Hydrogenation Of 1-butene Research Articles

Production of Butane from Methyl Ethyl Ketone over Pt/Al2O3

Methyl ethyl ketone (MEK) was catalytically converted to butane directly in one step over platinum (Pt) supported on alumina (Al2O3). The reaction was performed in the gas phase in a fixed bed reactor. Conversion of MEK to butane was achieved by hydrogenation of MEK to 2-butanol, dehydration of 2-butanol to butene, and further hydrogenation of butene to butane. The results showed that butane can be produced with selectivity reaching 95% depending on the operating conditions. The highest selectivity for butane was obtained at 220 °C and a H2/MEK molar ratio of 15. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Enhanced hydrogenation conversion efficiency of porous nickel particles with homogeneously distributed unimodal nanopores

Reactive nickel (Ni) catalysts with highly active sites on their surface are mainly used in selective hydrogenation reactions. In this study, we synthesized a few micron-sized porous Ni particles with homogenously distributed unimodal nanopores of size 50 nm using a precisely controlled spray pyrolysis process. Furthermore, the catalytic activity of the particles was investigated in the vapor phase of the 1-butene hydrogenation reaction at 100–300°C. The porous Ni particles exhibited superior catalytic conversion efficiencies at the reaction temperatures compared to those of alloyed Ni synthesized using the conventional method. These results indicate that increasing nano-sized reaction sites on a micron-particle is a key approach to accelerate hydrogenation by lowering activation energy for the reaction.Thus, the proposed reactive Ni particles effectively enhance the efficiency of metal catalysts by introducing a homogeneous distribution and connection of unimodal nanopores.

MIL-100(Fe) Supported Pt-Co Nanoparticles as Active and Selective Heterogeneous Catalysts for Hydrogenation of 1,3-Butadiene.

Superior catalytic performance for selective 1,3‐butadiene (1,3‐BD) hydrogenation can usually be achieved with supported bimetallic catalysts. In this work, Pt−Co nanoparticles and Pt nanoparticles supported on metal–organic framework MIL‐100(Fe) catalysts (MIL=Materials of Institut Lavoisier, PtCo/MIL‐100(Fe) and Pt/MIL‐100(Fe)) were synthesized via a simple impregnation reduction method, and their catalytic performance was investigated for the hydrogenation of 1,3‐BD. Pt1Co1/MIL‐100(Fe) presented better catalytic performance than Pt/MIL‐100(Fe), with significantly enhanced total butene selectivity. Moreover, the secondary hydrogenation of butenes was effectively inhibited after doping with Co. The Pt1Co1/MIL‐100(Fe) catalyst displayed good stability in the 1,3‐BD hydrogenation reaction. No significant catalyst deactivation was observed during 9 h of hydrogenation, but its catalytic activity gradually reduces for the next 17 h. Carbon deposition on Pt1Co1/MIL‐100(Fe) is the reason for its deactivation in 1,3‐BD hydrogenation reaction. The spent Pt1Co1/MIL‐100(Fe) catalyst could be regenerated at 200 °C, and regenerated catalysts displayed the similar 1,3‐BD conversion and butene selectivity with fresh catalysts. Moreover, the rate‐determining step of this reaction was hydrogen dissociation. The outstanding activity and total butene selectivity of the Pt1Co1/MIL‐100(Fe) catalyst illustrate that Pt−Co bimetallic catalysts are an ideal alternative for replacing mono‐noble‐metal‐based catalysts in selective 1,3‐BD hydrogenation reactions.

Carbon nanotube-zeolite composite catalyst - characterization and application

“Support on support” (SoS) core-shell nanostructure was prepared by using zeolite beads as supports for nitrogen-doped bamboo-like carbon nanotubes (N-BCNTs). The N-BCNTs were synthetized with catalytic chemical vapor deposition (CCVD) onto the surface of the beads to use later as primary catalyst support. On the SoS composite Pd, Rh, and Pt nanoparticles were successfully deposited (2 w/w%) with high dispersity. The prepared three catalytic systems (Pd-, Rh- and Pt-SoS) were characterized and tested in butene hydrogenation. The reactions were followed by FTIR spectroscopy. The butene conversion reached the maximum after about 6 minutes. Each catalyst was easy to handle and applicable in the studied reaction.

