Journal articles: 'Isothermal hydrogenation'

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Li, Jingzhu, Peng Fan, Zhigang Zak Fang, and Chengshang Zhou. "Kinetics of isothermal hydrogenation of magnesium with TiH2 additive." International Journal of Hydrogen Energy 39, no. 14 (2014): 7373–81. http://dx.doi.org/10.1016/j.ijhydene.2014.02.159.

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Gunawan, Melia Laniwati, IGBN Makertihartha, and Subagjo Subagjo. "Kinetika Reaksi Hidrogenasi Ester Lemak Menjadi Alkohol Lemak Dengan Katalis Tembaga- Mangan." Indo. J. Chem. Res. 8, no. 1 (2020): 21–27. http://dx.doi.org/10.30598/10.30598//ijcr.2020.8-mel.

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Fatty alcohol (FAOH) can be produced by hydrogenating of fatty acid methyl ester (FAME) using the copper-based catalyst. Copper-Chrom (Cu-Cr) is the best catalyst for high-pressure reaction condition, which is copper (Cu) as the main active component and chrom (Cr) as a promoter. Since Cr is feared to be toxic, one of the best replacement candidates is manganese (Mn). The research aims is to find the kinetic equation of hydrogenation FAME to FAOH using a Cu-Mn commercial catalyst. FAME with methyl laurate and methyl myristate as the main compounds is used as feedstock. The main products are lauryl alcohol and myristyl alcohol. The reaction was carried out in an isothermal continuous fixed bed reactor under conditions of temperature 220 – 240 oC, pressure 50 bar, and liquid hourly space velocity (LHSV) 5-12.5 hr-1. The kinetic equation is determined using the power law model. The FAME hydrogenation on copper - manganese catalyst is the half order reaction. The activation energy value is 86.32 kJ/mol and the Arrhenius constant value is 5.87x106 M0.5/s.

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Čapek, Pavel, and Karel Klusáček. "Kinetically induced multiple steady states during acetylene hydrogenation." Collection of Czechoslovak Chemical Communications 55, no. 7 (1990): 1708–20. http://dx.doi.org/10.1135/cccc19901708.

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An isothermal reaction model of acetylene hydrogenation on palladium catalyst is described. Steady-state solutions of the mass balances in a CSTR display regions of multiplicity caused by the very distinct rate and strength of adsorption and desorption of acetylene and hydrogen, respectively. Uniqueness and local stability of this model are investigated numerically; oscillatory behaviour is predicted to be absent for typical conditions.

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Li, Jingzhu, Chengshang Zhou, Zhigang Zak Fang, Robert C. Bowman Jr., Jun Lu, and Chai Ren. "Isothermal hydrogenation kinetics of ball-milled nano-catalyzed magnesium hydride." Materialia 5 (March 2019): 100227. http://dx.doi.org/10.1016/j.mtla.2019.100227.

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Kačer, Petr, Leiv Laate, and Libor Červený. "Competitive Catalytic Hydrogenation in Unsaturated Hydrocarbon Systems With Sterically Hindered Double Bonds." Collection of Czechoslovak Chemical Communications 63, no. 11 (1998): 1915–26. http://dx.doi.org/10.1135/cccc19981915.

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A competitive hydrogenation of unsaturated hydrocarbons (a-methylstyrene, cyclohexene, 1-methylcyclohex-1-ene, 1-tert-butylcyclohex-1-ene and 3-tert-butylcyclohex-1-ene) in binary and ternary systems with palladium-, platinum- and rhodium-supported catalysts in a semibatch isothermal reactor at 20 °C under atmospheric pressure was studied. It was found that considerable variance in selectivity values of competitive hydrogenation in a series of substrates with increasing substituent bulkiness is caused by differences in adsorption and in reactivity of adsorbed molecules. In the case of ternary systems, a change in selectivity of competitive hydrogenation of two substrates was observed, due to the presence of a third substance, caused by a competitive adsorption of all three substrates and their interaction on a catalytic surface.

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Lin, Ying Ying, Miao Quan Li, Y. Niu, and W. F. Zhang. "Effect of Hydrogenation on the Microstructure during the Isothermal Compression of Ti-5.6Al-4.8Sn-2.0Zr-1.0Mo Alloy." Materials Science Forum 551-552 (July 2007): 417–20. http://dx.doi.org/10.4028/www.scientific.net/msf.551-552.417.

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Isothermal compression tests were carried out on the Ti-5.6Al-4.8Sn-2.0Zr-1.0Mo alloy with and without hydrogen. A series of experiments including the optical microstructure and TEM (Transmission Electron Microscope) were performed to the compressed samples. The results show that hydrogenation not only increases the fraction ofβ phase, but also activates the propagation of the dislocation and formation of the twins, which are benefit for plastic or superplastic formability.

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Vasiliades, Michalis A., Konstantina K. Kyprianou, Nilenindran S. Govender, et al. "The Effect of CO Partial Pressure on Important Kinetic Parameters of Methanation Reaction on Co-Based FTS Catalyst Studied by SSITKA-MS and Operando DRIFTS-MS Techniques." Catalysts 10, no. 5 (2020): 583. http://dx.doi.org/10.3390/catal10050583.

