Stereochemistry and Mechanism of Hydrogenation of Naphthalenes on Transition Metal Catalysts and Conformational Analysis of the Products

Weitkamp, A. W.

doi:10.1016/s0360-0564(08)60428-9

Cited by 99 publications

(46 citation statements)

References 59 publications

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“…Thus, in the case of decalin, the conversion in the cis -isomer dehydrogenation in the temperature range 300–340 °C approaches the maximum values, while the highest conversion of trans -decalin in this range barely reaches 70%. At the same time, the calculation of the equilibrium constants of all elementary acts occurring during the dehydrogenation of decalin and perhydroterphenyl indicates that the cis -isomer has a tendency to transition to a more stable trans -isomer over the entire temperature range under study [ 18 , 19 ]. Taking into account the cis-trans transition during dehydrogenation of decalin, this leads to a decrease in the overall reaction rate and affects the completeness of hydrogen release.…”

Section: Resultsmentioning

confidence: 99%

Kinetic Modeling of Hydrogen Production by Dehydrogenation of Polycyclic Naphthenes with Varying Degrees of Condensation

Каленчук

Кustov

2022

Molecules

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The kinetics of reactions of dehydrogenation of polycyclic naphthenes (cyclohexane, decalin, bicyclohexyl, ortho-, meta-, and para-isomers of perhydroterphenyl) is modeled on the basis of a formal comparison of kinetic equations of the 1st and 2nd orders based on real experimental data. It is shown that the reaction of the 1st order is predominating in the series of cyclohexane–bicyclohexyl–perhydroparatherphenyl. For all other substrates, the probability of describing the reaction in accordance with the equation of the 2nd order increases markedly, and for trans-decalin it becomes the predominant form of describing the kinetics of the reaction.

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Section: Resultsmentioning

confidence: 99%

Kinetic Modeling of Hydrogen Production by Dehydrogenation of Polycyclic Naphthenes with Varying Degrees of Condensation

Каленчук

Кustov

2022

Molecules

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“…In considering various methods for the calculation of the relative distribution of isomers, perhaps the simplest approach is the semiempirical method developed by Weitkamp (1968) for the dimethylcyclohexanes, methyldecalins, and dimethyldecalins. The advantages of this procedure are that few thermodynamic data are needed and the results are easily extended to the methyl and polymethyl derivatives of other systems, e.g., anthracene, phenanthrene, diphenyl, etc.…”

Section: Resultsmentioning

confidence: 99%

“…The symmetry number can be incorporated into the calculation of isomer distribution as follows: 10.0 7.5 9.4 2.9 0.0 0.0 0.0 "Results obtained by calculation using CHEMIX; see text, (this work). bResulta obtained by calculation using the method described by Weitkamp (1968) with k = 1.5; see text (this work). 'Product from catalytic cracker unit, Bass Strait crude oil (this work).…”

Section: Resultsmentioning

confidence: 99%

Measurement and prediction of methyl-substituted naphthalene isomer ratios in liquid hydrocarbon fuels

Borrett¹,

Charlesworth²,

Moritz³

1991

Ind. Eng. Chem. Res.

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Results for the relative isomer abundance of di-and trimethylnaphthalenes in crude and processed products from petroleum, shale oil, and coal tar are reported, together with several procedures for the calculation of the isomer distribution a t equilibrium. The data suggest that the isomer distributions can approach the equilibrium values in certain circumstances. The mechanisms by which such equilibria are achieved may equally explain the distribution of the lower alkylbenzenes, with respect to both isomer distribution and equilibria involving trans-alkylation reactions. This is a t variance with the mechanism postulated for the acid-catalyzed isomerization of alkylnaphthalenes in which only intramolecular methyl migrations are thought to occur. The thermodynamic calculations employed here are easily extended to other polycyclic systems.

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“…Hydrogenation of NL is well studied in gas-phase and liquid-phase processes [5,6,9,[12][13][14].A few studies have reported data on the hydrogenation of aromatics in SC CO2 [15,16]but, to date, there are no reports on TL catalytic synthesis in SC solvent (i.e., hexane) conditions. The best catalytic systems of NL hydrogenation are based on nanoparticles (NPs) of platinum, palladium, nickel and their combinations with other metals supported on coal, alumina, zinc oxide, and zeolites [6,[9][10][11]14,[16][17][18][19][20][21] allowing integral selectivity with respect to TL in the range of 94-99% at high NL conversions, or transforming TL to DLs under more stringent conditions. Typically, the activity of platinum-containing catalysts to produce TL is in the temperature range of 200-300 °C and pressures of 4-6 MPa.…”

Section: Introductionmentioning

confidence: 99%

New Approach to Synthesis of Tetralin via Naphthalene Hydrogenation in Supercritical Conditions Using Polymer-Stabilized Pt Nanoparticles

et al. 2020

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Supercritical (SC) fluid technologies are well-established methods in modern green chemical synthesis. Using SC fluids as solvents instead of traditional liquids gives benefits of higher diffusivity and lower viscosity, which allows mass transfer intensification and, thus, an increased production rate of chemical transformations. Therefore, a conjugation of heterogeneous catalysis with SC media is a large step toward a green chemistry. Tetralin (TL) is an important hydrogen donor solvent used for biomass liquefaction. In industry, TL is obtained via catalytic hydrogenation of naphthalene (NL). Herein, for the first time we have demonstrated the NL hydrogenation with close to 100% selectivity to TL at almost full conversion in the SC hexane. The observed transformation rates in SC hexane were much higher allowing process intensification. The downstream processes can be also facilitated since hexane after depressurisation can be easily separated from the reaction products via simple rectification. The TL synthesis was studied in a batch reactor at variation of reaction temperature and overall pressure. For the first time for this process, low Pt-loaded (1 wt.%) nanoparticles stabilized within hyper-cross-linked aromatic polymer (HAP) were applied. The Pt/HAP catalyst was stable under reaction conditions (250 °C, 6 MPa) allowing its recovery and reuse.

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Stereochemistry and Mechanism of Hydrogenation of Naphthalenes on Transition Metal Catalysts and Conformational Analysis of the Products

Cited by 99 publications

References 59 publications

Kinetic Modeling of Hydrogen Production by Dehydrogenation of Polycyclic Naphthenes with Varying Degrees of Condensation

Kinetic Modeling of Hydrogen Production by Dehydrogenation of Polycyclic Naphthenes with Varying Degrees of Condensation

Measurement and prediction of methyl-substituted naphthalene isomer ratios in liquid hydrocarbon fuels

New Approach to Synthesis of Tetralin via Naphthalene Hydrogenation in Supercritical Conditions Using Polymer-Stabilized Pt Nanoparticles

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