Energy-power relationship, mechanical

In an energy-conscious world, SI provides a direct relationship among mechanical, electric, chemical, thermodynamic, molecular, and solar forms of energy. AH power ratings are given in watts. 

In accordance with ref. 35, the terms observed order and observed activation energy can be used correctly only for power kinetic relationships. Here we will examine the relationships between the experimentally observed values dlnWfdlnA and d nW/d(— 1/RT) and the characteristics of the detailed mechanism. We believe these relationships to be rather informative. As the subject of the analysis we will take a one-route catalytic reaction with a mechanism that is linear with respect to the intermediates. 

For clarity, the examples discussed in the text and used as problems do not as a rule include contributions from other techniques. One of the most serious problems associated with studies of reaction mechanism is over-confidence in the power of a single technique or theory. By its very nature a monograph focusses on a particular subject, and in this case the text should not be construed as an argument that the technique of free energy relationships is the only tool worthy of use in mechanistic studies. 

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. 

The initial objective of our work was to quantify solvent effects (particularly solvent nucleophilicity) by adapting the Grunwald-Winstein equation (2) (5). In equation 2, k is the rate of solvolysis of a substrate (RX) in any solvent relative to 80% v/v ethanol-water (k0) and Y is the solvent ionizing power defined by m = 1.000 for solvolyses of tert-butyl chloride at 25 °C. In this chapter, a discussion of equation 2 and similar free-energy relationships is presented. At the time our work began (1969), in collaboration with Schleyer, mechanisms of solvolytic reactions were close to a high in controversy (6-8). More recent mechanistic developments (9-13) are not reviewed in detail here, but increased recognition of the importance of nucleophilic solvent assistance should be noted. 

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