Application of carbonized ion exchange resin beads as catalyst support for gas phase hydrogenation processes

Carbonized ion exchange resin beads were prepared as catalyst for gas phase hydrogenation processes. Amberlite IR 120 polystyrene based sulfonated ion exchange beads were carbonized at 900 °C. The process of carbonization was monitored by FTIR combined thermogravimetric analysis. During the carbonization formed sulfur dioxide, carbon dioxide and organic compounds. The carbon pearls were used as catalyst support for Pd nanoparticles. The catalyst was characterized by scanning electron microscopy and X-ray diffractometry. The diameters of the palladium nanoparticles on the catalyst surface were between 15 and 50 nm, but bigger aggregates were also detected. The catalyst was tested during the gas phased heterogeneous catalytic hydrogenation of 1-butene. The hydrogenation process was followed by FTIR measurements, 93% conversion was reached after 10 min.

Development of nitrogen-doped bamboo-like carbon nanotubes coated zeolite beads as \u201csupport on support\u201d catalyst for the catalytic hydrogenation of olefins

“Support on support” type catalysts were developed by applying catalytic chemical vapour deposition (CCVD). Nitrogen-doped bamboo-like carbon nanotubes (N-BCNT) were synthetized on the surface of zeolite beads by using four different metals (Ni, Fe, Co and V). Based on the thermogravimetric analysis (TGA), the Ni, Co and Fe were catalytically active for nanotube production on the zeolite surface. It was confirmed by SEM measurements, that the surface of the beads was extensively covered by N-BCNTs. Based on the TGA and SEM results, two SoS systems were selected for further catalysts development, which differed the most in their nanotube content (difference 11.63 wt%) and surface coverage. These were two nickel containing samples with 6.72 and 18.35 wt% N-BCNT. Palladium nanoparticles were deposited (1 wt%) on the surface of the N-BCNT/zeolite systems, and the final Pd/SoS catalysts were tested in hydrogenation of 1-butene. The conversion maximum (X = 100%) was reached after 6 min in both cases independently of the nanotube content and coverage (WHSV: 5.49). To measure the lifetime of the selected catalysts, the WHSV was increased from 5.49 to 11 (by increasing the gas flow) and the systems were still active after 6 h. Thus, the lifetime of the catalysts is longer than 6 h. Furthermore, by increasing the gas flow (WHSV = 11), higher conversion was achieved (98%) with the sample which has a higher nanotube content Therefore, smaller carbon nanotube content is still as catalyst support. The final Pd/SoS catalysts were active, easy to treat and removable from the reactors and could work with smaller carbon nanotube content as well. Thus, a more economical catalysts was developed, than a solely carbon nanotube-based counterparts which lack the zeolite core.

Exploring the mechanism of alkene hydrogenation catalyzed by defined iron complex from DFT computation.

UB3LYP computation including dispersion and toluene solvation has been carried to elucidate the mechanisms of alkene hydrogenation catalyzed by bis(imino)pyridine iron dinitrogen complex (iPrPDI)Fe(N2)2, which has low stability towards N2 dissociation. The coordinatively unsaturated complexes, (iPrPDI)Fe(N2) and (iPrPDI)Fe(1-C4H8), favor open-shell singlet ground states. On the basis of our computations, we propose a new mechanism of 1-butene coordination and hydrogenation after N2 dissociation. The hydrogenation of 1-butene undergoes a concerted open-shell singlet transition state involving H2 dissociation, C-H bond formation and C=C bond elongation, as well as the subsequent C-H reductive elimination. In the whole alkene hydrogenation, the H-H bond cleavage is the rate-determining step. Graphical abstract The alkene hydrogenation catalyzed by redox-active pyridine(diimine)-chelate iron complex follows the open-shell singlet state path.

