scholarly journals WHEN CHOOSING CATALYSTS FOR THE CONVERSION OF ISOBUTYLENE PRINCIPLES OF QUALITY AND QUANTITY

2021 ◽  
Vol 11 (07) ◽  
pp. 29-34
Author(s):  
Irada Ahmadova Irada Ahmadova
Keyword(s):  
Catalytic Activity ◽  
Zeolite Catalyst ◽  
Catalyst Activity ◽  
Motor Fuel ◽  
Acid Sites ◽  
Oil Refining ◽  
High Catalytic Activity ◽  
Liquid Products ◽  
High Silica ◽  
Catalytic Processes

Catalysts play an extremely important role in wildlife and industry. Today it is difficult to describe chemistry and petrochemistry without catalytic processes. Catalytic processes account for 80-85% of oil refining. Therefore, the problem of choosing a catalyst is of interest both from the point of view of quality and quantity. In this paper, the activity of a high silicon zeolite catalyst used in the conversion of isobutene was studied at various temperatures, and it was determined that a sample of the zeolite catalyst during the process initially had no catalytic activity during the conversion of isobutene. The release of liquid products is observed only after the formation of 5-8% of compaction products (PM) on the surface within 25-30 minutes from the beginning. Consequently, modifiers have a positive effect on catalytic activity. In this case, the number and strength of the acid sites of the catalyst changes. The study of isobutene conversion process showed that the formation of liquid products is observed at 150°C. It was shown that in this case in the temperature range 150°C-300°C liquid products of isobutene reaction consist of primarily from aliphatic and at 350°C- 450°C from aromatic hydrocarbons. The process of conversion of hexane-1 on the high-silica zeolite catalyst is studied and it was shown that the decomposition of hexene-1 into ethene and propene is occure at the beginning, at 250°C and then the process takes place in a mixture of the two olefins. It was shown by the using of XRD, TG/DTA methods, that the formed products of seals in the conversion of isobutene and 1-hexene over the high silica zeolite catalyst,is composed of two phases that differ from each other in thermal stability. The obtained liquid products during the conversion of isobutene at 150°C-300°C can be used as high-octane gasoline fractions as motor fuel component. The adsorbed NH3 probe molecules method showed that during the conversion of propene, isobutene and hexene-1, the amount of acid sites of spent catalysts is reduced by 43-50%. In this state, the catalyst exhibits high catalytic activity. Keywords: catalyst, activity, isobutene, zeolite.

Selective isomerization of epoxides using magnetically recyclable ZSM-5 zeolite catalyst

RSC Advances ◽  
2015 ◽  
Vol 5 (96) ◽  
pp. 78441-78447 ◽  
Author(s):  
Phan Huy Hoang ◽  
Bach Nguyen Xuan
Keyword(s):  
Catalytic Activity ◽  
High Efficiency ◽  
Zeolite Catalyst ◽  
Isomerization Reaction ◽  
High Catalytic Activity ◽  
Long Lifetime

The magnetically recyclable ZSM-5 zeolite (MZZ) with high catalytic activity, high efficiency in separation, recycling and long lifetime for epoxide isomerization reaction was presented.

scholarly journals Furfural Hydrogenation on Modified Niobia

2019 ◽  
Vol 9 (11) ◽  
pp. 2287 ◽  
Author(s):  
Andrea Jouve ◽  
Stefano Cattaneo ◽  
Daniel Delgado ◽  
Nicola Scotti ◽  
Claudio Evangelisti ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Lewis Acid ◽  
Furfuryl Alcohol ◽  
Surface Acidity ◽  
High Surface ◽  
Pt Nanoparticles ◽  
Acid Sites ◽  
High Catalytic Activity ◽  
Lewis Acid Sites ◽  
Furfural Hydrogenation

In this study, niobia-based materials have been used as supports for Pt nanoparticles and used in the hydrogenation of furfural. The incorporation of dopants (W6+ and Ti4+) in the Nb2O5 structure induced modifications in the surface acidity of the support; in particular, the addition of W6+ increased the amount of Lewis acid sites, while the addition of Ti4+ decreased the number of Lewis acid sites. As a result, the catalytic activity towards the hydrogenation of furfural was affected; high surface acidity resulted in high catalytic activity. The selectivity of the reaction changed with the support acidity as well, with higher amount of furfuryl alcohol produced decreasing the Lewis acid sites.

scholarly journals Structure-Catalytic Properties Relationship in Friedel Crafts Alkylation Reaction for MCM-36-Type Zeolites Obtained by Isopropanol-Assisted Pillaring

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 299
Author(s):  
Karolina Ogorzały ◽  
Agnieszka Węgrzyn ◽  
Aleksandra Korzeniowska ◽  
Andrzej Sławek ◽  
Andrzej Kowalczyk ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Acid Sites ◽  
Alkylation Reaction ◽  
High Catalytic Activity ◽  
Large Molecules ◽  
External Acid Sites ◽  
Hierarchical Porous ◽  
Acid Centers ◽  
Ir Study

