPO nuclei is completed by the Ostwald ripening process. In these processes, KOH not only plays a role as a solvent, but also provides sufficient OH- concentration for the formation and condensation of B-site metal hydroxyl complexes, while the IL also makes significant contributions: first, a lower reaction temperature and lower dosage of KOH are achieved by the use of the IL; second, the IL with good dissolving ability and low surface tensions can promote the nucleation rate of HEPOs and improve the Ostwald ripening process; third, the compact adsorption of the IL on the surface of products ensures a small particle size and high dispersion of HEPO nanoparticles to a certain extent. In brief, the technique provides an innovative, low-cost, simple and nontoxic strategy for the synthesis of HEPOs, which can be extended to other high-entropy materials.

The liquid phase dehydrogenation of isopropanol to acetone on a porous nickel catalyst has readily measurable rates at a low temperature and normal atmospheric pressure.

The isomerization process is becoming increasingly important in the modern petroleum refining context due to the limitations on the content of benzene, aromatic compounds, and olefins in gasoline. Isomerization is an effective and profitable process for octane enhancement of gasoline unlike other octane increasing processes. Due to the low sulfur and benzene content, the isomerate can be used as an ideal blending gasoline component. Therefore, the isomerization process has a great importance in petroleum refineries to increase the fuel octane number. This article aimed to study the conversion process of normal hexane over palladium and platinum containing catalysts on the base of sulfated zirconium dioxide. It has been determined that due to their high-performance characteristics, catalytic systems based on sulfated zirconium dioxide can be considered the most promising for isomerization of normal alkanes. Moreover, comparison of palladium-containing catalysts based on sulfated zirconium dioxide with platinum-containing catalysts based on sulfated zirconium dioxide showed that palladium sulfated zirconia catalysts have high catalytic performance in the isomerization of normal hexane. Keywords: alkanes, catalyst, platinum, palladium, isomerization, temperature, sulfated zirconium dioxide. .

Isomerization ofn-Butane over Deuterated Sulfated Zirconia

Isomerization of n-butane over sulfated zirconia catalyst under supercritical conditions

In situ FTIR study of the adsorption and reaction of ortho-dichlorobenzene on Pd–Co sulfated zirconia catalysts

A survey of the mechanism in catalytic isomerization of alkanes

<p>Evaluation of catalytic performances of selected metal chlorides such as AlCl<sub>3</sub>, SnCl<sub>4</sub>, ZnCl<sub>2</sub>, FeCl<sub>3</sub>, InCl<sub>3</sub> and GaCl<sub>3</sub> with solid acids such as sulfated zirconia, and zeolite beta was accomplished for acetylation of anisole, toluene and naphthalene. Presence of super acidity (Lewis or Bronsted acid) is found to be indispensable for activation of substrates towards acetylation reactions. In addition, presence of redox centers would further complement with the Lewis acid sites rendering catalytic stamina against deactivation. Strength of Lewis acid basically determines the activity of the metal chlorides towards acetylation. Among the Lewis acids investigated, FeCl<sub>3</sub>, InCl<sub>3</sub> and GaCl<sub>3</sub> exhibit their catalytic behaviour mostly through redox property as is evident from the conservation of Turn over number even after first cycle. Sulfated zirconia surpasses all the acid catalysts including metal chlorides and exhibits extended catalytic activity in acetylation of anisole. The pre-eminence of sulphated zirconia over other catalytic systems is owing to the synergistic effect of Lewis and Bronsted acidity.</p>

Influence of alumina and titania on the structure and catalytic properties of sulfated zirconia: Beckmann rearrangement

To enhance dimensional stability and biological properties, low molecular weight phenolic resins of a conventional alkaline type and neutralized type were impregnated into Japanese cedar wood (Cryptomeria japonica D. Don) and heat-cured. The treatment with the neutralized type resin retained the original wood color, whereas the alkaline treatment changed the color of wood to red-brown. The concentrations of the resin solutions and the weight gains due to the resin loading of wood after treatment were highly correlated, and the target resin loading could be assessed from the solution concentration. A high dimensional stability of 60% antiswelling efficiency was attained when both types of resins were impregnated at about 30% resin loading and no significant difference was recognized between the two. To suppress decay attack from brown-rot and white-rot fungi, 15% and 10% resin loading due to treatment was required for the neutralized and alkaline types of phenolic resins, respectively. The penetration of resin into wood cell walls was investigated by means of light microscopy, Scanning Electron Microscopy (SEM), and Electron Probe X-ray Microanalysis (EPMA). A m-Bromophenol-formaldehyde resin of three levels of an average molecular weight was used to detect the presence of resin by bromine signals. The phenolic resins with low and medium molecular weights (290 and 470) were shown to penetrate into the cell walls the furthest, thereby contributing to the enhancement of dimensional stability and decay resistance in the resin-impregnated wood. Also, for phenolic resin with a high molecular weight (820), only the resin components of low molecular weight appeared to be present in the walls, making very little contribution to the dimensional stability.