Conversion of methyl ethyl ketone to butenes over bifunctional catalysts

The direct conversion of methyl ethyl ketone (MEK) to butene over supported copper catalysts was investigated in a fixed bed reactor over Cu-Al2O3, Cu-zeolite Y sodium (Cu-ZYNa) and Cu-zeolite Y hydrogen (Cu-ZYH). In this reaction, MEK is hydrogenated to 2-butanol over metal sites which is further dehydrated on acid sites to produce butene. Experimental results showed that the selectivity of butene was the highest over Cu-ZYNa, and it was improved by finding the optimum reaction temperature, hydrogen pressure and the percentage of copper loaded on ZYNa. The highest selectivity of butene (97.9%) was obtained at 270 °C and 20 wt% Cu-ZYNa. Over Cu-Al2O3, the selectivity of butenes was less than Cu-ZYNa since subsequent hydrogenation of butene occurred to produce butane. It was also observed that with increasing H2/MEK molar ratio, butane selectivity increased. However, when this ratio was decreased, hydrogenation of butene was reduced, but dimerization to C8 alkenes and alkane began to be favored. The main products over 20% Cu-Al2O3 were butene and butane, and a maximum selectivity of butene (87%) was achieved at an H2/MEK molar ratio of five. The lowest selectivity of butene was obtained using Cu-ZYH, reaching ∼40%. All catalysts were characterized by (NH3-TPD), (CO2-TPD), XPS and TPR to probe catalyst acidity, basicity and the reducibility of Cu loaded on the supports. It was found that the amount of acidity in Cu-ZYH is much higher than in Cu-ZYNa. This could have caused the selectivity of butene to decrease as a result of dimerization, oligomerization and cracking reactions.

Dimethyl ether to hydrocarbons over ZSM-5: Kinetic study in an external recycle reactor

DME provides advantages in the valorization of feed streams of low H2/CO ratio, which are formed from feedstocks such as biomass or coal.It is currently accepted that the conversion of oxygenates, such as DME or methanol, to hydrocarbons proceeds via the dual-cycle mechanism.After inspection of several kinetic models developed for the methanol-to-gasoline (MtG) reaction, we show in this investigation that they have limited applicability when dimethyl ether (DME) is used as feedstock. Therefore, the development of a kinetic model able to represent the DME-to-hydrocarbons (DtH) over a ZSM-5 catalyst was necessary.In this research, we have developed a new kinetic model that considers main steps of the dual cycle mechanism, including: (i) formation of aromatic intermediates (polymethylbenzenes); (ii) dealkylation of the intermediates to produce ethylene and propylene; (iii) methylation of small olefins to increase the chain size of the hydrocarbons; (iv) hydrogenation of ethylene, propylene and butenes to produce the corresponding saturated compounds; and (v) dimerization reactions between propylene and butenes to produce higher hydrocarbons. Moreover, the kinetic parameters of this new model were estimated from regression analysis using kinetic data measured under gradientless conditions in a fixed-bed external recycle reactor over a wide range of conditions, with temperatures from 325 to 375 °C, weight hourly space velocities (WHSV) from 25 to 125 h−1, a total pressure of 1 bar and undiluted DME as feed. The newly developed model allowed a good description of the experimental results, showed better performance than models available in literature for the MtG reaction, and rendered kinetic parameters that met physicochemical and statistical constraints, showing good agreement with results from DFT calculations reported by other authors.

