Model Of Catalytic Reactor Research Articles

Membrane assisted propane dehydrogenation: Experimental investigation and mathematical modelling of catalytic reactions

Selective propane dehydrogenation is one of the commercialised technology for the production of propylene. The main drawback of such process is closely linked to the high temperature required to reach a sustainable propane conversion that affects catalyst stability owing to coke formation on the catalyst surface. Accordingly, a periodic regeneration of catalytic bed is required. The simultaneous actions of performing the reaction in the presence of Pd-based membrane and optimization of employed catalyst could lead to a substantial reduction in the operating reaction temperature, decreasing the extent of reactions responsible for coke formation.To this aim a comprehensive study of catalytic behaviour is essential and accordingly a dedicated experimental program is reported for propane dehydrogenation on a Pt-based catalyst, by focusing the attention on the operating conditions compatible with membrane integration. Both activity and stability of the catalyst system was evaluated in the investigated conditions, in addition mathematical models were optimized to effectively describe the system behaviour and the catalyst deactivation.

Robust dynamic optimization in heterogeneous multiscale catalytic flow reactors using polynomial chaos expansion

This paper explores the application of optimal design and operational strategies under uncertainty to a transient multiscale catalytic flow reactor system. The catalytic reactor is modeled using a spatially-dependent multiscale model that comprises lattice-based kinetic Monte Carlo (kMC) models coupled with continuum partial differential equations (PDEs) to account for the fine-scale and the macroscale reactor behaviour, respectively. This work compares two uncertainty propagation techniques, power series expansion (PSE) and polynomial chaos expansion (PCE), to assess their performance in multiscale process systems. The analysis reveals that PCE provides accurate results at minimal computational cost for the multiscale catalytic reactor model under the conditions considered in this work. PCE is subsequently used to perform robust dynamic optimization studies on the catalytic reactor system under uncertainty. The first study determines the optimal temperature trajectories that maximize the reactor’s performance under uncertainty. The second study aims to identify the optimal design and operating policies that allow the reactor, under uncertainty in the multiscale model parameters, to meet targeted performance specifications within a level of confidence. Both studies illustrate the benefits of performing dynamic optimization studies to improve performance for multiscale process systems under uncertainty.

Interaction between thermal cracking and steam reforming reactions of aviation kerosene

Heat transfer and reaction behavior of aviation kerosene were investigated numerically and experimentally at a supercritical pressure. A global thermal cracking and catalytic reforming reaction model were modified and developed based on the experimental data. A set of surrogate components for aviation kerosene was built and its thermodynamic properties were predicted. Interactions among heat transfer, cracking and catalytic steam reforming reactions were simulated in a micro-channel reactor. Comparison between calculation and experiment showed that the numerical model can predict the wall and outlet fuel temperatures with an error not exceeding 5%. The conversion rate of kerosene and water were also in good agreement with experimental data. Heat transfer deterioration phenomenon can be observed when fuel contains water. Fuel with catalytic steam reforming reactions had the advantage of weakening the heat transfer deterioration and obvious promotion in heat sink. Heat transfer process can be divided into four sub-regions: entrance, gasification, transition and interactive reaction regions. The two kinds of reactions occurring in the reaction region significantly improve the heat sink of hydrocarbon fuel. Interactions between cracking and reforming reactions illustrated that the reaction region were considerably moved ahead due to the existing of steam reforming reactions, resulting in lower fuel temperature which led to a lower rate of thermal cracking and conversion. Thermal cracking reaction was inhibited by catalytic steam reforming reactions.

Metal-organic framework one-dimensional fibers as efficient catalysts for activating peroxymonosulfate

Metal-organic framework (MOF) nanocrystalline materials have received great attention because of their application in heterogeneous catalysis. However, they suffer from poor separation from reaction mixtures in practical applications. In this study, we report the first cobalt metal-organic framework containing zeolitic imidazolate framework (ZIF)-67 nanoparticles immobilized on electrospun polyacrylonitrile (PAN) nanofibers, which was used as a composite catalyst (ZIF-67/PAN) for activating peroxymonosulfate (PMS). Detailed characterization showed that the ZIF-67/PAN nanofibers possessed a flexible one-dimensional structure. To demonstrate the catalytic performance of the ZIF-67/PAN nanofibers, the activation of PMS for the catalytic degradation of acid yellow-17 (AY) was chosen as the model catalytic reaction. The results show that 95.1% of AY (500mgL−1) was removed by ZIF-67/PAN in 10min, which is much higher than many other PMS catalyst. More interestingly, the flexible ZIF-67/PAN composite nanofibers catalysts were not only easy to separate from solution but they also retained high catalytic stability. The influencing factors for PMS activation were also investigated, including the catalyst dosage, reaction temperature, solution pH, and doping with competing organic molecules. The degradation mechanism was elucidated by electron paramagnetic resonance experiments. This work provides a new sight into the fabrication of high-performance MOF catalysts with outstanding recycling properties, which may promote the use of MOF materials in more practical applications.

