Lithium ions incorporation in MgO for oxidative dehydrogenation/cracking of propane: Active site characterization and mechanism of regeneration

Trionfetti, C.; Crapanzano, Salvatore; Babich, Igor V.; Seshan, Kulathuiyer; Lefferts, Leon

doi:10.1016/j.cattod.2008.06.018

Cited by 14 publications

(5 citation statements)

References 41 publications

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“…(20)-(35). The occurrence of active sites on the catalyst surface is supported by the work of Trionfetti et al [16], who reported the characterization and mechanism of regeneration. Assuming a first-order reaction occurring in a spherical particle of radius r s , the concentration of A at any radial distance r from the centre of the catalyst to its concentration on the surface will be expressed by Eq.…”

Section: External Mass Transfer Effects On the Kineticsmentioning

confidence: 82%

Kinetics and deactivation of a dual-site heterogeneous oxide catalyst during the transesterification of crude jatropha oil with methanol

Olutoye

Hameed

2016

Journal of Taibah University for Science

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In this work, a dual-site heterogeneous catalyst was used to study the kinetics of the transesterification of crude jatropha oil with methanol in batch experiments. Experimental data were obtained between 150 and 182 • C at a constant molar ratio of alcohol to oil (11:1) and at a set catalyst concentration (3.32 wt% based on weight of oil). Kinetic modelling was performed with an assumed pseudo-first order to describe the rate and catalyst deactivation, which suitably fit the experimental data. The model parameters were determined for both the mass transfer controlled and reaction regimes. The triglyceride (TG) conversion, methyl ester (ME) formation, and system thermodynamics were also evaluated. Based on the calculated values, within an acceptable range, the equilibrium constant, K e = 1.42; activation energy, E a = 161 kJ/mol; and free energy, G = −1286 J/mol indicate that the developed model adequately described the methanolysis of the oil, which may be useful in reactor design and process simulation. The values that were calculated from the kinetic equations agree well with the experimental values, and the results help to understand and predict the behaviour of dual-site catalysts in practical applications for the production of biodiesel.

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Section: External Mass Transfer Effects On the Kineticsmentioning

confidence: 82%

Kinetics and deactivation of a dual-site heterogeneous oxide catalyst during the transesterification of crude jatropha oil with methanol

Olutoye

Hameed

2016

Journal of Taibah University for Science

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“…In this context, it is important to note that magnesium oxide is of particular interest in oxidation catalysis, as doped MgO materials are among the most promising catalysts for the partial oxidation of alkanes on a large scale. [12][13][14] …”

Section: Mgomentioning

confidence: 98%

Preferential Activation of Primary CH Bonds in the Reactions of Small Alkanes with the Diatomic MgO^+. Cation

Schröder

Roithová

Alikhani

et al. 2010

Chemistry A European J

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The C-H bond activation of small alkanes by the gaseous MgO(+*) cation is probed by mass spectrometric means. In addition to H-atom abstraction from methane, the MgO(+*) cation reacts with ethane, propane, n- and iso-butane through several pathways, which can all be assigned to the occurrence of initial C-H bond activations. Specifically, the formal C-C bond cleavages observed are assigned to C-H bond activation as the first step, followed by cleavage of a beta-C-C bond concomitant with release of the corresponding alkyl radical. Kinetic modeling of the observed product distributions reveals a high preference of MgO(+*) for the attack of primary C-H bonds. This feature represents a notable distinction of the main-group metal oxide MgO(+*) from various transition-metal oxide cations, which show a clear preference for the attack of secondary C-H bonds. The results of complementary theoretical calculations indicate that the C-H bond activation of larger alkanes by the MgO(+*) cation is subject to pronounced kinetic control.

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“…Alkali promoted alkaline earth metal oxides are one of the well-known solid super-base catalysts and have been widely used as catalysts for a variety of reactions such as condensation, oxidative coupling, oxidative dehydrogenation, etc. [12][13][14][15][16][17] These catalysts are prepared by different methods like co-precipitation, decomposition of carbonates, sol gel 18 and incipient wetness technique. Conventionally synthesized Li promoted on magnesium oxides requires high-temperature treatment which results in sintering and lower surface area of the resultant catalyst.…”

Section: Introductionmentioning

confidence: 99%

Green synthetic route for perfumery compound (2-methoxyethyl) benzene using Li/MgO catalyst

Tambe

Yadav

2017

J Chem Sci

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Ethers are one of the most prominent compounds among perfumery chemicals. (2-Methoxyethyl) benzene commonly known as phenyl ethyl methyl ether (PEME) is widely used in flavour and fragrance industries. Conventionally, synthesis of PEME involves the use of hazardous and polluting chemicals, which in turn affects the purity of perfumery compound. Thus, developing a green route to synthesise PEME without any hazardous chemicals is desirable. In the current work, a new process is developed for the synthesis of PEME using solid base catalysts including MgO and Li/MgO (with different loadings of lithium) and dimethyl carbonate (DMC) as a methylating agent as well as a solvent. Different kinetic parameters were studied to achieve the optimum yield of the desired product. At optimum reaction conditions i.e., 1000 rpm of speed, 1.33 × 10 −2 g/cm 3 of catalyst loading, 1:10.5 mole ratio (2-Phenyl ethanol: DMC), 180 • C, 95% conversion of 2-phenyl ethanol with 98% selectivity of PEME was achieved. A detailed kinetic model was also developed and apparent activation energy for the reaction was calculated as 11.93 kcal/mol.

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Lithium ions incorporation in MgO for oxidative dehydrogenation/cracking of propane: Active site characterization and mechanism of regeneration

Cited by 14 publications

References 41 publications

Kinetics and deactivation of a dual-site heterogeneous oxide catalyst during the transesterification of crude jatropha oil with methanol

Kinetics and deactivation of a dual-site heterogeneous oxide catalyst during the transesterification of crude jatropha oil with methanol

Preferential Activation of Primary CH Bonds in the Reactions of Small Alkanes with the Diatomic MgO^+. Cation

Green synthetic route for perfumery compound (2-methoxyethyl) benzene using Li/MgO catalyst

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Lithium ions incorporation in MgO for oxidative dehydrogenation/cracking of propane: Active site characterization and mechanism of regeneration

Cited by 14 publications

References 41 publications

Kinetics and deactivation of a dual-site heterogeneous oxide catalyst during the transesterification of crude jatropha oil with methanol

Kinetics and deactivation of a dual-site heterogeneous oxide catalyst during the transesterification of crude jatropha oil with methanol

Preferential Activation of Primary CH Bonds in the Reactions of Small Alkanes with the Diatomic MgO+. Cation

Green synthetic route for perfumery compound (2-methoxyethyl) benzene using Li/MgO catalyst

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Preferential Activation of Primary CH Bonds in the Reactions of Small Alkanes with the Diatomic MgO^+. Cation