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Linear free energy relationship method solvents, effect

This study is a comprehensive review of data reported on the effect of the composition of the reaction mixture on the hydrogenation of olefinic reactants in the liquid phase. It is mainly based on papers published by the authors, which deal with the effect of the structure of the reacting compounds on their reactivity and adsorptivity on hydrogenation catalysts, and with the effect of solvents on hydrogenation in the liquid phase. The majority of these studies were carried out with a view to quantify the particular effects, with the utilization of the LFER (linear free energy relationship) method. On the one hand, new possibilities for the application of these relationships appeared, but on the other, a number of limiting factors were found, connected predominantly with the considerably complex character of the systems involved in catalytic hydrogenation in the liquid phase. [Pg.336]

Solvents exert their influence on organic reactions through a complicated mixture of all possible types of noncovalent interactions. Chemists have tried to unravel this entanglement and, ideally, want to assess the relative importance of all interactions separately. In a typical approach, a property of a reaction (e.g. its rate or selectivity) is measured in a laige number of different solvents. All these solvents have unique characteristics, quantified by their physical properties (i.e. refractive index, dielectric constant) or empirical parameters (e.g. ET(30)-value, AN). Linear correlations between a reaction property and one or more of these solvent properties (Linear Free Energy Relationships - LFER) reveal which noncovalent interactions are of major importance. The major drawback of this approach lies in the fact that the solvent parameters are often not independent. Alternatively, theoretical models and computer simulations can provide valuable information. Both methods have been applied successfully in studies of the solvent effects on Diels-Alder reactions. [Pg.8]

Another method for studying solvent effects is the extrathermodynamic approach that we described in Chapter 7 for the study of structure-reactivity relationships. For example, we might seek a correlation between og(,kA/l ) for a reaction A carried out in a series of solvents and log(/ R/A R) for a reference or model reaction carried out in the same series of solvents. A linear plot of og(k/iJk ) against log(/ R/ linear free energy relationship (LFER). Such plots have in fact been made. As with structure-reactivity relationships, these solvent-reactivity relationships can be useful to us, but they have limitations. [Pg.388]


See other pages where Linear free energy relationship method solvents, effect is mentioned: [Pg.516]    [Pg.559]    [Pg.516]    [Pg.559]    [Pg.267]    [Pg.206]    [Pg.14]    [Pg.421]    [Pg.111]    [Pg.6]    [Pg.388]    [Pg.1176]    [Pg.230]    [Pg.330]    [Pg.174]   
See also in sourсe #XX -- [ Pg.356 ]




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Effect Relationships

Effective free energy

Energy methods

Energy relationships

Free energy methods

Free energy relationships

Linear Free Energy Relationships

Linear energy relationships

Linear free energy relationship method

Linear methods

Linear relationship

Linear solvent effect relationships

Linear solvent energy relationships,

Linearized methods

Linearized relationship

Solvent free methods

Solvent method

Solvent-free

Solvents energy

Solvents free energies

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