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A 20 wt% Co-0.05 wt% Pt/γ-Al2O3 catalyst was investigated to obtain a fundamental understanding of the effect of CO partial pressure (constant H2 partial pressure) on important kinetic parameters of the methanation reaction (x vol% CO/25 vol% H2, x = 3, 5 and 7) by performing advanced transient isotopic and operando diffuse reflectance infrared Fourier transform spectroscopy–mass spectrometry (DRIFTS-MS) experiments. Steady State Isotopic Transient Kinetic Analysis (SSITKA) experiments conducted at 1.2 bar, 230 °C after 5 h in CO/H2 revealed that the surface coverages, θCO and θCHx and the mean residence times, τCO, and τCHx (s) of the reversibly adsorbed CO-s and active CHx-s (Cα) intermediates leading to CH4, respectively, increased with increasing CO partial pressure. On the contrary, the apparent activity (keff, s−1) of CHx-s intermediates, turnover frequency (TOF, s−1) of methanation reaction, and the CH4-selectivity (SCH4, %) were found to decrease. Transient isothermal hydrogenation (TIH) following the SSITKA step-gas switch provided important information regarding the reactivity and concentration of active (Cα) and inactive -CxHy (Cβ) carbonaceous species formed after 5 h in the CO/H2 reaction. The latter Cβ species were readily hydrogenated at 230 °C in 50%H2/Ar. The surface coverage of Cβ was found to vary only slightly with increasing CO partial pressure. Temperature-programmed hydrogenation (TPH) following SSITKA and TIH revealed that other types of inactive carbonaceous species (Cγ) were formed during Fischer-Tropsch Synthesis (FTS) and hydrogenated at elevated temperatures (250–550 °C). The amount of Cγ was found to significantly increase with increasing CO partial pressure. All carbonaceous species hydrogenated during TIH and TPH revealed large differences in their kinetics of hydrogenation with respect to the CO partial pressure in the CO/H2 reaction mixture. Operando DRIFTS-MS transient isothermal hydrogenation of adsorbed CO-s formed after 2 h in 5 vol% CO/25 vol% H2/Ar at 200 °C coupled with kinetic modeling (H-assisted CO hydrogenation) provided information regarding the relative reactivity (keff) for CH4 formation of the two kinds of linear-type adsorbed CO-s on the cobalt surface.

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Smarzhevskaya, A. I., S. A. Nikitin, Viktor N. Verbetsky, Wacław Iwasieczko, and Alexey N. Golovanov. "The Magnetocaloric Effect and Magnetic Transitions in Hydride Compounds: GdNiH_3.2 and TbNiH_3.4." Solid State Phenomena 233-234 (July 2015): 243–46. http://dx.doi.org/10.4028/www.scientific.net/ssp.233-234.243.

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The paper presents the investigation of GdNiH3.2 and TbNiH3.4 hydrides magnetic transitions and magnetocaloric properties. The isothermal magnetization data in the fields up to 5T are obtained for GdNi and TbNi compounds and their hydrides and the values of magnetic entropy change are calculated. The maximum values of magnetic entropy change ΔSM in GdNiH3.2 and TbNiH3.4 are extremely large. It is shown that the hydrogenation shifts ΔSM(T) maximum to lower temperatures.

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Huang, Shu Hui, Ying Ying Zong, and De Bin Shan. "Research on Law and Mechanism of Hydrogen Induced Softening in Ti6Al4V Alloy in the Temperature Range 400 °C to 1010 °C." Advanced Materials Research 1120-1121 (July 2015): 1202–7. http://dx.doi.org/10.4028/www.scientific.net/amr.1120-1121.1202.

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The law and mechanism of hydrogen induced softening in Ti6Al4V alloy in the temperature range 400 °C to 1010 °C are researched by lots of isothermal hot compression experiment in this paper. The relationship between σh (the true stress when the test is compressed to half of its original height) and CH (hydrogen content) is investigated to describe the law. The results show that, Between 400 °C and 450 °C, the plasticity increases at first, and then decreases and the strength is almost changeless with the CH rising. Between 480 °C and 950 °C, the strength decreases at first, and then increases with the CH rising. In α+β phase region, the strength decreases with the CH rising. In β phase region, the strength increases with the CH rising. Hydrogenation induced α phase high temperature softening and hydrogenation promoting α→β phase transition are the main reasons for hydrogen induced titanium alloy softening. Hydrogenation induced β phase solution strengthening is the reason for hydrogen induced titanium alloy strengthening. And the relationship between furnace temperature and vacuum is investigated during dehydrogenation heat treatment.

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Shen, Chia-Chieh, Chung-Min Wang, and Hsin-Hung Chen. "Advanced nanostructured equiaxed Ti-6Al-4V alloys prepared via an isothermal hydrogenation process." Journal of Alloys and Compounds 657 (February 2016): 794–800. http://dx.doi.org/10.1016/j.jallcom.2015.10.124.

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11

Pan, Long, Chun-Ming Wang, Su-Fen Xiao, and Yun-Gui Chen. "Hydrogenation behaviors and characteristics of bulk Ti–6Al–4V alloy at different isothermal temperatures." Rare Metals 38, no. 12 (2017): 1131–35. http://dx.doi.org/10.1007/s12598-016-0852-y.

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12

SHEN, C., C. YU, and T. PERNG. "Variation of structure and mechanical properties of Ti–6Al–4V with isothermal hydrogenation treatment." Acta Materialia 57, no. 3 (2009): 868–74. http://dx.doi.org/10.1016/j.actamat.2008.10.026.

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13

Tanthapanichakoon, Wiwut, Shinichi Koda, and Burin Khemthong. "Dynamic Simulation of Adiabatic Catalytic Fixed-Bed Tubular Reactors: A Simple Approximate Modeling Approach." ASEAN Journal of Chemical Engineering 14, no. 1 (2014): 25. http://dx.doi.org/10.22146/ajche.49713.

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Fixed-bed tubular reactors are used widely in chemical process industries, for example, selective hydrogenation of acetylene to ethylene in a naphtha cracking plant. A dynamic model is required when the effect of large fluctuations with time in influent stream (temperature, pressure, flow rate, and/or composition) on the reactor performance is to be investigated or automatically controlled. To predict approximate dynamic behavior of adiabatic selective acetylene hydrogenation reactors, we proposed a simple 1-dimensional model based on residence time distribution (RTD) effect to represent the cases of plug flow without/with axial dispersion. By modeling the nonideal flow regimes as a number of CSTRs (completely stirred tank reactors) in series to give not only equivalent RTD effect but also theoretically the same dynamic behavior in the case of isothermal first-order reactions, the obtained simple dynamic model consists of a set of nonlinear ODEs (ordinary differential equations), which can simultaneously be integrated using Excel VBA (Visual BASIC Applications) and 4th-order Runge-Kutta algorithm. The effects of reactor inlet temperature, axial dispersion, and flow rate deviation on the dynamic behavior of the system were investigated. In addition, comparison of the simulated effects of flow rate deviation was made between two industrial-size reactors.Keywords: Dynamic simulation, 1-D model, Adiabatic reactor, Acetylene hydrogenation, Fixed-bed reactor, Axial dispersion effect

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14

Chen, Qiang, Xuebing Zhang, Shuxun Tian, et al. "Kinetics of Hydrogenation of Acetic Acid to Ethanol." Asian Journal of Chemistry 31, no. 12 (2019): 2915–23. http://dx.doi.org/10.14233/ajchem.2019.22277.

