Catalysts for Hydrogenations, Dehydrogenations and Metathesis

Busca, Guido

doi:10.1016/b978-0-444-59524-9.00010-9

Cited by 7 publications

(5 citation statements)

References 138 publications

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“…Spectroscopic studies confirmed that some of the hydride species are indeed active in hydrogenation, e.g., producing CHO formyl species from CO as a possible intermediate in methanol synthesis over ZnO [183]. The heterolytic dissociation of hydrogen-forming active metal hydride species has also been observed on chromia (Cr 2 O 3 ), a component of hydrodealkylation and paraffin dehydrogenation catalysts [178], where only terminal hydride species were found (νCr-H 1714, 1697 cm −1 [184]) and the combination of ZnO and Cr 2 O 3 , i.e., zinc chromite (ZnCr 2 O 4 ) catalysts [184]. The latter is the active phase of the old BASF industrial catalysts for methanol synthesis with the high temperature and pressure process, operated at above 300 bar and 573-673 K [70], industrially used until the seventies of the last century.…”

Section: The Adsorption and Activation Of Hydrogenmentioning

confidence: 78%

“…A number of oxides that can be used as supports or components of hydrogenation catalysts significantly adsorb hydrogen and show some useful activity as catalysts for hydrogenation and dehydrogenation reactions. This is the case of ZnO, Fe 3 O 4 , Cr 2 O 3 , Ga 2 O 3 , ZrO 2 , and CeO 2 [178]. Besides very weak and reversible molecular adsorption occurring only at very low temperatures, at moderate temperatures, the adsorption of hydrogen on several metal oxides was reported to be heterolytic, occurring on exposed cation-oxide couples.…”

Section: The Adsorption and Activation Of Hydrogenmentioning

confidence: 99%

“…The best-known case is that of ZnO, which has been the subject of a number of studies [179][180][181]. This oxide is an active catalyst in hydrogenations, such as methanol synthesis [182], as well as in alcohol dehydrogenation reactions [178]. Well-evident surface hydride species have been observed to be formed by H 2 adsorption at room temperature by vibrational spectroscopies (IR, HREELS, INS), both of the terminal Zn-H type I (1700-1600 cm −1 ), which is more weakly adsorbed, and of the bridging Zn-H-Zn type II (1450-1200 cm −1 ), which is more strongly adsorbed, formed together with new OH groups.…”

Section: The Adsorption and Activation Of Hydrogenmentioning

confidence: 99%

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Mechanistic and Compositional Aspects of Industrial Catalysts for Selective CO2 Hydrogenation Processes

Busca,

Spennati,

Riani

et al. 2024

Catalysts

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The characteristics of industrial catalysts for conventional water-gas shifts, methanol syntheses, methanation, and Fischer-Tropsch syntheses starting from syngases are reviewed and discussed. The information about catalysts under industrial development for the hydrogenation of captured CO2 is also reported and considered. In particular, the development of catalysts for reverse water-gas shifts, CO2 to methanol, CO2-methanation, and CO2-Fischer-Tropsch is analyzed. The difference between conventional catalysts and those needed for pure CO2 conversion is discussed. The surface chemistry of metals, oxides, and carbides involved in this field, in relation to the adsorption of hydrogen, CO, and CO2, is also briefly reviewed and critically discussed. The mechanistic aspects of the involved reactions and details on catalysts’ composition and structure are critically considered and analyzed.

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Section: The Adsorption and Activation Of Hydrogenmentioning

confidence: 78%

Section: The Adsorption and Activation Of Hydrogenmentioning

confidence: 99%

Section: The Adsorption and Activation Of Hydrogenmentioning

confidence: 99%

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Mechanistic and Compositional Aspects of Industrial Catalysts for Selective CO2 Hydrogenation Processes

Busca,

Spennati,

Riani

et al. 2024

Catalysts

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“…The sulfur resistant nickel- (Ni) or cobalt- (Co) promoted molybdenum- (Mo) and tungsten- (W) based catalysts are industrially used for hydrotreating purposes including HDO, hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) . The promotion with Ni or Co increases the activity of the edge sites in MoS 2 slabs. , Nickel-promoted Mo (NiMo) and cobalt-promoted Mo (CoMo) catalysts are initially in oxide form and therefore should be activated prior to use by sulfidation and formation of the active NiMoS and CoMoS phases.…”