Assessment of 1-Dimensional Catalytic Reactors Using Constrained Gibbs Free Energy Minimization Method: Water Gas Shift and Carbon Monoxide Methanation Case

Catalytic 1-dimensional reactor models were developed using the Gibbs energy minimization approach in order to describe gas composition, molar fractions, and conversions of both water gas shift and carbon monoxide methanation at low partial pressure ratios of CO/H2. The extent of reaction in terms of CO amount in the system was used as an additional constraint on the chemical system while solving the local thermodynamic equilibrium. The validity of the model was checked against experimental data gathered from the literature. The known theory about heterogeneous catalysis was incorporated in the Gibbsian multiphase analysis by means of the advancements of a diffusional limited water gas shift reaction and the catalyzed methanation of CO using virtual phases in the conservation matrix. The advantages of the use of this technique to describe a 1D catalyzed reaction, namely qualitative data regarding the chemical system and reduced ordinary differential equations (ODE) input, among others, are outlined in thi...

Kinetic Modelling of Catalytic Reactions in Solid Oxide Cells: Study of Its Coupling with Electrochemistry for Steam and CO2 Co-Electrolysis and Steam Reforming

Introduction The integration of renewable energies to the global energy market implies electricity storage. However, the available technologies for electricity storage have a low energy capacity and a short time-span. In this context, H2 or carbon molecules produced via water and/or water+CO2 electrolysis open up excellent perspectives for storing renewable electricity, especially the High Temperature Electrolysis (HTE). This technology, based on Solid Oxide Cell (SOC), consumes less electrical energy than low temperature electrolysis because of the energy demand is significantly lowered by the vaporization of water1. The required electrical power is also reduced at high temperature since the steam electrolysis is increasingly endothermic with temperature. Moreover HTE can also directly convert a mix of water and CO2 into syngas, (CO+H2) (co-electrolysis), which can be converted into methane or other hydrocarbon molecules. Moreover, this type of co-electrolyzer can operate under pressure which increases the energy efficiency of the system, reducing the compression costs of the downstream chemical processing unit and increasing cells performance.2 In addition, as nickel present in SOC is known to catalyze CO and CO2 (COx) methanation and water gas shift reactions3, a pressure increase in the electrolyser leads to higher rates of these reactions. HTE cells can also be used in fuel cell mode to generate electricity from methane and water4. In this case, nickel catalyzes steam reforming leading to syngas which can be used to produce electricity. However, the contribution of these catalytic reactions are not well-known in co-electrolysis and fuel cell modes. In this view, we propose to evaluate their impact in a SOC fed with carbonated gases by establishing a kinetic model necessary for a complete electrochemical SOC modelling. This work was carried out on two different SOCs to establish kinetic models for co-electrolysis and steam reforming at atmospheric pressure and then under pressure. Catalytic tests The cells studied come from two different suppliers (A and B). In order to study the catalytic reactions, induced by nickel in the hydrogen electrode, other layers have been removed by sandblasting. COX methanation catalytic tests were performed at 400°C with the cells reduced into powder with different inlet mixtures (CO and/or CO2 with H2 with COx/H2 molar ratio around 0.3). Tests were carried out with a total flow rate of 35NmL.min-1 (equivalent to 346NmL.min-1.cm-2 cell and 245NmL.min-1.cm-2 cell for cells A and B, respectively). These flowrates are far from those commonly used for electrochemical tests, but they allow to distinguish the catalytic activity of the two cells. The results showed that cells are not equivalent to each other regarding COx conversion whatever the conditions used (CO and/or CO2) (Figure 1). It also can be noticed that the CO2 hydrogenation activity is reduced after exposure to a CO/H2mixture (Figure. 2) due to carbon deposition blocking the active sites. Secondly, catalytic tests were achieved to demonstrate the influence of water at the inlet (up to 15mol.% of water). The temperature was varied from 400 to 800°C after initial stabilization at 400°C. These tests confirmed the negative effect of water due to a less favorable thermodynamic. Finally, methane steam reforming catalytic tests were carried out to simulate fuel cell feeding conditions (H2O/CH4 molar ratio around 2) with a total flow rate of 5.3NmL.min-1 (equivalent to 52NmL.min-1/cm-2 cell and 37NmL.min-1.cm-2 cell for cells A and B, respectively). These conditions make it possible to approach the operating conditions of an electrolyser. The temperature was varied from 600 to 800°C after initial stabilization at 600°C. It appears that the A cell is close to thermodynamic equilibrium up to 700°C followed by a decrease at higher temperature whereas the B cell does not exhibit this decrease (Figure 5). Conclusions and outlooks The cells exhibit similar catalytic activities with respect to COX methanation and methane reforming. Simulations carried out using the COMSOL software allowed to select three kinetic models for atmospheric SOC operation5 , 6. To discriminate these models and propose a quantitative kinetic model for the SOCs operating under pressure, catalytic and electrochemical tests will be carried out up to 15 bars. Simulations will then be performed (COSMOL) to simulate the functioning of a cell by coupling catalysis, electrochemistry, gaseous and thermal flows. 1. Ni M. et al. Int. J. Hydrogen Energy 33,2337–2354 (2008). 2. Bernadet L. et al. Int. J. Hydrogen Energy 40,12918–12928 (2015). 3. Gao J. et al. RSC Adv. 5,22759–22776 (2015). 4. Er-rbib H. et al. Energy 75,81–88 (2014). 5. Wang Y. et al. Int. J. Hydrogen Energy 34,3885–3893 (2009). 6. Peters R. et al. J. Power Sources 106, 238–244 (2002). Figure 1