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The intrinsic kinetic behaviour of catalytic hydrogenation of acetic acid in vapour phase was studied over a multi-metallic catalyst. The rate expression was derived from the sequence of elementary reaction steps based on a Langmuir-Hinshelwood-model involving two types of active sites. Experiments were carried out in a fixed bed reactor, which is similar to an isothermal integral reactor designed to excluding the negative effects of internal and external diffusion. The reaction conditions investigated were as follow:reaction temperature 275-325 ºC, reaction pressure1.5-3.0 MPa, liquid hourly space velocity (sv) 0.3-1.2 h-1, molar ratio of hydrogen to acetic acid (H/AC) 8:20. The results show that conversion of acetic acid increases with increasing the reaction temperature and pressure, but decreases with increasing the space velocity and H/AC. Furthermore, reducing the reaction pressure and increasing reaction temperature, space velocity and H/AC can improve the reaction selectivity of acetic acid to ethanol. The established kinetic model results agreed with experimental results. The relative difference between the calculated value and the experimental value is less than 6 %. The values of model parameters are consistent with the three thermodynamic constraints. The study provided evidence that the intrinsic kinetic model is suitable both mathematically and thermodynamically, and it could be useful in guiding reactor design and optimization of operating conditions.

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15

Costamagna, Paola, Federico Pugliese, Tullio Cavattoni, Guido Busca, and Gabriella Garbarino. "Modeling of Laboratory Steam Methane Reforming and CO2 Methanation Reactors." Energies 13, no. 10 (2020): 2624. http://dx.doi.org/10.3390/en13102624.

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To support the interpretation of the experimental results obtained from two laboratory-scale reactors, one working in the steam methane reforming (SMR) mode, and the other in the CO2 hydrogenation (MCO2) mode, a steady-state pseudo-homogeneous 1D non-isothermal packed-bed reactor model is developed, embedding the classical Xu and Froment local kinetics. The laboratory reactors are operated with three different catalysts, two commercial and one homemade. The simulation model makes it possible to identify and account for thermal effects occurring inside the catalytic zone of the reactor and along the exit line. The model is intended to guide the development of small size SMR and MCO2 reactors in the context of Power-to-X (P2X) studies.

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Sarkar, Mousumi De, P. G. Mukunda, Prajna P. De, and Anil K. Bhowmick. "Degradation of Hydrogenated Styrene—Butadiene Rubber at High Temperature." Rubber Chemistry and Technology 70, no. 5 (1997): 855–70. http://dx.doi.org/10.5254/1.3538465.

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Abstract Degradation of hydrogenated styrene—butadiene rubber (HSBR) having different levels of unsaturation has been studied over a wide range of temperatures under anaerobic and aerobic conditions using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), IR and NMR spectroscopy. TGA data indicate higher thermal stability of hydrogenated rubber as compared to SBR in nitrogen, although an anomalous behavior is observed in air due to crosslinking and oxidation of styrene—butadiene rubber (SBR). Isothermal data confirm the above observations. IR and NMR results reveal thermal isomerization, cyclization, oxidation, depolymerization, and chain scission processes. The nature and amount of products formed depend on the time and temperature of degradation and also on the level of hydrogenation of SBR.

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Pintar, A., J. Batista, and J. Levec. "Potential of mono- and bimetallic catalysts for liquid-phase hydrogenation of aqueous nitrite solutions." Water Science and Technology 37, no. 8 (1998): 177–85. http://dx.doi.org/10.2166/wst.1998.0323.

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Liquid-phase reduction using a solid catalyst provides a potential technique for the removal of nitrites from waters. Activity and selectivity measurements were performed for a wide range of reactant concentrations and reaction conditions in an isothermal semi-batch slurry reactor operating at atmospheric pressure. The effects of catalyst loading and initial nitrite concentration on the reaction rate were also investigated. The Pd monometallic catalysts were found to be advantageous over the Pd-Cu bimetallic catalyst with respect to both reaction activity and selectivity. Minimum ammonia formation was observed for the Pd(1 wt. %)/γ-Al2O3 catalyst. The reaction kinetics was found to be dependent on the catalyst surface hydroxylation, which has also been confirmed by runs conducted in a continuous-flow monolith reactor.

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Lei, Kun, Hongfang Ma, Haitao Zhang, Weiyong Ying, and Dingye Fang. "One-dimensional isothermal multicomponent diffusion-reaction model and its application to methanol synthesis over commercial Cu-based catalyst." Polish Journal of Chemical Technology 17, no. 1 (2015): 103–9. http://dx.doi.org/10.1515/pjct-2015-0015.

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Abstract The present work was a study on global reaction rate of methanol synthesis. We measured experimentally the global reaction rate in the internal recycle gradientless reactor over catalyst SC309. The diffusion-reaction model of methanol synthesis was suggested. For model we chose the hydrogenation of CO and CO2 as key reaction. CO and CO2 were key components in our model. The internal diffusion effectiveness factors of CO and CO2 in the catalyst were calculated by the numerical integration. A comparison with the experiment showed that all the absolute values of the relative error were less than 10%. The simulation results showed that decreasing reaction temperature and catalyst diameter were conducive to reduce the influence of the internal diffusion on the methanol synthesis.

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Rode, Chandrashekhar V., and Raghunath V. Chaudhari. "Hydrogenation of m-Nitrochlorobenzene to m-Chloroaniline: Reaction Kinetics and Modeling of a Non-Isothermal Slurry Reactor." Industrial & Engineering Chemistry Research 33, no. 7 (1994): 1645–53. http://dx.doi.org/10.1021/ie00031a001.

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LI, M., and W. ZHANG. "Effect of hydrogenation content on high temperature deformation behavior of Ti–6Al–4V alloy in isothermal compression." International Journal of Hydrogen Energy 33, no. 11 (2008): 2714–20. http://dx.doi.org/10.1016/j.ijhydene.2008.03.027.

