Participation of Water in the Secondary Transformations of Hydrocarbons on Cobalt–Zeolite Catalysts for the Fischer–Tropsch Synthesis

This review is dedicated to the effect of water as the main by-product of the Fischer–Tropsch synthesis on the process. The reasons for the negative effect of water are analyzed and the possible versions of the control of its participation in the process are considered. As an optimal solution to the problem, the use of zeolites in the H form as the constituents of cobalt catalysts for the Fischer–Tropsch synthesis is proposed. Bibliography: 148 references.     

Fischer–Tropsch Synthesis on Bifunctional Cobalt Catalysts with the Use of Hierarchical Zeolite HBeta

Kinetics and Catalysis - The production of fuel components in the integrated Fischer–Tropsch synthesis on bifunctional cobalt catalysts in the form of a mixture of the cobalt catalyst...     

Fischer–Tropsch Synthesis by Carbon Dioxide Hydrogenation on Fe-Based Catalysts

Impregnated and co-precipitated, promoted and unpromoted, bulk and supported iron catalysts were prepared, characterized, and subjected to hydrogenation of CO₂ at various pressures (1–2 MPa) and temperatures (573–673 K). Potassium, as an important promoter, enhanced the CO₂ uptake and selectivity towards olefins and long-chain hydrocarbons. Al₂O₃, when added as a structural promoter during co-precipitation, increased CO₂ conversion as well as selectivity to C₂₊ hydrocarbons. Among V, Cr, Mn and Zn promoters, Zn offered the highest selectivity to C₂–C₄ alkenes. The different episodes involved in the transformation of the catalyst before it reached steady-state were identified, on the co-precipitated catalyst. Using a biomass derived syngas (CO/CO₂/H₂), CO alone took part in hydrogenation. When enriched with H₂, CO₂ was also converted to hydrocarbons. The deactivation of impregnated Fe–K/Al₂O₃ catalyst was found to be due to carbon deposition, whereas that for the precipitated catalyst was due to increase in crystallinity of iron species. The suitability of SiO₂, TiO₂, Al₂O₃, HY and ion exchanged NaY as supports was examined for obtaining high activity and selectivity towards light olefins and C₂₊ hydrocarbons and found Al₂O₃ to be the best support. A comparative study with Co catalysts revealed the advantages of Fe catalysts for hydrocarbon production by F–T synthesis.     

The Influence of Alkali Treatment for Synthesizing Hierarchical Zeolite on Behavior of Cobalt Fischer–Tropsch Synthesis Catalysts

Hierarchical zeolites were synthesized by alkali treatment and their applications in Fischer–Tropsch (FT) synthesis were studied. It was found that alkali treatment not only created hierarchical structure but also could tune cobalt-support interaction. The dissolution of Si by alkali treatment became easier with the increase of Si/Al ratio, and thus the amount of mesopority increased. An optimal Si/Al molar ratio was identified over the zeolite with Si/Al ratio of 80, which was found to be superior to other catalysts in terms of better diesel selectivity and lower CH₄ selectivity due to its relatively narrow bimodal pore size distribution and moderate cobalt-support interaction. Meanwhile alkali treatment could enhance cobalt-support interaction via the formation of ɑ-SiO_2, Co/MZ-120 catalyst showed the lowest FT activity and higher CH₄ selectivity due to the increase of such new phase.     

Synthesis of α-Aminoarylacetic Acids in the Presence of Phase Transfer Catalysts

Inearlierpublications""aone-stepphasetransfercatalyzedreactionforpreparingaaminoarylaceticacidsfromarylaldehydesandchloroform,usingquaternarysaltsorf3CDasphasetransfercatalyst,wasdescribed;Itwasalsoreportedthatsomereactionsundersonicationconditionoftenoccurmorerapidlyandeasily'.Wenowfindthatthisreactioncanbeadvantageouslyrealizedbyphasetransfercatalysisundersonication.Optimumreactionconditionsweredeterminedwithbenzaldehyde.Inthepresenceoflithiumchloride,theyieldnoticeablydecreases(seeTablel)…     

Activation of the Surface of Carbon and Nitrogen-Doped Carbon Nanotubes by Calcium Nitrate: Catalytic Properties of Cobalt Supported Catalysts of the Fischer–Tropsch Process Based on Them

Kinetics and Catalysis - Using the methods of scanning and transmission electron microscopy (SEM and TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, the influence of...     

Hybrid Catalyst for the Selective Synthesis of Fuel Range Hydrocarbons by the Fischer–Tropsch Method

Kinetics and Catalysis - The results of the development of a hybrid catalyst for the one-pot synthesis of liquid hydrocarbons by the Fischer–Tropsch method are presented. The catalyst was...     

High Activity and Selective Fischer–Tropsch Catalysts for Use in a Microchannel Reactor

Each process configuration for practicing the Fischer–Tropsch synthesis places demands particular to that configuration on the catalyst to be used. We discuss how a particular catalyst, prepared by the OMX (organic matrix combustion) method, when used in conjunction with the Velocys microchannel reactor system, results in a very stable, high performance Fischer–Tropsch synthesis system. With the ability to remove heat far more effectively than a conventional reactor system, this microchannel reactor requires a catalyst with much higher volumetric reactive site density. Further, with such a high volumetric reaction rate, mass transfer effects will be important in both the observed activity and selectivity of the operating catalyst. Nevertheless, the catalyst prepared using the OMX method exhibits an apparent turnover frequency which is considerably higher than reported for other catalysts in the literature. In addition to high activity, an economically useful catalyst must exhibit a stable, high selectivity for liquid products and be able to recover near-fresh performance using a regeneration approach which can be carried out with the catalyst in-place. An example of such a stable, multiply regenerated catalyst is given. Finally, further development has focused on a catalyst with even higher C₅₊ selectivity.     