MWW type zeolites are characterized by the presence of zeolitic layers of 2.5 nm thickness, containing 10-member ring sinusoidal channels inside and supercavities with 12-member ring openings located on their surfaces. Expansion and pillaring of layered zeolites increase the access to active sites and can enable or facilitate catalytic activity towards larger reactant molecules. This goal is explored in this work reporting the pillaring of layered zeolite MCM-56 with MWW topology by tetraethylorthosilicate (TEOS) treatment with the assistance of isopropanol, aimed at obtaining hierarchical micro-mesoporous systems. MCM-56 (Si/Al = 12) was synthesized with hexamethyleneimine as a structure-directing and aniline as a structure-promoting agent. Hierarchical porous systems were obtained using two different pillaring methods: (1) with TEOS only and (2) with TEOS mixed with isopropanol. The MWW framework was preserved during swelling/pillaring in both methods. Pillared zeolites obtained via alcohol-assisted pillaring possessed unique intermediate micro-mesopores with the size of about 2 nm. IR study revealed a decrease in the concentration of accessible acid centers upon pillaring. However, the fraction of acid sites on the external surface, accessible for adsorption of large molecules, increased by up to 90%. Catalytic activity was evaluated in the Friedel-Crafts alkylation of mesitylene with benzyl alcohol. Pillaring resulted in reduction of the acid site concentrations, but the materials retained high catalytic activity. Pillaring in the presence of alcohol produced increased turnover frequency values based on the concentrations of the external acid sites.

Decoration of Graphene Oxide with Cobalt(II) Coordinated Silica and its Catalytic Activity for the Synthesis of Functionalized Indenopyrazolones

2020 ◽  
Author(s):  
Mahnaz Mirheidari ◽  
Javad Safaei‐Ghom
Keyword(s):  
Graphene Oxide ◽  
Catalytic Activity ◽  
Reaction Time ◽  
Catalyst Activity ◽  
Oxide Surface ◽  
High Catalytic Activity ◽  
Co Catalyst ◽  
Ft Ir ◽  
Heterogenous Catalyst ◽  
Ethylenediamine Ligand

Abstract We synthesized functionalized f-SiO2@GO@Co catalyst through decorating graphene oxide surface using SiO2 sphere with the help of ethylenediamine ligand and chelation with CoCl2.6H2O for increasing the catalyst activity to produce heterogenous catalyst. The heterogenous catalyst was characterized by FT-IR, XRD, SEM, Raman spectra, and TGA. We assessed activity of the catalyst in the synthesis of indenopyrazolones and results demonstrated high activity for the catalyst. The ability of the catalyst to increase the yield and reduction in reaction time as well as high catalytic activity, and recycling are prominent advantages of the catalyst.

scholarly journals THE INFLUENCE OF MECHANICAL ACTIVATION ON THE PROPERTIES SUPPORTS AND CATALYSTS OF OIL REFINING

2019 ◽  
Vol 62 (1-2) ◽  
pp. 131-140
Author(s):  
O.N. Baklanova ◽  
A.V. Lavrenov ◽  
A.V. Vasilevich ◽  
O.A. Knyazheva
Keyword(s):  
Catalytic Activity ◽  
Mechanical Activation ◽  
Mechanochemical Synthesis ◽  
Oil Refining ◽  
High Catalytic Activity ◽  
Molybdenum Oxides ◽  
Scientific Publications ◽  
Oil Processing ◽  
Highly Active ◽  
Inorganic Supports

The analysis of scientific publications and patents devoted to mechanochemical synthesis of inorganic supports and catalysts of oil processing processes: cracking, reforming, hydrotreating and hydrocracking is carried out. It s shown that the introduction of mechanical activation into the technological process of synthesis of inorganic supports and catalysts, as a rule, leads to an increase in catalytic activity and selectivity. Features of mechanochemical synthesis of complex nickel-molybdenum oxides, which are precursors of sulfide nickel-molybdenum hydrotreating catalysts, were considered. It is shown that under conditions of mechanical activation, it is possible to obtain a nickel-molybdenum highly active and thermostable β-NiMoO4, in which Mo is in a tetrahedral conformation. The technology of obtaining highly dispersed carbide-containing catalysts developed using the IHCP SB RAS using the method of mechanical activation is described. The texture and morphology of synthesized highly disperse massive carbide-containing catalysts are considered. It is shown that the size of active particles is 2–5 nm. Model catalytic tests have been carried out and it has been established that carbide-containing highly disperse catalysts exhibit high catalytic activity in the model hydrodesulphurization reaction of dibenzothiophene.

scholarly journals Surface Characterization and Catalytic Activity of Alumina and Alumina-Supported ZnSO4 Catalysts Prepared from Different Alumina Sources

2002 ◽  
Vol 20 (7) ◽  
pp. 695-705
Author(s):  
Farid Sh. Mohamed
Keyword(s):  
Catalytic Activity ◽  
Surface Characterization ◽  
Surface Acidity ◽  
Catalyst Activity ◽  
Total Pore Volume ◽  
Acid Sites ◽  
Aluminium Chloride ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Ft Ir