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21

Kantürk Figen, Aysel, Bilge Coşkuner, and Sabriye Pişkin. "Hydrogen desorption kinetics of MgH2 synthesized from modified waste magnesium." Materials Science-Poland 32, no. 3 (2014): 385–90. http://dx.doi.org/10.2478/s13536-014-0218-9.

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AbstractIn the present study, hydrogen desorption properties of magnesium hydride (MgH2) synthesized from modified waste magnesium chips (WMC) were investigated. MgH2 was synthesized by hydrogenation of modified waste magnesium at 320 °C for 90 min under a pressure of 6 × 106 Pa. The modified waste magnesium was prepared by mixing waste magnesium with tetrahydrofuran (THF) and NaCl additions, applying mechanical milling. Next, it was investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) techniques in order to characterize its structural properties. Hydrogen desorption properties were determined by differential scanning calorimetry (DSC) under nitrogen atmosphere at different heating rates (5, 10, and 15 °C/min). Doyle and Kissenger non-isothermal kinetic models were applied to calculate energy (Ea) values, which were found equal to 254.68 kJ/mol and 255.88 kJ/mol, respectively.

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Kugatov, P. V., B. S. Zhirnov, and A. E. Eremenko. "Study of Dependence of Softening Point on Mesophase Content of Petroleum Pitches from Heavy Pyrolysis Resin and Decantoil." Chemistry and Technology of Fuels and Oils 625, no. 3 (2021): 28–31. http://dx.doi.org/10.32935/0023-1169-2021-625-3-28-31.

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Samples of petroleum pitches were obtained from heavy pyrolysis resin and decantoil (heavy gas-oil of catalytic cracking) by thermal polycondensation at atmospheric pressure, temperatures of 380–400 and 410–440°С (for resin and decantoil, respectively) and isothermal holding time of 30–480 min. Analysis of the dependence of the softening point on the mesophase content for the obtained samples showed that at the same mesophase content, decantoil pitches exhibit a lower softening point compared to pyrolysis resin pitches, for which, even at 30 % mesophase, the softening point approaches 300°C. This suggests that it is impossible to obtain pitch from pyrolysis resin with high mesophase content without preliminary preparation (for example, by hydrogenation). On the other hand, it has been shown that for pitches from decantoil, it is possible to isolate the mesophase up to 65% or more with a softening point not higher than 250°C.

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Lali, Farzad, Felix-Aron Pahner та Rüdiger Lange. "Modeling and Simulation of the Hydrogenation ofα-Methylstyrene on Catalytically Active Metal Foams as Tubular Reactor Packing". International Journal of Chemical Engineering 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/7082381.

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This work presents a one-dimensional reactor model for a tubular reactor packed with a catalytically active foam packing with a pore density of 30 PPI in cocurrent upward flow in the example of hydrogenation reaction ofα-methylstyrene to cumene. This model includes material, enthalpy, and momentum balances as well as continuity equations. The model was solved within the parameter space applied for experimental studies under assumption of a bubbly flow. The method of orthogonal collocation on finite elements was applied. For isothermal and polytropic processes and steady state conditions, axial profiles for concentration, temperature, fluid velocities, pressure, and liquid holdup were computed and the conversions for various gas and liquid flow rates were validated with experimental results. The obtained results were also compared in terms of space time yield and catalytic activity with experimental results and stirred tank and also with random packed bed reactor. The comparison shows that the application of solid foams as reactor packing is advantageous compared to the monolithic honeycombs and random packed beds.

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24

Suwarno, Suwarno, and V. A. Yartys. "Kinetics of Hydrogen Absorption and Desorption in Titanium." Bulletin of Chemical Reaction Engineering & Catalysis 12, no. 3 (2017): 312. http://dx.doi.org/10.9767/bcrec.12.3.810.312-317.

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Titanium is reactive toward hydrogen forming metal hydride which has a potential application in energy storage and conversion. Titanium hydride has been widely studied for hydrogen storage, thermal storage, and battery electrodes applications. A special interest is using titanium for hydrogen production in a hydrogen sorption-enhanced steam reforming of natural gas. In the present work, non-isothermal dehydrogenation kinetics of titanium hydride and kinetics of hydrogenation in gaseous flow at isothermal conditions were investigated. The hydrogen desorption was studied using temperature desorption spectroscopy (TDS) while the hydrogen absorption and desorption in gaseous flow were studied by temperature programmed desorption (TPD). The present work showed that the path of dehydrogenation of the TiH2 is d®b®a hydride phase with possible overlapping steps occurred. The fast hydrogen desorption rate observed at the TDS main peak temperature were correlated with the fast transformation of the d-TiH1.41 to b-TiH0.59. In the gaseous flow, hydrogen absorption and desorption were related to the transformation of b-TiH0.59 Û d-TiH1.41 with 2 wt.% hydrogen reversible content. Copyright © 2017 BCREC Group. All rights reservedReceived: 21st November 2016; Revised: 20th March 2017; Accepted: 9th April 2017; Available online: 27th October 2017; Published regularly: December 2017How to Cite: Suwarno, S., Yartys, V.A. (2017). Kinetics of Hydrogen Absorption and Desorption in Titanium. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (3): 312-317 (doi:10.9767/bcrec.12.3.810.312-317)

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Russo, Vincenzo, Teuvo Kilpiö, Martino Di Serio, et al. "Dynamic non-isothermal trickle bed reactor with both internal diffusion and heat conduction: Sugar hydrogenation as a case study." Chemical Engineering Research and Design 102 (October 2015): 171–85. http://dx.doi.org/10.1016/j.cherd.2015.06.011.

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26

Bianchi, D., and J. L. Gass. "Hydrogenation of carbonaceous adsorbed species on an iron/alumina catalyst I. Experiments in isothermal conditions and exploitation by a kinetic model." Journal of Catalysis 123, no. 2 (1990): 298–309. http://dx.doi.org/10.1016/0021-9517(90)90129-8.