Stochastic surface walking reaction sampling for resolving heterogeneous catalytic reaction network: A revisit to the mechanism of water-gas shift reaction on Cu

Heterogeneous catalytic reactions on surface and interfaces are renowned for ample intermediate adsorbates and complex reaction networks. The common practice to reveal the reaction mechanism is via theoretical computation, which locates all likely transition states based on the pre-guessed reaction mechanism. Here we develop a new theoretical method, namely, stochastic surface walking (SSW)-Cat method, to resolve the lowest energy reaction pathway of heterogeneous catalytic reactions, which combines our recently developed SSW global structure optimization and SSW reaction sampling. The SSW-Cat is automated and massively parallel, taking a rough reaction pattern as input to guide reaction search. We present the detailed algorithm, discuss the key features, and demonstrate the efficiency in a model catalytic reaction, water-gas shift reaction on Cu(111) (CO + H2O → CO2 + H2). The SSW-Cat simulation shows that water dissociation is the rate-determining step and formic acid (HCOOH) is the kinetically favorable product, instead of the observed final products, CO2 and H2. It implies that CO2 and H2 are secondary products from further decomposition of HCOOH at high temperatures. Being a general purpose tool for reaction prediction, the SSW-Cat may be utilized for rational catalyst design via large-scale computations.

PEMODELAN DAN SIMULASI REAKSI DEGRADASI PARASETAMOL DENGAN KATALIS TiO2

The objective of this experiment is to determine the model and the optimum condition of the photocatalytic degradation of paracetamol. Based on the mechanism of the process, the suggested kinetics models are pseudo homogenous model, First Unimolecular Catalytic Reaction model, and Second Unimolecular Catalytic Reaction model.The first step of this research is determining the model then estimating the parameters of the model. k and n for the pseudo homogenous model; k sr , k ads , k des, K A , K P , K R ,and K S for the First Unimolecular Catalytic Reaction and Second Unimolecular Catalytic Reaction model. The validation and simulation of the parameters are based on the results of experiments conducted in the study (Desale et al., 2013). Validation of the models are carried out under the variations of catalyst loading and pH. This research shows that Surface reaction of First Unimolecular Catalytic Reaction’s model fitted the best from the data and there is no pattern on the error. The simulation gives the optimum conditions at catalyst loading 1 g/L and pH 9. In this optimum conditions, the simulation of paracetamol degradation can reach 99.961% on the conversion.

