Selectivity liquid phase

Fig. 2. Liquid-phase selectivity of UOP Olex adsorbent 0> olefins , paraffins.

The activity of elemental carbon as a metal-free catalyst is well established for a couple of reactions, however, most literature still deals with the support properties of this material. The discovery of nanostructured carbons in most cases led to an increased performance for the abovementioned reasons, thus these systems attracted remarkable research interest within the last years. The most prominent reaction is the oxidative dehydrogenation (ODH) of ethylbenzene and other hydrocarbons in the gas phase, which will be introduced in a separate chapter. The conversion of alcohols as well as the catalytic properties of graphene oxide for liquid phase selective oxidations will also be discussed in more detail. The third section reviews individually reported catalytic effects of nanocarbons in organic reactions, as well as selected inorganic reactions. 

Guo, G., Long, Y., and Sun, Y. (2001) Hydrophobic silicalite method for liquid-phase selective adsorption, separation and mixing of dichlorobenzene. C.N. Patent 1,315,217. 

Supported Polyoxometalate-Based Heterogeneous Catalysis for Liquid Phase Selective Oxidations... 

Polyoxometalates undoubtedly have enormous catalytic potential in liquid phase selective oxidation of organic compounds. Various strategies for immobilization of POMs on solid matrices have been developed during the past two decades and opened new opportunities for practical applications. The most developed and widely used technique is electrostatic... 

Is the liquid phase selective toward the components to be separated ... 

LIQUID-PHASE SELECTIVE HYDROGENATION OF 1,4-BUTYNEDIOL ON SUPPORTED Ni and Ni-Cu CATALYSTS. 

Liquid-Phase Selective Oxidation of Organic Compounds... 

Liquid-phase selective oxidations are of industrial importance for fine chemical syntheses. However, stoichiometric oxidizing agents have been mostly used and the generation of unwanted by-products exceeds that of desired products in quantity. To... 

Venkatesan, C., Jaimol, T., Moreau, P., Finiels, A., Ramaswamy, A. V. and Singh, A. P. Liquid phase selective benzoylation of chlorobenzene to 4,4 -dichlorobenzophenone over zeolite H-beta, Catal. Lett., 2001, 75, 119-123. 

Kimura and Sourirajan have offered a theory of preferential adsorption of materials at interfaces to describe liquid phase, selective transport processes in portms membranes. Lonsdale et al. have ofiered a simpler explanation of the transport behavior of asymmetric membranes which lack significant porosity in the dense surface layer. Their solution-diffusion model seems to adequately describe the cases for liquid transport considered to date. Similarly gas transport should be de-scribable in terms of a solution-diffusion model in cases where the thin dense membrane skin acts as the transport moderating element. 

Liquid-phase selective oxidations are normally catalysed homogeneously. A small but significant interest has recently arisen in the use of solid catalysts for liquid-phase oxidation, particularly of alkyl aromatics. Shalya et al. have compared the activity of copper, silver, and gold metals as catalysts for cumene oxidation (Table 2). Silver was found to combine good selectivity for the desired product, cumene hydroperoxide, with an activity similar to that of copper. With supported catalysts, silver is considerably more active than copper, while gold is totally inactive. 

It Is possible to exploit liquid phase selection to an even greater degree if we know what solutes are In the sample, we can select a "liquid phase" that maximizes the relative retentions of all the solutes In that sample. This route to "optimization" was first suggested by Maler and Karpathy ( ), and explored by Laub and Purnell It was these latter authors who gave us the... 

Fraction or percent removal of various ions from the liquid phase (selectivity). 

Here, our recent work on the synthesis and liquid-phase selective oxidation catalysis of y-SiW o Fe(OH2) 2038 with molecular oxygen is mainly described. ... 

Liquid-phase selective hydrogenation of ethyl linolate to ethyl oleate has been carried out on nickel catalysts supported on sepiolite as well as on several different supports. The influence of metal loading and Ni-Cu alloying has been studied as well. The results indicate that catalytic activity and selectivity correlate closely with some textural and/or acid-base properties of the support and selectivity increases with metal loading. Furthermore, as a general rule, Ni-Cu alloying improves in selectivity. 

The liquid-phase selective hydrogenation of the C=C bond in a, 3-unsaturated cinnamaldehyde was studied to show the benefit of the use of the CNTs support versus the traditional powder activated charcoal-based catalyst [75, 76]. The catalyst consisted of homogeneous palladium nanoparticles dispersed inside the carbon nanotubes. The characteristics of the Pd-based catalyst have already been detailed above. 

Liquid phase selective oxidations of propylene over TS-1 have also been achieved [153, 154] but while Laufer and Hoelderich extended their TS-l/propylene work to include epoxidations of styrene and pinene over a Ti-MCM-41-based catalyst [155], in situ epoxidation reactions of more complex alkenes than propylene remain poorly documented and have yet to attain the industrially relevant success of TS-1-based catalysts in selective oxidations of even simple alkenes. 

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