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Sales, Flávia Rhuana Pereira, Reynaldo Borges Galvão Serra, Gesivaldo Jesus Alves de Figueirêdo, Paulo Henrique Almeida da Hora, and Antonio Cícero de Sousa. "Wastewater treatment using adsorption process in column for agricultural purposes." Ambiente e Agua - An Interdisciplinary Journal of Applied Science 14, no. 1 (2019): 1. http://dx.doi.org/10.4136/ambi-agua.2178.

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Water is essential for life, important for the ecosystem and it is in great demand due to its scarcity. This study explored the reuse of the wastewater of the Water Treatment Plant in Gramame for agricultural purposes. A qualitative and quantitative investigation of the effluent was carried out through the characterization of its physical and chemical parameters, comparing the results to what is allowed by the current legislation, CONAMA Resolution 357/2005. After this process, the activated charcoal of coco-da-baia mesocarp, adsorbent material, was prepared and tested in a filter system in a column with a continuous flow and ascendant entrance, in which the kinetic effect was evaluated. This technique was evaluated by correlating the reduced values in the adsorption material, respecting the initial effluent concentration, obtaining a reduction of 50% in the hardness, 87.5% in chloride and 66.6% in acidity. These results verified the adequacy of the technique in potential hydrogenation (pH) and abrupt reduction of color and turbidity. This treatment is suggested to qualify the effluent for use in agricultural, safe for humans and the environment. The adsorbent substrate efficiency was verified by correlating it with the Thomas isothermal model.

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Öfner, Helmut, and Francisco Zaera. "Isothermal Kinetic Measurements for the Hydrogenation of Ethylene on Pt(111) under Vacuum: Significance of Weakly-Bound Species in the Reaction Mechanism." Journal of Physical Chemistry B 101, no. 3 (1997): 396–408. http://dx.doi.org/10.1021/jp963030q.

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Kilpiö, Teuvo, Päivi Mäki-Arvela, Mats Rönnholm, Victor Sifontes, Johan Wärnå, and Tapio Salmi. "Modeling of a Three-Phase Continuously Operating Isothermal Packed-Bed Reactor: Kinetics, Mass-Transfer, and Dispersion Effects in the Hydrogenation of Citral." Industrial & Engineering Chemistry Research 51, no. 26 (2011): 8858–66. http://dx.doi.org/10.1021/ie2019678.

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30

Klemm, E., B. Amon, H. Redlingshöfer, E. Dieterich, and G. Emig. "Deactivation kinetics in the hydrogenation of nitrobenzene to aniline on the basis of a coke formation kinetics — investigations in an isothermal catalytic wall reactor." Chemical Engineering Science 56, no. 4 (2001): 1347–53. http://dx.doi.org/10.1016/s0009-2509(00)00357-2.

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31

AHLAFI, H. "Isothermal hydrogenation of carbonaceous adsorbed species on an iron catalyst. III. Kinetic model and experimental verification of the variation of the surface hydrogen concentration." Journal of Catalysis 133, no. 1 (1992): 83–93. http://dx.doi.org/10.1016/0021-9517(92)90187-m.

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32

Reynoso, Alberto José, Jose Luis Ayastuy, Unai Iriarte-Velasco, and Miguel Ángel Gutiérrez-Ortiz. "Bimetallic Pt-Co Catalysts for the Liquid-Phase WGS." Catalysts 10, no. 8 (2020): 830. http://dx.doi.org/10.3390/catal10080830.

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Bimetallic Pt-Co catalysts derived from cobalt aluminate spinel were investigated in the liquid-phase water–gas shift (WGS) reaction and CO hydrogenation. Liquid-phase WGS is a key reaction in the aqueous-phase reforming (APR) of polyols; thus, WGS activity is essential to formulate good APR catalysts. In this work, catalysts with different Pt/Co molar ratios were synthesized together with a reference Pt/alumina. All the synthesized catalysts were characterized by various techniques in order to gain knowledge on their structural and surface characteristics. WGS activity was tested with a feedstream of CO/H2O = 1/15 (space-time of 76.8 kgcat·s/molCO), isothermal operation at 260 °C and 50 bar, for 10 TOS. Bimetallic Pt-Co catalysts showed improved activity in liquid-phase WGS in comparison to bare Co or Pt catalysts, which was ascribed to the synergistic effect. Despite being subjected to an increased hydrogen concentration in the feedstream (H2/CO between 0 and 12/3), these catalysts maintained a preferential selectivity towards WGS activity. In addition, the effect of temperature (220–260 °C) and pressure (25–50 bar) was investigated over a catalyst with 0.3Pt/CoAl. CO conversion and CO2 yield were more sensitive to temperature, while a higher pressure favored methane production. The measured activation energy in the 220–260 °C temperature range was 51.5 kJ/mol.

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Tristantini, Dewi, and Ricky Kristanda Suwignjo. "Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst." Bulletin of Chemical Reaction Engineering & Catalysis 11, no. 1 (2016): 84. http://dx.doi.org/10.9767/bcrec.11.1.424.84-92.

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This study investigated lump kinetic analysis of Fischer-Tropsch synthesis over Cobalt and Cobalt-Rhenium Alumina supported catalyst (Co/γ-Al2O3 and Co-Re/γ-Al2O3) at 20 bars and 483 K using feed gas with molar H2/CO ratios of 1.0 to 2.1. Syngas with H2/CO molar ratio of 1.0 represents syngas characteristic derived from biomass, while the 2.1 molar ratio syngas derived from coal. Rhenium was used as the promoter for the cobalt catalyst. Isothermal Langmuir adsorption mechanism was used to build kinetic model. Existing kinetic model of Fischer-Tropsch synthesis over cobalt alumina supported catalysts only valid for operating pressure less than 10 bar. CO insertion mechanism with hydrogenation step of catalyst-adsorbed CO by catalyst-adsorbed H component as the rate-limiting step is valid for operating condition in this research. Higher H2/CO ratio makes faster hydrogenation step and less-product dominated in the associative CO adsorption step and dissociative H2 adsorption equilibrium step. Kinetic constant for hydrogenation step increases 73-421% in syngas with 2.1 H2/CO molar ratio compared to condition with 1.0 H2/CO molar ratio. Faster hydrogenation step (with higher kinetic constant) results in higher reactant conversion. Equilibrium constant for associative CO adsorption and dissociative H2 adsorption step decreases 53-94% and 13-82%, respectively, in syngas with higher H2/CO molar ratio. Less product dominated reactant adsorption step (lower equilibrium constant for CO and H2 adsorption step) gives higher CH4 product selectivity, which occurred on 2.1 molar ratio of syngas. Rhenium (Re) metal on cobalt catalyst with composition 0.05%Re-12%Co/γ-Al2O3 only gives effect as structural promoter, which only increases reactant conversion with the same product selectivity. Copyright © 2016 BCREC GROUP. All rights reservedReceived: 10th November 2015; Revised: 10th February 2016; Accepted: 16th February 2016How to Cite: Tristantini, D., Suwignjo, R.K. (2016). Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst. Bulletin of Chemical Reaction Engineering &amp; Catalysis, 11 (1): 84-92. (doi:10.9767/bcrec.11.1.424.84-92)Permalink/DOI: <a href="http://dx.doi.org/10.9767/bcrec.11.1.424.84-92">http://dx.doi.org/10.9767/bcrec.11.1.424.84-92</a>