Effect of gas-phase reaction on catalytic reaction for H2/O2 mixture in micro combustor

The catalytic reaction characteristics of the hydrogen and oxygen mixture in the catalytic micro-combustor were detected by thermocouple, infrared thermal imager and OH-PLIF. The equivalence ratio of transition stage from coupling reaction (coupled homogeneous-heterogeneous combustion) to pure catalytic reaction (heterogeneous combustion) was obtained. The three-dimensional pure catalytic reaction model with detailed catalytic reaction mechanism was established in a rectangular catalytic micro-combustor. The simulation model was validated with experimental data. The effects of the intermediate and final products from gas-phase reactions on the pure catalytic reaction were discussed as well as the effects of gas-phase reactions on the catalytic reaction in the process of coupling reactions were studied. The intermediate product OH radical can improve the hydrogen conversion of the surface reaction, and the effect of O radical is not obvious. The final product H2O has an inhibitory effect on the surface reaction. Since the mass fraction of H2O is much higher than other gas-phase reaction products, the dominant effect of the gas-phase reaction on the catalytic reaction is suppression. In the coupling reactions, the fuel consumed by the gas-phase reaction weakened the catalytic reaction.

Kinetic Modelling of Catalytic Reactions in Solid Oxide Cells: Study of Its Coupling with Electrochemistry for Steam and CO2 Co-Electrolysis and Steam Reforming

High Temperature Electrolysis (HTE) can directly convert steam and CO2 into syngas, which may be converted into methane, methanol, DME, etc. The process efficiency should be increased by operating this type of co-electrolyzer under pressure. In this case, COx methanation and water gas shift reactions will occur in the cells with relatively high rates. HTE cells can also be used in fuel cell mode to generate electricity from methane and water by steam reforming, catalysed by nickel present in the cell. However, the contribution of these catalytic reactions are not well-known for these two modes. Consequently, an evaluation of their impact in a cell fed with carbonated gases will be proposed by establishing a kinetic model necessary for a complete electrochemical cell modelling. This work, firstly carried out at atmospheric pressure, allowed to validate only one kinetic model found in the literature for the two modes.

An equation-oriented approach to modeling heterogeneous catalytic reactors

At multiscale modeling of heterogeneous catalytic reactors there appear systems comprising a large number of equations. The solution of such systems is an arduous task and available algorithms require voluminous computations.A modeling strategy has been suggested for such systems. An effective solution algorithm has been developed for a large class of models based on the application of an identical set of numerical tools such as integro-interpolation method, method of straight lines, a special case of a second-order Rosenbrock method, tridiagonal matrix algorithm or Thomas algorithm on each scale of a multiscale reactor model. Step size control is implemented with account for the rate of change of the variables on each scale. The efficiency and robustness of this algorithm were demonstrated at multiscale modeling of heterogeneous catalytic reactors such as tubular reactors, monolith catalytic reactor, and fluidized bed reactor. When switching between reactor types at multiscale modeling it is not necessary to modify the algorithm. The algorithm can also be used for multiscale modeling of heterogeneous catalytic reactors of other types.

Mathematical modelling of catalytic cracking riser reactor

The quality and the yield of gasoline and light olefins from the catalytic cracking unit depend on a broad range of operation indicators including the feedstock composition, the process conditions, the type and activity of the catalyst. The aim of research is to develop the mathematical model of catalytic cracking reactor on the basis of the formalized mechanism of hydrocarbon conversion taking into account the catalyst deactivation by coke. The experimental research of the feedstock and the product of catalytic cracking using a liquid-adsorption chromatography, gas chromatography–mass spectrometry, gas-liquid chromatography and the structural-group composition methods allowed determining the list of the catalytic cracking reactions. According to the discovered reactions, the thermodynamic analysis was performed using the methods of quantum chemistry. Thermo-gravimetric analysis of the coked catalyst allowed estimating the coke structure formed on the catalyst surface. The developed mathematical model allows to predict the product yields including the content of propane-propylene (PPF) and butane-butylene (BBF) fractions, the group composition and octane number of the gasoline depending on the feedstock composition, the process conditions of reactor-regenerator unit and the catalyst activity. As a result, the high theoretical yield of the gasoline (60.4 wt.%, RON 93.5) according to requirements for the content of olefins and benzene can be achieved at the process temperature of 533°C. This temperature is possible at the keeping the catalyst circulation ratio of 6.9 toncat/tonfeed at the catalyst flow temperature after regeneration (685.8°C) with the catalyst activity of 0.79 unit and the feedstock temperature (328.0°C). The yields of rich gas and coke are 24.0wt% and 4.5 wt%, the concentrations of PPF and BBF are 31.5 and 34.8 wt%.

Porous Gold Nanoparticle-Decorated Nanoreactors Prepared from Smartly Designed Functional Polystyrene-block-Poly(d,l-Lactide) Diblock Copolymers: Toward Efficient Systems for Catalytic Cascade Reaction Processes.