Section: Introductionmentioning

confidence: 99%

Liquefaction of Lignosulfonate in Supercritical Ethanol Using Alumina-Supported NiMo Catalyst

Parto¹,

Christensen²,

Pedersen

et al. 2019

Energy Fuels

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Lignosulfonate was subjected to a reductive catalytic degradation in ethanol medium at 310 °C in the presence of alumina supported NiMo catalysts and H2. The liquid and solid products were analyzed with size exclusion chromatography (SEC), gas chromatography mass spectrometry (GC–MS), two-dimensional gas chromatography (GC × GC), heteronuclear single quantum coherence nuclear magnetic resonance (HSQC NMR) and elemental analysis. The highest oil yield and the lowest char yield obtained was 88 and 15 wt %, respectively. The liquefied species were mainly dimers and oligomers with minor yields of monomers. The catalyst was important for stabilization of reactive intermediates either by hydrogenation or coupling with ethanol. Simultaneous deoxygenation and desulfurization reactions took place in the presence of the catalyst; the oxygen and sulfur content in the oil fraction obtained after 4 h reaction time were 11.2 and 0.1 wt %, indicating considerable deoxygenation and desulfurization compared to the lignosulfonate feedstock (O, 30.8 wt %; S, 3.1 wt %). The effect of the reaction parameters such as temperature, reaction time and catalyst mass was studied. It was observed that by increasing the temperature from 260 to 310 °C the degradation increased, however, the SEC analysis showed that the degradation progressed only to a certain size range dimers to oligomers in the reaction temperatures studied. Investigating the effect of reaction time of 1, 2, 3, and 4 h indicated that degradation, deoxygenation, desulfurization and alkylation reactions progressed over time. The reusability of the catalyst without any pretreatment was confirmed by an almost constant oil yield in three repeated experiments with the same catalyst batch. The results show that alumina supported NiMo catalysts are very promising catalysts for conversion of lignosulfonate to liquid products.

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“…There are several industrial options for C 3 –C 5 paraffin dehydrogenation, differing in both technology and catalyst type. , …”

Section: Introductionmentioning

confidence: 99%

Recycling of Wastes from the Production of Alumina-Based Catalyst Carriers

Matveyeva

Пахомов

Murzin

2016

Ind. Eng. Chem. Res.

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Preparation of microspherical chromia−alumina KDM-type catalysts for alkane dehydrogenation is based on utilization of an amorphous nanostructured hydroxide−oxide Al 2 O 3 −x(OH) 2 •nH 2 O (where x = 0−0.28, n = 0.03−1.8) prepared via the centrifugal thermal activation (CTA) of gibbsite. The fine fraction of this carrier is considered as industrial waste, requiring efficient recycling options, which are explored in this work. A range of physicochemical methods was applied to analyze the main properties (phase composition, morphology, reactivity, etc.) of pilot and industrial batches of gibbsite CTA products. It has been clearly shown that the properties of CTA products are dependent on the nature of gibbsite used. The largest amount of the active amorphous phase of alumina is formed using gibbsite made from concentrated nepheline. Regularities of rehydration of the CTA-products fine fraction in acidic/ alkaline media and dissolution in sulfuric acid of the fine fraction of gibbsite and the industrial CTA product were explored to prepare aluminum sulfate, which is a water purification coagulant.

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Catalysts for Hydrogenations, Dehydrogenations and Metathesis

Cited by 7 publications

References 138 publications

Mechanistic and Compositional Aspects of Industrial Catalysts for Selective CO2 Hydrogenation Processes

Mechanistic and Compositional Aspects of Industrial Catalysts for Selective CO2 Hydrogenation Processes

Liquefaction of Lignosulfonate in Supercritical Ethanol Using Alumina-Supported NiMo Catalyst

Recycling of Wastes from the Production of Alumina-Based Catalyst Carriers

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