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Bohmhammel, K., B. Christ, and G. Wolf. "Kinetic investigations on the basis of isothermal DSC measurements of hydrogenation and dehydrogenation of magnesium hydride1Presented at the Twelfth Ulm-Freiberg Conference, Freiberg, Germany, 19–21 March 19971." Thermochimica Acta 310, no. 1-2 (1998): 167–71. http://dx.doi.org/10.1016/s0040-6031(97)00392-4.

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Shohoji, Nobumitsu. "Statistical Thermodynamic Analysis for Isothermal Hydrogenation Performances of Mg_2-_yPr_yNi₄Intermetallics (y = 0.6, 0.8, 1.0)." International Journal of Materials and Chemistry 2, no. 3 (2012): 90–100. http://dx.doi.org/10.5923/j.ijmc.20120203.02.

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Laplante, François, Nicolas-Alexandre Bouchard, Patrick Dubé, Hugues Ménard, and Louis Brossard. "The adsorption of cyclohexanone on aluminum oxide hydroxide powders in relation to its electrocatalytic hydrogenation." Canadian Journal of Chemistry 81, no. 10 (2003): 1039–43. http://dx.doi.org/10.1139/v03-127.

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Henry's law constants were determined for cyclohexanone adsorption onto aluminium oxide hydroxide powders by dynamic isotherm measurements using the HPLC method. The key parameters that control cyclohexanone adsorption were established. Further, it is suggested that the amount of cyclohexanone adsorbed onto aluminium oxide hydroxide compounds (AOHC) is of paramount importance for its electrocatalytic hydrogenation in the presence of composite nickelAOCH powders.Key words: adsorption isotherm, electrocatalytic hydrogenation (ECH), cyclohexanone, aluminum oxide hydroxide powders.

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Hong, Tae Whan. "Pressure-Composition-Isotherm Behavior of Partially Remelted Magnesium Alloys." Solid State Phenomena 116-117 (October 2006): 263–66. http://dx.doi.org/10.4028/www.scientific.net/ssp.116-117.263.

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Partially Remelted Mg alloys focused only to aspect of semi liquid forming until now. In presents study, for the purpose of proposition as economic lightweight hydrogen absorbing materials, the hydrogenation properties of pressure-composition-isotherm (PCI) apparatus. According to the results of experiments, globules (Mg rich solid phase) were regarded the storage system as a hydrogen absorption/desorption and eutectic/liquid droplets (quenched liquid phase) were considered the catalytic system as an improving factor of hydrogenation kinetics. Especially, the hydrogenation properties were depended on properties of globules and liquid fraction.

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Jang, Chol Ryong, Vasile Matei, Anca Borcea, Viorel Voicu, Raluca Proscanu, and Dragos Ciuparu. "Hydrogenation of 1-octene by Co-Mo/MCM-41 catalysts." Analele Universitatii "Ovidius" Constanta - Seria Chimie 23, no. 2 (2012): 133–36. http://dx.doi.org/10.2478/v10310-012-0022-5.

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AbstractThe synthesis and characterization of MCM-41 supported Co-Mo catalysts and catalytic hydrogenation of 1-octene to n-octane were discussed. BET specific surface area of MCM-41, calculated from N2 adsorption/desorption isotherm, was 1690 m2/g. The XRD patterns of the Co-Mo/MCM-41 catalysts show that metal species are finely dispersed and the size of CoO and MoO3 particles is below the detection limit by XRD. The 1-octene hydrogenation activity of the catalysts decreased with increasing the Co content up to 9 wt.% for the Co-promoted Co-Mo/MCM-41 catalysts with a MoO3 content of 12 wt.%. All the catalysts show increased hydrogenation activity with increasing reaction temperature in the temperature range from 200 to 350°C.

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Razafindramanana, Volatiana, Stéphane Gorsse, Jacques Huot, and Jean Louis Bobet. "Effect of Hafnium Addition on the Hydrogenation Process of TiFe Alloy." Energies 12, no. 18 (2019): 3477. http://dx.doi.org/10.3390/en12183477.

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The alloy TiFe has interesting hydrogen storage properties for practical applications: low cost, operation at room temperature, and good hydrogen capacity. However, the first hydrogenation is difficult and increases the cost of the alloy. In this work, we studied the effect of adding hafnium to TiFe in order to enhance the first hydrogenation process. TiFe + x Hf alloys, with x = 0, 4, 8, 12, and 16 wt.%, were synthesized by arc melting. The microstructure of the as-cast alloys was investigated by scanning electron microscopy and electron microprobe analysis. These alloys consisted of B2-TiFe, C14-Laves, and BCC (Body Centered Cubic) phases. A minimum of 8 wt.% of hafnium is required to obtain an enhancement of the first hydrogenation. In the first hydrogenation, the material reaches its maximal hydrogen capacity in less than two hours at room temperature and under 20 bars of hydrogen. Hafnium addition also had the effect of lowering the plateau pressure in the pressure-composition isotherm. It could be concluded that hafnium has a positive effect on the activation properties of TiFe.

