Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

High thermodynamic

Another reason for the increased use of gas turbines as prime movers in the process industry is the high thermodynamic cycle efficiencies and subsequent low operating cost. [Pg.294]

High thermodynamic selectivity (7) demands that the initially formed cis olefin be displaced rapidly relative to its saturation or to its isomerization. As the reaction nears completion and the acetylene concentration diminishes, its effectiveness in displacing olefin will diminish and selectivity will fall. Displacement by acetylene is also impeded through depletion of acetylene in the vicinity of the catalyst owing to intra- or interpartile diffusion resistance (53a). A change in a reaction parameter thus can have different influences... [Pg.57]

The outstanding characteristics of the noble metals are their exceptional resistance to corrosive attack by a wide range of liquid and gaseous substances, and their stability at high temperatures under conditions where base metals would be rapidly oxidised. This resistance to chemical and oxidative attack arises principally from the Inherently high thermodynamic stability of the noble metals, but in aqueous media under oxidising or anodic conditions a very thin film of adsorbed oxygen or oxide may be formed which can contribute to their corrosion resistance. An exception to this rule, however, is the passivation of silver and silver alloys in hydrochloric or hydrobromic acids by the formation of relatively thick halide films. [Pg.923]

This high thermodynamic activity shows that gold is extremely unstable in an oxygenated cyanide solution. [Pg.1253]

Thin-film solid electrolytes in the range of lpm have the advantage that the material which is inactive for energy storage is minimized and the resistance of the solid electrolyte film is drastically decreased for geometrical reasons. This allows the application of a large variety of solid electrolytes which exhibit quite poor ionic conductivity but high thermodynamic stability. The most important thin-film preparation methods for solid electrolytes are briefly summarized below. [Pg.543]

If 14 or more carbons are present, the product may be diamantane or a substituted diamantane. These reactions are successful because of the high thermodynamic stability of adamantane, diamantane, and similar diamond-like molecules. The most stable of a set of C H isomers (called the stabilomer) will be the end product if the reaction reaches equilibrium. Best yields are obtained by the use of sludge ... [Pg.1396]

C-functionalization of azamacrocycles is in general more difficult to achieve than N-functional-ization. The latter has been developed to an extent that macrocycles carrying side chains with various ligating groups are accessible, and Ni11 complexes can be prepared with high selectivity and predisposition for high thermodynamic and kinetic stability. [Pg.379]

The typical metalloporphyrins and metallophthalocyanines have in general very high thermodynamic stabilities. However, because it is difficult to establish conditions under which the... [Pg.956]

An important conclusion of this discussion is the fact that at very high <)> thermodynamic stability is re-established. Restabilisation is not a kinetic effect, as suggested by Feigin and Napper (10, 11), but is a consequence of lower free energy of the dispersion as compared to the floe. This conclusion is supported by experimental evidence for soft spheres (3, 5, 23). We should add, however, that for hard spheres is so high that experimental verification is difficult for most polymer-solvent systems due to the high viscosity of the solution. [Pg.257]

In conclusion, Gdm complexes currently used as MRI contrast agents can be considered as safe drugs, due to their high thermodynamic stability, kinetic inertness as well as to an efficient excretion from the body. Nevertheless, in case of renal impairment, the stability issues become much more important and macrocyclic chelates, which have considerably higher kinetic inertness, should be used instead of linear complexes. We should... [Pg.97]

This is because of retro-cycloaddition. In retro-cycloadditions, the reverse reactions are more favoured and the same selection rules apply. This is also because that X is normally a small inorganic molecule and of high thermodynamic stability. [Pg.98]

The dication 212+ composed of two methylium units connected to a p-phenylene spacer would be a candidate for new Wurster type violene-cyanine hybrid (Figure 12) (15). The reaction of four molar amounts of azulene 6b with terephthalaldehyde yielded the hydro precursor. Synthesis of the dication 212+ was accomplished by hydride abstraction with DDQ in almost quantitative yield. The dication 212+ was expected to show destabilization, but instead it exhibited high thermodynamic stability just like the corresponding monocation 3b+. [Pg.181]


See other pages where High thermodynamic is mentioned: [Pg.402]    [Pg.493]    [Pg.317]    [Pg.369]    [Pg.348]    [Pg.30]    [Pg.872]    [Pg.992]    [Pg.1190]    [Pg.443]    [Pg.3]    [Pg.3]    [Pg.40]    [Pg.197]    [Pg.169]    [Pg.630]    [Pg.18]    [Pg.35]    [Pg.127]    [Pg.158]    [Pg.843]    [Pg.854]    [Pg.857]    [Pg.897]    [Pg.898]    [Pg.918]    [Pg.128]    [Pg.317]    [Pg.65]    [Pg.70]    [Pg.92]    [Pg.115]    [Pg.213]    [Pg.146]    [Pg.348]    [Pg.204]    [Pg.173]    [Pg.181]    [Pg.14]   
See also in sourсe #XX -- [ Pg.14 ]




SEARCH



© 2024 chempedia.info