Three alumina samples were prepared from different sources including aluminium isopropoxide, aluminium chloride and aluminium nitrate, and were then used to prepare supported ZnSO4 catalysts via the impregnation method. The alumina and ZnSO4-supported samples were characterized by X-ray diffraction (XRD), FT-IR spectroscopy and nitrogen physisorption methods. Dehydration of 1-butanol and the cracking of cumene were undertaken over the prepared samples using a pulse microcatalytic technique. For a given alumina sample, the surface area and total pore volume decreased continuously with increasing ZnSO4 content. Loading alumina samples with ZnSO4 improved their dehydration and cracking activities. The source of alumina played a role in determining the surface acidity and catalyst activity of alumina and alumina-supported ZnSO4 catalysts. Impregnation of ZnSO4 on alumina samples resulted in an increase in the concentration of Lewis sites and the creation of Brönsted acid sites on their surfaces. The catalytic activity of the investigated catalysts was found to depend strongly on both the chemical composition and the type of acid site present on the catalyst surface.

scholarly journals High catalytic activity of Pt–Pd containing USY zeolite catalyst for low temperature CO oxidation from industrial off gases

2015 ◽  
Vol 6 (4) ◽  
pp. 589-595 ◽  
Author(s):  
Suchita Lokhande ◽  
Pradeep Doggali ◽  
Sadhana Rayalu ◽  
Sukumar Devotta ◽  
Nitin Labhsetwar
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Co Oxidation ◽  
Zeolite Catalyst ◽  
High Catalytic Activity ◽  
Usy Zeolite ◽  
Low Temperature Co Oxidation

scholarly journals Study of the Catalytic Activity of the Compounds Hydrotalcite Type Treated by Microwave in the Self-Condensation of Acetone

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Jamal Houssaini ◽  
Mohammed Naciri Bennani ◽  
Hamid Ziyat ◽  
Said Arhzaf ◽  
O. Qabaqous ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Condensation Reaction ◽  
Catalyst Activity ◽  
The Self ◽  
Conventional Heating ◽  
Molar Ratio ◽  
High Catalytic Activity ◽  
Adsorption Method ◽  
X Ray ◽  
Diacetone Alcohol

The self-condensation reaction of acetone, producing diacetone alcohol (DAA), is of great industrial importance. It was used to study the catalytic activity of Mg-Al catalysts synthesized by the coprecipitation method. For this purpose, we synthesized Mg-Al based hydrotalcite with a molar ratio of 3, obtained either after conventional heating or after microwave irradiation with of 100 W for three minutes. Structural and chemical properties of the obtained catalysts were characterized, using different techniques: X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), scanning electron microscope (SEM), equipped with energy dispersive X-ray (EDX), and specific surface area of the catalysts were determined by the methylene blue (MB) adsorption method. Also, these catalysts were tested in the self-condensation reaction of acetone at 273 K in the liquid phase without solvent, a reaction which requires very high catalytic activity. The microwave treatment improves the catalyst activity, and the conversion of acetone to diacetone alcohol increases from 13.2 to 18.3% after 8 h of reaction. Moreover, the microwave-treated hydrotalcite catalyst, calcined at 723 K and rehydrated under a flow of N2, is the most active and gives conversion of acetone of 52% under the same reaction conditions.

scholarly journals Toward the Sustainable Synthesis of Propanols from Renewable Glycerol over MoO3-Al2O3 Supported Palladium Catalysts

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 385 ◽  
Author(s):  
Shanthi Samudrala ◽  
Sankar Bhattacharya
Keyword(s):  
Catalytic Activity ◽  
Palladium Catalysts ◽  
Fixed Bed ◽  
Value Added ◽  
High Strength ◽  
Acid Sites ◽  
Fixed Bed Reactor ◽  
High Catalytic Activity ◽  
Impregnation Method ◽  
Glycerol Conversion

The catalytic conversion of glycerol to value-added propanols is a promising synthetic route that holds the potential to overcome the glycerol oversupply from the biodiesel industry. In this study, selective hydrogenolysis of 10 wt% aqueous bio-glycerol to 1-propanol and 2-propanol was performed in the vapor phase, fixed-bed reactor by using environmentally friendly bifunctional Pd/MoO3-Al2O3 catalysts prepared by wetness impregnation method. The physicochemical properties of these catalysts were derived from various techniques such as X-ray diffraction, NH3-temperature programmed desorption, scanning electron microscopy, 27Al NMR spectroscopy, surface area analysis, and thermogravimetric analysis. The catalytic activity results depicted that a high catalytic activity (>80%) with very high selectivity (>90%) to 1-propanol and 2-propanol was obtained over all the catalysts evaluated in a continuously fed, fixed-bed reactor. However, among all others, 2 wt% Pd/MoO3-Al2O3 catalyst was the most active and selective to propanols. The synergic interaction between the palladium and MoO3 on Al2O3 support and high strength weak to moderate acid sites of the catalyst were solely responsible for the high catalytic activity. The maximum glycerol conversion of 88.4% with 91.3% selectivity to propanols was achieved at an optimum reaction condition of 210 ∘ C and 1 bar pressure after 3 h of glycerol hydrogenolysis reaction.

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

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