Original porous catalytic supports can be engineered via an effective and straightforward synthetic route to polystyrene-block-poly(d,l-lactide) diblock copolymer precursors displaying an acid-cleavable acetal junction between both blocks. To this purpose, we synthesized an acetal-containing heterodifunctional initiator, thus enabling to combine two different polymerization methods, i.e., first atom transfer radical polymerization (ATRP) of styrene, and then ring-opening polymerization (ROP) of d,l-lactide. Thanks to the labile nature of the acetal junction, oriented porous frameworks could be obtained upon trifluoroacetic acid-mediated cleavage of the latter, after orientation of the block copolymer nanodomains by solvent vapor annealing. The resulting porous materials bearing a reactive aldehyde function at the pore surface allowed for further chemical modification via reductive amination with amino-containing compounds, such as tetraethylenepentamine, thus leading to amine-functionalized porous polystyrene. In situ generated gold nanoparticles could then be immobilized within such functionalized porous nanoreactors, and these hybrid materials could find interesting applications in heterogeneous supported catalysis. In this regard, model catalytic reactions, including C-C homocoupling of benzeneboronic acid derivatives, hydride-mediated reduction of nitroaromatic compounds, and especially unprecedented "one-pot" cascade reactions consisting of the latter consecutive reactions from 3-nitrobenzeneboronic acid, were successfully monitored by different chromatographic and spectroscopic techniques.

Golden Carbon Nanotube Membrane for Continuous Flow Catalysis

In this work, a high-performance catalytic membrane, composed of ultrasmall gold nanoclusters (AuNCs) and high aspect-ratio carbon nanotubes (CNTs), was designed for the continuous-flow catalytic reactions. In this hybrid catalytic membrane, the Au core of the NCs serves as high-performance catalyst, and the ligand of the NCs plays two key roles: (1) as a well-defined surfactant assembly to effectively dissolve CNTs in aqueous solution and (2) as an efficient protecting ligand for Au core to avoid agglomeration. Due to the above-mentioned features, a homogeneous 3D self-support catalytic membrane can be readily fabricated by vacuum filtration of the hybrid AuNCs/CNTs. The catalytic activity of the as-designed catalytic membrane was evaluated using 4-nitrophenol hydrogenation as a model catalytic reaction. The data suggest that the continuous flow catalytic reactor could achieve complete conversion of the substrate (i.e., 4-nitrophenol) within a single flow through the membrane with a hydraulic residence t...

POD-DEIM for efficient reduction of a dynamic 2D catalytic reactor model

Many computational difficulties in dealing with chemical process models often result from spatially distributed states as well as nonlinear correlations (e.g., for transport coefficients or reaction kinetics). Surrogate models with sufficient accuracy represent one remedy to this problem. Featuring a lower number of states, model order reduction (MOR) generates considerably less complex models and leads to faster model evaluations. Especially for nonlinear systems, snapshot-based MOR techniques are considered to be one of the most promising methods. In this study, we apply proper orthogonal decomposition together with the discrete empirical interpolation method (POD-DEIM) to a dynamic, two-dimensional reactor model for catalytic carbon dioxide methanation. Motivated by renewable energy integration, we consider this reactor in two different dynamic scenarios: Disturbed continuous operation and start-up. It can be shown that the reduced order model (ROM) is accurate and, furthermore, the solution of the FOM is accelerated at least by one order of magnitude.

Novel yolk-shell polymer/carbon@Au nanocomposites by using dendrimer-like mesoporous silica nanoparticles as hard template

The uniform yolk-shell structured resorcinol–formaldehyde (RF) nanocapsules containing a lot of ultrafine Au nanoparticles (NPs) in the cavity have been successfully fabricated by smartly employing dendrimer-like mesoporous silica nanoparticles (DMSNs) with three-dimensional dendritic superstructure as hard template. DMSNs have three advantages as the template to support the loading of more active species on particle surface (1), produce the rough internal surface of the RF nanocapsules (2), and cause the formation of large mesopores in the shell (3). Porous hollow carbon nanospheres containing many Au NPs in the cavity were fabricated by calcining DMSNs-NH2@Au NPs@RF in inert atmosphere and subsequently removing silica template. The RF nanocapsules@Au NPs exhibit excellent catalytic activity and stability in the model catalytic reduction reaction of 4-nitrophenol due to the unique structure of RF nanocapsules coupled with ultra-dispersed Au NPs.

Nanoengineering of aggregation-free and thermally-stable gold nanoparticles in mesoporous frameworks.