Effect of a Carbon Promoter on the Properties of a Co/MgAlO4 Catalyst for Fischer–Tropsch Synthesis

Kinetics and Catalysis - The influence of carbon on the genesis of the active phase of cobalt in aluminum–magnesium spinel supported catalysts on their catalytic properties in the synthesis...     

Effect of introduced zeolite on the Fischer–Tropsch synthesis over a cobalt catalyst

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Hydroformylation of olefins produced in the Fischer—Tropsch synthesis

Russian Chemical Bulletin - Alcohols were obtained by the one-stage hydroformylation of olefins from the hydrocarbon fraction C6–C9, which was produced in the Fischer—Tropsch synthesis...     

Synthesis and Study of Thermophysical Properties of Polystyrenes Prepared in the Presence of Conjugated α-Dinitrones Based on Glyoxal

Doklady Chemistry - A one-step convergent method was proposed for the synthesis of branched macromolecules in the presence of conjugated dinitrones (N,N-dimethylglyoxal dinitrone,...     

Kinetic Rates of the Fischer Tropsch Synthesis on a Co/Nb2O5 Catalyst

The kinetics of the Fischer-Tropsch reaction over a Co/Nb2O5 catalyst in a fixed bed reactor was investigated experimentally. Experiments were carried out under isothermal and isobaric conditions (T=543 K, P=2.1 MPa) and under different conditions of several H2/CO feed molar ratio (0.49-4.79), space velocities (0.2-3.8 h-1), mass of catalyst (0.3-1.5 g), and CO conversion (10%-29%). Synthesis gas conversion was measured and data were reduced to estimate the kinetic parameters for different Langmuir-Hinshelwood rate expressions. Differential and integral reactor models were used for the nonlinear regression of kinetics parameters. One of the rate equations could well explain the data. The hydrocarbon product distributions that were experimentally determined exhibited an unusual behavior, and a possible explanation was discussed.     

Promotion of lanthanum-supported cobalt-based catalysts for the Fischer–Tropsch reaction

This paper focuses on the effect of the La/Co ratio on the structure of alumina cobalt supported catalysts for Fischer–Tropsch synthesis. Catalysts are prepared by wetness impregnation of alumina followed by calcination in air. The catalysts contain 10 wt% of cobalt and between 0 and 20 wt% of La (0, 5, 10, 15, 20). The catalysts were activated by reduction in hydrogen at 673 K and the catalytic performance was evaluated in a fixed bed reactor at 20 bar and 493 K. A wide range of techniques (BET, XRD, TPR, and XPS) were used for catalyst characterization at each preparation step and showed strong impact of the La/Co ratio on the structure, reducibility of supported cobalt phases. It was shown that 10 wt% of lanthanum allows reducing cobalt aluminate and improving catalytic performances.     

Evidence of Structure Sensitivity in the Fischer–Tropsch Reaction on Model Cobalt Nanoparticles by Time-Resolved Chemical Transient Kinetics

The Fischer–Tropsch process, or the catalytic hydrogenation of carbon monoxide (CO), produces long chain hydrocarbons and offers an alternative to the use of crude oil for chemical feedstocks. The observed size dependence of cobalt (Co) catalysts for the Fischer–Tropsch reaction was studied with colloidally prepared Co nanoparticles and a chemical transient kinetics reactor capable of measurements under non-steady-state conditions. Co nanoparticles of 4.3 nm and 9.5 nm diameters were synthesized and tested under atmospheric pressure conditions and H₂/CO=2. Large differences in carbon coverage (Θ_C) were observed for the two catalysts: the 4.3 nm Co catalyst has a Θ_C less than one while the 9.5 nm Co catalyst supports a Θ_C greater than two. The monomer units present on the surface during reaction are identified as single carbon species for both sizes of Co nanoparticles, and the major CO dissociation site is identified as the B₅-B geometry. The difference in activity of Co nanoparticles was found to be a result of the structure sensitivity caused by the loss of these specific types of sites at smaller nanoparticle sizes.     

Industrial catalyst for the selective Fischer–Tropsch synthesis of long-chain hydrocarbons

The results of development of an industrial supported cobalt–silica gel catalyst for the Fischer–Tropsch synthesis are reported. The studies included the selection of a support and the determination of an optimum active component content, a calcination temperature, and the effect of doping with aluminum oxide on the physicochemical and catalytic properties of the Co–SiO₂ system. The catalyst samples were characterized by a set of physicochemical methods. The on-stream stability of the supported cobalt–silica gel catalyst was tested in the continuous mode for 1000 h. In the course of the entire test cycle, the catalyst exhibited stable operation under varied synthesis temperature and gas space velocity, and it can be recommended for industrial applications. The experimental results were used for the preparation of a pilot batch of the catalyst.     

Controlled synthesis of cobalt nanocrystals on the carbon spheres for enhancing Fischer–Tropsch synthesis performance

Non-porous carbon sphere was used as support to synthesize supported cobalt Fischer-Tropsch catalysts with high activity and durability. Strong metal-support interaction was avoided and intrinsic activity of pristine cobalt nano-particles was studied. Thermal decomposition synthesis method was applied to obtain cobalt catalysts with high dispersion and narrow particle size distribution. Furthermore the cobalt size can be controlled by the molar ratio of o-dichlorobenzene/benzylamine. Compared with supported cobalt catalysts prepared by incipient wetness impregnation method and ultrasonic impregnation method,the catalyst prepared by thermal decomposition method showed higher catalytic activity, higher long chain hydrocarbons selectivity and lower methane selectivity.