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Clark, Joshua L., Alaric Taylor, Ailsa Geddis, et al. "Supramolecular packing of alkyl substituted Janus face all-cis 2,3,4,5,6-pentafluorocyclohexyl motifs." Chemical Science 12, no. 28 (2021): 9712–19. http://dx.doi.org/10.1039/d1sc02130c.

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Theory and Langmuir isotherm analysis was used to explore the conformations and molecular packing of alkyl all-cis 2,3,4,5,6-pentafluorocyclohexyl motifs, which are prepared by direct aryl hydrogenations from alkyl- or vinyl-pentafluoroaryl benzenes.

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Chen, Wei-Sheng, Cheng-Han Lee, and Hsing-Jung Ho. "Purification of Lithium Carbonate from Sulphate Solutions through Hydrogenation Using the Dowex G26 Resin." Applied Sciences 8, no. 11 (2018): 2252. http://dx.doi.org/10.3390/app8112252.

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Purification of lithium carbonate, in the battery industry, is an important step in the future. In this experiment, the waste lithium-ion batteries were crushed, sieved, leached with sulfuric acid, eluted with an extractant, and finally sulphate solutions were extracted, through selective precipitation. Next, sodium carbonate was first added to the sulphate solutions, to precipitate lithium carbonate (Li2CO3). After that, lithium carbonate was put into the water to create lithium carbonate slurry and CO2 was added to it. The aeration of CO2 and the hydrogenation temperature were controlled, in this experiment. Subsequently, Dowex G26 resin was used to remove impurities, such as the calcium and sodium in lithium carbonate. Moreover, the adsorption isotherms, described by means of the Langmuir and Freundlich isotherms, were used to investigate the ion-exchange behaviors of impurities. After removing the impurities, the different heating rate was controlled to obtain lithium carbonate. In a nutshell, this study showed the optimum condition of CO2 aeration, hydrogenation temperature, ion-exchange resin and the heating rate to get high yields and purity of lithium carbonate.

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Sharonov, Nikolai Y., and Anastasia A. Fedorova. "2-CHLORO-4-NITROANILINE ADSORPTION ON ACTIVE CARBON FROM 2-PROPANOL SOLUTIONS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, no. 10 (2019): 84–88. http://dx.doi.org/10.6060/ivkkt.20196210.6014.

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Aromatic nitro compounds, such as nitro anilines and its halogen derivatives, are widely used in the industrial synthesis of dispersed azo dyes and some pharmaceutical products. For its preparation the processes of heterogeneous catalysis in various liquid media are used. One of the most important stages of catalysis, which in some cases determines its rate, is adsorption. The study of the nitro compounds adsorption from aqueous and non-aqueous solvents on the heterogeneous catalysts surface makes it possible to reveal the catalytic hydrogenation intimate mechanism features and the solvent influence on the hydrogenation process. In this work, we studied the 2-chloro-4-nitroaniline adsorption on active carbon from 2-propanol solutions at 293 and 313 K. Adsorption isotherms, two-dimensional state diagrams of the surface layers were obtained, and the isosteric heats of the process were calculated. The experimental adsorption isotherms are described in the framework of the volume filling of micropores for mesoporous adsorbents theory. The heat of adsorption is negative and decreases in absolute value with increasing degree of surface filling. On two-dimensional surface layers state diagrams the breaks presence, which corresponds to two-dimensional phase transitions, similar to second-order transitions in surface films. This fact indicates changes in the surface layers state with an increase in the degree of filling the coal surface with adsorbate, is observed.

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LANGE, T., R. KOPSEL, T. KUCHLING, and E. KLOSE. "Hydrogenation behaviour of a German brown coal2. Non-isothermic kinetics." Fuel 68, no. 3 (1989): 366–70. http://dx.doi.org/10.1016/0016-2361(89)90103-8.

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Hong, Tae Whan. "Hydrogenation Properties of Mg-TiNi Hydrogen Storage Composites Materials." Materials Science Forum 486-487 (June 2005): 586–89. http://dx.doi.org/10.4028/www.scientific.net/msf.486-487.586.

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Magnesium and Magnesium alloys have been studied as one of the good lightweight hydrogen storage materials, but the materials have strong difficulties in the fabrication process of mass production until now. The Rotation-Cylinder Method (RCM) has been developed to fabricate magnesium-based composites with moderate rotation under normal atmosphere. Inthis study, the Mg-TiNi hydrogen storage composites materials were manufactured by RCM and evaluated their hydrogenation properties by a Sieverts-type automatic pressure-composition-isotherm (PCI) apparatus at 523, 573 and 623K. The hydrogenation properties of Mg-TiNi composites depended on the behavior of TiNi reinforcements. The formation of Mg hydride, MgH2, on 4h milling samples of Mg-10mass% TiNi intermetallics hinted to the catalytic behavior of TiNi reinforcements. In addition, the dehydriding profile at 573K revealed the two steps of plateau pressure, which were affected by the existence of multi hydride phases.

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Kim, Ju-Seung, Jong Uk Kim, Mingzhe Kong, and Hal Bon Gu. "Electrical and Electrochemical Properties of Poly(P-Phenylene)-Based Carbon for Lithium Rechargeable Batteries." Materials Science Forum 486-487 (June 2005): 590–93. http://dx.doi.org/10.4028/www.scientific.net/msf.486-487.590.

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Magnesium and Magnesium alloys have been studied as one of the good lightweight hydrogen storage materials, but the materials have strong difficulties in the fabrication process of mass production until now. The Rotation-Cylinder Method (RCM) has been developed to fabricate magnesium-based composites with moderate rotation under normal atmosphere. In this study, the Mg-TiNi hydrogen storage composites materials were manufactured by RCM and evaluated their hydrogenation properties by a Sieverts-type automatic pressure-composition-isotherm (PCI) apparatus at 523, 573 and 623K. The hydrogenation properties of Mg-TiNi composites depended on the behavior of TiNi reinforcements. The formation of Mg hydride, MgH2, on 4h milling samples of Mg-10mass% TiNi intermetallics hinted to the catalytic behavior of TiNi reinforcements. In addition, the dehydriding profile at 573K revealed the two steps of plateau pressure, which were affected by the existence of multi hydride phases.