Loading catalytically active, aggregation-free and thermally stable metal nanoparticles (NPs) on a high surface area support represents a major interest in heterogeneous catalysis. Current synthetic approaches to these hybrid catalysts, however, still lack controllability in the thermal stability of metal NPs, particularly at high temperatures in the absence of organic ligands. We herein report a facile "co-assembly" methodology to prepare aggregation-free, ligand-free and thermally stable mesoporous hybrid nanocatalysts of metal-oxides and metal-carbons. Immobilization of catalytically active gold NPs (AuNPs) within high surface area mesoporous frameworks was achieved via the polymer-directed co-assembly of chemically and structurally equivalent Pluronic P-123 and poly(ethylene oxide)-modified metallic gold NPs (AuNP-PEO) as co-structure-directing-agents. The in situ immobilization of AuNPs partially embedded into periodically ordered mesoporous frameworks imposed a three-dimensional "nanoconfinement" effect and essentially enhanced the long-term thermal stability of AuNPs up to 800 °C. The mesoporous hybrids retained a high surface accessibility of AuNPs and they had a fantastic high-temperature catalytic durability (>130 h at 375 °C) confirmed by two model catalytic reactions, including aerobic oxidation of benzyl alcohol and CO oxidation, respectively. Our results may offer a new realm of possibilities for the rational applications of thermally stable nanocatalysts in renewable energy technology and high-temperature catalysis.

Review of Development and Calibration of one Dimensional Catalytic Reaction Model and its issue

Review of Development and Calibration of one Dimensional Catalytic Reaction Model and its issue

Mixed-ligand aminoalcohol-dicarboxylate copper(II) coordination polymers as catalysts for the oxidative functionalization of cyclic alkanes and alkenes

AbstractNew copper(II) catalytic systems for the mild oxidative C–H functionalization of cycloalkanes and cycloalkenes were developed, which are based on a series of mixed-ligand aminoalcohol-dicarboxylate coordination polymers, namely [Cu2(μ-dmea)2(μ-nda)(H2O)2]n·2nH2O (1), [Cu2(μ-Hmdea)2(μ-nda)]n·2nH2O (2), and [Cu2(μ-Hbdea)2(μ-nda)]n·2nH2O (3) that bear slightly different dicopper(II) aminoalcoholate cores, as well as on a structurally distinct dicopper(II) [Cu2(H4etda)2(μ-nda)]·nda·4H2O (4) derivative [abbreviations: H2nda, 2,6-naphthalenedicarboxylic acid; Hdmea,N,N′-dimethylethanolamine; H2mdea,N-methyldiethanolamine; H2bdea,N-butyldiethanolamine; H4etda,N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine]. Compounds1–4act as homogeneous catalysts in the three types of model catalytic reactions that proceed in aqueous acetonitrile medium under mild conditions (50–60°C): (i) the oxidation of cyclohexane by hydrogen peroxide to cyclohexyl hydroperoxide, cyclohexanol, and cyclohexanone, (ii) the oxidation of cycloalkenes (cyclohexene, cyclooctene) by hydrogen peroxide to a mixture of different oxidation products, and (iii) the single-pot hydrocarboxylation of cycloalkanes (cyclopentane, cyclohexane, cycloheptane, cyclooctane) by carbon monoxide, water, and a peroxodisulfate oxidant into the corresponding cycloalkanecarboxylic acids. The catalyst and substrate scope as well as some mechanistic features were investigated; the highest catalytic activity of1–4was observed in the hydrocarboxylation of cycloalkanes, allowing to achieve up to 50% total product yields (based on substrate).

Predictive Beyond-Mean-Field Rate Equations for Multisite Lattice–Gas Models of Catalytic Surface Reactions: CO Oxidation on Pd(100)

Tailored multisite lattice-gas (msLG) models are developed for CO-oxidation on Pd(100) at low-pressures. These models include multiple adsorption site types and superlattice adlayer ordering due to short-range exclusion for highly mobile reactant adspecies. However, they are simplified to neglect longer-range weaker adspecies interactions, so that the key energetic parameters are the CO desorption barrier and the reaction barrier. We discuss existing Density Functional Theory results for these energies, and present additional analysis for CO adsorption. After also including an appropriate non-trivial specification of the dynamics of adsorption onto mixed reactant adlayers, rate equations are developed for the reaction kinetics. Our formulation goes beyond traditional mean-field (MF) Langmuirian treatments by accounting for multiple adsorption sites and for the strong spatial correlations associated with superlattice ordering. Specifically, we utilize factorization approximations based on appropriate site ...