Browsing by Author "Linkov, Vladimir M"

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    The catalytic membrane reactor for the conversion of methane to methanol and formaldehyde under mild conditions
    (University of the Western Cape, 2005) Modibedi, Remegia Mmalewane; Linkov, Vladimir M; Dept. of Chemistry; Faculty of Science
    This thesis described the development of new catalytic system for the conversion of natural gas (methane) to liquid products such as methanol and formaldehyde. This technology can allow the exploitation of small and medium size gas fields without the need to build an expensive gas to liquid plants or long pipelines. The technology is based on a concept of non-separating membrane reactor where an inorganic membrane paper serves as a catalyst support through which a reaction mixture is flowing under mild conditions and short residence times.
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    Metal-organic frameworks and their derivatives as catalysts of magnesium hydrogenation
    (Institute of Physics, 2025) Lototskyy, Mykhaylo V; Pasupathi, Sivakumar; Linkov, Vladimir M
    This article presents the results of an experimental study on the preparation and characterisation of metal-organic frameworks (MOFs) formed by coordination polymers of Ni(II) and Co(II) itaconates (Ni-IA and Co-IA), as well as the products of thermolysis of their mixtures. It is found that the thermolysis results in the formation of heterometallic CoNi nanoparticles enveloped in a porous carbonaceous matrix (CoNi@C core-shell structures). The catalytic effect of the as-synthesised MOFs and their CoNi@C derivatives on the hydrogenation of Mg during high-energy reactive ball milling (HRBM) in hydrogen has been studied. These catalysts were shown to increase the rate of hydrogenation of Mg during HRBM by about ninefold as compared with non-catalysed magnesium. The kinetic improvements are superior to those observed earlier for other catalysts, including Pd-doped UiO-66 MOF and Ni nanoparticles deposited onto graphene-like materials. At the same time, the achieved reacted fractions when using MOFs and their derivatives as catalysts for magnesium hydrogenation were incomplete. It was found that the use of the as-synthesised MOFs as additives to Mg during HRBM results in the slow hydrogenation of pristine magnesium at room temperature during pauses between the first milling sessions. Almost full conversion of Mg into MgH2 was achieved when the milling vial was kept during these pauses until pressure stabilisation. Based on this observation, it was assumed that the intermediate products of MOF decomposition are more active catalysts of magnesium hydrogenation than the CoNi@C core-shell structures formed as the final MOF decomposition product.
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    The oxidation of the lower primary alcohols ln a catalytic membrane reactor
    (University of the Western Cape, 2000) Masters, Gerard Jerome; Linkov, Vladimir M
    Methanol and ethanol are important chemical feedstock used in industrial chemistry, since they are the starting materials for the synthesis of various products, including hydrocarbons and mild oxidation products. For instance, methanol can be oxidised to methyl format, which can be transformed into industrially important products such as N, N-dimethyl formamide or acetic acid. Both methanol and ethanol have also been used as probe reactions, in which they are used to characterise catalysts according to the type of active sites presents, namely redox, acidic or basic. The lower primary alcohols are also currently being used in fuel cell research, since the oxidation of alcohols has been proposed as an anode reaction for fuel cells. ln the latter case, the important reaction is the complete oxidation of the alcohol to carbon dioxide and water. lt is apparent from industrial examples that methanol oxidation can lead to various products by varying the nature of the catalyst and the reaction conditions.