Linear free-energy relationships power

The basic requirement for the development of a more generally applicable solvent concept is the need to try to separate the various factors responsible for the solvating power of a solvent. It is important to find criteria for the solvents character that can be correlated not only to salt solubility and apparent conductivity but also to the impact of the solvents on the thermodynamics and kinetics of the electrochemical reactions. There are several approaches to defining a typical solvent property that can represent its polarity and be correlated to the thermodynamics and kinetics of reactions conducted in its solutions (i.e., a linear free-energy relationship). A comprehensive review of such approaches by Reichardt [12] divides them into three categories ... 

H. Mayr et al.. Linear Free Energy Relationships A Powerful Tool for the Design of Organic and Organo-metallic Synthesis, J. Phys. Org. Chem., 1998,11, 642. 

The main drawback of these linear free-energy relationships is that they do not relate to reaction mechanisms. Curiously enough, like the original Brpnsted equation, the main objective appeared to be the correlation of rate data rather than the interpretation of reaction mechanisms. This deficiency was partly remedied in the concept (8) of hard-soft acid-base (HSAB), which was in effect a qualitative extension of the Swain-Edwards equation but was more powerful in the sense that different types of reaction were related to the hard-soft classification, and the concept therefore has a wide application in organic synthesis and inorganic equilibria. 

This procedure is far less reliable than that used for the diagonal energies and can benefit from ab initio calculations on the gas phase reaction (see [9]), which can be used as extra constraints on the parameters of eqn. (5.6). However, the calculated difference between the free energy surface in solution and in the enzyme is not very sensitive to the exact value of the It has previously been demonstrated [9] that the dependence of on the reaction free energy is almost linear. Moreover, the relation between and AG is virtually independent of the magnitude of the particular Hy (this is why linear free energy relationships were found to be so powerful in physical organic chemistry [10]). 

J. A. Jeneson, H. V. Westerhoff, T. R. Brown, C. J. Van Echteld, and R. Berger. Quasi-linear relationship between Gibbs free energy of ATP hydrolysis and power output in human forearm muscle. Am. J. Physiol., 268 C1474-1484, 1995. 

Miyata and Yamaoka [152] used scanning probe microscopy to determine the microscale friction force of silicone-treated polymer film surfaces. Polyurethane acrylates cured by an electron beam were used as polymer films. The microscale friction obtained by scanning probe microscopy was compared with macroscale data, such as surface free energy as determined by the Owens-Wendt method and the macroscale friction coefficient determined by the ASTM method. These comparisons showed a good linear relationship between the surface free energy and friction force, which was insensitive to the nature of polymer specimens or to silicone treatment methods. Good linearity was also observed between the macroscale and microscale friction force. It was concluded that scanning probe microscopy could be a powerful tool in this field of polymer science. Evrard et al. [153] reported coefficient of friction measurements for nitrile rubber. Frictional properties of polyacetals, polyesters, polyacrylics [63], reinforced and unreinforced polyamides, and polyethylene terephthalate [52] have also been studied. 

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