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Takasaki, Tomoaki, Daisuke Kyoi, Naoyuki Kitamura, Shigeo Tanase, and Tetsuo Sakai. "Hydrogen Storage Properties of FCC Type Mg-Transition Metal Hydrides Prepared by GPa High Pressure Method." Materials Science Forum 561-565 (October 2007): 1577–80. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.1577.

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Hydrogenation / dehydrogenation properties of a series of ternary face centered cubic (FCC) hydrides “Mg7MHx” (M = Sc, Ti, V, Zr, Nb, Hf and Ta), which were prepared by a high-pressure technique, were investigated. Differential scanning calorimeter (DSC) measurements under hydrogen atmosphere revealed that these hydrides exhibited reversible hydrogen releasing and re-storing properties at around 600 and 560 K, respectively. These releasing temperatures are lower by 100 ~ 120 K than that of MgH2. Furthermore, pressure-composition isotherm at 523 K shows that these FCC hydrides release 3.8 - 5 wt. % hydrogens.

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Růžička, Jiří, Jiří Hanika, Zdeněk Sedláček, and Vlastimil Růžička. "Determination of structure parameters of platinum hydrogenation catalysts and their supports." Collection of Czechoslovak Chemical Communications 52, no. 11 (1987): 2680–86. http://dx.doi.org/10.1135/cccc19872680.

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Six catalysts containing 5 and 6.1 wt. % Pt were prepared by impregnation of activated carbon (Atlas AET 300) with H2PtCl6 from aqueous solutions and subsequent calcination and reduction with hydrogen at 100, 200, and 300 °C. The specific surface area was determined for the catalysts, saturated supports and the untreated support. The adsorption isotherms of n-pentane at 0 °C were measured for the support, saturated support and catalyst (100 °C), and the experimental data were correlated by the BET, Langmuir, and Dubinin equations; the pore radii distribution was also calculated for them. The activities of the catalysts were evaluated by measuring the initial reaction rates of hydrogenation of 1-octene and nitrobenzene.

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Diaz-Droguett, D. E., S. Rojas, and M. Roble. "Hydrogen Sorption of Porous Tungsten Oxide Nanomaterial and Effect of a Pd Coating on its Storage Capacity Under Hydrogenation Cycles." Nano 13, no. 09 (2018): 1850107. http://dx.doi.org/10.1142/s1793292018501072.

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The H2 uptake performance at room temperature of porous tungsten oxide nanomaterials with and without a catalytic Pd coating was studied by the quartz crystal microbalance technique. Tungsten oxide composed mainly of WO3 was synthesized by inert gas condensation method using He. The samples consisted of semi-amorphous nanomaterials of low crystallinity and high porosity, as revealed by SAED, TEM, XRD, Raman spectroscopy and N2 adsorption–desorption isotherms. The H2 uptake capacity of the porous oxide was studied under increasing H2 exposure pressures (1000–7000[Formula: see text]Pa), with and without Pd coating. After reaching a maximum value of 1.2 H2[Formula: see text]wt.%, at 1160[Formula: see text]Pa, the H2 uptake capacity of the Pd-coated oxide consistently decreased. Successive hydrogenation cycles were carried out on the Pd-coated oxide at 3300 Pa and 6000 Pa to evaluate the H2 uptake performance of the sample under this H2 loading and unloading process. It was found that the H2 uptake capacity decreased from around 1 to values below 0.53[Formula: see text]H2[Formula: see text]wt.%, which is the reference H2 storage capacity achieved by a 15[Formula: see text]nm-thick Pd film. We argued that water molecule formation in the Pd/oxide interface and sublayers negatively affects the H2 uptake capacity of the oxide under successive hydrogenation cycles at room temperature.

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Kim, Whan Gi, Soon Chul Ur, Y. G. Lee, Young Jig Kim, and Tae Whan Hong. "Evaluations of Microstructure and Hydrogenation Properties on Mg₂NiHx Hydrogen Absorbing Alloys by Hydrogen Induced Mechanical Alloying." Materials Science Forum 544-545 (May 2007): 311–14. http://dx.doi.org/10.4028/www.scientific.net/msf.544-545.311.

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In order to fabricate high efficiency, light-weight hydrogen storage materials in an economical way, we have been made to propose a new mechanical alloying process by high-pressure hydrogen induced planetary ball milling(HIMA) using Mg and Ni chips. Microstructural evaluations of the Mg-Ni-H systems synthesized were investigated by scanning electron microscopy and the transmission electron microscopy. X-ray diffraction analysis was also made to characterize the lattice constant, crystallite size and misfit strain. The hydrogenation properties of the particles synthesized were evaluated by automatic PCI (pressure-composition-isotherm). Adopting 66:1 BCR (ball to chips mass ratio) for HIMA process, fully hydrogenated alloys were obtained after 96 hrs of milling, resulting in total hydrogen content of 2.25 mass%.

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Co Thanh, Thien, Giang Dinh Duc, Hai Le Viet, and Man Tran Van. "Highly efficient transfer hydrogenation of 4-Methoxybenzaldehyde over supported silver nanoparticles." Vietnam Journal of Catalysis and Adsorption 9, no. 4 (2020): 17–21. http://dx.doi.org/10.51316/jca.2020.064.

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Silver nanoparticles were simply synthesized via the reduction of silver salt using ascorbic acid as reducing agents. These silver nanoparticles were then embedded on the supports X (X = Bent, C, ZnO, Zeolit, and Al2O3) in high yield. The optical property of these catalysts was characterized by UV-Vis spectroscopy, the structure of Ag-X was studied by Powder X Ray Diffraction (PXRD), the distribution of Ag particles in X was studied by Transmission Electron Microscopy (TEM), the specific surface area of catalysts was evaluated by N2 adsorption isotherms analysis at 77K. All results consisted to the loading method, indeed, TEM image indicated that the silver nanoparticles size is in range of 10¸15 nm and fully loaded into X. The efficiency of these catalysts was performed on the transfer hydrogenation of 4-methoxybenzaldehyde in the presence of potassium hydroxide as base at atmosphere pressure. The results showed that Ag-X exhibited high activities of up to 89.8% conversion within 60 min at 60 °C in the case of Ag-C catalyst.

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Journal articles on the topic 'Isothermal hydrogenation'

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