When the nature of surface functionalities on modified carbon dominates the dispersion of palladium hydrogenation catalysts

Commercial carbon nanofibers with different graphitic structure and commercial multiwall carbon nanotubes (CNT) were chemically modified in order to introduce specific alkyl ligands on their surface. Palladium catalysts have been prepared using these modified supports and subsequently tested in the partial hydrogenation of 1,3-butadiene under conditions of excess hydrogen. Herein, we used thermogravimetry (TG), temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and nitrogen adsorption at 77K techniques in order to characterize both supports and catalysts. We focus on testing the effects of support surface functionalities either on morphology of supported palladium (Pd) nanoparticles (NPs) or on their catalytic performances. High selectivity to butenes was obtained with the catalysts prepared over supports containing alkyl chains, while over-hydrogenation to butane took place over oxygen-containing functional groups. Nicely the catalysts with modified supports minimize the secondary hydrogenation of butenes even at high conversions. Therefore, Pd NPs on modified nano-carbon catalysts may open up more opportunities to optimize the activity and the selectivity for partial hydrogenation reactions.

Mechanism of Olefin Hydrogenation Catalysis Driven by Palladium-Dissolved Hydrogen

The Pd-catalyzed hydrogenation of C═C double bonds is one of the most important synthetic routes in organic chemistry. This catalytic surface reaction is known to require hydrogen in the interior of the Pd catalyst, but the mechanistic role of the Pd-dissolved H has remained elusive. To shed new light into this fundamental problem, we visualized the H distribution near a Pd single crystal surface charged with absorbed hydrogen during a typical catalytic conversion of butene (C4H8) to butane (C4H10), using H depth profiling via nuclear reaction analysis. This has revealed that the catalytic butene hydrogenation (1) occurs between 160 and 250 K on a H-saturated Pd surface, (2) is triggered by the emergence of Pd bulk-dissolved hydrogen onto this surface, but (3) does not necessarily require large stationary H concentrations in subsurface sites. Even deeply bulk-absorbed hydrogen proves to be reactive, suggesting that Pd-dissolved hydrogen chiefly acts by directly providing reactive H species to the surface ...

Synthesis and 1-butene hydrogenation activity of platinum decorated bamboo-shaped multiwall carbon nanotubes

Bamboo-shaped carbon nanotubes (BCNT) were prepared from three different amines on supported iron (Fe) and nickel (Ni) catalysts by catalytic chemical vapor deposition. The main factors governing product morphology and defect site density were identified. Post-synthetic oxidative functionalization was used to add carboxyl groups to the nanotubes, and then platinum (Pt) nanoparticles were deposited on the surface by the in situ reduction of a platinum salt. The average Pt nanoparticle diameter was found to be affected by the extent of surface functionalization. The catalytic performance of the synthesized Pt/BCNT samples were examined in the hydrogenation of 1-butene, in order to show that the catalytic activity of the bamboo like carbon nanotube supported Pt catalyst is similar to the conventional Pt catalysts in heterogeneous catalytic hydrogenation. The best overall performance was achieved when the bamboo-shaped nanotube support was synthesized on 5 wt% Fe/Al(OH)3 catalyst from triethylamine and decorated with 5 wt% platinum nanoparticles.

Olefin Hydrogenation with Single-Site Gold

Butene hydrogenation activity is intimately connected with the occupied and unoccupied electronic states of gold active site. We prepare well-defined Au(III) sites in IRMOF-3 structure, and tuned the metal density-of-states by replacing the substituent group of the coordinating group at position 5. Resonant inelastic X-ray scattering experiments and theoretical calculations revealed an increase in unoccupied 5d states of Au when the substituent group is a donating group, which leads to a dramatic increase in catalytic activity.

Influence of toluene on the catalytic activity of NiPdCe catalyst for selective hydrogenation of 1,3-butadiene

The selective hydrogenation of 1,3-butadiene to 1-butene with toluene as a co solvent is studied experimentally over a NiPdCe/γ-Al2O3 catalyst. To reduce mass transfer limitations, an egg-shell catalyst is used in a fixed-bed reactor for liquid-phase hydrogenation of 1,3-butadiene at 40°C and two pressure levels, 90 and 210psig. Experimental results indicate that 1,3-butadiene conversion and selectivity of the hydrogenation process are improved when toluene is added. Conversion of 1,3-butadiene increases from 65% without toluene to 75% for 20% toluene concentration at 90psig, while for 210psig the observed increase is from 66% to 81%. The 1,3-butadiene selectivity toward 2-butenes is favored against 1-butene, always with preference for the thermodynamically stable trans-isomer. The 1-butene hydrogenation is controlled, decreasing the loss from 25% to 10% in the presence of toluene a 210psig. It can be concluded that the toluene presence enhances the 1,3-butadiene selective hydrogenation and controls 1-butene consumption.

Kinetic study of the liquid-phase selective hydrogenation of 1-butyne in presence of 1-butene over a commercial palladium-based catalyst

A kinetic investigation of the liquid-phase selective hydrogenation of 1-butyne in presence of 1-butene was performed over a commercial palladium-based/alumina catalyst of the eggshell type. This investigation is aimed at validating a kinetic expression to describe 1-butyne hydrogenation under experimental conditions around the typical operating conditions of industrial C 4 cuts hydrorefining processes. Seven levels of temperature between 27 °C and 62 °C were explored. 1-Butyne and n-butene initial mole fractions amounted to ca. 8% and 9% and hydrogen partial pressure was set between 0.85 atm and 7.82 atm. Experimental data and data analysis were extended to 1-butyne total conversion. Palladium proved to be quite selective towards 1-butyne hydrogenation. However, the intrinsic palladium selectivity is impaired by the presence in our experiments of severe intracatalyst diffusion limitations. This result turns the attention to the crucial influence of hydrogen partial pressure level on selectivity because unnecessary hydrogen excesses severely lessen selectivity when 1-butyne becomes the limiting reactant inside the catalyst. A kinetic expression of the Langmuir–Hinshelwood–Hougen–Watson type was proposed to describe the hydrogenation of 1-butyne. 1-Butene hydrogenation rate was described by a zero-order and first-order kinetic expression with respect to 1-butene and hydrogen, respectively. The kinetic model predicts experimental data with an average deviation of 17.1%. The relative inference intervals of the kinetic parameter estimates were less than ±14.8%.

Selective hydrogenation of olefins with mass transfer control in a structured packed bed reactor

Mass-transfer-controlled hydrogenation of butadiene in the presence of 1-butene and benzene using two differently-structured catalytic packings was studied. Kinetic expressions were developed in a continuous stirred-tank reactor (CSTR) using a PdNiCe/SiAl-SS-316 catalyst with two packing structures. The two packing methods were also tested in a trickle bed down-flow isothermal reactor at similar gas and liquid flow rates. To model the effects of mass transfer on reactor efficiency a simulation was developed using this reaction kinetics and published data regarding gas and liquid hold ups and mass transfer correlations. The results confirmed that the apparent kinetics follow a heterogeneous-type expression, which is first order for the hydrogenation of butadiene and butene and is of order 0.3 with respect to hydrogen isomerization and dimerization reactions followed respectively a first- and second-order with respect to hydrocarbon. Simulations showed that the rate of mass transfer of hydrocarbon in liquid and liquid–solid interface controls butadiene hydrogenation at low conversion rates because its reaction rate is 10 times faster than that of 1-butene or benzene hydrogenation. The benzene/olefin ratio and the temperature were the main parameters governing the selectivity, and there was an important difference in mass transfer behavior between the two catalytic packings used.

Hydrogenation of 1-butene on nanosized Pd/ZnO catalysts

The reaction concerning the hydrogenation of 1-butene has occupied the researchers conducting research based on the method of reversed-flow inverse gas chromatography (RF-IGC), for extended time periods. This work aims to define and record, with the utmost accuracy, the phenomena and their possible parallel reactions. It was a challenge for the RF-IGC, which was met. The venture consisted of many parts. Answers had to be provided to the following questions: (a) Can RF-IGC deal with issues of catalysis? (b) Can RF-IGC be applied to thin films? (c) Can RF-IGC identify peaks? (d) Can RF-IGC define the gnostic regions of adsorption, desorption, surface diffusion, surface reaction, the existence of more than one reaction? (e) Can it kinetically follow the above? The answer is certainly yes. The effort made is presented in this work and aims to answer all the above questions.

Kinetic Models for Hydrogenolysis of Thiophene on Co-Mo/γ-Alumina Catalyst

A feasible, comprehensive, and rigorous mechanistic kinetic model was developed for hydrogenolysis of thiophene on a commercial hydrodesulphurization Co-Mo/γ-Al2O3 catalyst. The kinetics were modeled with 24 rate expressions based on three modes of adsorption: molecular and atomic adsorption of hydrogen, and Eley Rideal mechanism. The experimental data were obtained in a bench-scale tubular reactor with plug flow, and the conditions varied over the following range: total pressure, P t = 2–30 bar, temperature = 533–625 K, and molar hydrogen to hydrocarbon ratios 4–9. The experimental rate data were described by a set of Lagmuir-Hinshelwood-Hougen-Watson rate equations for both the hydrogenolysis of thiophene to butene and the hydrogenation of butene to butane on two different sites, σ and τ. The kinetic rate constants and adsorption equilibrium constants were estimated for each model using the optimization routine of Nelder-Mead simplex algorithm. Discrimination among rival models was based upon physicochemical criteria, analysis of the residuals, and statistical tests. The surface reaction between adsorbed thiophene and adsorbed hydrogen on σ sites in the hydrogenolysis, and the surface reaction between adsorbed butene and adsorbed hydrogen on τ sites in the hydrogenation when hydrogen is adsorbed molecularly are found to be the rate-determining steps. The predicted activation energies, enthalpies of adsorption, Gibbs free energies, and adsorption entropies compare exceedingly well with previously reported values in the literature.

Development and characterization of ZnO, Au/ZnO and Pd/ZnO thin films through their adsorptive and catalytic properties

In this paper, we report (a) the development of ZnO thin films prepared by pulsed laser deposition and partially covered with nano-particles Pd or Au and (b) their physicochemical study, in order to investigate their catalytic and/or adsorptive properties. It is the first time where two different and popular methods, namely pulsed laser deposition and reversed flow-inverse gas chromatography, are combined. The inverse gas chromatographic technique with the corresponding time-resolved analysis is used for the first time in order to characterise compounds in the nano-scale domain. We focus on the determination of physicochemical quantities mainly concerning the adsorption in thin films, with (Pd/ZnO) or without (Au/ZnO) catalytic behaviour. Thus, entropy and other important physicochemical quantities are calculated which reveal the mechanism of adsorption as well as of isomerization–hydrogenation of 1-butene and contribute to the study of heterogeneity of thin film surfaces. The programs used have been written in Fortran. An important achievement is also the determination of the standard deviations of the kinetic constants.

Combined UHV and ambient pressure studies of 1,3-butadiene adsorption and reaction on Pd(1 1 1) by GC, IRAS and XPS

The hydrogenation of 1,3-butadiene on Pd(111) at 300K was studied at atmospheric pressure by infrared reflection absorption spectroscopy (IRAS) and gas chromatography (GC). Kinetic measurements showed 1-butene, trans-2-butene and cis-2-butene as primary products. Once 1,3-butadiene had been completely consumed, 1-butene was re-adsorbed on the surface producing trans-/cis-2-butene through isomerization and n-butane through hydrogenation. These results were corroborated by in situ IRAS spectroscopy. Post-reaction analysis by X-ray photoelectron spectroscopy (XPS) in the C1s region revealed a band at 284.2eV, corresponding to adsorbed butadiene and/or carbonaceous deposits. Quantification of this peak revealed a total carbon coverage of 0.3ML. Nevertheless, deactivation due to carbon deposition was a minor effect under our reaction conditions, as indicated by the kinetics of the subsequent butene hydrogenation reaction. Temperature-dependent XPS experiments after butadiene adsorption at 100K indicated a high stability of the diene molecule with hardly any desorption and/or decomposition up to 500K. Above this temperature, butadiene decomposed to carbon species that eventually dissolved in the Pd bulk above 700K.